Biopsychology Flashcards
1
Q
Define the nervous system
A
A specialised network of cells in the human body that makes up our primary internal communication system. It is based on electrical and chemical signals.
2
Q
What are the nervous system’s two main functions?
A
- To collect, process and respond to information in the environment
- To co-ordinate the working of different organs and cells in the body
3
Q
What two subsystems is the nervous system divided into?
A
- The central nervous system
- The peripheral nervous system
4
Q
What is the CNS made up of?
A
- The brain
- The spinal cord
5
Q
What is the brain’s role?
A
- It is the centre of all conscious awareness - It distinguishes our higher mental functions from those in other animals
6
Q
What is the spinal cord’s role?
A
- It is an extension of the brain
- It passes messages to and from the brain
- It connects nerves to the PNS
- It is responsible for reflex actions
7
Q
What is the role of the PNS?
A
- To transmit messages via millions of neurons (nerve cells) to and from the central nervous system
8
Q
How is the PNS divided up?
A
- Autonomic nervous system
- Somatic nervous system
9
Q
What does the autonomic nervous system do?
A
- Governs vital functions in the body such as breathing, heart rate, digestion, sexual arousal and stress responses
10
Q
What does the somatic nervous system do?
A
- Governs muscle movement and receives information from sensory receptors - Connects the CNS to the outside world
11
Q
What are the two divisions of the autonomic nervous system?
A
- Sympathetic division
- Parasympathetic division
12
Q
What is the first stage of a fight or flight response?
A
The situation is appraised and perceived as stressful
13
Q
What happens after a situation is appraised and perceived as stressful?
A
- The hypothalamus is alerted
- It recognises that the stress is acute so it activates that sympathetic branch of the autonomic nervous system (part of the PNS)
14
Q
What happens after the sympathetic branch of the autonomic nervous system is activated during a fight or flight response?
A
- The adrenal medulla is stimulated, which is part of the adrenal gland
15
Q
Where is the adrenal medulla located?
A
Just above the kidneys
16
Q
What happens after the adrenal medulla is activated during a fight or flight response?
A
- The adrenal medulla secretes the hormone adrenaline and the neurotransmitter noradrenaline into the blood stream
17
Q
What do adrenaline and noradrenaline do to the body?
A
Carry out physiological changes to the body to prepare it for fight or flight
18
Q
Give examples of changes that could occur to the body when the sympathetic division of the autonomic nervous system is activated
A
- Increased heart rate
- Increased body temperature
- Breathing quicker
- Nauseous/dry mouth
- Sweating
- Dilated pupils/tunnel vision
- Flushed face
19
Q
Why does your heart rate increase when the sympathetic division of the autonomic nervous system is activated?
A
To get more blood to the muscles to be used for running or fighting
20
Q
Why does your body temperature increase when the sympathetic division of the autonomic nervous system is activated?
A
More blood has travelled around the body
21
Q
Why does your breathing quicken when the sympathetic division of the autonomic nervous system is activated?
A
More oxygen needs to be taken into the body to travel to the muscles
22
Q
Why do you feel nauseous or have a dry mouth when the sympathetic division of the autonomic nervous system is activated?
A
As more blood travels to the muscles, less travels to the digestive system
23
Q
Why do you sweat when the sympathetic division of the autonomic nervous system is activated?
A
It cools the body down
24
Q
Why do your pupils dilate/ get tunnel vision when the sympathetic division of the autonomic nervous system is activated?
A
It allows more light into the eyes
25
Why does your face go flushed when the sympathetic division of the autonomic nervous system is activated?
Blood goes to the brain as it is needed for decision making
26
What do all the physiological changes that occur as a result of the sympathetic division of the autonomic nervous system being activated facilitate?
- Allows more oxygen to the muscles to allow them to work better
- Allows more oxygen to the brain to allow quicker thinking and problem solving
27
Why can the body not maintain the physiological changes that are a result of fight or flight for long?
It takes too much energy
28
What happens when the threat has been dealt with?
The parasympathetic branch of the nervous system is activated. It is antagonistic to the the sympathetic system and acts as a brake response to return the body back to its normal resting state.
29
The parasympathetic state (a) a process in the boy, whilst the sympathetic state (b) a process in the body
a) decreases b) increases
30
What does the endocrine system do?
Works alongside the nervous system to control vital functions in the body
31
The endocrine system acts more (a) than the nervous system but has very (b) effects
a) slowly b) widespread and powerful
32
What are glands?
Organs in the body which produce hormones which are secreted into the bloodstream and affect any cell that has a receptor for that particular hormone.
33
Which gland is known as the master gland and why?
The pituitary gland - It controls the release of hormones from all other glands
34
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35
What is at label 1?
The pineal gland
36
Give an example of what hormone the pineal gland releases
Melatonin
37
What does the pineal gland affect?
Metabolism
38
What does melatonin do?
Helps us sleep
39
What is at label 2?
The pituitary gland
40
Give examples of hormones released by the pituitary gland
- LH
- FSH
- Growth hormone
41
What does the pituitary gland affect?
Reproduction
42
What is at label 3?
Thyroid
43
Give an example of a hormone released by the thyroid
Thyroxine
44
What does the thyroid affect?
Metabolism
45
How does the thyroid affect metabolism?
It regulates temperature and heart rate, as well as weight loss/gain
46
What is at label 4?
The thymus
47
Give an example of a hormone released by the thymus
Thymosin
48
What does the thymus affect?
Growth
49
Give one function of the thymus
Involved in the production of t-cells which help to protect the body
50
What is at label 5??
The adrenal gland
51
Give an example of a hormone produced by the adrenal gland
Adrenaline
52
What does the adrenal gland affect?
Metabolism
53
How does the adrenal gland affect metabolism?
It regulates visceral functions and helps produce responses such as fight or flight
54
What is at label 6?
The pancreas
55
Give examples of hormones produced by the pancreas
- Insulin - Glucagon
56
What does the pancreas affect?
Metabolism
57
How does the pancreas affect metabolism?
Regulation of blood sugar
58
What is at label 7?
Ovary
59
Give examples of hormones produced by the ovaries
- Oestrogen
- Progesterone
60
What does the ovary affect?
Reproduction
61
How do the ovaries affect reproduction?
They regulate the menstrual cycle
62
What is at label 8?
Testes
63
Give an example of a hormone produced by the testes
Testosterone
64
What do the testes affect?
Reproduction Growth
65
How many neurons are in the human nervous system?
100 billion
66
What percent of neurons are located in the brain?
0.8
67
What is a neuron?
Nerve cells that process and transmit messages through electrical and chemical signals
68
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69
What is label A?
Nucleus
70
What is the nucleus?
It contains the cell's DNA
71
What is label B?
Dendrites
72
What are dendrites?
A short branched extension of a nerve cell, along which impulses received from other cells at synapses are transmitted to the cell body
73
What is label C?
Cell body (soma)
74
What is the cell body (soma)
The main part of the neuron which the dendrites branch off from
75
What is label D?
Node of ranvier
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What is the node of ranvier?
These speed up the transmission of the impulse by forcing it to jump across gaps in the axon
77
What is label E?
Axon terminal
78
What is the axon terminal?
The ending of one neuron, this is separated from the next neuron by a small gap called a synapse
79
What is label F?
Schwann cell
80
What is a Schwann cell?
The cells that produce the myelin sheath
81
What is label G?
Myelin sheath
82
What is the myelin sheath?
They cover the axon and work like insulation to help keep electrical signals inside the cell, which allows them to move more quickly
83
What is label H?
Axon
84
What is the axon?
Long thread-like part of a nerve cell along which impulses are conducted from the cell body to other cells
85
What type of neuron is labelled 1?
Sensory neuron
86
What is a sensory neuron?
It carries messages from the peripheral nervous system (receptors such as eyes, skin, ears, tongue) to the central nervous system (brain and spinal cord). This lead to sensations such as vision, touch, hearing and taste.
87
What type of neuron is labelled 2?
Relay neuron
88
What is a relay neuron?
These connect the sensory neurons which receive the sensory input to the motor neurons which lead to a movement output
89
What type of neuron is labelled 3?
Motor neuron
90
What is a motor neuron?
Connect the central nervous system to effectors such as muscles and glands. When stimulated they release neurotransmitters that bind to receptors on muscles which trigger movement.
91
What is label K?
Axon
92
What is label L?
Nucleus and cell body
93
What is label M?
Dendrite
94
What is label N?
Soma
95
What is label O?
Axon
96
What is label P?
Pre synaptic terminal
97
What is label Q?
Dendrites
98
What is label R?
Axon
99
What is label S?
Node of ranvier
100
What is label T?
Myelin sheath
101
What is label U?
Muscle fibre (an effector)
102
Where are the cell bodies of motor neurons located?
The central nervous system
103
Where are the long axons of motor neurons located?
They form part of the peripheral nervous system
104
Where are sensory neurons located?
- The peripheral nervous system in clusters known as ganglia
105
What percentage of neurons do relay neurons make up?
0.97
106
Where are most relay neurons found?
Within the brain and the visual system
107
What charge does a neuron have when it is in a resting state?
Negatively (compared to the outside)
108
What happens when a neuron is activated by a stimulus?
- The inside of the cell becomes positively charged for a split second
- This causes an action potential to occur
- This created an electrical impulse that travels down the axon towards the end of the neuron
109
What is synaptic transmission?
The process by which one neuron communicates with another
110
Neurons communicate with each other within groups known as what?
Neural networks
111
How is each neuron separated from the next?
By an extremely small gap called a synapse
112
Signals within neurons are transmitted (a) Signals between neurons are transmitted (b)
a) Electrically b) Chemically
113
How is information passed down the axon of a neuron?
As an electrical impulse known as action potential
114
What happens when the action potential reaches the end of the axon?
- It needs to be transferred to another neuron or tissue
- It must cross over the synaptic cleft between the presynaptic neuron and post synaptic neuron
115
What is located at the end of the neuron in the axon terminal?
The synaptic vesicles
116
What do the synaptic vesicles contain?
Chemical messengers, known as neurotransmitters
117
What happens when the action potential reaches the synaptic vesicles?
They release their contents of neurotransmitters. The neurotransmitters carry the signal across the synaptic cleft and then bind to receptor sites on the post synaptic cell. This completes synaptic transmission.
118
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119
What is label A?
Axon
120
What is label B?
Synaptic vesicle
121
What is label C?
Neurotransmitter
122
What is label D?
Dendrite
123
What is label E?
Postsynaptic receptor sites
124
What is label F?
Synaptic cleft
125
What is label G?
Presynaptic nerve terminal
126
What are neurotransmitters?
Chemicals that diffuse across synapses from one neuron to the next
127
How is information transferred from one neuron to the next?
- The neuron is taken up by the postsynaptic receptor site on the next neuron
- The message is converted back from being chemical into electrical
128
Each neurotransmitter has its own specific (a) and specific (b) that fits perfectly into a (c)
a) Function b) Molecular structure c) Post synaptic receptor site
129
What are the two types of neurotransmitters (some can be both)
- Excitatory
- Inhibitory
130
What does it mean if a neurotransmitter is excitatory?
The post synaptic neuron is more likely to fire an impulse
131
What does it mean if a neurotransmitter is inhibitory?
The postsynaptic neuron is less likely to fire an impulse
132
How is it decided whether the neuron fires off an impulse or not?
- The excitatory and inhibitory influences are summed
- If the net effect on the postsynaptic neuron is inhibitory, the neuron is less likely to fire
- If the net effect on the postsynaptic neuron is excitatory, the neuron is most likely to fire
133
Give an example of an inhibitory neurotransmitter
GABA
134
What does GABA do?
- Helps control fear and anxiety
- Lower levels of GABA have been linked to schizophrenia, depression and anxiety
- Linked to sleep
135
Give an example of an excitatory neurotransmitter
Serotonin
136
What does serotonin do?
- Stabilises mood
- Helps with feelings of wellbeing and happiness
137
What assumption about the brain was accepted before discoveries in the 19th century?
- The holistic theory
- The idea that all parts of the brain were involved in the processing of thought and action
138
Which scientists argued for the idea of localisation of function?
- Broca
- Wernicke
139
What is localisation of function also sometimes referred to as?
Cortical specialisation
140
What is localisation of function?
The theory that different areas of the brain are responsible for specific behaviours, processes or activities.
If a certain area of the brain becomes damaged, the function associated with that area will also be affected.
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142
What is label A?
Frontal lobe
143
What is the function of the frontal lobe?
- Higher cognitive function
- Attention and thought
- Decision making
- Emotional traits
144
What is label B?
Parietal lobe
145
What is the function of the parietal lobe?
- Allows us to understand the world with our senses
- Helps us coordinate movements in response to objects
- Reading
- Sensation
146
What is label C?
Occipital lobe
147
What is the function of the occipital lobe?
- Receives projections from the retina
- Visual area of the brain
148
What is label D?
Cerebellum
149
What is the function of the cerebellum?
- Regulates motor behaviour (ie: automatic movements)
- Balance, coordination
150
What is label E?
Brain stem
151
What is the function of the brain stem?
- Controls automatic functions (breathing, heart rate, blood pressure)
- Homeostasis
152
What is label F?
Temporal lobe
153
What is the function of the temporal lobe?
- Perception
- Face recognition
- Object recognition
- Understanding language
- Emotional reactions
154
What is label 1? Broca's area
Broca's area
155
Where is broca's area?
Frontal lobe
156
What is the function of broca's area?
- Production of language (spoken and written)
157
What happens if broca's area is damaged?
- Broca's aphasia (not being able to speak properly)
- Disordered speech
158
What is label 2?
Motor cortex
159
Where is the motor cortex?
Frontal lobe
160
What is the function of the motor cortex?
- Initiating motor movements
- Coordination
161
What happens if the motor cortex is damaged?
- Poor coordination
162
What is label 3?
Somatosensory cortex
163
Where is the somatosensory cortex?
Parietal lobe
164
What is the function of the somatosensory cortex?
- Sensory processing and integration
- The more sensitive a body part, the more of this area is devoted to it
165
What happens if the somatosensory cortex is damaged?
- Difficulties in perceiving touch
- Failure to recognise objects by touch
- Phantom limb pain
166
What is label 4?
Visual Cortex
167
Where is the visual cortex?
Occipital lobe
168
What is the function of the visual cortex?
- Receives, segments and integrates visual information
- Receives info from the eyes
169
What happens if the visual cortex is damaged?
Blindness
170
What is label 5?
Wernicke's area
171
Where is Wernicke's area?
Left temporal lobe
172
What is the function of Wernicke's area?
Language comprehension
173
What happens if Wernicke's area is damaged?
- Wernicke's aphasia: difficulty understanding words, production of meaningless speech
174
What is label 6?
Auditory area
175
Where is the auditory area?
Temporal lobe
176
What is the function of the auditory area?
- Processing and affecting emotions
- Analysing speech based information
177
What happens if the auditory area is damaged?
Loss of perception of sound
178
Name the strengths of localisation of brain function
- Brain scan research
- Neurosurgery
- Phineas Gage
179
Name a weakness of localisation of brain function
- Lashley (1950)
180
What brain scan research supports localisation?
- Petersen et al (1988) showed that Wernicke's area was active during a listening task while Broca's area was active during a reading task
- Tulving et al (1994) showed episodic and semantic memories reside in different areas of the prefrontal cortex
- Both studies show that different tasks are carried out in physically different areas of the brain
181
Why is neurosurgery rarely used today?
It is too brutal
182
Who conducted a study into neurosurgery?
Dougherty et al (2002)
183
What did Dougherty find?
- Studied 44 cases of OCD sufferers who underwent a cingulotomy
- Almost half experienced either a full or partial recovery
184
What does Dougherty's research show? OCD
The behaviours associated with mental disorders must be localised as the removal of small parts of the brain aids recovery from these disorders
185
What happened to Phineas Gage?
- He was impaled by a pole on accident
- He suffered brain damage to the area in the frontal cortex associated with planning, reasoning and control
186
What changes did Phineas Gage go through?
- Hid personality changed from being mild mannered to rude and hostile
- He displayed social and emotional disinhibition
187
What do scientists now understand about the part of Phineas Gage's brain that was damaged?
- It is linked to higher order functions such as reasoning, language and social cognition - His behaviour changed as a result of damage to just a part of his brain
188
What was Lashley's research?
- He removed different areas of the cortex of rats who were learning in a maze
- He found that learning was inhibited in the same way in all rats, despite how much/which cortex was removed
189
What does Lashley's research suggest?
- The processes involved in higher cognitive functioning (eg: learning) are distributed more holistically
- Complex processes are too complex to be localised to a single area
190
What is neural plasticity?
The apparent ability of the brain to change and adapt its structure and processes as a result of experience and new learning. This generally involves the growth of new connections.
191
What can the brain change as a result of?
- Experience
- Injury
192
When is the time of greatest growth of synaptic connections?
Infancy
193
How many synaptic connections are there per neuron at the age of 2 -3?
About 15,000 (Gopnik et al, 1999)
194
What is synaptic pruning?
As we age, rarely used connection are deleted and frequently used connections are strengthened.
195
What happens alongside synaptic pruning as we age?
New neural connections can be formed and existing ones changed as a result of learning and experience
196
What does synaptic pruning enable?
Lifelong plasticity where new neural connections are formed in response to new demands on the brain
197
Give an example of neural plasticity
Functional recovery
198
What is functional recovery?
A form of plasticity. Following damage through trauma, unaffected areas of the brain take over from damaged areas.
199
What is spontaneous recovery?
When the unaffected parts of the brain immediately take over functions from the parts damaged in trauma. This slows down later
200
What happens when spontaneous recovery slows down?
Therapies will take over the rehabilitation (ie: electrical stimulation or movement therapy)
201
How does the brain continue functioning despite trauma?
- The brain forms new synaptic connections - Dormant synapses (which have not received enough input to be active) near the trauma are activated or unmasked to allow functioning
- New pathways are formed through the growth of new nerve endings and the reformation of blood vessels serving the brain
202
What is axonal sprouting?
The growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways
203
What is denervation supersensitivity?
- This occurs when axons that do a similar job become aroused to a higher level to compensate for the ones that are lost -
This can have the negative consequence of oversensitivity to messages such as pain
204
What is recruitment of homologous (similar) areas on the opposite side of the brain?
- This means specific tasks can be performed
- An example: if Broca's area was damaged on the left side of the brain, the right sided equivalent would carry out its functions. After a period of time, the functionality may then shift to the left side
205
What is neurorehabilitation?
The process of supporting people after brain trauma to regain as much function as possible
206
Name the research that supports the theory of plasticity and functional recovery
- Maguire et al (2000)
- Kuhn et al (2014)
- Davidson et al (2004)
207
Outline the procedure of Maguire's study
- Grey matter volume was measured in the hippocampus of London taxi drivers
- They were matched to London bus drivers to control for extraneous variables such as stress and driving experience
- The bus drivers differed in that they were confined to a set route
208
What were the findings of Maguire's research?
- Taxi drivers had greater grey matter volume in mid-posterior hippocampi
- The posterior hippocampus is crucial for precise spatial and navigational behaviour
209
What did Maguire conclude from her research?
London cab drivers have to take a complex test called 'The Knowledge' which assesses their recall of the city streets and possible routes. Maguire found that this learning experience altered the structure of their brains
210
How does Maguire's research support plasticity and functional recovery?
It suggests that spatial knowledge is associated with the pattern of hippocampal grey matter volume in taxi drivers and the more experience they have of routes, the greater the grey matter.
211
What is grey matter responsible for?
It allows humans to function normally:
- Control our movements
- Retain memories
- Regulate emotions
- Many more functions!
212
What was the procedure of Kuhn et al (2014)'s research? plasticity
- For 30 minutes a day, over 2 months, participants were trained to play a platformer game
- Grey matter was measured and compared with a control group
213
What were the findings of Kuhn et al's research?
The gaming group experienced significant grey matter increase in brain areas crucial for spatial navigation, strategic planning, working memory and motor performance
214
How does Kuhn et al's research support plasticity and functional recovery?
It shows how the volume of grey matter can be altered through experience, in this case playing computer games can increase cognitive and motor skills
215
What was the procedure of Davidson et al's 2004 study?
It involved Tibetan monks who meditated frequently in comparison with a non-meditating control group
216
What were the findings of Davidson et al's study?
- The monks were found to have higher levels of gamma wave activity
- Gamma waves are associated with increased coordination of neuron activity
217
How does Davidson et al's research support plasticity and functional recovery?
It implies that meditation can increase brain plasticity and cause permanent and positive changes to the brain
218
What three individual differences must be considered when assessing the likelihood of functional recovery in the brain after trauma?
- Education
- Age
- Gender
219
Who conducted a study into the link between educational attainment and brain recovery after trauma?
Schneider et al (2014)
220
Outline the procedure of Schneider et al's study
- Conducted a retrospective 769 patients who experienced brain trauma
- Compared those who had 16 years or more of education with those who had 12
- 15 and those who had less than 12
- He looked at how likely each of these groups were to have a disability free recovery after one year
221
What were the findings of Schneider et al's study?
Patients with a college education were seven times more likely than those not finishing high school to be disability free a year after having a moderate to severe brain injury
222
Who conducted a study into the relationship between age and functional recovery?
Bezzola et al (2012)
223
Outline Bezzola's study and findings
- Demonstrated how 40 hours of golf training produced changes in neural representations of 40 - 60 year olds
- Compared to a control group of experienced golfers, there was reduced motor cortex activity in the golfers suggesting more efficient neural representations
- This shows neural plasticity can occur at any age
224
Who conducted a study into the relationship between gender and functional recovery?
Kim et al (2010)
225
What did Kim et al (2010) study?
He looked at difference in mortality and disability at discharge, 3 months and 1 year after stroke onset
226
What were the results of Kim et al's study?
- Among 1,500 patients with acute stroke, 575 were male and 480 were female
- There were no gender differences in mortality at 3 months and 1 year after stroke
- The frequency of poor outcomes was higher in female patients than in male patients at discharge, the 3 month follow up and the 1 year follow up
- After adjusting for multiple confounding factors including age and stroke severity, the female gender persisted as a predictor of poor functional outcome at 3 months and 1 year after stroke
227
The activity on the left side of the body is controlled by the (a) brain hemisphere. The activity on the right side of the body is controlled by the (b) brain hemisphere.
a) right b) left
228
What is hemispheric lateralisation?
The idea that the two halves of the brain are functionally different and that certain mental processes and behaviours are mainly controlled by one hemisphere rather than the other.
229
What side of the brain is responsible for reading and playing music?
Left
230
What side of the brain is responsible for interpreting (listening to) music?
Right
231
What side of the brain is responsible for viewing objects visible in the right visual field?
Left
232
What side of the brain is responsible for analytical tasks?
Left
233
What side of the brain is responsible for face recognition?
Right
234
What side of the brain is responsible for controlling the right side of the body?
Left
235
What side of the brain is responsible for controlling the left side of the body?
Right
236
What side of the brain is responsible for drawing?
Right
237
What side of the brain is responsible for language?
Left
238
What side of the brain is responsible for the emotional content of language?
Right
239
What side of the brain is responsible for spatial tasks?
Right
240
What side of the brain is responsible for viewing objects visible in the left visual field?
Right
241
Is language lateralised? Why?
Language is lateralised
- it is performed by one hemisphere rather than the other
- Broca's area is in the left frontal lobe
- Wernicke's area is in the left temporal lobe - The right hemisphere can only produce rudimentary words and phrases but contributes emotional context
242
Give an example of a function that is not lateralised
- Vision
- Motor
- Somatosensory areas
243
What is another word for 'cross-wired'?
Contralateral wiring
244
What function of the brain has contralateral wiring?
Movement
245
What does ipsilateral mean?
Same-sided wiring
246
What function of the brain is both contralateral and ipsilateral?
Vision
247
Explain how the eyes and brain connect to the left and right visual fields
- Each eye receives light from the left visual field and the right visual field
- The left visual field of both eyes is connected to the right hemisphere
- The right visual field of both eyes is connected to the left hemisphere
248
How does vision being ipsilateral and contralateral benefit sight?
It enables the visual areas to compare the slightly different perspective from each eye and aids depth perception
249
How are the two brain hemispheres connected?
The corpus callosum (a bundle of nerve fibres)
250
Why might it be necessary to sever the corpus callosum?
Treating epilepsy
251
What is the procedure of severing the corpus callosum called?
Corpus callosotomy
252
What does the term split brain patient refer to?
Epileptic patients who have had corpus callosotomy
253
In which hemisphere is the language centre?
The left
254
With which eye would a split brain patient need to see an object in order to state the name of it?
Right
255
What is aphasia?
The impaired ability to understand or produce speech as a result of brain damage
256
A split brain patient is shown a picture of his wife to the left visual field. What can he do and why?
- He is able to recognise who it is (face recognition is on the right side of the brain) - He is unable to say who it is (the language centre is on the left side of the brain)
257
A split brain patient is shown a picture of his wife to the right visual field. What can he do and why?
- He recognises that it is a face (facial recognition is on the right side of the brain so he cannot use it)
258
A split brain patient is shown a picture of a heart to his left visual field. What can he do and why?
- He sees a heart so visualises his wife (the right hemisphere is involved in emotional content)
259
A split brain patient is shown a picture of a heart to his right visual field. What can he do and why?
- He can see the heart (the left hemisphere controls vision of the right visual field)
- He can say what the heart is (the left hemisphere has the language centre)
260
A split brain patient is shown the word 'shark' to his left visual field. What can he do and why?
- He can read the word (the right hemisphere allows us to view objects in the left visual field)
- He can visualise a shark
- He cannot say 'shark' (the language centre is in the left hemisphere)
261
A split brain patient is shown the word 'shark' to his right visual field. What can he do and why?
- He is able to read the word (the left hemisphere allows us to view objects in the right visual field)
- He can speak the word 'shark' (the language centre is in the left hemisphere)
262
When did Sperry conduct his research?
1968
263
What surgery did some epilepsy patients undergo?
- Commissurotomy
- Cutting the corpus callosum
264
What is the purpose of a commissurotomy?
To reduce the damage caused by an epileptic seizure by containing it in one side of the brain
265
How did Sperry use split brain patients?
He wanted to determine whether there are differences between how the two hemispheres of human brains were specialised for different functions
266
What was Sperry's sample?
11 split brain participants (male and female)
267
Outline Sperry's set up
- Participants were sat in front of a projector in which an image could be projected to a participant's right visual field and the same, or different image could be projected to the left visual field. The image was shown for 1/10th of a second. - Below the screen was a gap so participants could reach unseen objects which had been placed in a 'grab bag'
268
Why did Sperry only want to show some images to one visual field?
- In a normal brain, the corpus callosum would immediately share the information between both hemispheres to give a complete picture
- Presenting the image to one hemisphere of a split brain participant meant that the information cannot be conveyed from that hemisphere to the other.
269
What 4 experiment types did Sperry conduct?
- Describing what you see
- Tactile tests
- Drawing tasks
- Matching faces
270
Outline Sperry's findings in his experiments involving participants describing what they saw
- When an image was shown to the left visual field, participants could point to a matching picture with their left hand, but insisted they hadn't seen anything
- When a nude pin-up image was shown to the left visual field, participants would giggle or blush but couldn't say why
271
Outline Sperry's findings in his experiments involving tactile tests
- Participants were unable to retrieve an object with their right hand if it had been sensed first with the left hand
- If an object was placed in their right hand, participants could name what they were holding. If it was placed in their left hand, they couldn't say what they were holding
272
Outline Sperry's findings in his experiments involving drawing tasks
- When participants were shown an item to their left visual field they were unable to name it (language production is in the left hemisphere) but could draw it with their left hand (the info went to the right hemisphere which control the left hand)
- When a saw was shown to the left visual field and a hammer shown to the right visual field, participants would say they saw a hammer but would draw a saw with their left hand (drew the object in their left visual field because it is controlled by the right hemisphere, described the object they saw in their right visual field)
273
Outline Sperry's findings in his experiments involving matching faces
- When presented with a different face to each visual field the participant consistently picked out the face presented to their left visual field and ignored that presented to their right visual field.
- This suggests that the right hemisphere is dominant in facial recognition
274
What conclusions can be drawn from Sperry's research?
- There is evidence for lateralisation of brain function
- Language is associated with the left hemisphere
- Drawing, emotion and facial recognition is associated with the right
275
Name a strength of Sperry's research
He used a mixture of quasi experiments and clinical case studies, combining quantitative and qualitative approaches
276
Explain how Sperry's research was both qualitative and quantitative
- The experiment provided data which Sperry was able to statistically analyse to look for commonalities amongst his patients
- The case study is a qualitative method of data collection in which Sperry was able to get richer data about participants' experiences
277
Name the weaknesses of Sperry's research
- Unrepresentative sample
- Contradicting views on lateralisation
- Lack of ecological validity
278
What were the problems with Sperry's sample?
- A sample size of 11 is very small
- We cannot be sure how long each of the participants had experienced ineffective drug therapy which could have been affecting the findings
279
Why was Sperry's control group a problem?
- The control group was non epileptic people with no hemispheric deconnection
- Epilepsy could have acted as an extraneous variable
280
Why can Sperry be let off for his small sample size?
He may not have had control over this small sample because there may not be very many split-brain patients available to study
281
Why do some scientists disagree with the theory that brain function is lateralised?
- Lashley argues that the two hemispheres do not function in isolation but form a highly integrated system
- They argue that higher level tasks involve a mixture of 'left' and 'right' skills
- Eg: when listening to speech we analyse both the words and the pattern of intonation. This involves both hemispheres
282
Why does Sperry's study lack ecological validity?
- Sperry showed the participants the stimuli for a tenth of a second so that the other eye did not have time to process the image
- In reality a person with a severed corpus callosum who had both eyes would be able to compensate for such a loss
- It doesn't help us understand how split brain patients live every day
283
Name the 4 methods of investigating the brain
- fMRI
- EEG
- ERP
- Post-mortem examinations
284
What does fMRI use to measure brain activity?
- Neural activity causes changes in the flow and oxygenation levels of blood in the brain - This is because when a part of the brain is carrying out a task it consumes more oxygen so blood can carry this oxygen
285
What is it called when a part of the brain is carrying out a task and it consumes more oxygen so blood can carry this oxygen?
The haemodynamic response
286
What is the output from fMRIs?
Activation maps which show which parts of the brain are involved when carrying out specific tasks
287
Name the strength of fMRI
It has high spatial resolution
288
What does spatial resolution refer to?
The number of pixels in the digital output of the brain activation maps that are produced
289
Why is high spatial resolution a strength?
- A greater number of pixels means that the data produced is clear, detailed and gives a very good picture of brain localisation
- The data is much more useful when diagnosing illnesses such as stroke
290
Name the weakness of fMRI
It has low temporal resolution
291
What is temporal resolution?
The difference between the neural activity occurring and the image appearing on the screen
292
What is the temporal resolution of fMRI?
There is around a 5 second time lag between a neuron firing and the output being displayed
293
Why is low temporal resolution a weakness?
It is difficult to ascertain whether the activity being viewed is a direct response of the stimulus
294
What is EEG short for?
Electroencephalogram
295
What do EEGs do?
Give an overall account of brain activity from electrodes that are attached to the scalp
296
What is the output of an EEG?
A scan recording which displays brainwave patterns generated from the action of millions of neurons
297
How do EEGs identify neural malfunction?
Where an arrhythmic pattern is detected
298
Name a strength of EEG?
They are particularly useful for diagnosing illnesses where there is abnormal brain activity
299
Give an example of an illness EEG can be used to diagnose
- Epilepsy
- Stages of sleep can be analysed
300
Why is EEG often better than fMRI?
EEG equipment is much cheaper
301
Name a weakness of EEG
Despite having high temporal resolution, EEGs have low spatial resolution
302
Why is the output of EEG not very helpful?
- It is a series of brainwave patterns which hold little information about the location of such activity
- It is generally considered quite crude
303
Why does the low spatial resolution of EEGs limit their usefulness?
They are not useful for investigating more complex brain behaviour
304
What does ERP stand for?
Event related potentials
305
What does ERP do?
- A technique that uses the data collected from an EEG
- It isolates the sensory, cognitive or motor responses to specific stimuli presented - All extraneous brain activity is filtered out allowing researchers to see the brain's response to a specific stimulus
306
Name a strength of ERPs?
It is non invasive (this is also a strength of EEGs)
307
How are ERPs non invasive?
- They don't use radiation
- They don't involve inserting instruments directly into the brain
308
Why is it good that ERPs are non invasive?
- They are virtually risk free
- More patients will be open to it, allowing more dysfunctional brains to be studied
309
Name a weakness of ERP
There is a lack of standardisation in ERP methodology
310
Outline the lack of standardisation in ERP methodology
- 10 to 20 electrode placements is commonly used by researchers but it has been suggested that the use of more electrodes would help improve spatial resolution
- Using larger numbers of electrodes to measure the entire scalp would also increase interference and noise, which is tricky to eliminate
311
What is post mortem?
The analysis of a person's brain after death
312
When are post mortems often used?
- When the person suffered from a rare condition and experienced unusual deficits - Scientists attempt to establish the cause of the disorder
313
Name a strength of post mortems
They have played a large part in the development of neuroscience
314
Give an example of how post mortems have played a large part in the development of neuroscience
- Broca and Wernicke used post mortems to develop their understanding of the language centre
- Wernicke observed that the brain of aphasic stroke sufferers showed lesions in the left hemisphere, allowing him to identify Wernicke's area
315
Name a weakness of post mortems
It is difficult to ascertain whether damage to the brain was a cause of the illness of a symptom of the illness
316
Give an example of how it is hard to establish the cause of illness with post mortems
- Post mortems of schizophrenia sufferers illustrate that they had particularly enlarged ventricles
- It is impossible to tell if the large ventricles caused their symptoms or if reduced brain tissue meant their ventricles were abnormally large
317
What is a biological rhythm?
A distinct pattern of changes in body activity that conform to cyclical time periods
318
What are biological rhythms influenced by?
- Endogenous pacemakers
- Exogenous zeitgebers
319
What are endogenous pacemakers?
Internal body clocks
320
What are exogenous zeitgebers?
External changes to the environment
321
Name four biological rhythms
- Infradian
- Circannual
- Ultradian
- Circadian
322
What is a circannual rhythm?
A type of infradian rhythm that occurs yearly
323
What is an infradian rhythm?
A biorhythm with a frequency of less than one cycle in 24 hours (occurs less often than daily)
324
What is an ultradian rhythm?
A biorhythm with a frequency of more than one cycle in 24 hours
325
What is a circadian rhythm?
A biorhythm with a daily frequency
326
Give an example of an infradian rhythm
Menstrual cycle
327
Give an example of a circannual rhythm
Seasonal affective disorder
328
Give an example of an ultradian rhythm
Stages of sleep
329
Give an example of a circadian rhythm
Sleep/wake cycle
330
Name the strengths of research into circadian rhythms
- Research helps shift workers
- Research can help drugs to be more effective
331
What research has helped improve the working conditions of shift workers?
- Boivin et al (1996) found workers experience a circadian trough at around 6am where accidents are more likely due to lack of concentration
- Knutsson (2003) found shift workers were 3x more likely to develop heart diseases
332
Why is it useful to know more about conditions that make for good shift work?
- It helps companies reduce risks
- Helps companies improve productivity
333
How has research into circadian rhythms had a positive impact in the area of drug efficacy
- As the body goes through a circadian cycle various bodily processes and chemicals will be altered
- There are times of the day when a clinical drug will have a greater effect
- Guidelines have been developed clearly stating the optimal timing of drug dosages
334
Give an example of how knowledge of circadian rhythms has improved a drug performance
Aspirin should be taken at night to ensure people with heart problems are protected in the mornings when blood pressure is at its highest
335
Name the weaknesses of research into circadian rhythms
- Research has limited samples
- In some studies participants were allowed to use lamps
336
Why are many of the samples of studies into circadian rhythms not representative of the wider population?
- A high proportion of participants were spelunkers who would be more comfortable in an isolated, dark environment
- Siffre observed that his own internal body clock ticked more slowly aged 60 compared to when he was a young man
337
Why is it a problem that in some studies participants were not exposed to daylight but were allowed to use lamps?
- Artificial light may affect the circadian rhythm in the same way as actual daylight
- It is likely that it could have stimulated the production of cortisol and melatonin
- Artificial light is a confounding variable
338
What is an infradian rhythm?
A biological rhythm that has a frequency of less than once in a 24 hour period (ie: they are less frequent than a circadian rhythm)
339
Give an example of an infradian rhythm
The menstrual cycle
340
Outline what happens during the menstrual cycle
- Rising levels of oestrogen cause the ovary to develop then release an egg (ovulation)
- Progesterone allows womb lining to grow thicker in preparation for pregnancy
- If this does not occur the egg is absorbed and the womb lining comes away (menstrual flow)
341
How long does the menstrual cycle last?
- Typically 28 days (though could be anything from 24 to 35)
- Starts on the first day of the period and ends the day before the next period
342
Who conducted a study into the menstrual cycle?
McClintock (1998)
343
What was the aim of McClintock's study?
To investigate whether the menstrual cycle is completely endogenous
344
What was the procedure of McClintock's study?
- 29 women with a history of irregular cycles were provided pheromone samples on cotton pads to be placed on their upper lips - These samples were provided by 9 of the women who were at various stages of their cycle and were collected from pads placed under their armpits
- This was repeated every day of the cycle
345
What were the findings of McClintock's study?
68% of women experienced changes to their cycle which brought them closer to the cycle of their odour donor
346
What can be concluded from McClintock's study?
- Infradian rhythms such as the menstrual cycle are not completely determined by endogenous pacemakers such as hormones - Infradian rhythms may be entrained by exogenous zeitgebers such as the pheromones of other females in close proximity
347
What does SAD stand for?
Seasonal affective disorder
348
What is SAD?
A depressive disorder which has a seasonal pattern of onset
349
What are the main symptoms of SAD?
- Persistent negative mood
- General lack of activity and interest in life
350
What triggers SAD?
The winter months when the number of daylight hours become shorter
351
Explain why SAD is an infradian (circannual) rhythm as well as circadian rhythm
- Infradian: it is subject to a yearly cycle
- Circadian: it may be due to to the disruption of the sleep/wake cycle and this can be attributed to the prolonged periods of daily darkness in winter
352
What hormone do scientists hypothesise is implicated in SAD?
Melatonin
353
Explain SAD using hormones and glands
- During the night, the pineal gland secretes melatonin until dawn when there is an increase in light
- During winter, the lack of light in the morning means this secretions process continues for longer
- This has a knock on effect on the production of serotonin in the brain: a chemical that has been linked to the onset of depressive symptoms
354
What is an ultradian rhythm?
A biological rhythm that has a frequency of more than once in a 24 hour period
355
Give an example of an ultradian rhythm
The sleep stages cycle
356
How long does each sleep cycle typically last?
Around 90 minutes
357
What brain waves are present in stage 1 of the sleep cycle?
Alpha
358
What percent of total sleep time is taken up by stage 1?
0.05
359
Describe sleep in stage 1
- Light sleep, person is easily woken -
Eyes move slowly
- Sometimes sudden muscle contractions occur (falling sensation)
- Breathing more regular
- Heart rate slows
- Hypnagogic hallucinations
- Dreaming is rare
360
What brain waves are present in stage 2 of the sleep cycle?
Theta
361
What percentage of total sleep time does stage 2 take up?
45-50%
362
Describe sleep in stage 2
- Still quite light - Eye movement stops - Brain waves become slower - Conscious awareness of outside world fades completely - Lay down memories - Synaptic pruning
363
What brain waves are present in stage 3 of the sleep cycle?
Delta
364
What percentage of total sleep does stage 3 take up?
15-20%
365
Describe sleep in stage 3
- Deep sleep
- Sleeper is now cut off from the world completely
- Deep sleep lasts longer in the first 2 cycles than in the later cycles
- Some dreaming but not as vivid as REM
366
What brain waves are present in stage 4 of the sleep cycle?
Delta
367
What percentage of total sleep does stage 4 take up?
5-10%
368
Describe sleep in stage 4
- Deepest sleep
- Difficult to wake someone from
369
What brain waves are present during the REM stage of sleep?
REM
370
What percent of total sleep time does the REM stage take up?
20-25%
371
Describe the REM stage of sleep
- Rapid, shallow breathing
- Eyes jerk
- Temporary limb paralysis
- Heart rate increases
- Blood pressure rises
- Males develop erections
- Temperature irregular
- Time when most dreams occur
372
Define circadian rhythms
A biorhythm with a daily frequency
373
Give an example of a circadian rhythm
- The sleep/wake cycle
- Body temperature
374
What parts of the sleep/wake cycle are internal and external?
- Drowsiness/alertness is the endogenous pacemaker
- Darkness/daylight is the exogenous zeitgeber
375
When does the body reach its highest core temperature and what is it?
38°C at 6-7pm
376
When does the body reach its lowest core temperature and what is it?
36°C at 4-5am
377
Although circadian rhythms are (a), they are (b) to the local environment by (c), the most important of which is commonly (d)
a) endogenous b) entrained c) zeitgebers d) daylight
378
Name the three pieces of research into circadian rhythms
- Case study of Michael Siffre
- Aschoff and Wever (1976)
- Folkard et al (1985)
379
What did Michael Siffre do?
- He spent several extended periods underground to study the effects of his own biorhythms
- He was deprived of exposure to natural light and sounds but had access to food and drink
380
What happened when Siffre left the cave?
- He believed it was mid-August when it was mid-September
- This is because his free-running biorhythm settled down to one that was around 24.5-25 hours
381
Where did Siffre spend his time?
A cave in the southern Alps
382
What was the procedure or Aschoff and Wever's study?
Participants spent 4 weeks in a world war 2 bunker where they were deprived of natural light
383
What were the findings of Aschoff and Wever's study?
- Most emerged with a circadian rhythm lasting between 24 and 25 hours
- One had a circadian rhythm of 29 hours
384
What does Aschoff and Wever's research show? sleep/wake cycle
- Our sleep wake/cycle is slightly longer than 24 hours
- Zeitgebers such as light are important because the clock was not perfectly accurate; it varied from day to day
385
Outline the procedure of Folkard et al's study
- 12 participants agreed to live in a dark cave for 3 weeks
- They retired to bed when the clock said 11:45pm and 7:45am
- Unbeknown to the participants, the researchers gradually sped up the clock so that a 24 hours day only lasted 22 hours
386
What were the findings of Folkard's study?
Only one participant was able to adjust to the new regime
387
What does Folkard's study show? extent of exogenous zeitgebers
- Circadian rhythms can only be guided to a limited extent by exogenous zeitgebers
- Individual differences need to be taken into account in the sleep/wake cycle
388
Name the strength of research into sleep cycles
- Empirical evidence from EEG studies
389
What is the research evidence that supports the stages of the sleep cycle?
- Dement and Kleitmen (1957)
- Monitored participants' sleep and found REM activity was highly correlated with dreaming
- Found brain activity varied dependent on how vivid dreams were
390
How does Dement and Kleitmen's study increase the validity of ultradian rhythms?
It shows the accuracy of understanding of the REM stage of sleep, where the body is paralysed yet brain activity speeds up
391
Name the weaknesses of research into infradian and ultradian rhythms
- Conflict in views when trying to understand the adaptive need for synchronicity of the menstrual cycle
- The use of phototherapy to treat SAD
- The use of EEGs as the primary source of data collection
392
Why does the synchronicity of women's menstrual cycles initially seem adaptive?
It meant females in a group would fall pregnant at the same time so newborns could be cared for collectively
393
Why does the synchronicity of women's menstrual cycles seem maladaptive?
- Schank (2004) argued it would lead to too much competition for the best mate and lower the fitness of the offspring
394
Why does questioning the evolutionary value of the synchronicity of women's menstrual cycles weaken the study of infradian rhythms?
It questions the strength of exogenous influences on this infradian rhythm
395
Why is phototherapy used to treat SAD?
- It is effective
- It is cheap
396
What were the results of Eastman et al's 1998 study? phototherapy
- Symptoms were relieved in 60% of sufferers who looked at a light box in the morning and evening
- There was a 30% improvement in sufferers treated with a placebo
397
Why does Eastman's study weaken the study of infradian rhythms? chemical influence of phototherapy
- It suggests the chemical influence of phototherapy
- It suggests SAD may be treated equally well using psychological techniques
398
Why is it good that EEGs are the primary source of data collection in this area?
- EEGs provide objective data
- All participants are measured in the same way therefore increasing the reliability and validity of results
399
Why is it bad that EEGs are the primary source of data collection in this area?
It means sleep must be measured in a laboratory and participants awareness of the situation may affect their sleeping patterns affecting validity of results
400
What are endogenous pacemakers?
Internal body clocks that regulate our biorhythms
401
What does SCN stand for?
The suprachiasmatic nucleus
402
What is the suprachiasmatic nucleus?
- A tiny bundle of cells located in the hypothalamus
- It is one of the primary pacemakers in mammals
403
Outline how the suprachiasmatic nucleus is influential in maintaining the circadian sleep/wake cycle?
- Nerve fibres connected to the eye cross in an area called the optic chiasm on their way to the visual area of the cerebral cortex
- The SCN lies just above this, receiving information about light from these fibres, even when we are asleep
- This enables the biological clock to adjust to changing patterns of daylight while we sleep
404
What two studies were carried out into the effects of endogenous pacemakers?
- DeCoursey et al (2000)
- Ralph et al (1990)
405
Outline DeCoursey's study
- He destroyed the suprachiasmatic nucleus in 30 chipmunks
- They were reinstated to a natural environment and observed for 80 days
- Their sleep/wake cycle disappeared
- Significant numbers were killed because they were up at night or were tired
406
Outline Ralph et al's study
- Bred 'mutant' hamsters with 20 hour sleep/wake cycles
- He transplanted suprachiasmatic nucleus cells to normal hamsters
- Their cycle defaulted to 20 hours too
407
How is the pineal gland an endogenous pacemaker?
- The suprachiasmatic nucleus passes the light information it collects to the pineal gland
- The pineal gland produces melatonin so it can use this information to increase/decrease the production fo melatonin dependent on daylight
408
What are exogenous zeitgebers?
External cues that entrain our biorhythms
409
What is an interaction between endogenous pacemakers and exogenous zeitgebers?
The sleep wake cycle
410
What is the main zeitgeber?
Light
411
What can light do as a zeitgeber?
- Can reset the suprachiasmatic nucleus
- Can indirectly control hormone secretion and blood circulation
412
Who conducted a study into the effects of light as an exogenous zeitgeber?
Campbell and Murphy (1998)
413
Outline Campbell and Murphy's study
- Woke 15 participants at various times and shone a light pad on the back of their knees - They were able to produce a deviation in the sleep/wake cycle of up to 3 hours
- The fact that the skin could detect light showed how powerful it is and doesn't necessarily rely on the eyes
414
Circadian rhythms start at (a) and are fully entrained by (b)
a) 6 weeks b) 16 weeks
415
How are parents responsible for entrainment?
- Meal times
- Bed times
416
How do social cues act as exogenous zeitgebers?
- Meals are eaten at socially determined mealtimes
- We go to bed and wake up at times designated for our age
- Our sleep/wake cycle is entrained by social conventions
417
Who researched exogenous zeitgebers in the sleep wake cycle?
Davidson (2006)
418
What did Davidson (2006) find?
The zeitgeber for cells in the liver and heart is likely to be mealtimes because these cells are reset by eating
419
In what areas is knowledge of biorhythms especially important?
- Shift work
- Jet lag
- SAD
- Sleep training
- Sleep disorders
420
Name the strength of research into endogenous pacemakers and exogenous zeitgebers
- Practical applications
421
What is the practical application?
- The alleviation of the symptoms of jet lag which is caused by the body's internal body clock being out of step with external cues
422
How can jet lag be alleviated?
- Travellers could stay awake until it gets to their normal bedtime in the new country allowing them to adapt to the new time zone
- A period of fasting before travel followed by eating at times relevant to the new time zone
423
What does alleviating jet lag show?
That we can entrain our bodies to the new time zone more quickly by adjusting our bodies drive to sleep and eat (endogenous pacemakers) and to be more inline with light and social cues (exogenous zeitgebers)
424
Name the weaknesses of research into endogenous pacemakers and exogenous zeitgebers
- Case study contradiction
- Ethics of animal studies
- Interactionist view
425
What case study contradicts the influence of exogenous zeitgebers?
Miles et al (1977)
426
Outline Miles et al's case study
- A man blind from birth had a natural circadian rhythm of 24.9 hours
- He struggled to adjust it despite social cues
- He had to take sedatives at night and stimulants in the morning to function in a 24 hours world
427
What does Miles et al's case study show?
That the exogenous zeitgeber of social cues had no bearing on entraining his natural circadian rhythm
428
What are the ethical issues with animal studies investigating endogenous pacemakers?
- DeCoursey exposed the animals to considerable harm and subsequent risk when returning them to the wild
- The knowledge gained from such research will never justify the means and so such research should never be permitted
429
What is the interactionist view?
- Endogenous pacemakers are rarely free-running or unaffected by exogenous zeitgebers
- Most circadian rhythms are affected by an interaction of EPs and EZs
- Total isolation studies such as Siffre's cave study are rare and probably lack external validity
- It makes no sense to separate them for the purpose of research
