4.Nervous system and Brain Flashcards
describe the brain vs heart debate
Historical debate sounding whether the heart or brain was responsible for central functions including thought, emotion and behaviour
describe briefly the brain hypothesis
thoughts and feelings are rooted in the brain
describe briefly the heart hypothesis
thoughts and feelings are rooted in the heart
Using specific examples, who supported the brain hypothesis
The greeks
-Alcmaeon was the first recorded person to locate the brain as the source of mental processes
-Pythagoras and Plato were also early supporters of the hypothesis
-Galen also posited the brain hypothesis through observation (most famously of pigs)
using specific examples, who supported the heart hypothesis
the egyptians
-empedocles believed that blood was the place for human cognition and thought, especially the blood around the heart’’
-aristotle also proposed that the heart was responsible for all mental functions
who ‘won’ the brain versus heart debate
thanks to empirical scientific evidence we now know that the brain is responsible for our mental functions, feelings and behaviour.
the mind body problem
The mind body problem concerns the questions of whether our mind and body are distinct separate entities or whether they are the same thing
two sides to the mind body problem
dualism
monism
dualism
The mind (non physical) and body (physical) are two distinct things but interact to produce sensations, thoughts, emotions and other conscious experience.
-descartes
monism
suggests that the mind and body are one and the same thing
Brain ablation
Brain ablation involves disabling, destroying or removing selected brain tissue, followed by an assessment of subsequent changes in behaviour
Pierre Flourens
-credited as introducing brain ablation experiments
-discrediting highly specific localisation of function and phrenology
-developed techniques of damaging or removing small areas of brain tissue to observe the effects on behaviour (used rabbits and pigeons)
-found evidence for neural plasticity (animals could eventually recover loss of movement)
Limitations of Pierre Flourens
-Imprecise surgical procedures
-did not provide detailed reports of findings
Karl Lashley
-used brain ablation on rats, monkeys and chimpanzees to find the location of learning and memory in the brain
Identify two key conclusion proposed by Lashley
Mass action
Equipotentiality
Mass action
Large areas of the brain function as a whole for complex functions
Equipotentiality
healthy part of the cortex can take over the function of the injured part (plasticity)
Moniz
-developed lobotomies
-idea that lobotomised chimpanzees became placid compared to the aggression displayed prior the surgery
lobotomy
-A form of psychosurgery to treat mental illness
-Involves scraping away (via the eye) most of the neural connections in the prefrontal cortex
Symptoms of lobotomies
-reduction in cognitive processes and behaviour
-Lack of emotional expression
-Reduction in interest and energy
-dull and lifeless personalities
Electrical stimulation of the brain (ESB) (EBS)
ESB may be done by placing electrodes on or inside a specific place on a persons head. These electrodes then send an electrical signal to that specific area of the brain, thereby stimulating the activity of neurones in that area
Key figures of ESB
-Fritsch and Hitzig
-Wilder Penfield
Penfield- Mapping the brain
-when the cerebral cortex was exposed, Penfield was able to stimulate different areas using an electrode
-Penfield used tiny numbered tags to mark areas of the cortex that he electrically stimulated as he developed his brain ‘map’.
Findings of a split brain patient
-Visual info in the L visual field is sent to the right hemisphere and vice versa
-Split brain patients were able to recognise and name images projected in the R visual field (sent to the left hemisphere-verbal)
-Split brain patients were able to recognise and detect images in the L visual field (sent to right hemisphere-non verbal) but were unable to verbalise what they saw but could draw it with their left hand
Left hemisphere function
The left hemisphere responsible for the organisation of language expression and comprehension
Why can non split brain patients recognise and verbalise visual images in both visual fields
Information processed in the right hemisphere can be transferred via the corpus callosum to the left hemisphere for language processing.
how does computerised tomography (CT) work?
-neuro-imaging technique that produces a computer enhanced image of a cross section from x rays taken at different angles
Do CT scans show brain structure or function
STRUCTURAL brain abnormalities
advantages of computerised tomography
-provides clear and accurate images
-allows for comparison between ‘normal’ and ‘abnormal’ brains
-relatively non invasive (just an injection called contrast)
what is contrast
a dye (contrast medium) used to make some tissue show more clearly. These dyes are harmless and removed from the blood via urinary system.
limitations of computerised tomography
-only shows structure not function
-pregnant women are not advised to have CT scans as there is risk radiation may cause some damage to the unborn child.
-in rare cases it is possible to have an allergic reaction to the contrast injection
how does positron emission tomography work (PET)?
-tracks blood flow by measuring the use of glucose by neurones in the active area of the brain
-radioactive material (flurodeoxyglucose) is injected into the participants bloodstream. This travels to the brain and emits various levels of radioactive signals. These are detected and processed by the PET computer to produce PET scans.
-Different colours are used to indicate different levels of brain activity
what colours represent various levels of brain activity (PET) scan
least to most activity :
violet, blue,green. yellow and red
advantages of positron emission tomography
-Displays detail colour coded images of a functioning brain
-allows researchers to see how different areas of the brain function together for certain tasks.
-colours make interpretation simple
do PET scans show brain structure or function
provide information regarding FUNCTION and ACTIVITY of brain during tasks
limitations of positron emission tomography
-requires injection (radioactive glucose)
-use of radioactivity means that longitudinal studies are difficult and dangerous
-PET scans require 40s rests between 30s scans, hence may miss rapid changes in brain function
how does magnetic resonance imaging (MRI) work?
uses magnetic fields and radio waves to vibrate the brans neurones and produce an image.
do MRI scans show brain structure or function
used to identify STRUCTURAL abnormalities
advantages of magnetic resonance imaging
-clearer and more detailed images than a CT scan
-non invasive
-no x rays or radioactivity involved
limitations of magnetic resonance imaging
-only shows structure and anatomy
-can not be used on people with internal metallic devices
how does functional magnetic resonance imaging work?
-uses magnetic fields and radio waves to vibrate the brains neurones and produce an image
-detects changes in oxygen levels and blood to show level of functioning neurones
do fMRi scans show brain structure or function
brain FUNCTION
advantages of functional magnetic resonance imaging
-no exposure to radiation
-detailed images of brain functioning
-shows a combination of brain structure and function
-detects changes in function in rapid succession
limitations of functional magnetic resonance imaging
-expensive and limited access
-can not be used on people with internal metallic devices
how does an electroencephalograph (EEG) work
detects, amplifies and records general patterns of electrical activity within the brain
-electrodes are placed along the scalp
does an EEG show brain structure or function
function
advantages of an electroencephalograph
-provides overall information about the brain without being invasive
-used to study patterns of activity over long periods of time eg sleep
-it shows different brain waves for different activity and is useful to study hemispheric specialisation
limitations of an electroencephalograph
-doesn’t provide detailed information regarding structures of the brain
-difficult to pin point specific areas of activity
-unable to distinguish a response from ‘background noise’ neural activity
-only provides a summary of neural activity
what is the central NS composed of
-composed of the brain and spinal chord
Central NS function
-processes sensory information to activate appropriate actions
spinal chord function
-connects the brain to the rest of the body
-send information from sensory neurones in various parts of the body to the brain
-relays motor commands back to muscles and organs via motor neurones
what does the Peripheral NS consist of
The peripheral NS consists of all the nerves outside the Central NS (ie brain and spinal chord)
Peripheral NS function
The Peripheral NS carries sensory information from the body to the Central NS, and motor information from the Central NS to the body
subdivisions of the Peripheral NS
Somatic NS
Autonomic NS
Two major divisions of the Nervous System
Central NS
Peripheral NS
Function of the Somatic NS
-The somatic NS transmits sensory information to the CNS and carries out its motor commands
-The somatic NS is involved in voluntary muscle movements
other name for somatic NS
voluntary nervous sytem
subdivisions of the somatic NS
sensory information and voluntary skeletal muscles
Function of autonomic NS
-responsible for AUTOMATIC responses
-carries information to internal bodily structures (eg heart, lungs and glands) that carry out basic life functions
-responsible for any life giving responses eg pumping blood
subdivisions of the Autonomic NS
Sympathetic and Parasympathetic NS
Function of Sympathetic NS
-readies the body for a fight or flight response when exposed to threats
-instantaneous reaction
-short term
-speedy/rapid
-involuntary
physiological changes by the Sympathetic NS
-slows digestion
-increases Heart rate
-dilates pupils
-diverts blood away from the stomach to muscles (which may need it more)
-decreased bladder control
Function of Parasympathetic NS
-supports more routine activities that maintains the bodys store of energy (eg regulating blood glucose levels)
-once a threat has passed the parasympathetic NS resumes control from the sympathetic NS
physiological changes by the parasympathetic NS
-Heart rate lowers
-Increased digestion
-blood pressure lowers
-stop sweating
-bladder control increases
-pupils constrict
subdivisions of the central NS
brain and spinal chord
what is the neural message within neurones
electrical impulse
what is the neural message between neurones
chemical messages (neurotransmitters)
dendrite function
receive input from other neurones
cell body/soma function
includes a nucleus which controls the neurone
axon function
transmits information to other neurones
myelin sheath function
-‘fatty covering’ that insulates the axon from chemical and physical stimuli that might interfere with the transmission of nerve impulses
-helps in speeding up the neural impulse
terminal buttons function
sends signals from a neurone to adjacent cells (release neurotransmitters)
synapse function
the space between neurones where transmission occurs
axon terminals function
branch like extensions from the axon that carries message to terminal buttons
another name for terminal buttons
synaptic knobs
difference between synapse and synaptic gap
synapse-pre synaptic terminal buttons + synaptic gaps + post synaptic dendritic spines
whereas
synaptic gap-only the gap
identify types of neurones
sensory neurons
interneurons
motor neurons
sensory/? neurons
sensory/ afferent neurons
motor/? neurons
motor/ efferent neurons
where are sensory neurones found
PNS
where are motor neurones found
in the lower brainstem and spinal chord
where are interneurons found
CNS (only)
what do sensory/afferent neurones do
-transmit information from sensory cells in the body (called receptors) to the brain (either directly or by the way of the spinal chord)
-sense the external world and monitor changes within our bodies
-some sensory neurones transit information directly to the spinal chord whereas others transmit info to the brain via the spinal chord
-sensory neurones have specialised functions depending on where they are found
what do motor/efferent neurones do
-also called effectors and motor neurones
-carry messages from the CNS to cells in skeletal muscles, organs and glands to simulate activity
what do interneurons do
-act as a link between sensory and motor neurones, relaying information from one neurone to another (this is because sensory and motor neurones are rarely directly connected)
-enable simple reflexes in spinal chord and complex functions in the brain
what do glial cells do
provide the structural framework that enable a network of neurones to remain connected
identify CNS glial cells
Astrocytes
Microglia
Oligodendroglia
identify PNS glial cells
Schwann cells
satellite cells
astrocytes functions
Provide physical and nutritional support for CNS neurones
microglia function
Are the immune cells of the CNS. They fight infection and respond to injury
oligodendroglia function
Produce myelin sheath of neurones in the CNS
Schwann Cells function
Produce the myelin sheath of neurones in the PNS. Essential to the maintenance, function and development of peripheral nerves
Satellite cells function
Surrounds and covers the cell bodies/soma. Maintain the cell body and keeps the neurone functional by supply nutrients to the soma
identify structures of hindbrain
cerebellum
medulla
pons
Hermione Completes Maths Problems
identify structures of midbrain
reticular activating system
Muddleheaded Ron
identify structures of forebrain
Hypothalamus
thalamus
cerebrum
Forgets How To Calculate
where is hindbrain found
-found at base of brain
-contains lower level brain structures
where is the medulla found
top of the spinal chord
another name for medulla
medulla oblongata
the medulla function
controls reflexive functions vital for survival (eg swallowing, breathing, heart pumping)
damage to medulla
death is most likely to occur
the pons function
-connects top of spinal chord to the brain
-involved in sleep, dreaming and arousal
-has a relay/bridge function from cerebrum to cerebellum- eg.passes messages related to movement form Cortex to cerebellum
damage to the pons
results in locked in syndrome
briefly describe locked in syndrome
Brain is functioning completely normal but messages are unable to get to the rest of the body
where is the cerebellum found
base of Brain towards back
the cerebellum function
-coordination of fine muscle movements (ensuring they are smooth and precise)
-regulates posture and balance
-plays a role in fluent speech
damage to cerebellum
-difficulty completing ADL’s
-difficulty speaking (stuttering)
-poor balance and coordination
where is the mid brain
deep within the brain
midbrain function
involved with movement, processing sensory information and sleep and arousal
function of reticular formation
-filters incoming sensory information so the brain is not overloaded
-maintains consciousness, regulates arousal and muscle tension
function of reticular activating system
-involved in arousal
-involved in attention especially selective attention. It initiates the attention response by alerting cortical areas of the brain to significant changes to the environment.
damage to reticular activating system
-coma
-disruption to sleep-wake cycle
-difficulties in maintaining attention
forebrain function
controls and regulates higher order functions
eg personality, cognitive functions, learning and perception
hypothalamus function
-maintains the body’s internal environment (state of homeostasis)
eg regulates
-body temperature
-emotions
-thirst
-hunger
-sexual functioning
-hormone release
damage to hypothalamus
-eating problems may occur
thalamus function
-filters and transfers ALL sensory information (except smell) to relevant areas of the brain for processing
-transfers neural info (concerning alertness and attention) from RF to CC
-directly linked to RF
-involved with arousal and alertness
-minimises sensory pathways during sleep
damage to thalamus
-loss of any sense (except smell)
-attention difficulties
-lower arousal due to lethargy
what is the cerebral cortex
The top layer of the cerebrum, it is divided into two hemispheres and four lobes
cerebral cortex function
-receiving and processing of sensory information
-initiating motor responses
what is meant by contralateral function
each hemisphere controls opposite sides of the body
-RH receives sensory info from, and controls the left side of the body
what is meant by ‘hemispheric specialisation’
term used to describe the unique functions of one hemisphere that is not shared with the other hemisphere
Left hemisphere function
-Verbal and analytical function:
-reading
-writing
-speaking (both production and interpretation of speech)
-sequential process of analysis
Right hemisphere function
Non verbal functions:
-visual awareness-recognising places, objects and faces
-spatial awareness
what lobe is the primary motor cortex located in
frontal lobe
what lobe is Broca’s area located in
frontal lobe
what lobe is the somatosensory cortex located in
parietal lobe
what lobe is the primary visual cortex located in
occipital lobe
what lobe is the primary auditory cortex located in
temporal lobe
what lobe is Wernicke’s area located in
temporal lobe
frontal lobe function
-concerned with higher order functions such as decision making, reasoning, planning and emotions
-expressing language
-executive functions and cognitive skills
includes capacity to:
-plan
-organise
-initiate
-self monitor
-controls one response in order to achieve a goal
primary motor cortex function
stores information about how to carry out different movements
damage to the frontal lobe
-inability to plan a sequence of complex movements needed to complete multi stepped tasks
-inability to express language
-inability to focus on tasks and filter out distractions
-mood fluctuations (emotional lability)
-difficulty problem solving
-difficulty inhibiting or controlling a response or impulse
parietal lobe function
-concerned with processing sensory information (temperature and touch), orientation and types of recognition and memory
-processing and interpreting somatosensory input
-integrating sensory input and construction of a spatial coordinate system
what does the homunculus show
represents the disproportionate areas of the primary somatosensory cortex devoted to different parts of the body
somatosensory cortex function
receives and processes sensory information from skin and body
-responsible for sense of position
-spatial reasoning (maps)
-locating objects and visual attention
what is the role of the central sulcus
separates the somatosensory cortex and Primary motor cortex
damage to the parietal lobe
-difficulty with drawing objects
-difficulty distinguishing left from right
-spatial disorientation and navigation difficulties
-lack of awareness of certain body parts/ surrounding space
-inability to focus visual attention
function of occipital lobe + primary visual cortex
processing information from the eyes including vision, colour, shape and perspective
damage to the occipital lobe
-difficulty identifying colours (colour agnosia)
-hallucinations
-visual illusions
-inability to recognise movement of objects (movement agnosia)
which hemisphere is Broca’s area in
left hemisphere
which hemisphere is wernicke’s area in
left hemisphere
temporal lobe function
-Concerned with processing auditory information (i.e. hearing, sound, recognition of speech) also involved in memory encoding faces and expression
other functions:
-role in processing info and visual perception
-left side-understanding language and learning and remembering visual info
-right side-learning and remembering non verbal info
Broca’s area function
Responsible for the production of clear and articulate speech
-coordinates muscles responsible for clear speech eg tongue,mouth
Wernicke’s area function
involved in the comprehension of speech (making sense/understanding verbal communication)
Broca’s aphasia
An impairment in language production brought about by neurological damage
-characterised by non fluent speech but can understand it
-unable to add suffixes
Wernicke’s aphasia
results in deficits in the comprehension of language
-characterised by fluent speech but difficulty understanding speech
-inability to select appropriate words from memory
damage to the temporal lobe
-persistent talking
-difficulty learning and retaining new info
-difficulty understanding words
-difficulty recognising faces
-impaired factual and long term memory
primary auditory cortex function
-receiving and processing auditory information
Left primary auditory cortex is involved in receiving and processing verbal auditory information
Right primary auditory cortex is involved in receiving and processing non verbal auditory information
identify the key stages of neural communication
- Resting potential
- Threshold
- Depolarisation (action potential)
- Repolarisation
READ THE DINGOS RESEARCH
Describe the resting potential
+state the charge inside the cell
= -70 mV
-neurone is ‘at rest’
-natural state for the nerve cell
-neurone is not sending an electrical signal
-there are more positive Na+ (sodium) ions outside the cell and more K+ (potassium) ions inside the cell
-The outside of the cell is positively charged compared to the negatively charged inside
(SOAPI PONI)
Describe the threshold
+state the charge inside the cell
= -55 mV
-An event (stimulus) causes the resting potential to move towards 0 mV
-Neurotransmitters bind with receptors at dendrites and cause sodium channels to open
-once the threshold is reached, the action potential will always fire in an all or nothing event
-if threshold isn’t reached, no action potential is fired
Describe Depolarisation
+state the charge inside the cell
= between 30 and 40 mV
-Once the threshold is reached, the inside of the neurones becomes more positive (depolarised)
-The action potentials causes Na+ (sodium) channels to open, and Na+ to flood the cell
-Na+ is positive, hence neurones becomes relatively positively charged (compared to outside of neurones) and hence is depolarised
Describe Repolarisation
+state the charge inside the cell
= -70 mV
-Potassium (K+) channels open, potassium rushes out of the cell, reversing the depolarisation (repolarisation)
-This makes the cell relatively more negatively charged so that it returns to the resting potential state
-action potential continues to travel along axon until reaches terminal buttons
What is the spinal reflex
-the spinal chord can initiate some simple responses on its own, independently of the brain
-a spinal reflex is an unconscious, involuntary and automatically occurring response to certain stimuli without any involvement of the brain
5 steps involved in the withdrawal response
- sensory neurones carry message along sensory pathway to spinal chord
2.interneurons in the spinal chord relay the message to motor neurones
3.motor neurones carry the message along the motor pathway to the effector (eg .hand muscles) causing a withdrawal response
4.The spinal reflex occurs at the same time that sensory neurones carry the message further up the spinal chord to the brain
5.The message is received in any area of the brain that processes that type of sensory information and interprets it as pain in the effector.
how does the patella knee jerk reflex differ form the withdrawal reflex
it is a monosynaptic reflex whereas the withdrawal reflex is a polysynaptic reflex
other name for spinal reflex
reflex arc or withdrawal reflex
what is meant by monosynaptic reflex
involves one synapse and the interaction between A sensory neurone and motor neurone
polysynaptic reflex
involves the activation of more than one synapse it includes an interneuron making a connection between the sensory and motor neurone
what is meant by ‘polarised’
the inside of the neurone is negatively charged compared to the outside
Describe the organisation of the primary somatosensory cortex
-contra-laterally organised
-upper half of the primary somatosensory cortex receives information from lower parts of the body
-the more sensitive the body part, the more physical space it occupies on the primary somatosensory cortex
describe the organisation of the primary motor cortex
the parts of the body more heavily involved in fine motor skills occupy more physical space on the primary motor cortex
describe what is meant by neural plasticity
neural plasticity refers to the manner in which the brain changes in response to stimulation from the environment
identify types of neural plasticity
-developmental plasticity
-adaptive plasticity
what is developmental plasticity
changes in the brains neural structure during its growth and development (maturation)
Identify the key processes of developmental plasticity
-Proliferation
-Migration
-Synaptogenesis
-Synaptic pruning
-Myelinantion
(Please Move She Sees Money)
other name for synaptogenesis
circuit formation
describe proliferation
Unborn baby’s neurones divide and multiply at a rapid rate
describe migration
new neurones in the foetus and newborn move to their location from the brain to the nervous system.
describe synaptogenesis
creation of multiple connections between neurones
describe synaptic pruning
the removal of connections that have not formed strong pathways and are no longer needed
eg teachers name in kindergarten
describe myelination
development of thick myelin sheath (which speeds up neural impulses and inhibits chemical and physical stimuli interfering with impulses). Process continues into very late adolescence
what processes of development plasticity occur during and just after birth
proliferation
migration
what processes of developmental plasticity occur after birth
synaptogenesis
synaptic pruning
myelinations
on average when is our brain full developed
25 years old
what is the last area of the brain to develop
last area to undergo myelination and synaptic pruning is the frontal lobe- the prefrontal cortex is the VERY last area to develop
what is the teenage brain highly responsive to
rewards and emotions
what is the significance of the striatum especially in adolescents and what effect does it have on behaviour
the striatum, located under the cerebral cortex is responsible for the reward system in the brain. It is more easily activated in adolescents.
This means that adolescents are more likely to make poor choices, engage in risk taking behaviour and confront new opportunities
identify two periods in developmental plasticity
sensitive and critical periods
what is a sensitive period
the period of time in which an organism is more responsive to certain stimulation
eg period of language acquisition
when is the sensitive period for language acquisition
0-12 years old
what happens If a sensitive period is ‘missed’
one may be able to relearn some of the basics that they missed
what is a critical period
the narrow period of time where development in an organism is preprogrammed for learning to occur
what happens if a critical period is ‘missed’
one is unable to relearn the development they missed
what is experience expectant development +eg
brain is primed (ready and expects) to make neural changes provided it gets the correct input- linked to sensitive periods
eg. learning a first language
what is experience dependant development +eg
not linked to sensitive periods, the creation and organisation of neurones connections that occur as a result of person’s life experiences
eg learning to play a musical instrument
what is adaptive plasticity
new synaptic connections are formed or synaptic connections are altered due to one/or more of the following:
-change in environmental conditions -(adapting to environment)
-learning a new concept
-relearning something after brain injury
identify the two key processes that underline rehabilitation
rerouting
sprouting
what is rerouting
Neurons near damaged areas seek new active connections with healthy neurones
what is sprouting
New dendrites grow to enable new connections between neurones
what is Parkinson’s disease
a neurodegenerative disease In which neurones at the base of the brain (substantia nigra) degenerate and gradually cease to function normally
Biological causes of Parkinson’s disease
basal ganglia function
-regulates movement, the basal ganglia depends on a certain amount of dopamine to function at peak efficiency
-when there is a deficiency of dopamine in the brain, movements may become delayed and uncoordinated
dopamine function
-carries messages between neurones to ensure effective planning, initiation and maintenance of motor movements
-less dopamine means the brain receives less or irregular message on how to control movement
where is dopamine produced
substantia nigra
motor symptoms of Parkinson’s disease
-tremors (uncontrollable and involuntary shaking)
-rigidity of muscles (muscle stiffness or tightness)
-akinesia (reduced motor control and recision of movements) and slower movements
-stooped posture
-poor balance
(TRAPS)
non motor symptoms of parkisnon’s disease
-fatigue
-increased sensitivity to temperatures
-decreased sense of smell
-REM sleep disorder
-constipation
-lowered cognitive ability and decision making, memory
-mental health problems
general causes of parkisnon’s disease
-parkinson’s disease is said to be idiopathic - has no specific cause
-other less common causes are genetics, toxins, head trauma and drug induced reasons
cure for parkinsons disease
NO known cure
how can Parkinson’s be treated
Levodopa
chemical converted to dopamine by neurones
Deep brain stimulation- Parkinson’s
is a last resort in which the basal ganglia is electrically stimulated
two categories of neurotransmitters
excitatory and inhibitory
-note that some may do both
define a excitatory neurotransmitter
When excitatory neurotransmitter binds with these receptor sites it makes it more likely for the post synaptic neuron to fire
what is glutamate + function
-major excitatory neurotransmitter in the brain
-when glutamate blinds with these receptor sites it makes it more likely for the post synaptic neuron to fire
ASSOCIATED with
-Cognition
-learning and memory
-behaviour
-movement
-sensations
identify the receptor sites for glutamate
-NMDA
-AMPA
-kainite
Long term potentiation
long lasting strengthening of synaptic connections resulting in enhanced or more effective (faster) neurotransmission across the synapse making the post synaptic neurones more likely to fire
-the more the neural pathway is activated the more its strengthened
too much glutamate
-MND
-abnormal neural development (inappropriate neural connections forming
what receptor site is associated with long term potentiation
glutamate- receptor site NMDA
What does GABA stand for
gamma amino butyric acid
define an inhibitory neurotransmitter
makes the post synaptic neuron less likely to fire
GABA function
-makes post synaptic neurones less likely to fire
-slows neural transmission- reverses the effects of excitatory neurotransmitters e.g. reduce the stress response
low GABA levels
High levels of anxiety
what is meant by the ‘lock and key process’
Receptor sites are specifically designed to only bind with certain neurotransmitters
- means that the receptor site will only respond to specific neurotransmitters and ignore others
What are Agonists +eg
Substances that increase the release of neurotransmitters or imitate their functioning making their effects on the post synaptic neuron more likely to occur
eg benzodiazepine
What are antagonists +eg
A substance that inhibits the release of neurotransmitters or blocks receptor sites making it less likely the post synaptic neuron respond to a neurotransmitter
eg snake venom
what is the ‘lock’ and what is the ‘key’ in neural transmission
lock-receptor site
key-neurotransmitter
Neural changes for long term potentiation
-increased number of neurotransmitters and more receptor sites
characteristics of neurones that have undergone LTP
increased receptivity and sensitivity of neurons
What is Hebbian learning
-learning results from the creation of cell assemblies ie interconnected groups of neurones that form pathways
‘neurones that fire together wire together’
Long term depression
a long lasting weakening of of synaptic connections, in which the post synaptic neurones becomes less responsive to neurotransmitters
what is the importance of LTP and LTD
allows for pruning of unwanted neural connections, so that new connections are able to from (have the capacity)
Long term depression vs synaptic pruning
-LTD is the weakening of connections whereas synaptic pruning is the elimination of synapses (connections)
