Biopsychology Flashcards
What are the 2 main functions of the nervous system?
- To collect, process and respond to info in the environment
- To co-ordinate the working of different organs and cells
Describe the structure of the human nervous system
Branches off to: Peripheral nervous system and Central nervous system
Peripheral: somatic and autonomic, autonomic branches to sympathetic and parasympathetic.
Central: Brain and Spinal cord
Explain what the peripheral nervous system does
Sends info to CNS from environment, and transmits messages from CNS to muscles and glands.
Is the somatic NS involuntary or voluntary?
Voluntary- muscle movements
Is the autonomic NS involuntary or voluntary?
Involuntary- automatic responses e.g breathing
What do the sympathetic and parasympathetic NS do in the autonomic NS?
Sympathetic- body is ready to react, fight or flight
Parasympathetic- relaxes body and clams it down
What is the role of the brain in the Central NS?
Centre of all conscious awareness
What is the role of the Spinal cord in the Central NS?
Passes messages to and from brain and connects nerves to the PNS.
What is the Endocrine system?
Works alongside the nervous system to control functions in the body. Glands release hormones, secreted into the blood and effects cells with these specific receptors.
What is the Pituitary Gland?
Controls the release of all other hormones from other glands.
Name the structures of a neuron from the left to right
-Dendrites
-Soma
-Nucleus
-Axon
-Myelin sheath
-Nodes of ranvier
-Terminal buttons
Describe the process of the fight or flight response
- When a stressor in the environment is percieved, the hypothalamus activates the pituitary gland and triggers the sympathetic NS.
- The autonomic NS changes from resting state (parasympathetic) to physiologically aroused sympathetic state.
- The stress hormone adrenaline is released from the adrenal medulla into the bloodstream.
- Adrenaline triggers physiological changes, ready for fight or flight.
- This happens in an instant, an acute response and an automatic reaction. Stress, panic and anxiety are felt= sympathetic response.
- Once the threat has passed, the parasympathetic NS returns the body to its resting state.
Parasympathetic and sympathetic NS work in opposition, what is this called?
Antagonistic
What are some biological changes in the sympathetic response?
-Increased heart rate
-Increased breathing rate
-Dilates pupils
-Inhibits digestion
What are some biological changes in the parasympathetic NS response?
-Decreased heart rate
-Decreased breathing rate
-Constricts pupils
-Stimulates digestion
What is a sensory neuron?
Carry messages from the PNS to the CNS.
-Long dendrites
-Short axons
What is a Relay neuron?
Connect sensory and motor neurons or other relay neurons.
-Short dendrites
-Short axons
What is a motor neuron?
Connects CNS to effectors such as muscles and glands.
-Short dendrites
-Long axons
Explain the role on the Central nervous system
Consists of brain and spinal cord, origin of all complex commands and decisions.
Explain the role of the somatic NS
Transmits info from receptor cells in sense organs to CNS, and from CNS to muscles.
Explain the role of the Autonomic NS
Transmits info from internal body organs.
The brain is divided into…
2 hemispheres
What is a neuron?
Nerve cells that process and transmit messages through electrical and chemical signals.
What is the function of the soma?
Cell body or nucleus that contains genetic material
What is the function of a dendrite?
Carry nerve impulses to neighbouring neurons
What is the function of an axon?
Carries impulses away from soma, down the length of the neuron
What is the function of the myelin sheath?
Fatty layer that protects axon and speed up transmission
What is the function of the nodes of ranvier?
Speed up transmission
What is the function of the terminal buttons?
Communicate with the next neuron over the synapse
Neurons in the PNS are located in clusters known as…
Ganglia
How does the firing of a neuron work?
-Neuron in resting state is negatively charged
-When activated by a stimulus, inside of the cell becomes positively charged causing an action potential.
-Creates an electrical impulse down the axon.
Briefly outline the reflex arc
- Stimulus e.g fire
- Detected by sensory neuron
- Impulse travels towards spinal cord and passes onto relay neuron
- This is then passed to the motor neuron, to the muscle effector
Neurons communicate with eachother in groups known as…
Neural networks
Define excitation
A neurotransmitter, such as adrenaline, increases the positive charge of the postsynaptic neuron, therefore increases the likelihood that the postsynaptic neuron will pass on the electrical impulse.
More likely to fire
Define inhibition
A neurotransmitter, such as serotonin, increases the negative charge of the postsynaptic neuron, therefore decreases the likelihood that the postsynaptic neuron will pass on the electrical impulse.
Less likely to fire
What decides if a postsynaptic neuron fires or not?
Summation
What is summation?
Action potential of postsynaptic neuron is only triggered if the sum of excitatory and inhibitory signals at any one time reaches the threshold.
What is a neurotransmitter?
Brain chemicals released from synaptic vesicles that relay signals across the synapse
What is ‘localisation of function’?
The theory that different areas of the brain are responsible for specific behaviours, processes, or activities.
What is the Motor Area?
A region of the frontal lobe involved in regulating movement.
What is the Somatosensory area?
An area of the parietal lobe that processes sensory info such as touch.
What is the Visual Area?
A part of the occipital lobe that receives and processes visual info.
What is the Auditory area?
Located in the temporal lobe and concerned with the analysis of speech-based info.
What is Broca’s Area?
An area of the frontal lobe in the left hemisphere, responsible for speech production
What is Wernicke’s Area?
An area of the temporal lobe in the left hemisphere, responsible for language comprehension.
What is the holistic theory of the brain?
All parts of the brain were involved in the processing of thought and action
The cerebrum is divided into two parts…
Left and right hemisphere
Activity on the left hand side of the body is controlled by the ____ hemisphere
right
The outer layer of both hemispheres?
Cerebral cortex
The cerebral cortex is divided into 4 lobes, what are their names?
-Frontal
-Parietal
-Occipital
-Temporal
At the back of the frontal lobe is the _____ area
motor
At the front of both parietal lobes is the _____ area
Somatosensory
The somatosensory and motor areas are separated by….
a ‘valley’ called Central Sulcus
In the occipital lobe is the ____ area
visual
In the temporal lobe is the ____ area
auditory
Language is restricted to the _____ side of the brain
left
Where is Broca’s area?
Left frontal lobe
Where is Wernicke’s area?
Left temporal lobe
What happens when the broca’s area is damaged?
‘Broca’s Aphasia’ , speech is slow
What happens when Wernicke’s area is damaged?
‘Wernicke’s Aphasia’ , produce nonsense words (neologisms)
Evaluate ‘Localisation of Function’
+ Evidence from neurosurgery:
damage has been linked to mental disorders. 44 people with OCD had a Cingulotomy, post surgery, 30% met criteria for successful response to surgery- mental disorders can be localised.
+ Evidence from brain scans:
Perterson et al. used brain scamns to demonstrate how Wernicke’s area was active during a listening task, whereas Broca’s area was active during a reading task.
- Language may not be localised to just Wernicke’s and Broca’s area:
Dick & Tremblay, only 2% of modern researchers think language is completely controlled by W and B area. Advances in tech such as fMRI mean we can study the brain in more clarity, and it seems language is distributed more holistically than first thought. - a study where 10-50% of cortex in rats- no area was proven to be more important than others when learning the route through a maze
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.
We can say that language is _____ as it is performed by one hemisphere rather than the other
Lateralised
The right hemisphere (RH) can contribute to emotional context so is known as ______ and LH is ______
RH- synthesiser
LH- analyser
What areas are not lateralised (appear in both hemispheres)?
Vision, motor, somatosensory
The motor area in the brain is cross-wired, what does this mean?
RH controls left hand side movements and vice versa.
Vision is contralateral and ipsilateral, what does this mean?
opposite and same sided.
Explain the visual area with regards to how the hemispheres process it.
-Eyes receive light from from both left and right fields of vision (LVF & RVF)
-LVF is connected to right hemisphere
-RVF is connected to left hemisphere
Evaluate ‘Hemispheric Lateralisation’
+ Fink et al. used PET scans to identify what areas of the brain were active when doing a visual processing task. P’s with connected brains, asked to look at whole elements of image= RH more active, look at finer details= LH more active.
- Idea of LH as an analyser and RH as a synthesiser may be wrong:
Nielsen et al. analysed brain scans from over 1000 , 7-29 yr olds, found they did use different sides for different tasks, but not a dominant side.
What is ‘Split brain research’?
A series of studies involving people with epilepsy who had experienced a surgical separation of the hemispheres of the brain to reduce the severity of their epilepsy- enabled researchers to test lateral functions of the brain in isolation.
Outline Sperry’s Research
Devised a system to study how separated hemispheres deal with speech and vision.
-11 people who had a split-brain operation were studied using a set up in which an image could be projected to a participants RVF, and then the same for the LVF. In the normal brain the corpus callosum would share the info between both hemispheres creating a full image, but for a split-brain participant it could not be conveyed from one hemisphere to the other.
-Picture of object was shown to p’s RVF, p could describe what they could see, but could not do this if object was shown to LVF as in a split-brain, these language centres cannot be relayed between hemispheres.
-If a pinup picture was shown to LVF there was an emotional reaction (giggle) but p’s reported they could not see anything.
Conclusion: Show how certain functions are lateralised in the brain and support the view that the LH is verbal and RH is ‘silent’ but emotional.
Evaluate the ‘Split-brain’ research
+ Research support:
Luck et al. showed split-brain p’s actually perform better than connected on some tasks. e.g faster at identifying odd one out in an array of objects. In normal brain, LH better cognitive strategies are ‘watered down’ by the inferior RH.
- Casual relationships are hard to establish:
Behaviour of the split-brain p’s were compared to a neurotypical control group, yet none of these had epilepsy, so a major confounding variable. Any unique features to split-brain p’s may be due to their epilepsy.
Define brain ‘Plasticity’
Describes the brain’s tendency to change and adapt as a result of experience and new learning- generally involves the growth of new connections.
Describe the research in to ‘Plasticity’
Maguire et al. studied brains of London taxi drivers, found significantly more grey matter in the posterior hippocampus than in a control group. This part of the brain is associated with development of spatial and navigational skills. Having to learn all streets in London alters their brain structure, and was more pronounced the longer they had been doing it.
Draganski et al. imaged brains of medical students 3 months before exams and after. Learning-induced changes were found in the posterior hippocampus and parietal cortex.
Evaluate brain ‘Plasticity’
- May have negative behavioural consequences: brains adaptation to prolonged drug use leads to poorer cognitive function, increased risk of dementia. Also, 60-80% of amputees develop phantom limb syndrome, they feel intense pain where the limb would be- brains ability to adapt is not always beneficial.
+ May be a life-long ability:
In general plasticity reduces with age, but Bezzola et al. used fMRI, showed 40 hours of golf training produced changes in neural representations of movement in p’s aged 40-60. Observed reduced motor cortex activity in novice golfers compared to control group.
What is ‘Functional Recovery’?
A form of plasticity- following damage through trauma, the brains ability to redistribute or transfer functions usually performed by damaged areas to other undamaged areas.
What happens to the brain during functional recovery?
Able to rewire itself by forming new synaptic connections close to the area of damage.
Structural changes:
-Axonal sprouting
-Denervation supersensitivity
-Recruitment of homologous areas
What is ‘Axonal sprouting’ in functional recovery?
The growth of new nerve endings which connect with other undamaged nerve cells to form new neuronal pathways.
What is ‘Denervation Supersensitivity’ in functional recovery?
Axons that do a similar job become aroused to a higher level to compensate for the ones that are lost
What is ‘Recruitment of homologous areas’ in functional recovery?
On the opposite side of the brain, carries out the function- specific tasks can still be performed
Evaluate ‘Functional recovery’
+ Real world application:
contributed to the field of neurorehabilitation. Axonal growth encourages new therapies to be tried
- Level of education may influence recovery rates:
Schneider et al. found the more time people spent in education, the greater their chances of disability-free recovery (DFR). 40% who achieved DFR spent more than 16 yrs in education compared to 10% who had less than 12 yrs.
Define fMRI and its use
Functional Magnetic Resonance Imaging:
used to measure brain activity while a person is performing a task. Detects radio waves from changing magnetic fields which enables researchers to detect regions of the brain that are rich in O2, thus active.
Describe the fMRI
Detects changes in blood O2 levels, and when a brain is more active it consumes more O2.
fMRI produces a 3D image showing parts of the brain involved in particular mental processes.
Evaluate fMRI
+ Does not rely on radiation, so risk-free
+ Produces images with high spatial resolution
- Expensive in comparison to other techniques
- Poor temporal resolution, a 5 sec time lag.
Define what an EEG is
Electroencephalogram:
records tiny electrical impulses produced by brain activity. By measuring characteristic wave patterns, EEG can help diagnose certain conditions in the brain.
Describe how EEGs work
Measure electrical impulses via electrodes fixed to scalp using a skull cap- shows brainwave patterns generated by neurons.
Evaluate EEGs
+ Useful in studying sleep
+ Diagnose conditions such as epilepsy
+ High temporal resolution
- Generalised nature, not useful in pinpointing the exact source of neural activity.
Define what ERPs are
Event-related potentials:
The electrophysiological response of the brain to a specific sensory, cognitive, or motor event can be isolated through statistical analysis of EEG data.
Describe how ERPs work
ERPs are types of brainwave that are triggered by a certain event. They take the statistical data of EEGs and isolate certain responses, filtering out any extraneous responses.
Evaluate ERPs
+ Bring more specificity to measurement of neural processes
+ High temporal resolution as based off EEGs
- Lack of standardisation in ERP methodology between research studies
- In order to establish pure data, background noise and extraneous variables must be eliminated, hard to do
Define ‘Post-mortem examinations’
Brain is analysed after death to determine whether certain observed behaviours during the persons lifetime can be linked to structural abnormalities in the brain.
How do post-mortem examinations work?
Areas of damage within the brain are examined to establish a likely cause of the affliction.
Evaluate Post-mortem examinations
+ Vital for providing early understanding of key processes in brain e.g Broca and Wernicke
+ Used to study damage in HMs brain
- Ethical issues of consent
- Observed damage may not be linked to deficits but to other unrelated trauma.
Define Biological rhythms
Distinct patterns of changes in the body activity that conform to cyclical time periods.
Influenced by internal body clocks as well as external changes to environment.
Define Circadian Rhythms
Biological rhythms subject to a 24-hour cycle, which regulate a number of body processes such as the sleep/wake cycle and changes in the core body temp.
What are the body’s internal biological ‘Clocks’?
Endogenous pacemakers
What are the external changes in the environment called?
Exogenous zeitgebers
Explain the sleep/wake cycle
Governed by an internal pacemaker (endogenous), a biological clock called the suprachiasmatic nucleus (SCN) which lies just above the optic chiasm, providing info from the eye about light. Light can reset the SCN (exogenous).
Describe Siffre’s cave study
Spent several extended periods underground to study the effects of his own biological rhythms, deprived of light and sound. He resurfaced in mid-September after 2 months believing it to be mid-August.
Then repeated years later for 6 months.
His ‘free running’ biological rhythm settled to around 25 hours not 24, but did have a regular sleep/wake schedule, due to lack of external cues.
Describe other research into circadian rhythms (not Siffre)
- Group spent 4 weeks in a WW2 bunker, no light. All but 1 of P’s displayed a circadian rhythm between 24 and 25 hours: supports exogenous zeitgebers entraining internal clock.
- Group of 12 lived in dark cave for 3 weeks, going to bed at 11.45pm and waking at 7.45am. Researchers gradually sped up the clocks until the day actually was only 22 hours. Only 1 participant could comfortably adjust to the new regime, circadian rhythm is not easily over-run by exogenous zeitgebers.
Evaluate Circadian Rhythms
+ Provides an understanding of consequences that occur when they are disrupted, such as shift work. Night workers have reduced concentration at about 6am, and is linked to poor health e.g heart disease.
+ Used to improve medical treatments: they coordinate body processes, so more knowledge means we can administer medicine in correspondence to bio rhythms to increase effectiveness.
- Generalisations are difficult to make: studies are only on a small sample and sleep/wake cycles may vary from person to person. Studies have found cycles vary from 13-65 hours and may change with age.
- Investigating sift work uses correlational methods, so difficult to establish cause and effect.
Define Infradian Rhythms
A type of biological rhythm with a frequency of less than one cycle in 24 hours such as menstruation and seasonal affective disorder.
Define Ultradian Rhythms
A type of biological rhythm with a frequency of more than one cycle in 24 hours, such as the stages of sleep.
Briefly explain the menstrual cycle (Infradian rhythm)
-Normally 28 days
-Rising of hormone levels of oestrogen cause ovary to develop an egg and release.
-Progesterone helps womb lining to thicken.
-If egg is not absorbed into body, womb lining comes away and leaves body.
Describe the study on synchronising menstrual cycles
Evidence suggests that the cycle can be influenced by exogenous factors:
Stern & McClintock- 29 women with a history of irregular periods. Pheromones were gathered from 9 of the women at different stages of cycle via a cotton pad in armpit. They were then treated by freezing with alcohol, then rubbed on the upper lip of P’s.
68% of women experienced changes to their cycle which brought them closer to the cycle of their ‘odour donor’.
Explain Seasonal Affective Disorder with regards to infradian rhythms
SAD is a depressive disorder with a seasonal pattern.
-Depression, low mood and activity
-Triggered by lack of daylight hours
-Particular type of infradian rhythm called circannual rhythm as it is a yearly cycle.
-Can also be classed as a circadian rhythm as it may be due to disruption of sleep wake cycle.
-Hypothesised that hormone melatonin is implicated as is produced during darkness hours, has a knock on effect to serotonin.
Evaluate Infradian Rhythms
+ Menstrual synchrony research is explained by natural selection: for distant ancestors it may have been advantages to menstruate at the same time, have babies together, access to breast milk if mother died- adaptive.
- Methodological Limitations: Many factors contribute to menstruation cycles such as stress, diet, exercise, which may be confounding variables- so synchronisation may occur by chance. Other researchers failed to replicate findings.
+ Real world application for light therapy in SAD treatment to reset internal body clock. Reduces effects of SAD in 80% of people.
Briefly outline stages of sleep as an ultradian rhythm
5 stages that span 90 mins, each characterised by a different level of brainwave activity, monitored by ECG.
Stages 1&2 : Light sleep, easily woken. Stage 1, brain waves have high frequency and short amplitude, alpha waves. In stage 2, alpha waves continue, but random changes in pattern called ‘sleep spindles’.
Stages 3&4 : Deep sleep or slow wave sleep. Brain waves are delta waves with a lower frequency and higher amplitude. Harder to wake someone.
Stage 5 (REM): Body is paralysed yet brain activity closely resembles an awake brain. Brain produces theta waves and eyes may move around, rapid eye movement (REM) where dreams most often occur, but can also occur in deep sleep.
Evaluate Ultradian rhythms
+ Improved understanding of age related changes in sleep: scientists have observed slow wave sleep reduces with age, where the growth hormone is normally produced. May explain issues in older people such as reduced alertness.
- Significant variation between people:
Tucker et al. found large differences between P’s in terms of the duration of each stage, biologically determined.
What are ‘Endogenous Pacemakers’?
Internal body clocks that regulate many of our biological rhythms, such as the influence of the suprachiasmatic nucleus (SCN) on the sleep/wake cycle.
What are ‘Exogenous Zeitgebers’?
External factors that affect or entrain our biological rhythms, such as the influence of light on the sleep/wake cycle.
Define the ‘Sleep/wake cycle’
A daily cycle of biological activity based on a 24-hour period (circadian rhythm) that is influenced by regular variations in the environment, such as the alternation of night and day.
Explain the ‘suprachiasmatic nucleus’
-Tiny bundle of nerve cells located in the hypothalamus in each hemisphere in the brain
-Primary endogenous pacemakers and is influential in maintaining circadian rhythms.
-SCN lies just above the optic chiasm and receives info about light from this structure.
Describe the animal study into SCN
DeCoursey et al. destroyed the SCN connections in the brains of 30 chipmunks who were then observed in their natural habitats for 80 days.
-Sleep/wake cycle disappeared by the end, and a significant proportion had been killed.
Ralph et al. bred mutant hamsters with a 20 sleep/wake cycle, SCN cells from mutants were transplanted into brains of normal hamsters, cycles defaulted to 20 hrs.
Discuss the pineal gland and melatonin in relation to endogenous pacemakers
SCN passes info about day length and light to pineal gland, which increases production of melatonin during night- this induces sleep.
Evaluate endogenous pacemakers
- May obscure other body clocks: research shows that circadian rhythms are found in many different organs and cells that are influenced by the SCN, but also act independently. A study where the feeding patterns of mice was changed showed the the circadian rhythm of liver cells became 12 hrs, but SCN did not change.
- Cannot be studied in isolation: in everyday life pacemakers and zeitgebers interact so makes little sense to separate for research, lacks validity.
- Ethics: most chipmunks died.
+ Animals used have similar mechanisms to humans so can generalise to an extent.
What is entrainment?
Process by which external factors in the environment reset biological clocks.
Discuss light as a zeitgeber, and the study
-Can reset the SCN
-Has an influence on hormone secretion and blood circulation.
Campbell and Murphy- light may be detected by skin receptors, 15 p’s were woken at various times and a light was shone at the back of their knees, sleep/cycle was deviated up to 3 hours in some cases.
Discuss social cues as a zeitgeber
A newborns sleep/wake cycle is pretty random- by 16 weeks, their circadian rhythm has been entrained by parents schedules.
Evaluate exogenous zeitgebers
- Do not have the same effect in all environments: people who live in the arctic circle have the same sleep pattern all year round yet live in darkness for 6 months- therefore must be primarily controlled by pacemakers.
- challenging evidence:
Miles et al. study of man blind from birth with an unusual circadian rhythm of 24.9 hours, and despite social cues, it was not adjusted.
Evaluate the fight or flight response
- FFR can have negative impact on health in modern times: used to be adaptive for stressors such as predators, giving more energy, but now we have stress such as exams where we don’t need them responses, can cause increased blood pressure
+Suffers beta bias: FFR does not include women, research found that i stressful times, women protect themselves by protecting and nurturing the young or forming alliances with others
What are the 2 neural networks involved in brain plasticity?
Pruning- where connections are lost due to lack of use
Bridging- where new connections are created due to use and new stimulus
