biopsych Flashcards
what does the nervous system do
does communication
collects, processes and responds to info in environment
coordinates cells and organs
central nervous system (what does it do)
brain+spinal cord
transfers messages to/from environment and brain
brain: centre of conscious awareness
SC: responsible for reflex actions, transmits signals between brain+body
peripheral nervous system (autonomic and somatic)
limbs+torso
sends messages to/from CNS
- autonomic nervous system: important for survival (breathing, heart rate, digestion, stress response)
- somatic nervous system: movement and sensory information from the skin
endocrine system is used to
maintain levels of hormones using glands (slower than nervous system)
hormones = chemicals that travel via blood and affect diff organs
pituitary gland = controls when other glands secrete hormones
adrenal gland
fight or flight response (facilitates release of adrenaline)
pineal gland
produces melatonin when it’s dark to induce sleep
fight or flight response
endocrine system and autonomic nervous system work together (part of the ANS is activated, and a hormone is released)
we perceive a stressor => adrenal gland secretes adrenaline into blood => sympathetic NS is activated
- causes physiological changes so body is prepared to fight challenge or run from it
- once threat has passed the parasympathetic NS brings body back to resting state
ANS: sympathetic system
heart and BP increases
respiration accelerates, blood sugar released from liver
adrenaline/noradrenaline released from adrenal gland
=> fight or flight
ANS: parasympathetic system
heartbeat slows
what is a neuron and what do they do
nerve cell that transfers info between the nervous systems
in a reflex arc, info doesn’t go to the brain, it passes through the 3 neurons
dendrites
branch like, carry impulse from other neurons to cell body (collect in)
axon
carries impluse away from cell body
myelin sheath
fatty, protects the neuron, speeds up transmission of impulse
nodes of ranvier
gaps in myelin sheath that help to speed up the transmission
terminal buttons
at the end of axons, where communication with the next neuron happens
function of 3 different types of neurons
sensory => carry messages from PNS to CNS
relay => connect sensory and motor
motor => connects CNS to effectors
synaptic transmission
neurons separated by synapse
impulse must be transferred chemically
= when the impulse (action potential) reaches the end of the neuron it triggers the release of a neurotransmitter from the synaptic vesicles
when on the other side (dendrite of next neuron) neurotransmitter is converted back to electrical impulse
neurotransmitters role - excitation
increasing +ve charge of a neuron which increases likelihood of the next neuron firing (adrenaline)
neurotransmitters role - inhibition
increases -ve charge of a neuron which decreases likelihood of next neuron firing (serotonin)
neurotransmitters role - summation
a neuron can receive both +ve and -ve potentials, which are then summed to see what effect will be had
localisation of function in the brain: localisation vs holism theory
early theories => all parts of the brain used in processing (holistic theory)
Broca and Wernicke studies suggest diff parts perform diff tasks
=> if a certain part is damaged, function associated with it is affected
cerebral cortex
outer layer of brain
3mm thick
grey and highly folded
very developed
the 4 lobes
frontal lobe
temporal
parietal
occipital
frontal lobe function
risk assessment and decision making
motor area
parietal lobe function
processes sensory info eg pain
occipital lobe function
processes visual information
temporal lobe function
auditory/acoustic info
motor area (location, function, damage)
at the back of the frontal lobe
controls voluntary movement in opposite side of body
damage => loss of control of movements
somatosensory area
in parietal lobe
separated from motor area by the central sulcus (a valley)
deals with sensory info from skin
(the amount of that area dedicated to each body part is related to sensitivity of that body part)
visual area
in occipital lobes
eyes send info to opposite hemisphere
damage => problems seeing / understanding what you see
auditory area
in temporal lobes
analyses speech based info
damage => loss of hearing
language areas general info
restricted to left side of brain in most people
Broca’s area
(non fluent speech)
in left frontal lobe
- speech production
damage => slow speech that lacks fluency (Brocas aphasia) (can still understand words tho)
Wernickes area
(fluent speech)
in left temporal lobe
responsible for language comprehension
damage => difficult to understand speech produce meaningless speech (Wernickes aphasia)
says neologisms (nonsense words)
Phineas Gage case study (and which theory does it support)
(NOT FINISHED)
working on a railway line
=> supports localisation of function theory
Phineas Gage evaluation
in 1848 - technology not the same as now, lacks research and validity
lacks reliability - can’t replicate this as unethical so we don’t know for sure if frontal lobe causes personality for everyone
case study - not perfectly controlled so EVs could’ve caused his change in behaviour, like trauma etc
Lashley study (and which theory does it support)
rats learned to run a maze
L then removed between 10 and 50% of their brains
rats were still able to remember maze route
=> supports holistic theory
Lashley evaluation
used rats - we are more developed eg cerebral cortex so different impact on brain development
flawed task/lacks internal validity - task involves many different things (vision, spatial awareness, memory, smell) so even though he’s taking out some of the brain, they still have some of the bits that help the rats
evaluation for localisationVholistic debate
brain scans - objective and controlled, and support localisation (eg Clive Wearing, hippocampus damaged)
neurosurgery - still used in extreme cases to treat disorders eg OCD and depression
plasticity - brain reorganises itself after damage, transfers functions to other areas (supports holistic theory)
hemispheric lateralisation def
when one hemisphere controls specific activities (has a certain job)
split brain studies general (how to qualify)
Sperry studied people with no communication between hemispheres, corpus callosum separated
Sperry experiment for split brain - describing section
quasi - 11 Ps who had surgery for epilepsy
patients look at dot in middle of screen
item flashed up to either visual field for 1/10th of a second (to stop other eye sees it so just one hemisphere)
shown to left visual field (right hemisphere) = can not describe / say nothing was there
shown to right visual field (left hemisphere) = easily describe
therefore language centre us in left hemisphere
Sperry split brain - recognising by touch
objects shown, had to select matching object from options hidden behind a screen
left visual field (right hemi) = could select with left hand, and select item most associated to picture
can’t verbally identify but can recognise
Sperry split brain - composite words
two words at same time, one on either side of visual field
left visual field (right hemi) = can draw with left hand what is seen in left visual field
right visual field (left hemi) = can say what they see in right visual field
Sperry split brain - matching faces
shown a face and asked to match it from a series of other faces
left visual field (right hemi) = correctly matched
right visual field (left hemi) = ignored
composite pictures (eg man on right side woman on left)
- described a man (left hemi), selected woman for matching picture (right hemi)
so what does each hemisphere control
left = language centres, describes what it sees, doesn’t match faces
right = recognises what it sees, dominates drawing ability
plasticity def
brains ability to change and adapt
synaptic pruning def
“use it or lose it”
- connections we rarely use are deleted
- connections we frequently use are strengthened
plasticity research: Maguire et al
studied brains of 16 London taxi drivers using MRI
found significantly more grey matter (connections) in the posterior hippocampus (development of spatial and navigation skills) than in matched control group
‘The Knowledge’ test assesses recall of city streets and routes
=> the longer they’d been doing the job the bigger the structural difference (+ve correlation)
Maguire et al evaluation
+ control group shows there is a significant difference between taxi drivers and others (good design)
+ use of scientific objective measurements (MRI)
+ attempt to study real world phenomena (external validity)
- can’t be sure difference is due to knowledge
functional recovery (what is it, when does it happen)
following damage and trauma -eg physical injury or stroke/infection
unaffected areas sometimes able to compensate for damaged areas
can happen quickly after trauma (spontaneous recovery) and then slow down after several weeks/months
what happens during recovery (3 methods)
axonal sprouting - new nerve endings grow and connect with undamaged area’s nerves to form new pathways
denervation supersensitivity - axons that do a similar job become aroused at a higher level to compensate for the lost ones
recruitment of homologous areas - on opposite hemisphere to do specific tasks, eg broca’s area damaged in left, right takes over
factors affecting functional recovery
exhaustion, alcohol, stress (affect effort put into recovery)
age (old age lessens extent and speed)
gender (women recover better as brain function is not as lateralised)
education (more educated, more likely to recover)
functional recovery - Schneider et al
769 Ps with a brain injury
more time spent in education, greater chance of disability free recovery DFR
40% of those with 16+ years education achieved DFR
10% of those with <12 years education achieved DFR
functional recovery evaluation
+ application - contributed to neurorehabilitation (recovery slows down after a few weeks so therapy needed to maintain improvements
- sometimes no record of functioning prior to trauma (eg no brain scans from before) so difficult to know how much the brain has recovered or whether it was like that to begin with
- case studies / small sample sizes
ways of studying the brain - fMRI
(functional magnetic resonance imaging)
measures blood flow (blood takes O2 to active areas) so low o2 areas high in deoxyhaemoglobin, which absorbs signal and appears brighter on the screen
+ shows/supports localisation of function
+noninvasive unharmful
+ high spatial resolution
- expensive
ways of studying the brain - EEG
(electroencephalogram)
measures electrical activity using electrodes fixed to scalp
+ safe/painless
+ temporal resolution so can see something as it happens
+ used to diagnose epilepsy and brain activity in sleep
- increases seizures in people already prone
- low spatial resolution
ways of studying the brain - ERP
event related potentials
uses EEG with a specific stimulus response
+ done multiple times and use average, accurate
+easy, non invasive
- low spatial resolution
ways of studying the brain - post mortem
compares structural differences in dead brain and neurotypical one (broca and wernicke used)
+ can see deeper into the brain than the scans
- makes assumption that the structure difference is what causes change, but can’t be sure
biological rhythm def
change in body activity in a cycle
3 types of rhythms are
circadian 24h
infradian more than 24h
ultradian less than 24h
sleep wake cycle influenced by
exogenous zeitgeber (daylight) or would it be the same without external influences
circadian rhythm sleep wake cycle study Siffre
he spent 6 months underground alone in a cave (no natural light / sounds)
sleep/wake cycle erratic at first but settled to a 25 hour cycle
=> we have an innate mechanism for a circadian rhythm even in absence of exogenous zeitgebers
sleep wake cycle study Folklard et al
12 Ps lived in dark cave for 3 weeks
went to bed and woke up according to time on clock
researchers gradually sped up the clock (what P thought was 24h was 22)
- only one P could adjust comfortably
=> suggests our circadian rhythm cannot be easily influenced by external factors
circadian rhythm eval
+ real life application with shift workers, better understanding of how desynchronisation affects productivity
- artificial light in studies can influence (exogenous zeitgeber)
- individual differences, age, lark/owls affect case studies, small sample sizes
infradian rhythm - menstrual cycle
approx 28 days
oestrogen rises ovary releases egg, progesterone thickens womb lining, egg absorbed and womb lining shed
menstrual cycle study Stern and McClintock
29 women with history of irregular periods
pheromones collected from 9 of them at different points during cycle (sponge under armpit for 8h)
sponge from start of cycle rubbed on upper lip of other Ps on day 1 (same on day 2 etc)
- 68% Ps experienced changes to their menstrual cycle
=> menstrual cycle can be influenced by exogenous factors (other women)
infradian - seasonal affective disorder
depressive disorder with seasonal pattern, circannual rhythm
symptoms triggered in winter (less daylight)
melatonin secreted for longer because it’s darker for longer
can affect production of serotonin - lower levels
eval infradian
+ evolutionary explanation for syncing - women fall pregnant together to care for offspring together
- menstrual cycle affected by loads, stress, diet, EVs
+ application to real life - SAD treatment phototherapy (light box to reset melatonin)
ultradian rhythms - stages of sleep
5 stages, spans 90 mins, different level of brainwave activity measured by EEGs
stage 1 and 2 - light sleep easily woken. brainwave patterns slow and more rhythmic (alpha waves)
stage 2 and 3 - deep sleep not woken easily (slow waves) (delta waves)
stage 5 - REM (rapid eye movement) sleep paralysis, brain activity speeds up (dreaming) resembling awake brain (theta waves)
eval ultradian
+ Van Carter et al real world application - slow wave sleep reduces in older adults, growth hormone normally released in SWS is also reduced, relaxation and meditation can be used to increase SWS
+ EEGs scientific and objective measure
- but people may not sleep in a normal way due to being connected to machinery
endogenous pacemakers def
internal body clock that regulates biological rhythms
(suprachiasmatic nucleus influences sleep/wake cycle)
=> bundle of nerve cells in hypothalamus in each hemi , receives light info even if eyes closed, adjusts body clock)
=> sends info to pineal gland for melatonin
DeCoursey et al study endogenous pacemakers
destroyed SCN connections in 30 chipmunks
observed for 80 days
- sleep wake cycle disappeared and a lot were killed by predators
=> shows importance of SCN in maintaining sleep wake cycle
exogenous zeitgebers def
external factors influencing body clock
LIGHT - influences SCN and also affects hormone secretion
exogenous (light) study - Campbell and Murphy
15 Ps, light shone on back of knee, affected sleep wake cycle
= light can be detected by skin receptor sites and doesn’t have to be received by the eyes
other exogenous zeitgebers- social cues
mealtimes and bedtimes influence biological rhythms
from 6 weeks old we develop sleep wake cycle, by 16 weeks entrained to circadian rhythm, influenced by parents
general eval for internal external factors
- animal studies - generalisability and ethics
- in real life both interact, so may not be valid to study them individually (interactionist)
