P- biopsychology

phrenology

personality reflected in the lumps and bumps on the skull, reflecting functions of the brain

localisation

specific part of the brain in which a function is carried out

e.g. Broca’s area for speech production

corpus callosum

• bundle of fibres that is essentially a communication pathway between two hemispheres

• cutting the area can ensure epilepsy is kept to one side of the brain

  • one side of the brain can also be removed - a hemispherectomy

hemispheric lateralisation

when some physical or psychological functioning is controlled (or dominated) by a particular hemisphere

mostly contralateral, supported by stroke patients

left hemisphere

language processing

Broca’s and Wernicke’s area

areas in the brain (clockwise from front)

• frontal

• parietal

• occipital

• temporal

Frontal lobe

• motor cortex

• Broca’s area

motor cortex

• both hemispheres

• involved in regulating voluntary movement

• sends signals to the muscles

Broca’s area

• only left hemisphere

• responsible for speech production

Parietal lobe

• somatosensory centre

somatosensory centre

• both hemispheres

• separated from motor by a valley → ‘central sulcus’

  • adaptable people who read brail have larger area dedicated to their fingers

• sensations: touch, pain, temp, pressure

occipital lobe

• primary visual cortex

primary visual cortex

• receives and process visual information

• different regions: colour, shape, depth, movement

• contralateral

temporal lobe

• Wernicke’s area

• primary auditory cortex

Wernicke’s area

• only in the left

• responsible for speech comprehension

primary auditory cortex

• receives and processes auditory information

• contralateral

Genie

• dichotic listening tasks indicated she was using her right cerebral hemisphere to process language

• Lennenburg 1967 suggested critical period for language acquisition (before puberty)

• use of right hemisphere may have been direct consequence of not acquiring language in CP

• Curtiss 1977 suggested left cerebral hemisphere was no longer available for language acquisition

  • but he adopted her so he’s biased

Oxana Malaya

• raised by dogs, adopted a lot of their qualities

• never learned language

• claimed critical age was 5

Herasty 1997

• females have larger Wernicke’s and Broca’s area than males

• gender bias

  • beta bias → many studies downplay differences between M+F brains

Lebornge (Domanski 201)

• suffered from epilepsy, lost ability to speak

• Broca conducted post-mortem and found lesion on the left frontal lobe, only visible site of damage

  • concluded it was area responsible for speech - Broca’s aphasia

  • preserved and kept in Paris, scanned to confirm area is correctly localised

Wernicke

• identified region in left temporal lobe as being responsible for language comprehension - Wernicke’s aphasia

  • nonsense words as part of speech

  • brain scans by Peterson 1988, Wernicke’s active in listening, Broca’s when reading

Meyer et al. 2010

when people watch silent films, their primary auditory cortex in both hemispheres will activate if a door is shut with a force - imagining the bang

Case study → GR

• developed blindness in RVE, CT scan = haemorrhage

• brain damaged in the visual cortex, cortically blind

• could not identify letters but expressed awareness, blindsight

Phinneas gage

• after incident: hostile, unreliable, rude, swore a lot

• Dr Harlow believed that the damaged area housed the planning, reasoning and control of individual

Case study: EB

• 17yr boy, entire left hemisphere removed at 2.5yrs

• surgery to remove huge benign tumour, immediate loss of his language abilities - suggesting that emerging language ability was already left-lateralised

  • this is the case for 95% of right handers)

• intensive rehab, beyond age 5, EB’s language fluency improved, found that right hemisphere compensated

• some areas not at expected standard, grammatical, slower at naming objects - loss compensated to a degree

• factors: age, trauma, time spent in rehab=less time in school, individual differences

• supports functional recovery

Viewing the brain holistically

• Karl Lashey 1950 removed areas of the cortex (between 10% and 50% in rat’s brains; the rats were learning to run a maze, he did not find a specific area involved

  • concluded tat complex tasks are supported by the holistic theory of brain function

Left hemispheric lateralisation

localisation of function, language, is lateralised to the left hemisphere

Right hemispheric lateralisation

• dominant in recognising emotions in others (Narumoto et al.)

• if photo of face is split so one half is smiling and the other is neutral, left hand side emotion is recognised faster (Heller and Levy)

• spatial relations

• left hemisphere focuses on details and right processes overall patterns

neurosurgery

• can be used in extreme cases of OCD and depression

• Dougherty et al. reported on 44 OCD patients who had undergone cingulotomy

  • involves lesioning of the cingulate gyrus (inability to stop worry-cycles)

  • post surgical follow up at 32 weeks, 1/3 met criteria for successful response, 14% partial

  • supports localisation, but not fully as not majority

Brain plasticity

• rehabilitation, particularly successful in children

• EB case study challenges, but also supports as Hemispheric lateralisation can be compensated for at least to a basic degree

• case studies provide evidence to support, not proof

hemispherectomy

half the brain removed, disconnected, or disabled

comisurotomy

corpus callosum severed to reduce symptoms of epilepsy - stops the electrical storm from travelling across

Sperry 1968: AIM

investigate the extent to which the two hemispheres were specialised for certain functions

Sperry 1968: PROCEDURE

compare split brain patients to others w no separation

Visual tasks: words projected into left/right visual field and asked about it

Tactile tasks: hands underneath screen, ‘feel’ only

Sperry 1968: SHOWN IN LVF

would not be able to describe as left visual field goes to right hemisphere which does not have comprehension and language centres

Sperry 1968: SHOWN IN RVF

would be able to describe

Sperry 1968: NORMAL BRAINS

information would be able to travel across corpus callosum to left hemisphere

Sperry 1968: SHOWN IN LVF, FIND OBJ W LEFT HAND

would be able to find as LVF→RH→LeftHand

Sperry 1968: SHOWN IN LVF, FIND OBJ W RIGHT HAND

would not be able to as LVF→ RH does not go to right hand

Sperry 1968: HOLDING OBJ, HIDDEN + TOLD TO FIND

would, but only with same hand, e.g. pen → lefthand → RH → lefthand → pen

Sperry 1968: SHOWN DIF WORDS TO BOTH F, PICK UP W LEFT AND SAY

key → LVF → RH → LeftHand

Ring → RVF → LH → say

Sperry 1968: DRAW PIC SHOWN TO BOTH VF

consistently better when drawn with left hand

• right hemisphere was superior at drawing ability

Sperry 1968: CONCLUSIONS

hemispheres process information separately, have different functions, seem to have two separate streams of consciousness with own memories and perceptions

Sperry 1968: EVALUATION

• scientific, objective, ethical, opportunity sample, internal validity

• 11 split brain patients - small sample, all Hx seizures may have a unique effect, control should be epileptic

• disconnect greater in some than others, some on drug therapy longer

• comparison had no history of drug therapy or epileptic seizures

• data artificially produced, in real life corpus callosum can be compensated for

gazzinga 1970

corpus callosum severed shown picture of nude women in LVF, she giggled but couldn’t explain why

Plasticity

ability for the brain to change and adapt it’s structures and processes as a result of experience and new learning

• used to limit to infancy and childhood, more research demonstrated the brain continues to create new neural pathways

• Machin 2018 found that the fathers planning and problem solving areas became more active

Functional recovery

the way certain abilities of the brain may be moved or redistributed rather than lost following damage/trauma to the brain (RTAs, assaults, falls, strokes → very dependent on level of damage)

• much recovery due to anatomical compensation, brought about by intensive rehabilitation, brain learns to compensate for function

plasticity → Maguire et al. 2000

greater volume of grey matter in the posterior hippocampus(spatial) in London black cab drivers than matched control group due to 3yr intensive training

plasticity → Draganski et al. 2006

medical students 3 months before and after final exams, learning induced changes in posterior hippocampus and parietal cortex

Plasticity → Kuhn 2014

• supermario at least 30min/day over 2 months, compared to control and found significant differences in the grey matter, particularly in cortex and hippocampus (+spatial navigation, strategy, working memory, motor performance

Functional recovery → Scotty Cramer

• professional BMXer, accident in 2016 = paralysis

• extremely motivated, regained control within 10 months

ways of functional recovery

• axonal sprouting/neural regeneration

  • growth of new nerve endings will connect with other undamaged nerve cells to form new neural pathways

  • can be used to strengthen existing connections or repair damaged parts TNS by repairing damaged neural pathways

• Reformation of blood vessels, nourishing brain and strengthening connections

• Recruitment of homologous areas on the opposite side of the brain to perform specific tasks, after period of time, may shift back

  • e.g. damage to Broca’s area on left side due to a stroke, right side equivalent carries out function

Evaluation of plasticity and functional recovery - age

• decreases with age as greater propensity for reorganisation in childhood as constantly adapting

  • Bezzola et al. 2012, 40hr gold training = reduced motor cortex activity using fMRI in novice golfers 40-60

Evaluation of plasticity and functional recovery - practical application

• neurorehabilitation grown; following trauma, spontaneous recovery tends to slow after number of weeks, so nr may be required to maintain improvements (fixes itself to an EXTENT)

Evaluation of plasticity and functional recovery - cognitive reserve

• educational attainment influences how well brain functionality adapts after injury (socially sensitive)

• Schneider et al. 2014, time in education=cognitive reserve, increases chance of disability free recovery, 40% achieved DFR >16yrs, 10% <12yrs

Evaluation of plasticity and functional recovery - chronic traumatic encephalopathy

• from multiple traumas: professional sports, domestic violence, extreme sport, armed forces

• develops slowly with: STM loss, cognitive decline, depression symptoms, poor impulse control

• no treatment (aside from for individual symptoms)

• diagnosed at post-mortem

methods of studying the brain

• post-mortems

• fMRI

• EEGs

• ERPs

Port mortem

• analysis of a person’s brain following their death

• in research, likely individuals who have a rare disorder and experience unusual deficits in behaviour or mental processes

• often compared to neurotypical brains to establish likely cause

post mortem - strengths

• informs theories of cognitive functioning

• establishes causal relations between impaired brain and patient behaviour

• play an essential role in developing understanding of conditions such as schizophrenia

• more detailed examination of anatomical and neurochemical aspects

post mortems - limitations

• single case studies

• damage not usually one area or caused by other factors

  • modularity theories (localisation of function is a simplistic view of the brain)

• have to treat the brain - process takes 2 to 3 working days (treated with formalin)

• more invasive than scan

• Einstein brain donation, findings unreliable as the(240) brain pieces have been handled a lot, may have effected brain

  • differences identified by comparing to much younger brain

  • correlation versus causation retrospective so unknown if differences contributed to intelligence or if intellectual activity caused differences

fMRI

• measures energy released by haemoglobin (Hb-protein content of blood that binds with O₂)

• increase in activity = increase in oxygen = increased blood flow

• gives dynamic 3D image of brain, can map involvement of areas (implications for localisation of function)

• high spatial resolution: 1-2mm

• poor temporal resolution: 5 seconds

fMRI - strengths

• non-invasive

• no radiation(physical health not at risk) unlike PT

• objective and reliable measure of psychological processes

  • not possible for verbal reports

  • e.g. lie detection

EEG

• skull cap with electrodes placed on scalp of individual to measure electrical activity within the brain

• scan recording represents brainwave patterns

• low spatial resolution

• extremely high temporal - single ms or less

EEG - strengths

• diagnosis of conditions(epilepsy) and understanding of ultradian rhythms

• much cheaper by does require level if expertise to interpret

• measure of brain functioning in real time, active brain, accurately measures task with brain activity associated

EEG - limitations

• generalised nature of information received, not useful for pinpointing exact source of neural activity

  • cannot distinguish between but adjacent locations

• cannot reveal deeper regions(e.g. hypothalamus) without invasive procedure

ERPs - event related potential

use same equipment as EEGs but uses statistical averaging techniques, all extraneous filtered out to leave responses to related stimulus

ERPs - strengths

• increases understanding of cognitive processes - attention and perception

• a lot more specific than EEGs

• tests the reliability of self-report answers, especially when area of research is potentially sensitive and open to social desirability bias

ERPs - limitations

• not easy to filter out background noise and extraneous material

• can only be interpreted by trained professional (requires intensive and expensive training)

• used ERP to record responses to nude pictures of both sexes, men said they were aroused by female and women said neutral but ERP showed higher response to opposite sex in both

biological rhythms

a change in body processes or behaviour in response to cyclic time periods, influenced by internal body clock and external environment (endogenous pacemakers and exogenous zeitgebers)

circadian

year e.g. migrations, hibernation

circalunar

month e.g. menstrual, moon affects marine organism

circatidal

twice a day

e.g.

• hormone cycles: cortisol-stress, adrenal cortex with HPA in morning

• bivalves: muscles/oysters open and close with the tide

circadian

once a day

e.g. sleep-wake, core body temperature

why does melatonin secretion stop?

pineal glands respond to light changes, affects serotonin

in winter when there’s less light, can lead to seasonal affective disorder

Sleep-Wake cycle - Siffre 1975

• case study, spent 6 months in a cave with no light

• given flashlight to navigate

• found internal body clock of 25 hours

• concluded light source does not impact 24 hour cycle

Sleep-wake cycle - Aschoff and Wever 1976

• studied participants living in WWII bunker over a 4-week period, only electrical light, allowed to turn on and off as they wished

• eventually free running body clock settled into sleep-wake cycle of 24-25 hours

• concluded that we use natural light to entrain, our biological sw-cycle is slightly longer

Sleep-wake cycle individual difference

length of sleep wake cycle can vary between 13-65 hours

Core body temperature

• lowest ~04:30 (36 degrees)

• highest ~18:00 (38 degrees

Folkard 1977

• read children stories at 3pm versus 9am, recall superior for children who read at 3pm

Gupta 1991

• improvement on IQ tests at 7pm compared to 2pm and 9am (highest core temperature)

Endogenous pacemakers

• internal body clocks that regulate many of our biological rhythms (e.g. hormones such as melatonin, cortisol, metabolic rate, and temperature)

• research demonstrates that EPs still function without cues, but may vary as a consequence

Superchiasmatic nucleus (SCN)

• most influential EP in the body - bundle of nerve cells in the hypothalamus - found in many mammalian species, regulated by light from environment

Superchiasmatic nucleus - process

• retina passes info along the optic nerve to the CNS, the SCN passes info on day length and light to the pineal gland

• during night, the pineal gland increases production of melatonin (induces sleep, inhibited during periods of wakefulness)

Superchiasmatic nucleus - research

difficult and unethical in humans, so animal research generalised - controversial

Superchiasmatic nucleus - Decoursey et al. 2000

• removed SCN connections in the brain of 30 chipmunks and returned to natural habitat

• 80 day observation, sleep wake cycle disappeared and by end most were killed by predators

  • assumed because they were awake and vulnerable

• SCN all-important body clock, supported its role in establishing and maintaining the circadian sleep-wake cycle

Superchiasmatic nucleus - Ralph et al. 1990

• removed SCN out of genetically abnormal(mutant) hamsters which only had a sleep-wake cycle of 20hours,

• transplanted these cells into rats that functioned on the normal 24hour cycle

• after transplant, rat’s rhythms shortened to 20hours

  • suggests SCN is pivotal

  • ethical issues and extrapolation easier

exogenous zeitgebers

• cues from the environment that play an important role in regulating time

• act as cues for EPs and help regulate body clock so the individual is synchronised with the environment

  • e.g. sunlight, noise, seasons, clocks, the moon

exogenous zeitgebers - entrainment

• opposite to free running (body does it owns thing) is where EP adjusts in line with environment

• e.g. when crossing time zones as EP not synchronised with environment anymore

exogenous zeitgebers - challenge

• sun does not set during the summer months in the arctic, still show normal sleep patterns despite prolonged exposure to light

exogenous zeitgebers - support

Visual impairments

Skene and Arendt found that those able to perceive light had normal circadian rhythms, those unable had abnormal rhythms

affect of light on circadian rhythms

Campbell and Murphey

• light also detected by skin

• introduced light to them during the night at a series of intervals by shining a beam of light on to the back of their knees

• their circadian rhythms were disrupted by up to three hours

• HEAVILY CRITISISED - disruption of EEG, know they’re being observed, environment was very disruptive

affect of social cues on circadian rhythms

• at 6 weeks, circadian rhythms begin

• about 16 weeks, most babies are entrained

• schedules imposed by parents are likely to be a key influence here, including adult determined meal-times and bedtimes

desynchronisation

practical applications to shift work

Biovin et al. 1996

• night workers engaged in shift work experience a period of reduced concentration around 6am

Knutsson 2003

• found a relationship between shift work and poor health, shift workers 3x more likely to develop heart disease

ECONOMIC IMPLICATIONS

practical application of research on biological rhythms

• use of light therapy as a clinical treatment for depression has now been recognised as an effective and affordable intervention

• used alongside drug treatment to max success or as sole treatment

• Benedetti et al. 2007 conducted a study examining the effects of light therapy and sleep deprivation on individuals suffering with bipolar

  • found the use of chronotherapeutics(light therapy) reduced two thirds of the patients’ depression score

Infradian rhythms

cycle LONGER than 24 hours

e.g. the menstrual cycle, governed by the endocrine system, impacted by EZs - light and odours

ultradian rhythms

cycle SHORTER than 24 hours, can happen more than once a day

Affect of light on MC - Reinburg 1967

• female ppts spend 3 months in a cave with a small lamp as the only light source

• circadian rhythms lengthened to 24.9 hours and her menstrual cycle shortened to 25.7 days

• levels of light in the cave could have affected mc

• after study, her body took a year to readjust her menstrual cycle back to the original

pheromone

chemical substance produced and released into the environment by an animal, especially a mammal or insect, affecting the behaviour or physiology of others of its species

affect of pheromones on MC - McLintock and Stern 1998

procedure

• compounds transferred by the women wiping a pad, which had previously been wiped across the donor’s armpit, above their upper lips

affect of pheromones on MC - McLintock and Stern 1998

at end of cycle

• when females received ‘odourless compounds’ from the armpit of women in the latter half of their menstrual cycle

  • cycle was shortened, presumable by the effects of the other women’s pheromones as they approached the end of their cycle

• found 68% of females experienced changes to their cycle, brought them closer to the cycle of their ‘odour donor'

affect of pheromones on MC - McLintock and Stern 1998

at start of cycle

• if the compounds were collected from women at the beginning of their cycle, this had the opposite effect, lengthening the cycle of those who had received the compound

affect of pheromones on MC - McLintock and Stern 1998

evaluation

• sample mostly women with a history of irregular periods

• changes observed were no more likely to appear by chance due to the confounding variables

• Trevanthan et al. 1993 - failed to find synchronicity in the menstrual cycle in their female sample