biopsychology statistics

roughly how long is the spinal cord?

40cm

approximately how many neurons are there in the nervous system?

100 billion

size of a neuron

width- 4 micrometers-100 micrometers

length- few mms- 1 meter

how thick is the cerebral cortex?

3mm

what did Paul Broca do?

Paul Broca performed a post-mortem on a patient (known as Tan as this was the only word he could produce) with severe speech production issues and found extensive damage to the left frontal lobe. This led to the discovery of Broca’s area

what did Carl Werncike do?

Carl Wernicke found that patients who had damage in the area close to the auditory cortex in the left temporal lobe struggled comprehend language and locate words. This led to the discovery of Wernicke’s area

what did Peterson et al do and find?

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

• These findings support a theory of localisation as they show specific areas of the brain having specific and different functions

how many OCD patients did Dougherty use?

44

what did Dougherty do?

lesioned the cingulate gyrus of 44 OCD patients

what did Dougherty find?

1/3 of patients significantly imrpoved and a further 14% showed partial improvement- suggests OCD is localised

what proportion of patients significantly improved in Dougherty’s study?

1/3

what percentage of patients partially improved in Dougherty’s study?

14%

case study of Clive Wearing

• damage to hippocampus due to viral infection caused damage to his semantic long term memeory but not to his procedural memory

• This suggests localisation because if the function was spread throughout the entire brain there would not be specific deficits in this way.

  • HOWEVER- he could still remember specific facts- holistic?

what percentage of the rats’ cortex did Lashley remove

10-50%

what did Lashley do and find?

• Lashley removed between 10-50% of areas in the rats’ cortex

• the rats were learning a maze

• no particular area proved to be more important in the rats’ ability to complete the maze

• this suggests that higher cognitive functions are distiuted throughout the brain

when do connections peak in the brain?

age 2-3

how many connections are there in the brain at the peak at age 2-3

15,000

who were Maguire’s experiment participants?

London taxi drivers

why were London taxi drivers chosen to be Maguire’s experiment participants?

they were chosen because a part of a London taxi driver’s training involves a test known as ‘the knowledge’, which assesses their ability to recall the names and locations of streets in the city.

what did Maguire find?

• significantly greater volume of grey matter in the posterior hippocampus of taxi drivers than in matched control group- - suggests that the learning the drivers undertake as part of their training alters the structure of the brain

• positive correlation between how great the volume of grey matter was and how long they had been in the job - this provides correlational evidence for structural differences in the brain due to extensive experience of spatial navigation

what did Kuhn et ak find?

significant increase in grey matter in various regions of the brain after participants played video games over a period of 2 months for 30 minutes each day- brain plasticity

how long did ps in Kuhn’s experiment have to play video games for each day?

30 mins

how long a period did ps in Kuhn’s experiment have to play video games every day?

2 months

what did Draganski do and find?

• imaged the brains of medical students 3 months before and after their final exams.

• learning induced changes were seen to have occured in the posterior hippocampus and parietal cortex (presumably as a result of the exam)

when did Draganski image the brains of medical students?

3 months before and after their final exams

what did Mechelli et al find?

larger parietal cortex of billingual people compared to non-billingual people

what did Danelli do?

investigated EB- a 17yr old Italian boy who had his entire left brain removed at age 2

how old was EB (Danelli’s case study) when he had his entire left brain removed

2yrs old

what did Danelli find?

• By 17yrs old his language abilities were almost normal

• even though the left hemisphere (responsible for language) had been removed his language ability was virtually normal.

what did Schneider do and find?

• investigated patients with traumatic brain injury (TBI)

• found that patients who had more years in education were more likely to recover disability free

• he concluded that a cognitive reserve (associated with greater academic attainment) could be a factor in neural adaptation

what did Marquez de la Plata find?

• older patients (40+) regained less function in treatment than younger patients following brain trauma.

• Their brain functions were also more likely to decline for the first 5 years following the trauma

what did Bezola et al find?

40hrs of golf training completed by ps aged 40-60 reduced motor cortex activity (shown on an FMRI) compared to novice golfers)- This suggests more efficient neural activity after training.

how many hours of golf training did participants complete in Bezola’s study?

40hrs

how old were the ps in Bezola’s study?

40-60yrs

what research did Sperry complete?

split-brain research

when do the highlighted images appear in an fMRI

approx 4/5 seconds later

Siffre’s cave study procedure

Flashcard: Siffre’s Cave Study (1962)

Researcher: Michel Siffre

Duration: 2 months (1962)

Location: Cave (France)

Objective: Study effects on circadian rhythm in isolation

Conditions: No natural light, clock, calendar, or sound; adequate food and drink, when requested

how long did Siffre spend in the cave in France>

2 months

Siffre’s cave study findings

Findings:

• Internal body clock (endogenous pacemaker) influences sleep/eating

• Misjudged time: believed it was mid-August when it was mid-September

• Circadian rhythm lengthened to 25hrs

• Significance: Highlights the impact of external cues on circadian rhythms.

how long did Siffre’s circadian rhythm become?

25hrs

who completed Circadian Rhythm Study in WWII Bunker

• Aschoff and Wever

how long did circadian rhythm study in WW11 bunker last

4 weeks

procedure of Aschoff and Wever’s study

• Participants shielded from natural light, temperature changes, and environmental cues.

• Access to artificial light (on/off).

Ashcoff and Wever findings

• Displayed circadian rhythm of ~25 hours (one extended to 29 hours).

• Suggests natural sleep/wake cycle may be longer than 24 hours; natural light helps entrain our 24-hour clock

What did Morgan do and find?

• removed and transplanted the SCN cells from hamsters bred to have a circadian rhythm of 20hrs rather than 24 onto the brains normal hamsters

• These normal hamsters began to adopt the same abnormal circadian rhythm as their 20hr donor

• Hamsters with normal nocturnal patterns of activity had their SCNs replaced with SCNs from mutated hamsters, which slept through the night and were active during the day

• Hamsters followed new daytime activities of donor

• SCN had imposed its pattern onto the hamsters - shows significance of SCN and endogenous pacemakers

Campbell and Murphy

• 15 participants were woken up at various times and a light pad was shone on the back of their knees.

• The researchers found a change in their sleep/wake cycle of up to 3hrs in some cases

• Showed that light may be detected by skin receptor sites even when same information is not received by the eyes

• Light is a powerful exogenous Zeitgeber- does not rely on eyes to influence brain

McClintock and stern

• Aim- to show that the menstrual cycle is influenced by pheremonal secretions from other women.

• 29 women in total, uni students, no birth control

• IV- donor pheromones of someone who was about to ovulate or someone had ovulated

• DV- affect on length of cycle

• pheromones gathered from 9 women at various stages of the cycle- cotton pads placed under armpit for 8 hrs to ensure pheromones were picked up. Odour of pads rubbed upon upper lip of 20 other women (experimental group). On day 1- pads from start of cycle applied. On day 2- pads from day 2 etc.

• Results:

  1. Cycle shortens if inhaled secretions from women about to ovulate

  2. Cycle lengthened if inhaled from women who had already ovulated

  3. 68% of women had changes to cycle which brought them closer to their ‘odour donor’

• Supports role of exogenous zeitgebers and explains why some women who live together have synchronised cycles

Reinberg

• conducted a study where one female participants spent 3 months in a cave with only light from a small lamp

• her menstrual cycle shortened from her usual 28days to 25.7days-

• Suggests that lack of light (exogenous zeitgeber) affected her menstrual cycle - demonstrates influence of external factors

How long does one cycle of sleep typically last

90mins

How many cycle of sleep in average do we experience in a typical night

4 or 5

Dement and Kleitman aim

investigate the relationship between eye movements and dreaminginvestigate the relationship between eye movements and dreaming

Dement and Kleitman method

• 7 adult males and 2 adult females.

• ps studied under controlled laboratory conditions

• ps had to report to the laboratory at bedtime where they were connected to an EEG

• the EEG took measurements throughout their time asleep all night

• ps were asked to not drink caffeine

Dement and Kleitman results

• REM sleep is predominantly, though not exclusively, associated with dreaming

• NREM sleep is associated with periods of non-dreaming sleep

• ps were able to recall dreams if awakened during REM periods. If they were awakened in other stages they were less likely to report dreaming

• the REM period occured at regular intervals during the night, though each p had their own patterm

• the mean period of each REM phase for the whole group was 92mins, with individual norms varying between 70 and 104mins

Dement and Kleitman conclusions

1. stages of sleep follow a pattern throughout the night

2. dreams mostly occur in REM

3. ps did go into REM on average every 90mins but there were still individual differences

Dement

• compared ps who had been deprived of REM sleep with a control group who had been deprived of the same amount of NREM sleep

• he found that the REM deprived group were more irritable, more aggressive and unable to concentrate on various tasks

Borbely

REM deprived individuals made 31 attempts to re-enter REM on the first night of deprivation, 51 attempts on the second night and 60 on the third night

called REM re-bound

Randy Gardner

• Randy Gardner remained awake for 264hrs

• while he experienced numerous problems- e.g. blurred vision and disorganised speech, he coped incredibly well despite his significant sleep deprivation

• after his experience, he slept for just 15hrs

• over several nights he recovered only 25% of his lost sleep

• he recovered about 70% of stage 4 sleep, 50% of REM sleep and very little of the other stages

• These results suggest the wide degree of flexibility in terms of the different stages within the sleep cycle and the variable nature of this ultradian rhythm

Tucker et al

differences in terms of duration of each stage, particularly stages 3 and 4 (NREM).