Cognitive and behavioural neuroscience Flashcards
is thought physical?
processes = abstract Implementation = in a physical substrate, the brain
what is dualism
the mind and brain are fundamentally different
therefore they are separate things
how are the mind and brain fundamentally different
physical (brain) vs non-physical (mind)
what is the problem for dualism
how can physical events in the brain interact with the influence of the non-physical mind
eg: damage brain = change of the mind - so the mind can be influenced by the physical despite being nonphysical
who is associated with dualism
rene descartes
how did Descartes get around the problem of dualism
the mind interacted with the brain through the pineal gland
what is monoism
there is one being not a brain and mind. this is supported by the fact you cannot distinguish between the brain and mind - they are supreme being.
so they claim brain operations lead to mental events
counter evidence for monoism
subjective factors near death experiences out of body experiences ghost sightings re-incarnation (re-calling events from past lives)
gross bits of the nervous system - big division
Central (CNS) vs Peripheral (PNS)
make up of CNS
Brain and spinal chord -covered with layers of protective tissue (three layers called the meninges) the three meninges: dura mater (hard mother) arachnoid membrane (spider membrane) pia mater (pious mother)
make up of PNS
nervous system outside central
- typically called nerves
- covered in 2 meninges:
- -dura mater
- -pia mater
what does the PNS allow and how
allows the CNS to interact with its environment
has two loops (autonomic nervous system and sensory-somatic nervous system) each containing efferent and afferent section
meaning of efferent
outgoing, motor
meaning of afferent
incoming, sensory
autonomic nervous system
what does it do
voluntary?
eg
controls internal state involuntary heart rate digestion swallowing
sensory and somatic nervous system
what does it do?
voluntary?
eg
deals with external world
skeletal muscles under voluntary control
senses
3 major divisions of the brain
forebrain
mid brain
hind brain
how is the forebrain sub divided
telencephalon
diencephalon
what are the principle structure of the telencephalon
cerebral cortex
basal ganglia
limbic system
what are the principle structures of the diencephalon
thalamus
hypothalamus
how is the mid brain sub divided
mesencephalon
principle structures of the mesencephalon
tectum
tegementum
how is the hind brain subdivided
metencephalon
myelencephalon
what are the principle structures of the metencephalon
cerebellum
pons
what are the principle structures of the myelencephalon
medulla oblongata
cerebellum, volume and musicians
Hutchinson et al 2003
MRIs of male professional keyboard players vs controls
musicians had larger cerebellum (whole brain size the same, other parts shrunk)
size of cerebellum depends on how much practice you do (lifelong intensity of practice correlation)
what does the medulla oblongata do
role in the autonomic control of cardio-vascular system, swallowing etc
what does the cerebellum do
little brain - approx. 30 billion neurones
sensory information
modulates motor commands - precise movement, sensitive to alcohol
what does the pons do
bridge between cerebellum to cortex
role is sleep / arousal, facial muscles, tongue
what experiments are used to find out about the functions of the hind and mid brains
decerebrate experiments
low-decerebrate animal experiments
hind brain intact
transect above pons / cerebellum (rest of brain apart from hind cut out)
still do basic movements but fall over
move but not coordinated
high decerebrate animals experiment
mid and hind brain intact transect above tectum / tegmentum can stand without support walk, chew, swallow have the ability to do things but no purpose - eg wont run from danger or eat if hungry
from the decerebrate experiments what does the cortex do
allows us to adapt to an unpredictable world
two major parts of the forebrain: diencephalon and what they do
thalamus - control input to cerebral cortex
hypothalamus - controls autonomic nervous system
three parts of basal ganglia
putamen - merges with head of caudate nucleus
globus pallidus - inside putamen
what is the sub-cortical nuclei involved in and where is it
control of movement
lateral to thalamus
what does the caudate nucleus do
urge to do things
related to reward system
what does the putamen do
leanred autonomic movements eg driving
what is the striatum
caudate nucleus + putamen
what doe the globus pallid so
control of voluntart movement
major output nucleus of the basal ganglia
parts of the limbic system
cingulate cortex- error signals, attention, emotion
amygdala - emotion (fear)
hippocampus - formation and recall of memories, navigation
two main parts of telencephalon by diencephalon
basal ganglia
limbic system
cerebral cortex
size
hemispheres
lobes
big bit in primates - disproportionately large in humans
2 hemispheres
4 lobes
what are the four lobes in the brain
occipital
parietal
temporal
frontal
hemispheric specialisation
looks the same but asymmetrically function
left brain controls right body; left side of brain is better at certain things
even ambidextrous have preferred actions with preferred hands
not one side or other but does show more activation
language as an example of hemispheric specialisation
pierre paul broca (1860s)
-damage to left frontal lobe
patient could understand but not generate speech
Wernicke
- damage to left superior temporal lobe
-comprehension not generation
language left dominant in 90% of right hander and right dominant in 50% of left
how are the two hemispheres connected
by commissures
corpus callosum is the biggest
masa intermedia in the thalamus (missing in many people so not important?)
sometimes commissures cut (epilepsy treatment) = split brain
testing for hemispheric specialisation
split brain patients - briefly flash words or pictures in the left or right visual field flash in right can say what was seen flash in left cannot say but can point or draw
reaction time experiments for hemisphere experiments
intact brains
present stimuli to left or right visual field
record reaction time
what evidence is there for hemispheric specialisation
left specialised for language, speech, local image feature extraction
right specialized for visuo-spatial processing, global image properties, face processing
what is the primary cortices for
first for sensory input, last for output
at back of is primary motor cortex - premotor and supplementary
rest is executive functions
what are secondary cortices
adjacent to primary, short connection distance
receive input from many different sources
Phineas Gage
iron through his cheek and brain
damage to frontal cortices
marked personality changes?
good man turned nasty
role of
dorsolateral prefontal cortex
planning of action
underactive in depression
role of
anterior cingulate cortex
errors and the feeling of self
overactive in depression
role of
orbito-frontal cortex
inhibition of changes from unusual behaviors
punishment / reward in decision making
overactive in depression
role of
ventromedial prefrontal cortex
emotional meaning
overactive in depression
what are the major cortical pathways of the brain
auditory, olfactory, visual, motor, somasensory
visual pathways
two visual pathways
lots of connections between them
-dorsal
-ventral
how does the visuo-motor system work
Pulvinar - superior colliculus visual input from LGN see look locate reach V1 - see parietal cortex (eye movements, directed reaching) - locate motor allows for reaching / grabbing
where is fear processed
thalamus
limbic and cortical interplay
most things that keep us alive skip visual cortex in order to act quicker
two types of cells in the brain and what they do
glia - keep brain alive
neurones - do psych part
anatomy of a neurone
input - dendrite
integration - cell body, soma, contains nucleus
output - axon, very long
what is neural activity
electric current and ionic flow
what are the major ions in neural activity
sodium chlorine and potassium
what forces does every ion have acting on it
chemical
electrical
explain the resting membrane potential
permeability high for K and low for Na and Cl
equilibrium point at -50 to -70mV
impulse to do all or nothing - action potential explained
sodium wants to balance sodium gradient and charge
sodium channels open and close quickly - sodium rushes in
potassium channels slow - potassium is pushed out by sodium and then channels close because of the membrane potential
how does an impulse travel - propagating the signal
start in the axon hillock and move down the axon because sodium raises membrane potential locally so channels once activated cant go again, pushes signal down the axons as next lot are activated
myelin sheath
causes a jump from one load to another which is faster = speeds up the impulse travelling
what did Sherrington’s behavioural studies find
the end of the axon - pre-synaptic terminal -axons brach and make many synapses -not all onto dendrites, but most are the dendrite -post-synaptic terminal -many inputs to each neurone -most on dendrites gap between = synaptic cleft
what two types of synapse are there and what are their relative speeds
chemical - slow, ionotropic (directly opens channel), metatropic (slowest, cascade system opens channel), amenable to drugs
electrical - fast, reliable, poor processing
chemical synapse
release of molecule into cleft
activates specific receptor (can be excitatory or inhibitory)
variable effects - good at processing
what are vesicles and what do they do
contain neuro-transmitter molecules
when calcium ions enter, vesicle fuse with membrane and release neuro-transmitter into cleft
4 step action of neurotransmitters
ligand-gated ion channels
g-protein-coupled receptors
kinase-linked receptors
nuclear receptors
estrogen changes..
the way the cell responds
ending synaptic action
after neuro transmitter recognised by post synaptic receptor it must be removed / inactivated
transporter proteins take neurotransmitter back to pre-synapse
specialised enzyme for inactivation
acetylcholine - acetate + choline
peptides vs non-peptides
effect on post-synaptic membrane
long lasting
np short lasting
peptides vs non-peptides
synthesis location
endoplasmic reticulum of soma
np nerve terminal
peptides vs non-peptides
replenishing speed
slow (not recycled)
np - fast
peptides vs non-peptides example of each
pep - enkephalins
non pep - ACh, DA, 5HT, NMDA
what types of drugs reduce transmission and by what mechanisms do they work
antagonist pre-synaptic mechanisms -decrease production of transmitter block calcium ion influx stop vesicles filling with transmitter stop vesicels emptying into cleft post-synaptic mechanisms -block receptors -stop ion channel opening
what types of drugs enhance transmission and by what mechanisms do they work
agonist pre-synaptic mechanisms -increase production of transmitter -enhance calcium ion influx -decrease re-uptake process post-synaptic mechanisms -activate receptor -decrease enzymatic breakdown (ACh)
ACh and what disease, explain
acetylcholine
alzheimers - loss of neurones which use ACh as their neurotransmitter in areas of basal ganglia and basal forebrain
drugs which block or reduce breakdown of ACh in the synaptic cleft are used to slow the process
dopamine related drugs named and explained (4)
L-DOPA - agonist, relives symptoms of parkinsons (alsom some MAOIs do too)
methylphenidate (Ritalin) - agonist treatment for ADHD
amphetamine - agonist, complex action via norepinephrine
cocaine - blocks uptake
what is unipolar depression
major depressive disorder
majority of people at sometime in their life will be affected (20-30% of total population at any given time)
women twice as likely as men to report
thought to have genetic component as 60% concordance for identical twins
environment factors important
treatment of depression
1950s reperine given for high blood (MOA reduced) pressure made some patients depressed
iproniazid for TB made patients happier
animal studies showed these drugs act on mono-amine release = mono-amine hypothesis (excess then happy) - action doesn’t really fit this
tricyclic antidepressants
block re-uptake of transmitter to increase post-synaptic response
what did Asberg’s 1990 studies find
post-mortem studies of suicide victims
measured post-synaptic serotonin 5-HT and metabolite 5-HIAA
decreases in CSF serotonin is associated with suicide
3 types of drug in the treatment of depression
SSRIs
TCAs
MAOIs
7 levels of explanation and why this matters
many individuals individual brain neural systems neuronal biochemical atomic common sense - only certain things are appropriate to study at the level of the brain, processes underlying behaviour
2 methods of study using observation
damage to the nervous system produces deficits in psychological processes
damage to other body parts can influence psychological processes but does not cause deficits
role of brain in methods of study of psychological processes
brain is the site of psychological processes
but this does not mean you must study the brain
2 ways to study the anatomy of the bran explained
computer tomography - CT (X-rays to image inside the body)
magnetic resonance imaging - MRI (pulse radio waves and use magnetic field to map reaction of hydrogen - a water and fat cell map
4 ways of monitoring brain activity
electrocephlogram EEG
positron emission tomography PET
functional magnetic resonance imaginf fMRI
single unit recording
explain EEG
electrode cap, measures voltage over time
explain PET scan
shows activity and strength of, uses injection of dye and radioactive traces
explain fMRI
MRI over time, detects changes in blood flow
explain single unit recording
fine electrodes to record single cell electrical activity
name 7 methods of studying the brain from disruption
brain damage disorders stimulation micro-stimulation cortical cooling trans-cranial magnetic stimulation lesions each technique only monitors part of the brain at once so must combine techniques
spatio-temporal resolution discussed for EEG, fMRI and single unti recording
EEG - poor spatial resolution, high temporal
fMRI - medium spatial, low temporal
single unit recording - high spatial and temporal resolution
whats wrong with low and high spatial and temporal temporal resolutions
SPATIAL
poor = miss fine details, interactions between groups or individual neurones
high = what is the rest of the brain doing
TEMPORAL
poor = miss fine timing
high = can we see the relevant signal, is there strong enough data