The Brain

Question 1

Localisation of function and brain lobes

Answer 1

Functions have specific locations in brain
Hemispheric lateralisation (left controls right and vice versa) and functions split between brain lobes
Frontal lobe at front, occipital lobe at back, parietal between frontal and occipital (top half), temporal below parietal, brain stem thin below temporal and cerebellum between occipital and brain stem

Question 2

Cortex + locations

Answer 2

Motor - frontal lobe of both hemispheres. voluntary movements with logical arrangement of sections based on parts controlled - damage can lead to muscle dysfunction/ paralysis
Somatosensory - parietal lobe of both hemispheres - processes sensations like pain and pressure
Visual - occipital lobe both sides - processing of colour and form starts in retina after light strikes photoreceptors - impulses travel via optic nerve then thalamus relays to visual cortex
Auditory cortex - temporal lobes of both hemispheres - process pitch and volume - starts at cochlea in inner ear w converts to nerve impulses sent via auditory nerve to cortex - decoding occurs in brain stem

Question 3

Language areas

Answer 3

Brocas area in left hemisphere frontal lobe -lEsions causes expressive aphasia - affects language production not understanding so e.g grammatically incorrect sentences e.g no ‘it’ or ‘the’
Wernickes area also in left but temporal lobe -lesion in area unable to understand language but produce fine - receptive aphasia so can’t process/understand language and say grammatical sentences but they don’t make sense

Question 4

Localisation of function eval

Answer 4

+ Link brain issues to behavioural e.g meg to W/B area
- Some functions more localised than others - higher functions like personality and language too complex to be assigned, but can be broken into sectors e.g B/W area for language
-Equipotentiality theory - intact cortex areas can take over some functions of damaged areas
- Re mri scans of 2 Broca patients Lesions to broca’s area cause temporary speech disruption but not severe - so less localised than thought
- Could be more important how brain areas communicate with each other - one could not read due to bad comms between visual cortex and Wernicke
- individual differences of brain functions - during silent reading activity in frontal, temporal and occipital so many possibilities

Question 5

Hemispheric lateralisation

Answer 5

Certain functions principally governed by one side of brain.
Right hemisphere dominant for visio spatial functions and facial recognition
Left hemisphere dominant for language (and has the B/W regions)
Right hemisphere controls left body and vice versa
Hemisphere connected by nerve fibre bundle called corpus callosum - info can be communicated between
2 hemispheres work together to do most tasks as an integrated system

Question 6

Hemispheric lateralisation eval

Answer 6

+ Makes sense from evolutionary as more neural processing capacity so adaptive - allows multitasking e.g finding food while vigilant for predators
- Lateralisation shifts with age - less lateralisation in healthy adulthood
+ Extensive left hemisphere damage causes global aphasia - loss of speech production + comprehension) - so language lateralised to left
- Some ppl able to speak with right hemisphere when items shown in left visual field so not fully lateralised (split brain patient)
- One hemisphere can compensate for other - EB had left side mostly removed at 2, but his language and grammar seem sound, but some subtle grammar errors and struggles with loan words - so right side alone pretty good but cannot be perfect

Question 7

Split brain research

Answer 7

people who had corpus callosum cut to stop electrical activity from seizures crossing between hemisphere
when info presented in left visual field they can draw a picture with left hand but can’t say what they saw as the info is in right hemisphere
when info in right visual field they can say what they see and answer with the right hand as info in left hemisphere

Question 8

Split brain research eval

Answer 8

+ Controlled and specific experiments
- Disconnection between hemispheres greater in some than others
- Some patients had drug therapy for longer than others - participant variables
- Invalid samples with no history of epileptic seizures
- Very small sample study sizes so hard to generalise
- Artificial research, in real life severed corpus callosum can be compensated by unrestricted use of both visual fields - so lacks ecological validity

Question 9

Post Mortem Examinations

Answer 9

Look for abnormalities after death to explain behaviour - compare to neurotypical brains - linked to disorders e.g less glial cells in frontal lobe linked to depression
+Can examine deeper areas like hippocampus
- Lacks validity due to confounding variables like length after death, drug treatment, stages of disease
- Small sample size as special permission needed so hard to generalise
+ Used e.g to connect language and brain by Brocas and Wernicke area

Question 10

fMRI

Answer 10

Indirectly measures neural activity with magnetic fields and radio waves to monitor blood flow (which is extended to neural activity) - change of energy release by haemoglobin (lie oxygen) to show moving brain picture - regions compared to control to assess activity levels during tasks
+ dynamic measurement of activity
Good spatial resolution
-Poor temporal resolution so hard to interpret as shows an overall change
- Very expensive so small hard to generalise samples

Question 11

EEG

Answer 11

Electroencephalogram - directly measures general neural activity e.g sleep and arousal
Electrodes placed directly above areas of focus and used to graph electric waves. Epilepsy shows spikes of activity while brain injury shows slowing of activity
+ Useful for clinical diagnoses
+ Cheaper than fMRI
- Poor spatial resolution

Question 12

ERPs

Answer 12

Event related potential - directly measures neural activity to a specific stimulus introduced by researcher - hard to pick out the potentials between other activity, so averaged out through multiple presentations as extraneous non stimulus activity won’t be as
+ Measures processing without clear behavioural response so can observe covertly
+ Cheaper than fMRI so more widely used
+ Good temporal resolution
- Bad spatial resolution
- Only detects strong enough voltages in the neocortex - misses important activity deeper in brain

Question 13

Brain plasticity

Answer 13

Modify the structure and function based on experience - e.g to cope from indirect effects of brain damage or e.g inadequate blood supply from stroke. Maybe synaptic pruning and shrink/ growth of areas based on usage
+ More grey matter in hippocampus, visual cortex and cerebellum in brain after ppl played vid games 30mins a day for 2 month
+ Buddhist monks who meditate frequently have greater gamma wave activation permanently (which coordinate neural activity) than students with no experience
+ Volume of posterior hippocampus positively correlated in taxi drivers and time as a driver, and much larger than a control group

Question 14

Functional recovery

Answer 14

Example of plasticity where recovers abilities previously lots by damage
Neuronal unmasking - dormant synapses activated to compensate- axon sprouting when axons grow nerve endings to reconnect severed links, reformation of blood vessels to facilitate new pathway growth and recruitment of homologous areas (intact hemisphere tales over damaged functions)
Neural reorganisation - transfer of functions for damaged to underaged areas
Neural regeneration - new neurons grow/ connections to compensate for damaged areasRecovery higher for educated (uni level) people, younger people, women, those who receive therapy on the side
Spontaneous recovery limited and may slow down so treatment may be required to maintain improvements

Question 15

Functional recovery eval

Answer 15

+Practical applications to neurohabilitation - understanding helps develop
techniques like motor therapy and electrical stimulation to counter motor and cognitive deficits following injury
- Variable factors affect recovery so hard to generalise case studies and not fully passive - going to uni provides cognitive reserve, children have higher capacity for neural reorganisation, women more likely to recover from brain injuries, exhaustion/stress/alcohol reduce functional recovery