Biopsych Flashcards
Nervous system
- central nervous system; brain (cerebral cortex is outer layer), highly developed in humans
- spinal cord connects brain to PNS, reflex actions
Endocrine System
- glands + hormones; hormones distributed in bloodstream, pituitary is the master gland
- fight or flight; sympathetic arousal: pituitary →> adrenal gland -> adrenaline
Localisation of function in the brain A01
- localisation vs holistic theory; are brain functions in specific areas or across the whole brain?
- hemispheres of the brain; brain (cerebrum) divided in half + each hemisphere controls
the opposite side of the body = lateralisation - motor, somatosensory, visual + auditory centres; each of the 4 lobes of the brain (frontal, parietal, occipital + temporal lobes) is linked to different fut nctions
- language centres in the brain; Broca’s related to production (left frontal), Wernicke’s related to understanding (left temporal)
Localisation of function in the brain A03
- evidence from neurosurgery; isolation (severing connections) of cingulate gyrus (cingulotomy) improves OCD in 30% of ppts (Dougherty et al)
- evidence from brain scans; Broca’s + Wernicke’s areas identified (Peterson et al), semantic + episodic areas identified (Buckner + Peterson) → COUNTER →> learning in rats is holistic not localised (Lashley)
- language localisation questioned; multiple pathways (e.g. right hemisphere + thalamus), not just Broca’s + Wernicke’s (Dick + Tremblay)
Neurons
- types of neurons; sensory, relay + motor neurons
- structure of a neuron; cell body contains nucleus, has dendrites + axon covered in myelin sheath divided by nodes
of Ranvier - electrical transmission; positive charge leads to action potential
Synaptic transmission
- synapse; terminal buttons at synapse, presynaptic vesicles release neurotransmitter
- neurotransmitters; postsynaptic receptor site receives neurotransmitters from dendrites of adjoining neuron + specialist functions, e.g. acetylcholine for muscle contraction
- excitation, inhibition + summation; adrenaline is excitatory, serotonin is inhibitory + postsynaptic neuron triggered if sum of excitatory + inhibitory signals reaches threshold
- psychotherapeutic drugs; SSRIs increase serotonin activity
Plasticity A01
- brain plasticity; research suggests that neural connections can change or new connections can be formed
- research into plasticity; hippocampus in taxi drivers changes structure after learning The Knowledge (Maguire et al) + changes in hippocampus and the parietal cortex betore and after exams (Draganski et al)
Plasticity A01
- brain plasticity; research suggests that neural connections can change or new connections can be formed
- research into plasticity; hippocampus in taxi drivers changes structure after learning The Knowledge (Maguire et al) + changes in hippocampus and the parietal cortex betore and after exams (Draganski et al)
Plasticity A03
- negative plasticity; drug use may cause neural changes (Medina
et al) + phantom limb syndrome due to reorganisation in
somatosensory cortex (Ranachandran + Hirstein)
- age + plasticity; plasticity reduces with age, though Bezzola et al
showed how golf training caused neural changes in over-40s
Functional Recovery A01
- after brain trauma; healthy brain areas take over lost functions after trauma, happens quickly
- what happens in the brain during recovery?; new synaptic connections, secondary pathways ‘unmasked’ -> axon sprouting + denervation supersensitivity + recruitment of homologous brain
areas
Functional Recovery A03
+ Real-world application: understanding of brain recovery aids in neurorehabilitation
therapy, e.g. after strokes
+ Cognitive ability correlation: (Schneider et al) negative correlation between cognitive
functioning and time spent in recovery after brain damage, higher level of education =
less time in recovery = more likely to recover
- Functional & spontaneous recovery limited: law of equipotentiality means the brain can
only repair itself up to a certain point, after which rehabilitation is needed to continue
recovery
Hemisphere Lateralisation A01
- localisation + lateralisation; some functions localised (e.g. vision), or localised + lateralised (e.g. language)
- left + right hemispheres; language areas in LH (for most), LH is the analyser, RH is the synthesiser
- motor areas are contralateral + visual areas are contralateral & ipsilateral, LVF of both eyes to RH and RVF to LH - same for auditory
areas
Hemisphere lateralisation A03
- lateralisation in the connected brain; global elements processed by RH and finer detail by LH
(Fink et al) - one brain; certain hemispheres dedicated to certain tasks but no dominant RH O LH (Nielsen et al)
Split Brain Research A01
- procedure; 11 participants, split-brain operation for epilepsy (deconnect hemispheres)
- findings; objects shown to RVF (LH), person describes object, shown to LVF (RH), says ‘nothing there’ - object shown to LVF (RH), cannot name but can select item with left hand - pinup picture to LVF, participant giggles but reports nothing
- conclusions; lateralised brain, LH verbal + RH ‘silent’ but emotional
Split Brian research A03
- research support; split-brain participants faster at some LH tasks (Luck et al), normally slowed down by inferior
RH (Kingstone et al) - generalisation issues; epilepsy is a confounding variable when comparing ppts to ‘normal’ controls
Ways of studying Brian A01
- fMRI; detects changes in blood flow to show active areas (where more oxygen consumed), 3D
- EEG; measures brainwave patterns from 1000s of neurons via electrodes
- ERP; types of brainwave triggered by particular event filtered out from
EEG recordings - post-mortems; study of the brain after death, in order to link brain areas to observed behaviour deficits
Ways of studying brian A03
- fMRI; + risk-free, non-invasive + 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, can’t 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 an issue, consent issues (e.g. HM)
Circadian Rhythms A01
- biological rhythms; controlled by internal body clocks (endogenous pacemakers) and
external cues (exogenous zeitgebers) -> take 24hrs to complete
- the sleep/wake cycle; governed by daylight and by biological clock (suprachiasmatic
nucleus), gets light information from the eyes
- Siffre’s cave study; his free-running rhythm extended slightly to 25 hrs when deprived of
daylight - other research; support for exogenous zeitgebers entraining internal clock (Aschoff +
Wever, bunker, natural rhythm longer) + support for endogenous cues if difference is too
big (Folkard et al, cave with 22 hr day)
Circadian Rhythms A03
+ Application: provides knowledge applicable to night-shift work and the negative consequences of disrupted circadian rhythms - shift workers are 3x more likely to develop heart disease (Knutsson)
+ Application: used to improve medical treatments by co-ordinating administrating medication with the body’s processes, eg. aspirin is most effective for treating heart attacks when taken late at night + Research support: Siffre’s cave studies
+ Research support: (Aschoff & Wever) a group of participants who spent four weeks in a WW2 bunker had sleep/wake cycles that extended to 25 hours (except one: 29 hours)
+ Research support: (Folkard et al) 12 people lived in a cave for 3 weeks with a clock and were told to sleep at 11:45
They did not know the clock was running fast to adjust their sleep/wake cycles to 22 hours unconsciously: only one adjusted comfortably
- Individual differences make generalisations difficult: Czeisler found significant individual differences in sleep/wake cycles from 13-65 hours, and sleep/wake cycle studies (Siffre, Folkard et al, Aschoff & Wever) have small samples.
(Duffy et al.) different people have different weferences, ‘morning’ vs ‘evening people’
Infradian Rhythms A01
- takes more than 24hrs to compete
- the menstrual cycle; ostrogen regulates ovulation, progesterone readies body for pregnancy (endogenous factors)
- synchronising the menstrual cycle; menstrual cycles synchronised through pheromones, exogenous factor (Stern + McClintock)
- seasonal affective disorder; form of depression triggered in the winter months + regulated by melatonin, a circannual rhythm
Infradian Rhythms A03
+ Menstrual synchrony may have an evolutionary basis, as females menstruating and becoming pregnant at the same time to raise offspring together and to protect females from males
- Confounding variables in menstrual synchrony studies: stress, changes in diet, exercise, etc. may impact the menstrual cycle which are confounding variables as they cannot be controlled and making any results likely due to chance
Ultradian Rhythms A01
- takes less than 24hrs to complete
- stages of sleep; 5 stages that occur in a 90-minute cycle:
- stages 1 + 2: alpha waves + sleep spindles
- stages 3 + 4: deep sleep, delta waves
- stage 5: REM sleep, theta waves
Ultradian Rhythms A03
+ Improved understanding: research into sleep and ultradian rhythms has improved our understanding of impacts of age on sleep, slow-wave sleep (stages 3&4) reduces with age, which is the stage where the growth hormone is mostly produced, which may explain various issues of old-
age such as attention
+ Research support: (Kleitman) EEGs have been used to research sleep cycles by detecting brain activity in different stages and waking participants in different stages to assess dream recall and ease of waking up
- Significant individual differences: (Tucker et al.) large differences in the duration of sleep stages between people, and may be largely biologically determined, so research lacks generalisability
Endogenous Pacemakers and sleep/wake cycle A01
- the suprachiasmatic nucleus; SCN receives information about light from optic chiasm
- animal studies + the SCN; sleep/wake cycle disappeared when SCN destroyed (DeCoursey et al) + SCN transplanted from mutant hamsters with 20-hour sleep cycle (Ralph et al)
- the pineal gland + melatonin; the SCN passes information to the pineal gland that control melatonin
