Biopsychology

What was phrenology and who came up with it?

By Gall in 1700s - linked human behaviour/ mind to shape of head. When use a brain region, it forms a bump - the more you use region, the bigger the bump.

How did Gall come up with phrenology? What happened during his childhood?

Observed childhood classmates great at memorisation often had big protruding eyes - Gall said part of brain behind eyes must be associated with verbal memory. Origins of localisation.

Difference between localisation (of function) and holism. Include 2 people who helped come up with localisation.

• Holism = brain works as a whole - all parts process thoughts and actions

• Localisation (1800s) - Wernicke and Broca found specific areas of brain are responsible for specific behaviours, processes or activities (do diff tasks and involved with diff body parts)

What is the general rule for which part of the body is controlled by which hemisphere? What words describes this?

Left side of body = controlled by right hemisphere

Right side of body = controlled by left hemisphere

— It's contralateral

What is the cerebral cortex?

3mm thick outer layer of both hemispheres - covers inner parts of brain. More developed than animals, separating us from them.

Why does the cerebral cortex appear grey?

Because of the location of cell bodies (surface appearance of brain is called grey matter)

Motor area: location, function and consequence of damage to it

• Found in frontal lobe

• Controls voluntary movements in opposite side of body by sending signals to muscles. Regions = arranged in logical order, e.g. region for finger movement = next to region for hand

• Damage causes loss of control over fine movements

Hitzig and Fritsch (1870) - motor areas of dogs

Electrically stimulated motor areas of dogs - caused contractions in different muscles, depending where inserted probe in motor area.

Somatosensory area: location and function

• Found in parietal lobe

• Receives sensory info from skin to produce sensations related to pain, temp etc. Diff areas of it receive messages from diff body parts - amount devoted to a body part demonstrates its sensitivity

Robertson (1995) - somatosensory area and Braille readers

In their somatosensory area, Braille readers have larger areas related to their fingertips, compared to normal sighted Ps.

Visual area: location, function and consequence of damage to it

• Found in occipital lobe

• Receives and processes visual info - info from right-hand side visual field = processed in left visual cortex (L hemisphere) and vice-versa; diff parts which process diff types of visual info, like colour and shape

• Damage to L hemisphere can cause blindness in part of R visual field of both eyes and vice-versa

Auditory area: location, function and consequence of damage to it

• Found in temporal lobe

• Analyses and processes acoustic info; info from L ear mainly goes to R hemisphere and vice-versa

• Diff parts - mainly processes simple sound features, like volume and tempo

• Damage can cause partial hearing loss - more extensive damage = greater loss

Broca's area - what is it, where is it and consequence of damage to it - give an e.g. if someone with damage to it

• Small area in L frontal lobe - responsible for speech production

• Damage causes Broca's aphasia - slow and laborious speech that lacks fluency - e.g. patient Tan who could only say "Tan"

Wernicke's area - what is it, where is it and consequence of damage to it

• in temporal lobe - responsible for language comprehension

• Damage causes Wernicke's aphasia - includes producing nonsense words (neologisms) - fluent, but meaningless speech

Plasticity

The brain's tendency to change and adapt (functionally and physically) due to experience and new learning

Gopnik et al (1999) - infants and synaptic connections

During infancy, brain rapidly grows num of synaptic connections - peaks at approx 15K at age 2-3 (2x adult brain)

Synaptic pruning

As we age, rarely used synaptic connections are deleted and those used often are strengthened

When does synaptic pruning occur?

Existing neural connections can change at any time due to learning and experience (used to think only happened in childhood)

Maguire et al. (2000) - what did they do and find? (Taxi drivers)

Studied brains of London taxi drivers - found much higher vol of grey matter in posterior hippocampus (to do with spatial and navigational skills,) compared to control group

Maguire et al (2000) - explain their results (Taxi drivers)

When training, drivers must be able to recall London city streets and routes to get there - detailed navigational info may have changed struc of their brains — the longer they'd had job, the more pronounced the diff were

Draginski et al (2006) - med students and exams

Took brain scans of med students 3 months before and after final exams - found learning-induced changes occurred in posterior hippocampus and parietal context, likely due to revision and exam prep

Michelli et al. (2004) - bilingual plasticity

Found bigger parietal cortexes in bilingual Ps, compared to matched monolingual controls

Functional recovery

Form of plasticity after damage from trauma/ injuries - brain redistributes function normally done by damaged area(s) to undamaged area(s)

Spontaneous recovery

When functional recovery initially occurs fast post-trauma, then slows down after several weeks/ months

Doidge (2007) - how functional recovery works

Secondary neural pathways not normally used for certain functions are activated to continue function, often in same way as before (brain rewires itself by forming new synaptic connections near damaged area)

3 structural changes in the brain which support functional recovery

1) Axonal sprouting - grow new nerve endings to connect with undamaged nerve cells to make new neuronal pathways

2) Reformation of blood vessels

3) Recruitment of homologous (similar) areas on opposite sides of brain to do certain tasks - e.g. if Broca's area was damaged (L side,) R-sided equivalent would do its functions

Hemispheric lateralisation

Idea that the 2 hemispheres of brain are functionally diff - certain mental processes and behaviours are mainly controlled by only 1 hemisphere, e.g. lang is controlled by left

Sperry (1968) - who were his split-brain research on? What procedure had his Ps undergone?

Ps had undergone a commissurotomy - corpus callosum and other tissues connecting hemispheres were cut to separate them. So, hemispheres wouldn't communicate properly. Did this to control frequent and severe epileptic seizures.

Aim of Sperry's research

Wanted to see extent the 2 hemispheres were specialised for certain functions and if could perform tasks independently from each other (extent brain function is lateralised)

Sperry's procedure

An image/ word was shown to P's right visual field (processed by L hemisphere) and showed same/ diff one to left visual field (processed by R hemisphere) - in split-brain Ps, hemispheres can't share info to give full image (as lack corpus callosum)

Findings of Sperry's research to do with what Ps SAW - explain why this happened

When showed pic of object to their R visual field (processed by L hemisphere,) Ps easily described what saw, BUT couldn't describe if showed it to L visual field (processed by R hemisphere)

— Lang centre = in L hemisphere - couldn't describe objects in L field as don't have lang centres in R hemisphere (and can't send messages from R hemisphere to lang centres in L because don't have corpus callosum)

Findings of Sperry's research to do with what Ps TOUCHED - explain why this happened

Couldn't name objects shows in L visual field, but could select matching object from a bag out of view using L hand - L hand could also choose object most closely associated with object shown.

— Could understand what object was using R hemisphere and choose appropriate object.

Findings of Sperry's research to do with composite words (e.g. KEY_RING)

If showed 2 words simultaneously, one on each side of visual field - e.g. key on L and ring on R - P would choose key with L hand and say ring.

Findings of Sperry's research to do with recognising faces, including using composite (made of 2 halves) faces.

Ps had to match a face from several other faces - pic processed by R hemisphere (L field) was consistently selected, but ignored when processed by L hemisphere (R field.) When showed composite pic - 1 half of a face shown to each hemisphere - L hemisphere was better at verbal description and R was better at selecting a matching pic.

How do fMRI scans work? Include which type of pictures they produce and what these show about the brain.

• Detects changes in blood oxygenation and flow when doing a task - more active areas use more oxygen so more blood flows there.

• Produces 3-D images - show which brain areas = involved in a mental process (localisation.)

How do EEGs work? Include how they're used to diagnose conditions.

• Measure electrical activity (impulses) in brain - reps brainwave patterns made from activity of millions of neurons

• Fix electrodes to P's scalp via scull cap

• Used to diagnose brain conditions - unusual arrhythmic patterns of activity may suggest of neurological abnormalities, e.g. tumours

How do ERPs work?

• EEGs = overly general - but data has neural responses associated with cognitive, sensory and motor events

• Isolate responses via stat averaging technique - filters extraneous brain activity from EEG - leaves responses triggered by specific events - AN ERP

How do post-mortem exams work?

• Analyse dead person's brain who likely had rare disorder and abnormal mental processes/ behaviour

• Examine damaged brain areas to establish likely cause of disorder - can link them to observed behaviours when they were alive

• Can compare brain with neurotypical one to see extent of diff

2 advantages of functional magnetic resonance imaging (fMRI)

• Doesn't use radiation - if done right, is virtually risk-free, non-invasive and straightforward to use

• Produces images with high spatial resolution - depicts detail by the mm and shows clear pic of how brain activity is localised

2 disadvantages of functional magnetic resonance imaging (fMRI)

• Expensive and can only take clear pic if person stays perfectly still

• Only measures blood flow, can't depict activity of individual neurons - hard to tell what kind of brain activity is being shown

2 advantages of electroencephalograph (EEG)

• Aids brain diagnoses - e.g. epilepsy - characterised by random bursts of brain activity that EEGs can detect

• Contributed to understanding of sleep stages - has high temporal resolution of 1 millisecond (time-lag between image shown and initial firing of neurons)

2 disadvantages of electroencephalograph (EEG)

• Info received is too general (it's about thousands of neurons)

• Hard to pinpoint source of neuronal activity and researchers can't distinguish between activities originating in diff areas (localisation)

2 advantages of event-related potentials (ERP)

• Great temporal resolution - has caused widespread use in measuring cog functions and deficits

• Researchers have identified diff types of ERPs and describe their precise roles in cog functioning - e.g. P300 = involved in allocating additional resources and maintaining working memory

2 disadvantages of event-related potentials (ERP)

• Lack of standardised methodology between different studies - hard to confirm findings

• Must completely remove background noise and extraneous materials to get pure data - hard to achieve

2 advantages of post-mortem examinations

• Provided foundation for early understanding of key brain processes - e.g. Broca and Wernicke relied on them to link lang, brain and behaviour, decades before neuroimaging

• Improve medical knowledge and help generate hypotheses for further study

2 disadvantages of post-mortem examinations

• Issues of causation - observed brain damage may be linked to unrelated trauma/ decay, not brain deficits under review

• Ethical issue of patient's consent before they died - e.g. did post-mortem exam on patient HM, even though he couldn't give consent as he couldn't form new memories

Which 2 things control biological rhythms?

Endogenous pacemakers and exogenous zeitgebers

Circadian rhythms - include 2 examples

Biological rhythms which have 24 hour cycle, e.g. sleep/ wake cycle and body temp

Siffre - APFC (cave studies)

A: Investigate effect of ex. zeitgbers on sleep/wake cycle

P: 1962 - spent 2 months in caves of Southern Alps, being deprived of natural light and sound; did same in 1972 - spent 6 months in Texan cave

F: Free-running biological rhythm settled to approx. 25 hours - but fell asleep and awoke on regular schedule

C: Have natural sleep/wake cycle of 25 hours, but it's entrained by ex. zeitgebers associated with our 24-hour day, e.g. meal times

Aschoff and Weaver (1976) - APFC (war bunker)

A: Investigate effect of ex. zeitgebers on sleep/wake cycle

P: Groups of Ps spent 4 weeks in WW2 bunker, deprived of material light

F: Ps adjusted to CR OF 24-25 hours - only 1 had cycle of 29 hours

C: Have natural sleep/wake cycle of 25 hours, but it's entrained by ex. zeitgebers associated with our 24-hour day, e.g. num of daylight hours

Folkard et al (1985) - APFC (cave and clock manipulation)

A: Investigate effect of ex. zeitgbers on endo. pacemaker

P: Group of Ps lived in dark cave for 3 weeks - went to bed when clock said 11:45pm and awoke when said 7:45am. Researchers slowly sped up clock (Ps = unaware) - eventually, their 'normal' day only lasted 22 hours (ex. cue of time)

F: Only 1 P comfortably adjusted to 22 hour day

C: Suggests have free-running rhythm which can't easily be overridden by changes in ex. environment

Infradian rhythm - include 2 examples

Biological rhythm with cycles that last longer than 24 hours - e.g. menstruation and seasonal affective disorder (SAD)

Ultradian rhythm - include 2 examples

Biological rhythm with cycles that last less than 24 hours - e.g. sleep stages and meal patterns

Describe seasonal affective disorder (SAD) - what is it, how long is the cycle and what hormone causes it

• Seasonal changes in mood - can become depressed in winter

• IR governed by annual cycle

• Melatonin = secreted at night by pineal gland - lack of light in winter causes more melatonin to be secreted, which affects serotonin production, which is linked to depressive symptoms

Menstrual cycle: how often does it occur, what 2 hormones is it controlled by and when does ovulation occur

• Monthly IR - controlled by oestrogen (promotes ovulation) or progesterone (stimulate uterus for fertilisation)

• Ovulation = approx halfway through cycle when oestrogen levels = at highest - usually lasts 16-32 hours

Menstrual cycle: when does progesterone increase and how long does the menstruation cycle last?

• Progesterone levels increase after ovulation to prep for possible implantation of embryo in uterus

• Usually lasts 28 days - can last from 23-36 days

What happens if pregnancy doesn't occur?

Egg is absorbed into body and womb lining come away and leaves body (menstrual flow)

Stern and McClintock (1998)- APFC (pheromone pads)

A: Investigate effect of ex. zeitgbers on menstrual cycle

P: Ps = 29 women with irregular periods. 9 of them who were Ayt diff stages in cycle had cotton pad on armpit for 8 hours to pick up pheromones. Treated pads with alcohol and rubbed on upper lips of other Ps - on day 1, applied pads from start of menstrual cycle, on day 2, were given pad from 2nd day of cycle etc

F: 68% had changes in cycle which brought them closer to cycle of odour (pheromone) donor

C: Menstrual cycle = influenced by ex. zeitgebers

Sleep cycle: what does it alternate between, how many stages does it have and how often does it repeat?

• Alternates between REM (rapid eye movement) and NREM (non-rapid eye movement) sleep

• 5 stages - repeat every 90min

Describe the 5 stages of sleep (stages 1&2, stages 3&4 and stage 5)

• 1 & 2 - light sleep - slower brain patterns (start with alpha and progress to theta waves)

• 3 & 4 = deep sleep - slow brain waves (delta waves)

• 5 = REM sleep - body is paralysed, desynchronised brain waves (brain activity greatly speeds up to resemble awake brain) and dreaming occurs

How is human appetite an ultradian rhythm?

Most humans eat 3 meals a day and appetite rises and falls because of food consumption

Endogenous pacemakers

Internal body clocks that regulate many of our biological rhythms

Exogenous zeitgebers

External cues that may affect/ entrain our biological rhythms (rest our biological clocks)

Suprachiasmatic nucleus (SCN)- what is it, where is it found and what does it do?

• Main endogenous pacemaker and is in hypothalamus

• Controls other biological rhythms - links to brain areas responsible for sleep and arousal

How does the SCN receive info about light levels in the environment?

• Nerve fibres connected to eyes cross in optic chiasm on way to visual area in cerebral context

• SCN = above chiasm - receives info about light directly from it, even when eyes are closed so SCN can adjust to changing daylight patterns when we're asleep

Describe how the SCN relates to melatonin production

SCN passes info on light levels to pineal gland to stop it producing melatonin (sleep chemical) when it's daylight, keeping us awake (gland produces more melatonin at night)

DeCoursey et al (2000) - APFC (chipmunks and SCN)

A: Investigate importance of SCN

P: Destroyed SCN connections in brain of 30 chipmunks, then returned them to natural habitat and observed for 80 days

F: Sleep/ wake cycle disappeared and many were killed by predators (as were awake and vulnerable when should've been asleep)

C: SCN is important in regulating our sleep/ wake cycle

Ralph et al (2000) - APFC (mutant hamsters)

A: Investigate importance of SCN

P: Bred mutant hamsters with 20 hour sleep/ wake cycle. Transplanted SCN cells from their foetal tissue into brains of normal hamsters

F: Cycles of normal hamsters became 20 hours

C: SCN is important in regulating our sleep/ wake cycle

Give 2 reasons why light is an important exogenous zeitgeber

1) Resets SCN (main EP,) affecting sleep/wake cycle

2) Indirectly influences key processes that control functions like hormone secretion and blood circulation

Campbell and Murphy (1998) - APFC (light pad and knees)

A: Investigated importance of light on sleep/wake cycle

P: 15 Ps were woken at diff times and had light pad shone on back of their knees

F: Caused a deviation of up to 3 hours in normal sleep/wake cycle

C Light = powerful ex. zeitgeber which doesn't need to rely on eyes to affect brain (can be detected by body's skin receptors)

When does the circadian rhythm first established and entrained in babies? Why?

Begins at about 6 weeks and is entrained by about 16 weeks

- likely because of parents deciding schedules, like meal and bed times (social cues as ex. zeitgebers)

How can you entrain your circadian rhythms and beat jet lag when travelling far?

Adapt to local times for eating and sleeping, rather than responding to own feelings of hunger

Biological rhythms

Distinct patterns of changes in body activity which occur in cycles