biopsychology Flashcards
the nervous system
central nervous system
peripheral nervous system
central nervous system
brain - cerebral cortex is outer layer, highly developed in humans
spinal cord - connects brain to PLS, reflect actions
pheripheral nervous system
autonomic nervous system - sympathetic and parasympathetic
somatic nervous system
the endocrine system
glands and hormones
fight or flight
glands and hormones
hormones distributed in the blood steam
pituitary is the master gland
fight or flight
sympathetic arousal
pituitary -> adrenal gland -> adrenaline
localisation versus 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 and auditory centres
each of the four lobes of the brain (frontal, parietal, occipital and temporal lobes) is linked to different functions
language centres of the brain
broca’s related to production (left frontal)
wernicke’s related to understanding (left temporal)
evidence from neurosurgery
isolation - severing connections of cingulate gyrus - improves OCD in 30% of participants
evidence from brain scans
broca’s and wernicke’s area identified - petersen et al
semantic and episodic areas identified - buckner and peterson
counterpoint - learning in rats is holistic not localised - lashley
language localisation questioned
multiple pathways eg RH and thalamus not just broca’s and wernicke’s dick and tremblay
case study of localisation
unique case studies support localisation eg phineas gage but lack generalisability
localisation and lateralisation
some functions localised eg vision or localised and lateralised eg language
left and right hemispheres
language areas in LH
LH is analyser
RH is synethesiser
motor areas are contralateral
visual areas are contralateral and ipsilateral
LVF of both eyes to RH and RVF to LH
same for auditory areas
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 or LH - nielsen at al
lateralisation versus plasticity
lateralisation enables multitasking but plasticity allows recovery of lost lateralised functions
split brain research
eleven participants, split-brain operation for epilepsy
object shown to RVF - person describes object - shown to LVF - nothing there
object shown to LVF - cannot name but can select item with left hand
pinup picture to LVF - giggles but reports nothing
lateralised brain, LH verbal and RH silent but emotional
research support brain research
split-brain participants faster at some LH tasks - luck et al
normally slowed down by inferior RH
generalisation issues split brain
epilepsy is a confounding variable when comparing participants to normal controls
ethics for split brain
operation not done for the study and participants gave informed consent
but may not have fully understood and participation was stressful
types of neurons
sensory, relay and motor neurons
structure of 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
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 and summation
adrenaline is excitatory, serotonin is inhibitory
postsynaptic neuron triggered if sum of excitatory and inhibitory signals reaches threshold
psychotherapeutic drugs
SSRIs increase serotonin activity
fMRi
detects changed in blood flow to show active areas
risk free, non-invasive and high spatial resolution
expensive, poor temporal resolution
EEG
measures brainwave patterns from thousands of neurons via electrods
real world uses - sleep stages, epilepsy, high temporal resolution
comes from 1000s of neurons, can’t identify source
ERP
types of brainwave triggered by particular events filtered out from EEG recordings
more specific than EEG - higher temporal resolution than fMRI
no standardised method, background noise not easy to control
post-mortems
study of brain after death, in order to link brain areas to observed behaviour deficits
early research eg broca
causation an issue, consent issues eg HM
brain plasticity
research suggests that neural connections can change or new connections can be formed
research into plasticity
hippocampus in taxi divers changed structure after leaning
the knowledge - maguire et al
changes in hippocampus and the parietal cortex before and after exams - draganski et al
negative plsticity
drug use may cause neural changes - medina et al
phantom limb syndrome due to reorganisation in somatosensory cortex - ramachandran and hirstein
age and plasticity
plasticity reduces with age, though Bezzola et al showed how golf training caused neural changes in over-40s
seasonal brain changes
songbirds’ SCN shrinks in spring and expends in autumn
- tramontin and brenowitz
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
- axonal sprouting
- denervation supersensitivity
- recruitment of homologous brain areas
real world application of functional recovery
knowledge of axonal growth leads to eg constraint induced movement therapy
cognitive reserve
40% recovery for people with 16 years’ education, 10% for those with less than 12 - schneider et al
functional recovery - small sample
100% recovery from stroke using stem cells - banerjee - but small sample of 5 people
