Biopsychology Flashcards
1
Q
What is the Human Nervous System Made Up of?
A
Peripheral Nervous System
Central Nervous System
2
Q
What is the CNS Made Up of?
A
Brain
Spinal Cord
3
Q
What is the PNS Made Up of?
A
Autonomic Nervous System
Somatic Nervous System
4
Q
What is the ANS Made Up of?
A
Sympathetic Nervous System
Parasympathetic Nervous System
5
Q
What is the Human Nervous System?
A
A specialised network of cells in the human body, and is our primary internal communications system
6
Q
What are the Two Main Functions of the Human Nervous System?
A
- Collect, process and respond to information in the environment
- Co-ordinate the workings of different organs and cells in the body
7
Q
CNS - 3 Points
A
- Consists of Brain and Spinal Cord
- Basis of all complex commands and decisions
- Passes messages to and from the brain and connects nerves to the PNS
8
Q
The Brain - 3 Points
A
- Centre of conscious awareness
- Cerebral cortex is more developed, which distinguishes us from animals
- Split into 2 hemispheres
9
Q
Spinal Cord - 2 Points
A
- Extension of brain and connected by brain stem
- Responsible for reflex actions
10
Q
What is the Role of the PNS?
A
Sends information from the outside world to the CNS via millions of neurones (nerve cells) and information from the CNS to muscles and glands
11
Q
What is the Role of the ANS?
A
Governs necessary automatic functions in the body
12
Q
5 Things Controlled by the ANS
A
- Breathing
- Heart Rate
- Digestion
- Sexual Arousal
- Stress responses
13
Q
What is the Role of the SNS?
A
Controls muscle movement using information from the CNS and receives information fro the sensory receptors, which is passed to the CNS
14
Q
What is the Endocrine System?
A
One of the body’s major information systems that instructs glands to release a hormones into the bloodstream which are then carried to target organs in the body
15
Q
What is a Gland?
A
An organ in the body which synthesises substances such as hormones
16
Q
What are Hormones?
A
Chemical substances that circulate in the bloodstream and affect target organs - produced in large quantities but disappear quickly
17
Q
6 Main Glands in the Human Body
A
- Pituitary gland
- Thyroid gland
- Adrenal gland
- Pancreas
- Ovary
- Testes
18
Q
The Endocrine System - 5 Points
A
- Works with the nervous stem to control vital bodily functions
- Works slower than nervous system and has more widespread effects
- Glands in the body produce hormones which are secreted into the bloodstream and affect any cells in the body that have a receptor for that hormone
- Most hormones affect cells in several organs/throughout the body, leading to powerful responses
- Pituitary gland controls the secretion of hormones from other glands in the endocrine system - master gland
19
Q
The Process of Flight or Fight Response - 5 Points
A
- Perception of stressor
- Hypothalamus triggers activity in sympathetic nervous system
- ANS changes from resting state (parasympathetic) to physiological aroused state (sympathetic)
- Adrenaline released from adrenal medulla into bloodstream
- Adrenaline triggers physiological changes in the body needed for fight or flight
20
Q
What Happens When the Threat has Passed in the F/F Response?
A
Rest and Digest Response - Parasympathetic nervous system returns bod t resting state - antagonistic to sympathetic nervous system (acts as a brake and reduces activity increased by sympathetic nervous system)
21
Q
6 Things that the Parasympathetic Nervous System Does
A
- Decreases heart rate
- Relaxes rectum
- Stimulates digestion
- Constricts pupils
- Decreases breathing rate
- Stimulates saliva production
22
Q
6 Things that the Sympathetic Nervous System Does
A
- Increases heart rate
- Contracts rectum
- Inhibits digestion
- Dilates pupils
- Increases breathing rate
- Inhibits saliva production
23
Q
Definition of a Neuron
A
Basic building blocks of nervous system which process and transmit messages through electrical and chemical signals
24
Q
Name the 8 Parts of a Neuron
A
- Dendrites
- Soma
- Nucleus
- Axon
- Myelin sheath
- Scwann cell
- Node of ranvier
- Axon terminal
25
How many Neurons are in the Human Nervous System?
100 billion
26
What % of Neurons are Found in the Brain?
80%
27
What is the Soma in a Neuron?
The Cell body
28
What Does the Nucleus Do in a Neuron?
Holds the genetic material of the cell
29
What Do the Dendrites Do in a Neuron?
Carry nerve impulses from neighbouring neurons towards the cell body
30
What Does the Axon Do in a Neuron?
Carries nerve impulses away from cell body down the length of a neuron
31
What is the Myelin Sheath in a Neuron?
Fatty layer that covers the axon
32
What Does the Myelin Sheath in a Neuron?
Protects the axon and speeds up electrical transmission of impulses
33
What are the Nodes of Ranvier in a Neuron?
Gaps between the myelin sheaths
34
What are the Axon Terminals in a Neuron?
Terminal buttons at the end of the axon that communicate with the next neuron in the chain
35
What are the 3 Types of Neurons?
Sensory Neurons
Motor Neurons
Relay Neurons
36
Sensory Neurons - 5 Points
- Found in receptors like eyes, ears, tongue and skin
- Carry nerve impulses from PNS to CNS
- When nerve impulses reach the brain, they are translated into sensations
- Not all sensory neurone reach the brain - some stop at spinal cord to allow for reflex actions
- Long dendrites and short axons
37
Relay Neurons - 3 Points
- Connect sensory neurons to motor neurons or other relay neurons
- Found in the CNS - allow sensory and motor neurons to communicate
- Short dendrites, short axons
38
Motor Neurons - 5 Points
- Connect CNS to effectors like muscles and glands
- Found in CNS
- Control muscle movements
- When stimulated, they release neurotransmitters that bind to the receptors on muscles -> movement
- Short dendrites and long axons
39
Definition of Action Potential
Explosion of electrical activity created by a depolarising current
40
3 Steps of Electric Transmission (Firing AP)
- In resting state, inside of the cell is negatively charged compared to the outside
- When a neuron is activated by a stimulus, the inside of the cell becomes positively charged for a split section (action potential)
- This creates an electrical impulse which travels down the axon towards the end of the neuron
41
Process of Synaptic Transmission - 6 Points
- AP in pre-synaptic neuron reaches pre-synaptic terminal
- Vesicles bind to pre-synaptic membrane
- Releases neurotransmitters into synaptic cleft
- Neurotransmitters bind to post-synaptic receptors, but only if the receptor is for that specific neurotransmitter
- Post-synaptic neuron releases AP
- More likely to fire if excitatory, less likely if inhibitory
42
What is Synaptic Transmission?
How messages are chemically transmitted between neurons
43
Definition of Neurotransmitter
Brain chemicals released from synaptic vesicles that relay signals across the synapse from one neuron to another
44
2 Examples of Inhibitory Neurotransmitters
- Serotonin
- GABA
45
Inhibitory Neurotransmitters and Their Effect
Cause inhibition in the receiving neuron making it less likely to fire action potential
46
Example of Excitatory Neurotransmitter
Noradrenaline
47
Excitatory Neurotransmitters and Their Effect
Cause excitation in the receiving neuron making it more likely to fire action potential
48
6 Parts of the Brain
- Frontal Lobe
- Parietal Lobe
- Occipital Lobe
- Temporal Lobe
- Cerebellum
- Limbic System
49
Frontal Lobe - 6 Points
- Movement of body
- Executive functions (concentrating, planning, problem solving)
- Personality
- Emotional reactions
- Speech
- Smell
50
Parietal Lobe - 3 Points
- Touch and pressure
- Taste
- Body awareness
51
What is the Occipital Lobe Responsible for?
Sight
52
Cerebellum - 3 Points
- Latin for 'little brain'
- Fine motor control
- Balance and co-ordination
53
Temporal Lobe - 4 Points
- Receive and process sounds
- Recognise faces
- Emotions
- LTM
54
Limbic System - 2 Points
- Inside brain
- Controls emotions
55
Definition of Localisation of Function
The theory that different brain areas are responsible for different behaviours, activities or purposes
56
Phineas Gage Case Study - 2 Points
- Tamping iron went through left cheek behind left eye and out through top of head and took most of left frontal lobe with it
- He went from being calm and reserved to short-tempered and rude
57
Which Hemisphere Controls the Right Side of the Body?
Left hemisphere
58
Which Hemisphere Controls the Left Side of the Body?
Right hemisphere
59
Where is the Motor Area Found?
Back of frontal lobe
60
Where is the Somatosensory Area Found?
Front of parietal lobe
61
Where is the Visual Area Found?
Back of occipital lobe
62
Where is the Auditory Area Found?
Temporal lobes
63
What is the Function of the Motor Area?
Controls voluntary movement in opposite side of body
64
What is the Function of the Somatosensory Area?
Area where sensory information from skin is represented
65
What Separates the Somatosensory Area from the Motor Area?
'Valley' called the central sulcus
66
What is the Function of the Visual Area?
Each eye sends information from right visual field to left visual cortex and from left visual field to right visual cortex
67
What is the Function of the Auditory Area?
Analyses speech-based information
68
What is the result of Damage to the Motor Area?
Loss of fine motor movements
69
What is the result of Damage to the Visual Area?
To left hemisphere, can produce blindness in left part of visual field in both eyes, same goes for right hemisphere
70
What is the result of Damage to the Auditory Area?
Can produce partial hearing loss
71
What are the 2 Language Centres of the Brain?
Broca's area and Wernicke's area
72
What is Broca's Area?
Small area in left frontal lobe responsible for speech production
73
What is Wernicke's Area?
Small area in left temporal lobe responsible for language comprehension
74
What is Broca's Aphasia?
Slow laborious speech that lacks fluency (patient Tan)
75
Wha is Wernicke's Aphasia?
Often produced nonsense words (neologisms) as part of their speech
76
LoF A03 - Brain Scan Evidence - 3 Points
- Peterson et al - used brain scans to show the Wernicke's area was active during a listening task and the Broca's area was active during a reading task which suggests the areas have different functions
- Tulving - showed the right pre-frontal cortex was active when recalling episodic memories, whilst the left pre-frontal cortex was active when recalling semantic memories
- Now many sophisticated, objective methods for measuring brain-activity
77
LoF A03 - Neurosurgical evidence - 6 Points
- 1950s - development of the practice of surgically removing brain areas to control aspects of behaviour (early attempts)
- Freeman - developed the lobotomy
- Sometimes used today in cases of extreme OCD and depression
- Dougherty et al - reported on 44 OCD patients who had undergone a cingulotomy
- At follow up after 32 weeks, 1/3 met criteria for successful response to surgery and 14% for partial response
- Suggests symptoms and behaviours associated with severe mental disorders are localised
78
LoF A03 - Case Study Evidence
Uniques cases of neurological damage such as Phineas Gage and HM
79
LoF A03 - Lashley's Research - 5 Points
- Suggests high cognitive functions are not localised, but distributed in a more holistic way across the brain
- Lashley - removed ares of the cerebral cortex (10 - 50%) in rats learning a maze
- No area was shown to be more important than any other in terms of their ability to learn the maze
- Process of learning seemed to require every part of cerebral cortex rather than being confined to a certain area
- Issues with generalisability but especially because cerebral cortex is more developed in humans
80
LoF A03 - The Concept of Plasticity - 5 Points
- Evidence of cortical remapping (plasticity)
- Means when the brain becomes damaged, the rest of the brain is able to reorganise itself to recover the lost functions
- Lashley - described this as the 'law of equipotentiality'
- Doesn't happen on every occasion
- Cases of several stroke victims who were able to recover functions they seemingly lost
81
Definition of Plasticity
Brain has the tendency to change and adapt as a result of experience and new learning
82
What is Plasticity Also Known as?
Neuroplasticity or cortical remapping
83
What Happens to Synaptic Connections During Infancy?
Rapid growth
84
At What Age and Number Do Synaptic Connections Peak According to Gopnick et al?
Ages 2-3 and at about 15,000
85
How Many Synpatic Connections are in the Adult Brain?
30,000
86
What is Synpatic Pruning?
Connections we rarely use are 'deleted' and frequent connections are strengthened
87
Plasticity Research - Draganski et al - 2 Points
- Brain imaging of Medical students three months before and after their final exam
- Learning-induced changes seen in posterior hippocampus and parietal cortex
88
Plasticity Research - Michelle et al
Larger parietal cortex in brains of people who were bilingual compared to matched monolingual controls
89
Plasticity Research - Maguire et al - 4 Points
- London taxi drivers have significantly more grey matter volume in posterior hippocampus than in matched control group
- Brain part associated with development of spatial and navigational skills in humans and other animals
- Complex test 'The Knowledge' assess recall of city streets/possible routes and it appears that this learning experience alters the structure of taxi drivers' brains
- Positive correlation also existed between how long they had been in the job and how pronounced the structural differences were
90
Definition of Functional Recovery
A from of plasticity where the brain redistributes or transfers functions usually performed by one area to another following damage to the brain
91
Jodie Case Study - 6 Points
- From 3 years old, she had epileptic seizures
- Medicine wasn't working
- Came from right hemisphere (Rasputin Syndrome)
- Hemispherectomy on right side and replaced with spinal fluid
- Surgery went well
- Left hemisphere started reconnecting quickly, and she no longer has seizures and developed normally
92
Functional Recovery After Trauma - 5 Points
- Following physical injury or any other trauma (stroke and seizures), unaffected brain areas can often adapt or compensate for damaged areas
- Functional recovery is an example of neural plasticity
- Healthy brain areas may take over functions of damaged, destroyed or missing areas
- Neuroscientists suggest this process can happen quickly after trauma (spontaneous recovery)
- After weeks/month, this may slow down and the person may need rehabilitative therapy to aid their recovery
93
2 Structural Changes in the Brain During Trauma Recovery
Axonal Sprouting
Denervation Supersensitvity
94
Definition of Axonal Sprouting
Growth of new nerve endings which connect with other undamaged neurons to form new pathways
95
Definition of Denervation Supersensitivity
Axons that do similar job become more aroused to compensate for lost ones
96
Meditation and Mindfulness - 3 Studies
- Lazar et al
- Holzel et al
- Tang et al
97
Meditation and Mindfulness - Lazar et al
MRI scans showed thicker cortex in experienced meditators than non-meditators, especially in areas related to attention and sensory processing
98
Meditation and Mindfulness - Holzel et al
Increase in grey matter, in left hippocampus (learning and memory) for people who took part in an 8 week mindfulness-based stress reduction course
99
Meditation and Mindfulness - Tang et al
Four weeks of mediation resulted in increase in white matter in anterior cingulate cortex (self-regulation and control)
100
Plasticity and Functional Recovery A03 - Practical Application - 5 Points
- Understanding the process involved in plasticity has contributed to the filed of neurorehabilitation
- Techniques include movement therapy and electrical stimulation of the brain when the body's initial repair response begins to slow down, which leads to more successful recovery
- Without the research and the theory around plasticity, it would not be possible to have these supervisions in place to account for the natural slowing down of spontaneous bodily recovery post-trauma
- Because we are aware of this instance however, the recovery rate is now much more successful
- This increases the credibility of the theory
101
Plasticity and Functional Recovery A03 - Age and Plasticity - 4 Points
- Bezzola et al - demonstrated how 40 hours of golf training produced changes in the neural representation of movement in participants aged 40-60
- Using fMRI, the researchers observed reduced motor cortex activity in the novice golfers compared to a control group
- Suggests there were more efficient neural representations after training
- Shows us that neural plasticity does continue throughout the lifespan, which leads to an increase in explanatory power of the theory
102
Plasticity and Functional Recovery A03 - Animal Studies - 4 Points
- Hubel and Wiesel - involved sewing one eye of a kitten shut and analysing the brain's cortical responses
- Found that the area of the visual cortex associated with the shut eye was not idle, but continued to process information from the open eye
- This is a strength because it developed the theory that our brain compensates when there is trauma, and that functional recovery will occur to allow for 'regular' neurological functioning
- Credibility of theory is increased, but there are major ethical issues
103
Plasticity and Functional Recovery A03 - Negative Plasticity - 4 Points
- Prolonged drug use has been shown to result in poorer cognitive functioning as well as an increased risk of dementia later in life
- 60 - 80% of amputees have been known to suffer from phantom limb syndrome, thought to be caused by cortical reorganisation in the somatosensory cortex caused by limb loss
- Plasticity can have negative and painful consequences due to the rewiring and cortical reorganisation
- Not considered by the theory, only the positive, which reduces the explanatory power
104
Plasticity and Functional Recovery A03 - Not Universally Applicable - 3 Points
- Evidence suggests that a person's educational attainment may influence how well the brain functionally adapts after injury
- Schneider et al - discovered that the more time brain injury patients had spent in educations, the greater their chances of a disability-free recovery
- 2/5 patients studied who achieved disability-free recovery had more than 16 years education compared to only 10% of patients who had less than 12 years of education
105
Definition of Hemisphere Lateralisation
The idea that the two hemispheres are functionally different and that certain mental processes and behaviours are mainly controlled by one hemisphere
106
What is a Corpus Callosum?
A bundle of nerve fibres which connect the left and right hemispheres, allowing them to communicate
107
What is a Commissurotomy?
Severing of the corpus callossum and other tissues which connect the two hemispheres
108
Why are Commissurotomies Usually Performed?
To control aggressive and frequent seizures
109
What is the Result of the Commissurotomy?
Removes the main line communication between the two hemispheres
110
Sperry - Procedure - 2 Points
- Devised procedure where word or image could be projected into participants left/right visual field (processed by the opposite hemisphere)
- In a healthy brain, the corpus callosum would share the information between hemispheres, but this cannot happen for split-brain patients
111
Sperry's Findings - Describing What You See - 2 Points
- When picture of object shown to right visual field, participants had no difficulty in saying what was seen
- When same object, was shown in left visual field, patient could not say what they'd seen, often saying there was nothing there
112
Sperry's Findings - Recognition By Touch - 4 Points
- Though unable to attach verbal labels to objects presented in left visual field, they could select matching object from grab-bag using left hand
- Objects behind screen so they couldn't be seen
- Left hand could also select object most closely associated with object presented to left visual field
- Could understand what object was, just not able to verbally identify it
113
Sperry's Findings - Composite Words - 2 Points
-Two words presented simultaneously
- Dominance of left hemisphere for language and right for visual motor tasks
114
Sperry's Findings - Matching Faces - 3 Points
- When asked to match faces from a series of other faces, picture presented to left visual field consistently selected
- Picture presented to right visual field was consistently ignored
- When shown composite picture made of two different halves of a face, left dominated for verbal description and right dominate for facial recognition
115
Lateralisation and Split-Brain Research A03 - Theoretical Value - 2 Points
- Sperry's work is an impressive body of evidence
- Main conclusion is that left hemisphere geared towards analytic and verbal tasks, right more for spatial tasks
116
Lateralisation and Split-Brain Research A03 - Methodological Strengths - 4 Points
- Split-brain experiments use highly specialised, standardised procedures
- Sperry developed a procedure to show information to only one hemisphere at a time
- Participants stared at fixation point with one eye blindfolded, image projected for 1/10 second so there would be no time to move eye across image and spread information into other visual field and therefore both sides of brain
- High control allowed Sperry to vary aspects of the basic procedure to collect lots of information
117
Lateralisation and Split-Brain Research A03 - Theoretical Basis - 3 Points
- Sperry's work promoted theoretical/philosophical debate about degree of communication between hemispheres and the nature of consciousness
- Pucetti - says the hemispherses are so functionally different they represent duality in the brain
- Other theorists suggest the hemispheres are highly integrated and both involved everyday tasks
118
Lateralisation and Split-Brain Research A03 - Generalisation Issues - 4 Points
- Split brain patients are an unusual sample
- 11 Participants took part in variations of the basic procedure, all with a history of epilepsy
- Participants differed in the extent of their disconnection between the hemispheres due to surgery
- Control group of 11 people with no epilepsy history could have been inappropriate
119
Lateralisation and Split-Brain Research A03 - Functional Differences May Be Overstated - 2 Points
- Unfortunate legacy is the pop-psychology idea that over emphasises/oversimplifies distinction between the hemispheres
- 'Verbal' and 'non-verbal' labels can be useful to summarise differences but neuroscientists say it is more 'messy' than this
120
4 Ways of Investigating the Brain
- Functional Magnetic Resonance Imaging (fMRI)
- Electroencephalogram (EEG)
- Event-Related Potentials (ERPs)
- Post-Mortem Examination
121
Definition of Functional Magnetic Resonance Imaging (fMRI)
A method to measure brain activity whilst a person is performing a task - relies on the use of MRI, allowing researchers to see which parts of the brain are rich in oxygen (implies they are active)
122
Definition of Electroencephalogram (EEG)
A record of the electrical impulses produced by the brain's activity
123
Definition of Event-Related Potential (ERP)
The brain's electrophysiological response to a specific sensory, motor or cognitive event isolated through statistical analysis of EEG data
124
Definition of Post-Mortem Examination
The brain is analysed after death to determine whether certain observed behaviours during the patient's life can be linked to brain abnormalities
125
What is Involved in an fMRI? - 5 Points
- Detects changes in blood oxygenation and flow occurring as a result of neural activity in specific parts of the brain
- When a brain area is more active, it uses more oxygen
- To meet this demand, blood flow is directed to active area (known as haemodynamic response)
- fMRI produces 3D images showing which parts of the brain are active during a particular mental process
- Important implications for localisation of function
126
What is Involved in an EEG? - 4 Points
- Measures electrical activity in the brain via electrodes fixed to an individual's scalp using a skull cap
- Scan recording represents brainwave patterns generated from the action of millions of neurons
- This gives an overall account of brain activity
- Often used as a diagnosis tool as unusual arrhythmic patterns of activity may indicate neurological abnormalities
127
What is Involved in an ERP? - 5 Points
- Although EEG is clinically useful, in its raw form its an overly general measure of brain activity
- However, it does contain all the neural responses associated with specific sensory, cognitive, and motor events that could be interesting to cognitive neuroscientists
- ERPs are therefore a way to isolate these responses by using a statistical averaging technique which filters out extraneous brain activity from the original EEG recording
- This leaves us with ERPs, which are types of brainwaves triggered by particular events
- There are many types of ERPs and research has shown how they are related to cognitive processes like perception and attention
128
What is Involved in a Post-Mortem Examination? - 4 Points
- Involves analysing someone's brain after they die
- In psychological research, brains which are subject to post-mortem examination usually belonged to those with rare disorders who have experienced unusual deficits in mental processes or behaviour during their lifetime
- Areas of damage examined after death as a way of establishing the likely cause of the problem the person suffered
- Often involves comparison with a neurotypical brain to see the extent of differences
129
2 Strengths of fMRIs
- Does not use radiation so, when administered correctly, it is virtually risk free, non-invasive and straightforward to use
- High spatial resolution, which is able to depict detail by the millimetre and provide a clear picture of how brain activity is localised
130
3 Strengths of EEGs
- Valuable in diagnosis of conditions like epilepsy
- Contributed towards a lot of our understanding of stages involved in sleep
- Extremely high temporal resolution
131
3 Strengths of ERPs
- Bring much more specificity to measuring neural processes than could be achieved by raw EGG data
- High temporal resolution
- Researchers have been able to identify many types of ERP and describe their role in cognitive functioning
132
2 Strengths of Post-Mortem Examinations
- Vital in providing a foundation for our early understanding of key processes in the brain
- Improve medical knowledge and help generate hypotheses for future studies
133
4 Weaknesses of fMRIs
- Expensive compared to other methods
- Can only capture a clear image if the person stays still
- Poor temporal resolution due to the 5 second time lag between the initial firing of neuronal activity and the projection of the image on the screen
- Can only measure blood flow in the brain, and not hone in on the activity of individual neurons so it can be hard to decipher exactly what sort of brain activity is being represented on the screen
134
Weakness of EEGs
Information produced is very generalised - the information is therefore not very useful for pin pointing exact source of neural activity, and often doesn't allow researchers to distinguish between activities originating in different, but adjacent, locations
135
2 Weaknesses of ERPs
- Lack of standard of standard ERP methodology between recent studies which makes it hard to confirm findings
- To establish pure data in ERP studies, background noise and extraneous material must be completely eliminated which is not easy to achieve
136
2 Weaknesses of Post-Mortem Examinations
- Causation is an issue as observed damage in the brain might not be linked to the deficits being reviewed but to some other trauma or decay
- Raise issue of ethical consent from patients before death - patients may not be able to provide informed consent, but whose brain still be subject to post-mortem examination
137
Definition of Biological Rhythms
Distinct changes in body activity that conform to cyclical time periods - they are influenced by internal body clocks (endogenous pacemakers) and external changes to the environment (exogenous zeitgebers)
138
Definition of Circadian Rhythms
A type of biological rhythm subject to a 24 hour cycle which regulates many body processes
139
Siffre - 5 Points
- Spent several extended periods underground to study effects of his own biological rhythms
- Deprived of natural light and sound but with plenty of food and water
- Spent 2 months in underground caves
- Did similar experiment later on for 6 months
- In both studies, his free-running biological rhythm settled down to one around 25 hours
140
Aschoff and Wever - Procedure
Participants spent 4 weeks in WW2 bunker deprived of natural light
141
Aschoff and Wever - Findings
All but one (29 hours) displayed circadian rhythms between 24 and 25 hours
142
Folkard et al (Sleep/Wake Cycle) - 5 Points
- 12 participants lived in a dark cave for 3 weeks
- Went to bed when the clock was 11 : 45 pm and waking when it was 7 : 45 am
- Researchers gradually sped up clock to end as a 22 hour day
- None of the participants could comfortably adjust to the new regime
- Strong free-running circadian rhythm was not easily overridden by external stimuli
143
Core Body Temperature - 3 Points
- Core body temperature varies by around 2 degrees centigrade during the course of day
- Its at its lowest around 4 am (36 degrees) and peaks around 6 pm (38 degrees)
- Evidence suggests the higher our core body temperature, the better our cognitive performance
144
Folkard et al (Core Body Temperature)
Children who heard a story at 3 pm had superior recall and comprehension a week later, compared to those who heard the story at 9 am
145
Gupta's Study
Improved recall performance on IQ tests when assessed at 7pm, compared to 2pm and 9pm
146
Research into Circadian Rhythms A03 - Practical Applications to Shift Work - 4 Points
- Because of our understanding of circadian rhythms, we also have a good understanding of the adverse consequences of desynchronisation
- Night workers who work shifts experience reduced concentration around 6 am (circadian trough), which makes mistakes and accidents more likely
- Knuttson - discovered a relationship between shift work and poor health, with shift workers being 3 times more likely to develop heart disease
- Can have economic implications in terms of how to manage shitf worker productivity
147
Research into Circadian Rhythms A03 - Practical Application to Drug Treatments - 4 Points
- Circadian rhythms co-ordinate many of the body's basic processes, like heart rate, digestion and hormone levels
- Baldardo - suggests that research into circadian rhythms has revealed certain real times during the day and night when drugs are likely to be the most effective
- Led to development of guidelines around the timing of drug doing for a multitude of medications (e.g. cardiovascular and anti-epileptic drugs)
- Research has led to vast improvements for treating and managing life-limiting conditions
148
Research into Circadian Rhythms A03 - Most Research Relies on Small Samples and Case Studies - 4 Points
- Much of the research into sleep/wake cycle include small groups of participants or single people
- People involved may not be representative of the wider population and individual differences can have a large impact on circadian rhythms
- In Siffre's most recent study, at the age of 60, he observed that his internal clock 'ticked' much more slowly than in prior experiments when he was younger
- Reduce generalisability of the findings, especially when exacerbated by the impact of factors such as age, which appear to have an impact on the circadian rhythm of the same person
149
Research into Circadian Rhythms A03 - Poor Levels of Control - 4 Points
- Participants in Ashcoff and Weaver's study, and Siffre himself, were deprived of natural light but still had access to artificial light, as they assumed this would have no effect
- Czeisler et al - able to adjust participants to circadian rhythms to 22 - 28 hours using dim lighting
- Could be suggested that the use of light could have a similar effect to taking a drug that resets the biological clock
- Doubt over internal validity of the studies
150
Research into Circadian Rhythms A03 - Fails to Recognise Individual Differences - 4 Points
- Czeisler et al - found the sleep/wake cycle can vary from 13 to 65 hours depending on the individual
- Cycle is affected by age differences
- Some people display a preference for going to bed and getting up early (larks) whilst some prefer to do the opposite (owls)
- These individual differences complicate the use of small samples and case studies, so it makes it difficult to generalise to larger groups
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Definition of Infradian Rhythms
A type of biological rhythm with a frequency of less than one cycle in 24 hours, such as menstruation and SAD
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Menstrual Cycle - 7 Points
- Menstrual cycle is governed by monthly changes in hormone levels regulating ovulation
- The cycle is the time between day 1 of a period and the day prior to the subsequent period
- Typical cycle is 28 days, but 24 - 35 days is considered normal
- During a cycle, rising levels of oestrogen cause the ovary to develop and release an egg
- After ovulation, progesterone helps the womb lining thicken in preparation for pregnancy
- If the egg is not fertilised, it is absorbed and leaves the body with the lining of the uterus
- Is an endogenous system, but there is evidence to suggest it is affected by exogenous factors like the cycles of other people who have a period
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Stern and McClintoke - 5 Points
- Sample of 29 women with a history of irregular periods
- Pheromone sample fathered from 9 participants at different stages of their menstrual cycle via a cotton pad placed in their armpit
- Pads left for at least 8 hours, then treated with achoo and frozen to later be placed on the upper lip of other participants
- On day 1, pads from start of cycle were given to all of the other 20 participants, and this repeated for the whole cycle
- 68% of participants experienced changes to their cycle which brought them closer to their 'odour donor'
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Seasonal Affective Disorder - 7 Points
- Depressive disorder with a seasonal pattern of onset
- Main symptoms = persistent low mood, general lack of activity and interest in life
- Subject to yearly cycle (circannual rhythm)
- Can be considered a circadian rhythm because of disruption to sleep/wake cycle
- Hypothesised that melatonin is implicated in SAD
- During night pineal gland secretes melatonin util dawn when there's an increase in light
- During winter, the lack of light in the morning means this secretion process is longer, which has a knock-on effect for the production of serotonin in the brain
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Definition of Ultradian Rhythms
A type of biological rhythm with a frequency of more than one cycle in 24 hours
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What are the 3 Stages of Sleep?
- Stage 1 - Alphas waves
- Stage 2 - Theta Waves (light)
- Stage 3 and 4 - Delta Waves
- Stage 5 - REM Sleep
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Stages 1 and 2 of Sleep Cycle - 3 Points
- Light sleep where a person may easily be woken up
- At the beginning of sleep, brainwave patterns start to become slower and more rhythmic (alpha waves)
- The waves become slower as sleep gets deeper (theta waves)
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Stages 3 and 4 of Sleep Cycle - 2 Points
- Involve delta waves which are even slower with a greater amplitude than earlier wave patterns
- This is deep sleep or slow wave sleep - it is hard to wake someone at this point
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Stage 5 of Sleep Cycle - 2 Points
- Body Paralysed but brain activity speeds up in a manner that resembles the awake brain
- Research has suggested REM activity during sleep is highly correlated with the experience of dreaming
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What Does REM Stand For?
Rapid Eye Movement
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Research into Infradian and Ultradian Rhythms A03 - Methodological Limitations - 4 Points
- Early synchronisations studies and their methods have been criticised, as some have said there are many other factors that can change a menstrual cycle, including stress, changes in diet, and exercise etc
- Any pattern of synchronisation seen in studies is no more than would be expected by chance
- Research typically involves small samples, relying on the participants to self-report the onset of their menstrual cycle
- Other studies have failed to find evidence of menstrual synchrony
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Research into Infradian and Ultradian Rhythms A03 - Evolutionary Basis of Menstrual Cycle - 6 Points
- Menstrual synchrony is thought to have evolutionary value because it could have been useful for females to menstruate together so they fell pregnant around the same time
- New borns could be collectively care for within a social group, increasing the chances of their survival
- The validity of the evolutionary perspective has been questioned
- Schank - has argued that too many females cycling together would produced too much competition for the highest quality males, so lots of people would have to reproduce with lower quality males
- This would lower the genetic fitness of potential offspring
- It would seem that the most adaptive evolutionary strategy, which would be naturally selective, would be to avoid synchrony
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Research into Infradian and Ultradian Rhythms A03 - Animal Studies - 4 Points
- A lot of our knowledge on the effects of pheromones comes from animal studies
- Role of pheromones in animal sexual selection is well-documented
- We know that sea-urchins release pheromones into the surrounding water so-other urchins will eject their sex cells at the same time
- Evidence for the effects of pheromones in human behaviour remains speculative and inconclusive
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Research into Infradian and Ultradian Rhythms A03 - Evidence for the Distinct Sleep Stages - 5 Points
- Dement and Kleitman - monitored the sleep patterns of nine adults in a sleep lab
- Brainwave activity was recorded using EEG, and the researchers controlled for the effects of caffeine and alcohol
- REM activity was found to be highly correlated with the experience of dreaming and brain activity varied depending on how vivid the dreams were
- Participants who were woken up during dreaming reported very accurate recall of their dreams
- Replications of this have found similar findings, but the small size of the original sample has been criticised
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Research into Infradian and Ultradian Rhythms A03 - Practical Applications - 5 Points
- One of the most effective treatments for SAD is phototherapy, using a light-box that stimulates very strong light in the morning and evening
- This is though to reset melatonin levels in people with SAD
- Eastman et al - found phototherapy relieves symptoms in up to 60% of sufferers
- The same study recorded a placebo effect of 30% using a sham-negative ion generator, which participants were told was another form of treatment
- Casts doubt on the chemical influence of phototherapy
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Definition of Endogenous Pacemakers
Internal body clocks that regulate many of our biological rhythms on the sleep/wake cycle
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Definition of Exogenous Zeitgebers
External cues that may affect or entrain our biological rhythms on the sleep/wake cycle
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Suprachiasmatic Nucleus - 7 Points
- Tiny bundle of neurons in the hypothalamus in each hemisphere of the brain
- The SCN is one of the primary endogenous pacemakers
- Influential in maintaining circadian rhythms
- 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 the optic chasm
- SCN receives information about light directly from this structure even when eyes are closed
- Means our biological clock is able to adjust to changing daylight patters whilst we are asleep
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DeCoursey et al - 4 Points
- Destroyed the SCN connections in the brains of 30 chipmunks then returned them to their natural habitat and observed them for 80 days
- Sleep/wake cycle, of the chipmunks disappeared
- By the end of the study, a significant proportion has been killed by predators
- Most likely because they were awake and vulnerable to attack when they should've been asleep
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Ralph et al - 3 Points
- Bred mutant hamsters with a 20 hour sleep/wake cycle
- He then translated SCN cells from the foetal tissue of these hamsters into the brains of normal hamsters
- The sleep cycles of the normal hamsters defaulted to 20 hours
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The Pineal Gland - 3 Points
- SCN passes information to pineal gland about light and day length
- Located behind the hypothalamus
- Increases its production of melatonin during the night
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Exogenous Zeitgebers - 3 Points
- Reset our biological clocks through the process of entrainment
- In the absence of external cues, the free-running biological clock controlling the sleep/wake cycle continues to tick in a cyclical pattern
- Sleeping seems to be controlled by an interaction of internal and external factors
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Campbell and Murphy - 4 Points
- Light may be detected by skin receptor sites on the body, even when the same information is not received by the eyes
- 15 participants woken at various ties and a light pad was shone on the back of their knees
- Researchers able to produce a deviation in unusual sleep/wake cycle of up to 3 hours in some cases
- Light is powerful zeitgeber that doesn't necessarily need the eyes to exert influence on the brain
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Social Cues on the Sleep/Wake Cycle - 4 Points
- Infants are rarely on the same sleep/wake cycle as the rest of the family, and theirs is generally random
- Circadian rhythms typically start at about 6 weeks, and most babies are entrained by about 16 weeks
- Schedules imposed by adults often have a big influence for this
- There os research to suggest adapting to local times for eating and sleeping, rather than responding to won feelings is an effective way to entrain circadian rhythms and beat jet lag
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Research into Endogenous Pacemakers and Exogenous Zeitgebers A03 - Ethics in Animal Research - 3 Points
- Not only is there anise with generalisation, but also ethics involved in the studies
- DeCoursey et al - animals exposed to considerable harm and risk when turned to natural habitat
- Matter of debate whether our subsequent understanding justifies the aversive procedures
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Research into Endogenous Pacemakers and Exogenous Zeitgebers A03 - Effects of Exogenous Zeitgebers May Be Exaggerated - 3 Points
- Miles et al - young man who was blind from birth with CR of 24.9 hours
- Despite social cues, sleep/wake cycle could not be adjusted, so he had to take sedatives at night and stimulants in the morning to keep him in the 24 hour world
- Studies of those who lived in Artic regions, where sun doesn't set during summer, show normal sleep patterns
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Research into Endogenous Pacemakers and Exogenous Zeitgebers A03 - Methodological Issues - 3 Points
- Campbell and Murphy's research is yet to be replicated
- Critics have suggested there may have bene some limited light exposure to participants eyes (confounding variable)
- Isolating one Zeitgeber also does not give us insight into many other zeitgebers affecting sleep/wake cycle and how these may interact
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Research into Endogenous Pacemakers and Exogenous Zeitgebers A03 - Interaction Between Pacemakers and Zeitgebers - 3 Points
- Only exceptional circumstances where EPs are entirely free-running and unaffected by EZs
- Total isolation studies, like Siffre's, may lack validity
- In real life pacemakers and zeitgebers interact so there may be little point separating them for the purpose of research
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Research into Endogenous Pacemakers and Exogenous Zeitgebers A03 - Influences Beyond the SCN - 5 Points
- Research has shown numerous CRs in many organs and cells across the body
- Found in adrenal gland, oesophagus, lungs, liver, pancreases, spleen, thymus, and skin
- Although highly influenced by SCN, they can also act independently
- Damida et al - found changing feeding patterns in mice can alter CRs in liver by up to 12 hours, leaving the rhythm of SCN unaffected
- May be other complex influences on sleep/wake cycle aside from master clock
