Biopsych Flashcards
function of cerebellum
-controls motor skills, balance, coordination of muscles to allow precise movement
function of cerebrum
-enables speech, judgement, thinking, problem solving, emotions
function of diencephalon
-contains thalamus (relay for nerve impulses between senses and brain) and hypothalamus (temp reg, hunger, thirst, acts as link between endocrine system and nervous system)
function of brain stem
-regulates automatic functions eg. breathing, heart rate, swallowing
-motor and sensory neurons travel through brain stem, allowing impulses to pass between brain and spinal cord
what does the spinal cord do
-connects brain w peripheral nervous system to relay info between brain + body to allow regulation of breathing, digestion etc
-contains circuits of nerve cells to allow reflex actions
2 parts of peripheral nervous system (brief)
-somatic nervous system
-autonomic nervous system
function of somatic nervous system
-responsible for relay of sensory and motor info to and from CNS
function of autonomic nervous system
-responsible for involuntary actions eg. heartrate, digestion
2 parts of autonomic nervous system
-sympathetic nervous system (SNS)
-parasympathetic nervous system (PNS)
function of sympathetic nervous system (SNS)
-involved in emergency responses (fight or flight)
-increase heartrate, dilate pupils, slows digestion, dilate blood vessels in muscles. increase BP
function of parasympathetic nervous system (PNS)
-involved in calming down after emergencies
-decreases heartrate, decreases BP, restarts digestion
structure and function (of parts) of neurons
-dendrites - receive signals from other neurons
-axon - carries action potential towards axon terminal, surrounded by myelin sheath
-axon terminal - has vesicles that contain neurotransmitters, connects neuron to others by synaptic transmission
function of sensory neurons
-found in sensory receptors (eyes, ears, nose etc)
-carry impulses to spinal cord and brain
-impulses translated into sensations (vision, hearing)
-not all reach brain - some stop at spinal cord for reflex actions
function of relay neurons
-found in brain and spinal cord
-allow sensory and motor neurons to communicate
function of motor neurons
-found in CNS
-control muscle movements
-when stimulated, they release neurotransmitters that bind to receptors on muscles and trigger a response which leads to movement
process of synaptic transmission
- action potential travels down axon and arrives at axon terminal
- AP stimulates synaptic vesicles to release neurotransmitters
- neurotransmitters diffuse across synapse and bind to receptor sites on dendrites of post-synaptic neuron
- chemical message is converted to an electrical impulse to begin transmission again (if summation allows)
- neurotransmitters ‘re-uptaken’ by pre-synaptic neuron
what are excitatory neurotransmitters
-make post-synaptic neuron MORE likely to fire as they increase the pos charge
-this results in an excitatory post-synaptic potential (EPSP)
what are inhibitory neurotransmitters
-make post-synaptic neuron LESS likely to fire as they cause a more neg charge
-this results in an inhibitory post-synaptic potential (IPSP)
what is summation
-the net sum of adding up the excitatory and inhibitory synaptic input
-this determines whether the neuron will fire or not
what is the endocrine system
-network of glands that produce and secrete hormones via circulatory system to target organs
-system is regulated by feedback to ensure stable conc of hormones
location and function of the pituitary gland
-‘master gland’
-located in brain
-stimulates all other glands to release hormones
location and function of adrenal glands
-located above kidneys
-release adrenaline/cortisol
function of testes
-produce testosterone which deepens voice, stimulates growth and sperm production
function of ovaries
-produces progesterone which maintains uterine lining and oestrogen which stimulates egg production and release
function of thyroid gland
-releases thyroxine which is responsible for regulating metabolism
5 glands (brief)
-pituitary
-adrenal
-thyroid
-testes
-ovaries
structure and function (of parts) of pituitary gland
- anterior pituitary (front) - produces ACTH as response to stress - ACTH stimulates adrenal glands to produce cortisol. Also produces LH and FSH
- posterior pituitary (back) - releases oxytocin which stimulates uterus contraction in childbirth and is important for bonding
structure and function (of parts) of adrenal glands
- adrenal cortex (outer) - produces cortisol
- adrenal medulla (inner) - produces adrenaline and noradrenaline - prepare body for fight or flight
what do low cortisol levels lead to
-low BP
-poor immune functioning
-inability to deal w stress
what is the fight or flight response (brief)
-evolutionary survival mechanism that allows animals and humans to respond quickly to life-threatening situations
acute stress response
- Sympathetic NS (SNS) triggered by hypothalamus (after amygdala sends distress signal)
- SNS sends signal to adrenal medulla to release adrenaline
3.adrenaline causes increased heartrate/BP, vasoconstriction etc
4.when threat has passed, parasympathetic NS (PNS) calms the body down again
chronic stress response
-HPA axis
1.Hypothalamus activates HPA axis by releasing CRH
2. CRH causes pituitary gland to release ACTH
3. ACTH stimulates adrenal cortex to release cortisol, which causes glucose to be continually released from liver to provide energy
what does continual release of cortisol lead to
-increased risk of heart attack
-weakened immune system
-increased blood sugar
limitations of fight or flight response
-gender differences - women have less ‘flight’ response due to being primary caregiver, not wanting to leave children
-not generally needed in modern society and can cause health risks - high BP can cause damage to blood vessels, weakened immune system
-also a ‘freeze’ reaction - Gray - 1st phase of reaction is to avoid confrontation and freeze. allows us to become aware of surroundings and prepare
location and function of motor cortex
-located in posterior region of (both) frontal lobes on PREcentral gyrus
-responsible for voluntary movement
-works contralaterally
location and function of somatosensory cortex
-located in (both) parietal lobes on POSTcentral gyrus
-responsible for processing sensory input and locating them to specific parts of body
-works contralaterally
location and function of visual cortex
-located in (both) occipital lobes
-responsible for processing visual info
-works contralaterally
location and function of auditory cortex
-located in (both) temporal lobes
-responsible for processing auditory information and speech
2 language centres (brief)
-brocas area
-wernickes area
location and function of brocas area
-located in LEFT hemisphere
-posterior region of frontal lobe
-responsible for speech production
location and function of wernickes area
-located in LEFT hemisphere
-posterior region of temporal lobe
-responsible for understanding language
type of aphasia damage to brocas area causes
-expressive aphasia
-inability to produce speech
type of aphasia damage to wernickes area causes
-receptive aphasia
-inability to understand language
strengths of localisation of function
-Aphasia studies - ppl w damage to brocas had expressive aphasia, ppl w damage to wernickes had receptive aphasia
-Case study - Phineas Gage - personality change after damage to frontal lobe
limitations of localisation of function
-individual differences - bavelier - diff patterns in activation and gender differences in size of lang centres
-equipotentiality - Lashley - intact areas can take over function for damaged areas
-communication - Dejerine -some behaviours move through diff areas of brain - case study of loss of ability to read = damaged connection between visual cor and wernickes
what is meant by hemispheric lateralisation
-each hemisphere of the brain is specialised for certain functions
what is the left hemisphere specialised for
-language
what is the right hemisphere specialised for
-visual motor tasks
what connects the 2 hemispheres
-corpus callosum
split brain research method
-Sperry and Gazzaniga
-11 patients w severe epilepsy who had procedure to sever corpus callosum
-flashed word/image for 1/10 of a second to right or left visual field (means eye wouldnt have time to move)
split brain research findings
-found that images flashed to left visual field couldnt be talked abt by ppts
-could draw images shown to left visual field w left hand
definition of plasticity
the brains ability to change and adapt as a result of experience
definition of functional recovery
the brains ability to transfer the functions of damaged areas to healthy areas, allowing normal function to continue
plasticity research - boyke et al
-evidence of plasticity in 60yr olds by teaching them to juggle
-found increased grey matter in visual cortex
-changes reversed when practice stopped
plasticity research - kuhn et al
-compared a control group w a video game training group (trained for 2 months for at least 30 mins a day) and found sig increase in grey matter in the cortex, hippocampus and cerebellum.
-researchers concluded new synaptic connections had been created in areas involved in spatial nav, strategic planning, working mem and motor function
plasticity research - davidson et al
-compared 8 practitioners of tibetan meditation with 10 students w no meditation experience
-found much greater activity of gamma waves (coordinate neuron activity associated w intense focus) in the monks, students showed slight increase
how does plasticity work
-brain continues to create new neural pathways and alter existing ones to adapt to new experience as a result of learning
-nerve pathways that are frequently used gain stronger connections, whereas ones that are rarely/never used eventually die
2 mechanisms for functional recovery (brief)
- neuronal unmasking
- stem cells
how does neuronal unmasking work
-increasing rate of neural input to ‘dormant synapses’, as would happen when a surrounding brain area becomes damaged, can unmask these synapses and open connections to regions of the brain that are not normally activated.
how do stem cells aid functional recovery
-unspecialised cells can be either directly implanted to replace dead or dying cells, secrete growth factors that ‘rescue’ damaged cells, or form new neural networks that link uninjured sites to the damaged site
4 ways of studying the brain (brief)
- fMRI
- EEG
- ERP
- post-mortem examination
how does fMRI work
-measures changes in brain activity while a person performs a task by measuring blood flow to specific areas of the brain
-increased blood flow suggests increased neural activity as it is needed to supply a higher demand for oxygen
uses of fMRI
-mapping location of function
-preparing for brain surgeries
-assessing effect of strokes or degenerative diseases eg. Alzheimers
eval of fMRI
-high spatial resolution
-non invasive
-expensive
-poor temporal resolution - 5 sec lag time
how does post-mortem examination work
-examination of the physical structures and neurobiology of a brain after a person has died
uses of post-mortem examination
-determine whether behaviours a person showed in life are linked to structural abnormalities in brain
-establishing links between psychiatric disorders and abnormalities eg. reduced no of glial cells in patients w depression
eval of post mortem exam
-foundation of early understanding
-Broca + Wernicke research
-causation is difficult to establish
-ethical issues - informed consent
how does EEG work
-measures all electrical activity in the brain using electrodes placed on the scalp
uses of EEG
-detect and diagnose disorders eg. epilepsy and Alzheimers
eval of EEGs
-prac applications - diagnosis
-high temporal resolution
-generalised info recieved
how does ERP work
-measures small voltage changes in the brain triggered by specific stimuli.
1. Sensory ERP - first 100 milliseconds, initial response
2. Cognitive ERP - after first 100 milliseconds, cognitive processing of info
uses of ERP
study working memory and cognitive processing
eval of ERPs
-high temporal resolution - 1 millisecond
-lack of standardisation between studies makes comparison difficult, so cant confirm findings
-all background noise/extraneous material must be eliminated
how long do circadian rhythms last
24hrs
how long do ultradian rhythms last
less than 24hrs
how long do infradian rhythms last
more than 24hrs
2 main Endogenous Pacemakers (EPs)
-SCN
-Pineal gland
2 main Exogenous Zeitgebers (EZs)
-Light
-Social Cues
examples of circadian rhythms
-sleep-wake cycle
-core body temp
-hormone production
explain sleep-wake cycle as a circadian rhythm
-controlled by EZ of light as when light is dim, retinal cells containing melanopsin send message to SCN (via optic nerve), which determines light level and then instructs pineal gland to release melatonin. When light is bright, pineal gland is told to stop producing melatonin.
-also controlled by homeostasis - energy used up when awake.
explain core body temp as a circadian rhythm
-core body temp increases during evening until its highest at 6pm, then begins to drop and sleep occurs when body temp begins to drop.
-lowest temp occurs at around 4am, and then begins to rise during last hours of sleep, promoting feeling of alertness in morning
explain hormone production as a circadian rhythm
-production and release of melatonin from pineal gland occurs when it is dark, which encourages feelings of sleep
-melatonin release then drops during daylight hours, promoting feelings of wakefulness
strengths of circadian rhythms
-practical applications - chronotherapies - drugs timed for hours of most use due to understanding
-research support for importance of light - Hughes -highest cortisol levels at noon instead of early morning due to continuous darkness at Antarctic station
limitations of circadian rhythms
-Individual differences - cycle lengths (13-65 hours) and cycle onset (morning/night people)
-temperature more important than light - Buhr et a - small changes in body temp send powerful messages to body clocks, causing tissues and organs to become active or inactive
research evidence for free-running circadian rhythm (brief)
-Michel Siffre - cave
-Aschoff and Wever - ww2 bunker
-Folkard - changing clock
Michel Siffre - free running circ rhythm
-1st study: spent 61 days in cave and thought it was 17th september when it was actually 20th august
-2nd study: spent 6 months in a cave and found circ rhythm had settled to 24hrs (BUT w dramatic variations)
-3rd study: 60yrs old - found circ rhythm had extended to 48hrs.
