Biopsychology

AO1 for nervous and endocrine system

AO1 for nervous and endocrine system

• Central nervous system - brain, spinal cord, brain stem

• Peripheral nervous system

  • Somatic - voluntary reactions

  • Autonomic - involuntary reaction

    • Sympathetic - 'fight or flight'

    • Parasympathetic - 'rest and digest'

• Endocrine system - main gland is pituitary gland

AO1 for localisation of function

• Localisation vs holistic theory

• Localisation = the theory that different areas of the brain are responsible for specific behaviours, processes, or activities

• Motor area, visual area, somatosensory area, auditory area, Broca's area, Wernicke's area are all localised (but Broca's and Wernicke's are also lateralised)

• Motor area - area at back of frontal lobe responsible for regulating movement

• Visual area - area in occipital lobe that receives and processes visual information

• Somatosensory area - area in front of parietal lobe that processes sensory information such as touch

• Auditory area - area in front of temporal lobe concerned with analysis of speed-based information

• Broca's area - area in left frontal lobe, responsible for speech production

• Wernicke's area - area in left temporal lobe, responsible for language comprehension

Define localisation

The theory that different areas of the brain are responsible for specific behaviours, processes, or activities

Where are the following areas and their functions: motor, visual, somatosensory, auditory, Broca’s, Wernicke’s

• Motor area - area at back of frontal lobe responsible for regulating movement

• Visual area - area in occipital lobe that receives and processes visual information

• Somatosensory area - area in front of parietal lobe that processes sensory information such as touch

• Auditory area - area in front of temporal lobe concerned with analysis of speed-based information

• Broca's area - area in left frontal lobe, responsible for speech production

• Wernicke's area - area in left temporal lobe, responsible for language comprehension

AO3 for localisation of function

Neurosurgery evidence - Dougherty patients have surgery to isolate cingulate gyrus, 1/3 (of 44) successful - symptoms and behaviours associated with serious disorders are localised.

Brain scan - Peterson in PET scans found Broca’s active during reading aloud and Wernicke’s during listening

Holistic (not localisation) - Lashley rats’ ability to learn mazes impaired by large lesions on visual areas but not smaller ones - size important. Also localisation = too idiographic (case studies)

AO1 for lateralisation of function

• Lateralisation = the idea that the two halves of brain are functionally different and that certain mental processes and behaviours are mainly controlled by one hemisphere

• Broca's area and Wernicke's area are lateralised

• Broca's area - area in left frontal lobe, responsible for speech production

• Wernicke's area - area in left temporal lobe, responsible for language comprehension

• Strokes generally affect only one side of the brain as each has it's own blood supply

• Many simple functions (motor and somatosensory areas) are not lateralised - maybe only complex functions e.g. language (Broca's and Wernicke's both on LHS)

• Contralateral control - left side brain control right side body and vice versa

Define lateralisation

The idea that the two halves of brain are functionally different and that certain mental processes and behaviours are mainly controlled by one hemisphere

AO3 for lateralisation

Split brain research - Sperry’s commissurotomies (cut corpus collosum), describe what was seen, recognition by touch, composite words - what was seen by either visual field could be described only by right v.f (left brain), recognised by left v.f (right brain), said by right v.f. and written by left v.f.(NB generalisation issues - epileptic patients)

Lateralisation vs plasticity - Rogers chickens show lat. as adaptive as two tasks can be done simultaneously with greater efficiency BUT plasticity also adaptive - lat. first preference for adaptivity but plasticity more important as deals with damage for survival

Lateralisation evolutionary advantage - Rogers chickens

Lateralisation changes with age - Szaflarski found language more lateralised to left in kids as age increases but after 25, decreases each decade of life - extra processing resources of other hemisphere may compensate for age-related decline of function

AO1 for plasticity and functional recovery

• Brain increases number of synaptic connections most during infancy - peaking at about 15,000 per neurone at 2-3 years.

• Synaptic pruning (getting rid of less used ones, strengthening most used ones) allows lifelong plasticity in brain

• After trauma, unaffected areas of brain adapt and compensate for damaged areas

• Functional recovery (example of neural plasticity) initially very fast, then slowly after a few weeks or months

• Functional recovery includes: growth of new nerve endings to form new neuronal pathways, axons with similar function more aroused to compensate for lost axons, using homologous areas on opposite side of the brain

• Factors affecting recovery: age (brain plasticity), type and severity of trauma, rehab type (effort and time), general health and stress levels, level of education, gender?

AO3 for plasticity and functional recovery

Maguire taxi drivers - increased grey matter in hippocampus of London cabbies compared to matched control group. Area associated with development of spatial and navigational skills. Positive correlation between job length and depth of difference.

Age - older = slower recovery - Tueber soldiers with brain damage recovery from movement and visual issues is age dependent. 60% under 20yrs showed sig. improve., only 20% of over 20yrs.

Level of education and cognitive reserve - Schneider et al effects of cognitive reserve on disability free recovery (DFR). 40% of patients with DFR had 16+ yrs in education. 10% of patients with 12+ yrs had DFR. NB groups may not be directly comparable

RLApp of constraint induced therapy (CIT) - Taub found monkeys with paralysis of one side, sling on healthy arm so forced to use unhealthy had sig. improvement in function - reorganisation of neuronal networks in motor cortex

AO1 for ways of studying the brain

• fMRI - detects changes in blood flow to show active areas (more O2 consumed) in 3D

• EEG - measures brainwave patterns from thousands of neurones via electrodes

• ERP - type of brainwave triggered by particular events filtered out from EEG recordings

• Post-mortems - study of brain after death, in order to link brain areas to observed behaviour deficits

AO3 for ways of studying brain (fMRI, EEG, ERP, post-mortem)

• fMRI

  • Risk-free, non-invasive and high spatial resolution

  • Expensive, poor temporal resolution

• EEG

  • Real world uses (e.g. sleep stages, diagnosing epilepsy), high temporal resolution

  • Comes from 1000s of neurons, cannot identify source

• ERP

  • More specific than EEG, higher temporal resolution than fMRI

  • No standardised method, background 'noise' not easy to control

• Post-mortem

  • Early research (e.g. Broca)

  • Causation is an issue, consent issues (e.g. HM)

AO1 for circadian rhythms

• Circadian rhythms are rhythms that last for around 24 hours. For example, the sleep-wake cycle, or the core body temperature

• Biological rhythms are influenced by endogenous pacemakers and exogenous zeitgebers

• Endogenous pacemakers = the body's internal biological 'clocks' (e.g. SCN)

• Exogenous zeitgebers = external changes in the environment which affect biological rhythms

AO3 for circadian rhythms

Siffre - lived in cave without exogenous zeitgebers, tried several times - avg 25 hr sleep-wake cycle. Supported by Aschoff and Wever - also around 25hr.

Folkard - body temp affects cognitive abilities. Kids read stories at 3pm have better recall and comprehension than at 9am. Supported by Gupta - improved IQ tests at 7pm (vs 9am and 2pm) - but reductionist explanation (could be eating schedule, general conc etc).

RLApp shift work and medical treatment - better understanding of negative consequences of desynchronisation of circadian rhythms. Bolvin - night shift workers have reduced concentration at around 6am so mistakes and accidents more likely. Chronotherapeutics - medical treatment given based on person’s bio rhythms. Bonten - aspirin for heart attacks most effective at night as it reduces platelet activity and heart attacks most likely in morning.

Individual differences - almost idiographic (small sample), difficult to make generalisations. Czeisler found individual differences in sleep-wake cycles from 13 to 65 hours.