Biopsychology descriptions Flashcards
Nervous system
-divides into CNS (brain/spinal cord) and peripheral NS
-PNS divides into somatic and autonomic NS
-ANS divides into sympathetic and parasympathetic branch
Somatic NS
-nerves we actively control
-SNS receives information from sensory receptors + sends info to CNS which controls muscle movement
ANS
-works automatically, don’t have to think for nerves to work eg. heart beat
-has 2 sub divisions sympathetic and parasympathetic branch
Differences between ANS and SNS
-ANS only motor, SNS sensory + motor
-ANS controls internal organs/glands , SNS controls muscle
-ANS control centre in brain stem, SNS in motor cortex
Sensory neurones
-carry messages from sensory receptors to CNS
-long dendrites and short axons
-cell body in the middle of the axon
Relay neurons
-connect sensory neurones to motor or other relay neurones
-found in CNS
-short dendrites and axons
Motor neurones
-connect CNS to muscles or glands
-release neurotransmitters that bind to receptors on the muscle causing movement
-short dendrites, long axons
Neurotransmitters
-chemicals that diffuse across the synapse to the next neurone
-bind to post synaptic receptor sites
-re-uptake then occurs where neurotransmitter returns to pre-synaptic neuron
Excitation
Inhibition
-post synaptic neurone becomes positively charged + more likely to fire eg. adrenaline
-Post synaptic neurone becomes negatively charged + less likely to fire eg. GABA
-these influences are summed, so if the net is excitatory, neurone is more likely to fire
2 Glands and what hormone is released
-Pineal gland releases melatonin which regulates sleep-wake cycle
-Adrenal medulla releases adrenaline for flight or fight response
Fight or flight
-generated from ANS specifically sympathetic branch
-perceived stressful event
-hypothalamus sends message to pituitary gland
-this releases ACTH
-this causes adrenal medulla to release adrenaline
-this triggers physiological changes leading to flight or fight response
-parasympathetic branch returns the body to resting state
Localisation of function
Specific functions have specific locations within the brain
Location of 6 areas
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Starting at top of brain + working clockwise
Motor cortex
Somatosensory cortex
Visual cortex
Wernicke’s area
Auditory cortex
Broca’s area
Motor cortex
description, lobe, hemisphere
-responsible for voluntary muscle movements
-frontal lobe
-both hemispheres
Somatosensory cortex
description, lobe, hemisphere
-processes sensory input from skin, muscle and joints related to touch
-parietal lobe
-both hemispheres
Visual cortex
description, lobe, hemisphere
-associated with vision, different areas each processing different types of visual information eg. shape, colour
-occipital lobe
-both hemispheres
Wernicke’s area
description, lobe, hemisphere
-patients who had damage to this area couldn’t formulate coherent sentences + couldn’t understand language
- temporal lobe
-left hemisphere
Auditory cortex
description, lobe, hemisphere
-processes sound along with volume, pitch and location
-temporal lobe
-both hemispheres
Broca’s area
description, lobe, hemisphere
-Patients with damage to this area could understand spoken language but were unable to speak
-frontal lobe
-left hemisphere
Brain lateralisation
-the 2 halves of the brain aren’t alike and have different functional specialisms eg. left=language
-the two halves of the brain are connected through the corpus callosum
Split brain research
Sperry
-participants all had corpus callosum surgically removed to help treat epilepsy
-pps had to focus on a dot on the centre of the screen
-information was flashed to either the left or right visual field for 200 milliseconds
3 tasks
1. say the word they had seen, if information shown to left visual field its sent to the right hemisphere of the brain so pps would say they didn’t see anything as the language centres are in the left hemisphere
2.pick up and object that matched the word, if information shown to left visual field, they could pick up the correct object but couldn’t explain why they were holding it
3.face recognition, shown 2 halves of different faces if information was shown in the left visual field and sent to right hemisphere pps could recognise the face. but if shown to right visual field pps couldn’t recognise the face.
Neuroplasticity
the ability of the brain to change and adapt synapses, pathways and structures due to experiences
Plasticity in childhood
-brain has most neurones when a child
-as we get older, the brain is sculptured by our environment and experience
-pathways that aren’t used will die off this is called synaptic pruning
Neuroplasticity research
Maguire
-16 right handed male taxi drivers compared to 50 right handed males
-MRI scans to analyse grey matter in brain
-posterior hippocampus had larger volume of grey matter in taxi drivers
-correlation between time spent as taxi driver and volume of grey matter
Functional recovery
3 ways1
-axon sprouting- axons of surviving neurones grow new branches that make synapses in areas of the brain with formerly damaged neurones
-denervation super sensitivity- axons that do a similar job become more aroused to compensate for ones that are lost
-recruitment of homologous areas- areas on the other side of the brain take over when the other side is damaged
functional recovery research evidence
-Danelli et al
-case study of EB who had most of left hemisphere removed due to tumour when he was 2
-lost his linguistic ability
-by the age of 17 EB’s language was comparable to controls
-the right hemisphere compensated for the loss of the left hemisphere
fMRI
functional magnetic resonance imaging
-records energy released by haemoglobin
-so when an area of the brain is active, its using more oxygen so the scanner detects the energy
-this gives a moving picture + shows activity one second after it occurs
-produces 3D images showing which parts of the brain is used for different abilities
EEG
Electroencephalogram
-measure electrical activity in the brain
-electrodes placed on scalp that detect small electrical changes
-shown on a graph
-used for epileptics of sleep disorders
ERP
Event-related potentials
-similar to EEG as measures electrical activity
-uses statistical averaging to filter extraneous brain activity
-leaving only ones that relate to task of interest
-a stimulus is presented to pp and psychologists looks for specific electrical responses
Post mortem
-brain after individual has passed away
-brain examined to see where damage occurred
-carried out on people with rare disorder eg. people with Broca’s aphasia
-find links between psychiatric disorders and brain abnormalities
Ultradian-
Infradian-
Circadian-
-occur more than once in 24hrs eg. sleep cycle
-take longer than 24hrs to complete eg. menstrual cycle
-last for around 24hrs eg. sleep/wake cycle
Internal body clock-
External changes in environment-
-endogenous pacemaker
-exogenous zeitgeber
Circadian rhythm research
Siffre
-spent 6 months in a cave in Texas
-measured his sleep/wake cycle without any clues as to the time of day
-found his rhythm lengthened to 25-30 hrs
-shows the existence of endogenous pacemaker as kept steady circadian rhythm
-also show influence of exogenous zeitgeber of light to keep our circadian rhythm to 24hrs
Effect of endogenous pacemakers and exogenous zeitgebers on sleep/wake cycle
-Superchiasmatic nucleus in hypothalamus is regulated by light
-when dark the SCN sends signal to pineal gland to increase melatonin levels
-melatonin inhibits the brain mechanisms that promote wakefulness
-SCN and pineal gland act as endogenous pacemakers
Research evidence of endogenous pacemakers
Ralph et al.
-removed SCN of genetically abnormal hamsters with 20 hr circadian rhythm
-abnormal SCN was transplanted into other hamsters with normal 24hr rhythm
-found hamsters cycle changed to 20hrs
Research evidence of exogenous zeitgebers (light)
Campbell + Murphy
-15 pps woken at different times during the night
-light pad shone on the back of their knees
-their sleep/wake cycle changed by up to 3 hrs
Research evidence of exogenous zeitgeber (social cues)
Klein + Wegmann
-investigated jet lag
-found circadian rhythms adjusted quicker if they went outside more at their destination
-thought to be due to social cues of new time zone eg. meal times
Examples of infradian rhythm + research evidence
Menstrual cycle
-ranges from 24-35 days
-controlled by hormones which regulate ovulation
-oestrogen causes an egg to develop and be released from the ovary
-progesterone levels rise, thickening the womb lining
-if pregnancy doesn’t occur lining leaves the body
-McClintock- 29 women and found when women received odourless compounds from other women’s armpits, their cycle changed showing effect of EZ
Seasonal affective disorder (SAD)
-mood disorder that occurs mainly during winter
-melatonin is thought to be involved in cause of SAD
-lack of sunlight=more melatonin
-this effects production of serotonin
-Golden et al. - meta analysis and found using a bright light was effective in reducing symptoms of SAD
Examples of ultradian rhythms
-sleep cycle lasts 90 mins
-each stage has different brainwave activity
-alternates between REM and NREM
-Kleitman suggests 90 min cycle continues when we’re awake (BRAC)
-we move through stages of alertness and psychological fatigue
-research suggests human mind can focus for a period of 90 mins before losing concentration, feeling hungry, fatigued
