Biopsychology studies

Localisation of language

Broca

Case study of French man who could only say the word ‘tan’. He could understand speech easily. When he died, Broca performed an autopsy of Tan’s brain and identified an area of damage in the left frontal lobe. Later reported 25 similar cases and concluded that the area (Broca’s area) is responsible for speech production

Wernicke

Studied patients who could not understand speech and failed to follow instructions but could produce fluent speech (though often bizarre and nonsensical). Autopsy findings showed they had all damaged area in left hemisphere at top of temporal lobe (Wernicke’s area) which is responsible for comprehension of language

Link between damage to brain areas and mental disorders

Dougherty

Reported on 44 people with OCD who had undergone a cingulotomy. At post-surgical follow-up after 32 weeks, about 30% had met criteria for successful response to surgery and 14% for partial response

Everyday brain functions are localised

Peterson

Used brain scans to demonstrate how Wernicke’s area was active during a listening task and Broca’s during a reading task

Tulving

Revealed that semantic and episodic memories reside in different parts of the prefrontal cortex

Opposing localisation of function

Lashley

Removed parts of rats’ cortex. Found their cortex’s importance in their ability to learn the route of a maze. Their process of learning seemed to require every part of the cortex rather than being confined to a particular area

Language not only localised to Broca’s/Wernicke’s areas

Dick and Tremblay

Found that only 2% of modern researchers think that language in the brain is completely controlled by these areas. Brain imaging techniques suggest that language function is distributed more holistically in the brain than first thought. Language also identified across cortex including subcortical regions in right hemisphere like the thalamus

Split-brain research

Sperry

Studied 11 people whose 2 brain hemispheres were disconnected through surgery cutting their corpus collosum. Used the divided field, had to sit and stare straight ahead at a screen. Images or words would be shown in a patient’s right visual field (processed by left hemisphere) or left visual field (processed by right hemisphere). Then asked to respond in some way (reading word, drawing image).

Found that they could read words or images shown in RVF but not in LVF. Concluded this is because things in RVF processed in left hemisphere where language centres are located

Important not to simplify hemispheric lateralisation

Turk

Reported on a patient called JW who damaged his left hemisphere but developed the ability to speak using his right hemisphere. Eventually he was able to talk confidently about info shown to both visual fields. Suggests hemispheric lateralisation is not fixed and can adapt

Plasticity

Maguire

Studied brains of taxi drivers before and after they sat ‘the Knowledge’. Found the volume of grey matter was larger in their posterior hippocampus compared to a match control group - associated with spatial and navigational skills.

Support for Maguire study

Draganski

Studied medical students for 3 months - before and after their med exams. Found differences in hippocampus and parietal cortex due to the demands of revision

Plasticity does not always decline with age

Bezzola

Demonstrated how 40 hrs of golf training produced changes in the neural representations of movements in ppts aged 40-60. Using fMRI, observed increased motor cortex activity in novice golfers compared to a control group

Functional recovery much better in younger patients

Danelli

Case study of Italian boy EB who had most of his right hemisphere removed at 2.5 to remove a tumour. With intensive therapy, his right hemisphere was able to take over left hemisphere functions like language. By 5, his language abilities had largely recovered. By 17, there was only minor errors in functioning

Education affects functional recovery

Schneider

Found that the longer brain injury patients had been in education, the greater their chances of making a full recovery. 40% of those who had 16+ years in education made a better recovery compared to 10% of patients who had less than 12 yrs

Functional recovery quicker in women

Ratcliffe

Studied 325 16-45 year old brain injury victims before and after 1 year of rehab. Overall women showed better cognitive skill recovery (did vary across different cognitive skills)

Sleep-wake cycle

Siffre

Spent extended periods in a cave to remove himself from exogenous zeitgeist’s that would ordinarily help regulate the sleep-wake cycle. He found that his free-running biological rhythm was 25 hours but continued to fall asleep and wake up on a regular schedule. Shows endogenous pacemakers are main influences on cycle but exogenous zeitgebers are needed to keep exactly 24 hours

Difficult to make generalisations about circadian rhythms

Czeisler

Found individual differences in sleep/wake cycles varying from 13-65 hours.

Duffy

Revealed that some people have a natural preference for going to bed and waking up early (larks), and others prefer going to bed and waking up late (owls)

Menstrual cycle (infradian rhythms)

McClintok

Asked 135 college girls in dormitories to recall their period start dates at 3 times throughout the academic year. Found that close friend groups had periods closer together in April compared with October - lessening from average of 6.4 to 4.6 days apart

SCN - endogenous pacemakers

DeCoursey

Destroyed the SCN connections in 30 chipmunk brains who then returned to natural habitat and observed for 80 days. Their sleep/wake cycle disappeared so a lot of them were killed by predators as they were awake and vulnerable at the wrong times)

Light - exogenous zeitgebers

Campbell and Murphy

Demonstrated that light may be detected by skin receptor sites on the body even when not received by the eyes. 15 ppts were woken at various times and had a light pad shone on the back of their knees. Produced a deviation in their sleep/wake cycle of up to 3 hrs

Other body clocks vs SCN

Damiola

Demonstrated how changing feeding patterns in mice could alter the circadian rhythms of cells in the liver by up to 12 hours, while leaving the rhythm of the SCN unaffected