Biopsychology

What does the cell body of a neurone do?

Includes nucleus containing DNA which controls the cell

What do dendrites do?

Protrude from cell body, carry in impulses from neighbouring neurones

What does the axon do?

Carried impulses away from the cell body, down the neurone

What does the myelin sheath do?

Protects and speeds up electrical transmission

What do Nodes of Ranvier do?

Force the impulse to jump between Schwann cells, speeding up transmission

Where do sensory neurones carry information to and from?

From receptor to CNS

Where do motor neurones carry information to and from?

From CNS to effector

In what division of the nervous system are sensory neurones found?

Peripheral

Where are relay neurones found?

CNS

What is a synapse?

A small space between neurones

What is a neurotransmitter?

A molecule that transmits the electrical impulse across the synapse chemically

Describe the stages of synaptic transmission

1. Action potential reaches end of axon

2. Vesicles move towards synapse and release neurotransmitters

3. Neurotransmitters bind to receptor sites on post-synaptic neurone which triggers it

4. Neurotransmitters are reabsorbed into pre-synaptic neurone

What is excitation?

Makes post-synaptic neurone more positively charged so next neurone more likely to fire

What is inhibition?

Makes post-synaptic neurone more negatively charged so it is less likely to fire

What is the CNS made up of?

brain and spinal cord

What are the two divisions of the nervous system?

central nervous system and peripheral nervous system

What is the peripheral nervous system split into?

somatic and autonomic nervous system

What is the autonomic nervous system split into?

sympathetic and parasympathetic

What does the brain do?

The centre of all conscious awareness, complex mental functions

What does the spinal cord do?

transmits information to and from the brain

What does the peripheral nervous system do?

transmits information to and from the central nervous system

What does the autonomic nervous system do?

controls involuntary actions

What does the sympathetic nervous system do?

Fight or flight response

What does the parasympathetic nervous system do?

Rest and digest

What does the somatic nervous system do?

Voluntary muscle movement

Give examples of what bodily processes change when sympathetic nervous system is activated

Digestion inhibited (directing blood flow to muscle), HR increases, inhibits saliva productions, stimulates glucose production, pupils dilate, bronchi dilate

Give examples of what bodily processes change when parasympathetic nervous system is activated

Increased digestion and saliva production, HR decreases, bile production stimulated, pupils and bronchi constrict

What is the endocrine system?

the body's "slow" chemical communication system; a set of glands that secrete hormones into the bloodstream

What does the pituitary gland do?

Coordinates endocrine system

What do the testes do?

Secrete testosterone, male growth hormone linked to aggression and puberty

What does the adrenal gland do?

Releases adrenaline and cortisol

What do the ovaries do?

Release estrogen and progesterone stimulating menstruation

Describe the fight or flight response

Stimulus seen, hypothalamus activates pituitary gland, activating sympathetic NS, adrenaline released into blood stopping digestion and increasing HR

What happens when the feared stimulus leaves after fight or flight response?

Parasympathetic NS activated for rest and digest

Give some physiological changes brought about by adrenaline during fight or flight response

Raised heart rate + blood pressure, raised blood glucose, airways open, pupils dilate, digestion inhibited

Evaluate the fight or flight response

-ve - most research done on males - females tend to take a more ‘tend and befriend’ response - this is an evolutionary advantage as FoF by females threatens survival of their offspring - androcentric

-ve - most research done on animals when have an actual threat to lives, not just psychological panic experienced by humans - cannot compare experiences

+ve - based on biological, objective research

What does localisation mean?

Particular areas of the brain carry out specific functions

Which scientists argued for localisation?

Broca and Wernicke

How did scientists originally think the brain worked?

Holistic theory = all areas involved in all thoughts and actions

What does lateralisation mean?

Some functions are only found in one hemisphere

Give an example of a function that is lateralised on the brain

Language only found in left hemisphere

What is the cerebral cortex?

The outer wrinkly layer of the brain, controls consciousness, memory and language

What are the four lobes of the brain called?

Frontal, temporal, parietal, occipital

What does the auditory area do?

analyses speech based information

What does Broca's area do?

Speech production

Which hemisphere are Broca's and Wernicke's found in?

Left

What does the motor area do?

controls voluntary movement

What does the somatosensory area do?

processes sensory information from the skin

What does the visual area do?

receives and processes visual information

What does Wernicke's area do?

Speech comprehension

What happens when Broca's area is damaged?

Broca's aphasia - slow, laborious speech lacking in fluency

What happens when the motor area is damaged?

Loss of fine movements

What happens when the somatosensory area is damaged?

Loss of sense of touch, pain and heat

What happens when visual area is damaged?

Damage to left hemisphere will mean loss of sight in right visual field and vice versa

What happens when Wernicke's area is damaged?

Wernicke's aphasia - fluent but meaningless speech

What are 4 evaluations of localisation?

Brain scans, neurosurgical evidence, Phineas Gage case study, plasticity

Localisation evaluation - brain scans

Peterson (1988) - Wernicke’s active during listening and Broca’s during reading - objective + scientific

BUT may be reductionist - <2% of researchers believe speech is completely controlled by B + W

Localisation evaluation - Phineas Gage case study

Suffered injury to frontal lobe during dynamite explosion, become v aggressive + lost rationality

BUT change in personality may due to years of pain + case study is not scientific as individual circumstances

Localisation evaluation - neurosurgical evidence

Dougherty (2002) - studied 44 OCD patients who had undergone cingulotomy - 32 weeks after 1/3 had responded successfully (so OCD may reside in the brain for them)

BUT reductionist as for other 2/3, OCD could be cognitive, genetics, environmental factors - complex disorder reduced to one area of brain

Localisation evaluation - plasticity

Suggests that brain constantly changes due to experience - Gabby Giffords case study - Broca’s aphasia BUT regained speech, suggesting functions are localised at first but plasticity allows brain to regain functions through repair

What area in the brain may be implicated in OCD?

Cingulate gyrus

What does plasticity mean?

Brain changes with experiences and new learning

What did Maguire’s research suggest overall?

Spatial awareness is localised to posterior hippocampus

Describe Maguire (2000) study

Right-handed male London taxi drivers, MRI scans, posterior hippocampi was significantly larger so may be used for spatial memory

In what ways does the brain recover after trauma?

Axonal sprouting, denervation supersensitivity, recruitment of homologous areas

What is axonal sprouting?

growth of new nerve endings - either in replacement or around damaged nerves

What is denervation supersensitivity?

Axons that do similar jobs become more aroused to compensate for those that are lost

What is recruitment of homologous areas?

Equivalent area in other hemisphere may take over function when area damaged

What are 3 evaluations of plasticity?

Practical applications, negative effects of plasticity, Maguire (2000)

Plasticity evaluation - practical applications

Understanding plasticity led to development of neurorehabilitation

Counters negative effects and deficits in motor and cognitive functions by electrical stimulation of the brain

Can lead to recovery of functions

Plasticity evaluation - negative effects of plasticity

Phantom limb syndrome - continued sensation in missing limb, often painful - area still present grows over lost area so feeling is activated

Shows that brain is able to change over time

what surgery did split brain patients undergo?

Commissurotomy - the corpus callous is cut meaning the connections between the 2 hemispheres were severed

What is split brain surgery used to treat?

Epilepsy

What is hemispheric lateralisation?

Some functions are only found in one hemisphere

Why are split brain patients useful for researchers?

Researchers can see the extent that hemispheres are specialised for certain functions as there is no overlaps between the two

Describe the procedure Sperry used to study split brain patients

• 11 split brain patients

• image/word projected for 0.1 seconds to either left or right visual field

• Information won’t be conveyed to both hemispheres as corpus callosum cut

What were Sperry’s (split brain patient) findings?

• when shown to left visual field, patient could not describe it (said there was nothing there)

• found that language is only in the left hemisphere

What did the researchers who studied split brain patients conclude?

Certain functions are lateralised in the brain

• left hemisphere is verbal, logical and deals with calculations

• Right hemisphere is ‘silent’ but emotional - synthesises information

Evaluate split brain research - strength

Sperry’s ingenious method - highly specialised and standardised procedure, didn’t allow other hemisphere to pick up image/word, won Nobel Prize

Evaluate split brain research - limitations

Generalisation issues - Sperry uses neurotypical control group, so difficult to know if difference in brain function due to epilepsy for having a split brain

Some lateralisation in ‘normal’ brains - right brain does holistic thinking, left focuses on finer details

Define circadian rhythm

Biological cycle lasting 24 hours

Describe Siffre’s cave study - procedure

Spent 2 months in darkness without natural light (eliminated light as an exogenous zeitgeber)

Describe Siffre’s cave study - findings

Sleep-wake cycle extended to 25 hours, so he emerged after what he thought was 2 months but actually 3 months

Even without light his biological clock kept a steady rhythm (evidence for SCN)

Evaluate circadian rhythms - shift work

Has shown that desynchronisation can lead to serious consequences

Shift workers most likely to make mistakes at 6am, so accidents most likely at this time

Economic implications

Evaluate circadian rhythms - chronotherapeutics

Taking meds at specific time of day to optimise its effects eg, aspirin taken at night as most heart attacks occur in morning

Crucial in effectively treating diseases

Define infradian rhythm

A biological cycle lasting more than 1 day but less than a year

Give examples of infradian rhythms

Menstrual cycle, seasonal affective disorder

Describe seasonal affective disorder

A depressive condition that occurs in winter months due to lack of serotonin due to increases melatonin production

Evaluate infradian rhythms - application of SAD

Phototherapy - strong lights (10,000 lux) used in evening and/or morning

SAD sufferers report that daily use is enough to relieve them of lethargy and depression

Evaluate infradian rhythms - Russell et al (1980) - menstrual cycle opposition

Challenges assumption that the female menstrual cycle is purely controlled by an endogenous infradian rhythm

• daily sweat samples taken from one group of women and applied to another on upper lip

• found menstrual cycles synchronised with individual donors of sweat despite being kept separated

• cycle affected by pheromones, an exogenous factor

Define ultradian rhythm

A biological cycle lasting less than 24 hours

Give an example of an ultradian rhythm

Stages of sleep

Give the stages of sleep

1-4 and REM

Describe the different stages of sleep

Brainwave activity decreases from 1-4 but then becomes highly active during REM

Evaluate ultradian rhythms - Dement and Kleitman

monitored 9 participants in sleep lab, brainwave activity recorded using EEGs

REM sleep highly correlated with dreaming - when woken during REM, participants reported accurate recall of their dreams

Suggests REM is an important and distinct sleep cycle

Define endogenous pacemaker

Biological ‘clocks’ in the brain that control biological rhythms

Describe the main endogenous pacemaker and the effect light has on it

Suprachiasmatic nucleus - found in hypothalamus

SCN receives information from light via the optic nerve, will stop producing melatonin (which is the sleep hormone)

Where is melatonin produced from?

Pineal gland

Which exogenous zeitgeber has an effect on the sleep/wake cycle?

Light