Brain and behaviour Flashcards
what is mental representation
the sense in which properties of the outside world (e.g colours/objects) are copied/simulated by cognition
what is neural representation
way in which properties of the outside world manifest themselves in the neural signal (e.g different spiking rates for stimuli)
In what direction does neuraxis go
rostral to caudal ( front to back)
what are the 3 planes of the brain
transverse, saggital, horizontal
what is the horizontal plane parallel to
the ground
what is the horizontal plane parallel to
the ground
what is the sagittal plane parallel to
the neuraxis, it is perpendicular to the ground
at what angle does the transverse plane intersect the neuraxis
right angle intersection
how much does the brain weigh
1400g , 2% of body weight
how much oxygen does the brain does the brain consume and how much of the blood supply does it use up
around 20% for both
what are the 3 protective layers of the brain called. What are the individual layers called
The layers are called Meninges. The outermost layer is the dura mater. The middle layer is the arachnoid, the last layer is the pia mater
Where is cerebrospinal fluid kept?
In the subarachnoid space (between arachnoid and pia) and in the ventricles of the brain
what are brain ventricles
hollow chambers in the brain filled with CSF
What generates/produces CSF
choroid plexus
What is the total volume of CSF at one time and how many times does this turnover within a day
125-150ml, 3-4 times a day
What is hydrocephalus
the consequence of CSF not being reabsorbed and there being too much liquid in the brain (can occur in babies)
what is the cerebral cortex
a thin wrinkled layer of tissue covering brain, consisting of two hemispheres
what is the neocortex
thin layer of cerebral cortex
what is special about dolphin brains
they have more crumpling in their cerebral cortex but they have a thinner neocortex
what are the two divisions of the cerebrum
white and grey matter
what is grey matter composed of
cell bodies of neurons
what is white matter composed of
axons and dendrites of the neurons, bundles of ‘cables’ connecting regions of the brain & spinal cord
what are the four divisions of the cerebral cortex
Frontal Lobe
Parietal Lobe
Temporal Lobe
Occipital lobe
what are the primary cortices of the cortex
primary auditory , primary motor , primary visual , primary somatosensory
what is the function of the primary somatosensory cortex
receives info from body sense; different regions receive info from different body parts
what is brodmanns area
a region of the cerebral cortex defined based on its architectonics (structure & organisation of its cells)
what is the limbic system
a set of structures involved in learning, memory and emotion
what are the structures of the limbic system
limbic cortex, hippocampus, amygdala, fornix & mammillary bodies
what is the basal ganglia
set of structures involve in processing info for motor movement
what are some of the major structures of the basal ganglia
Caudate Nucleus
Putamen
Globus Padillius
what is the tectum (part of mesencephalon) involved in
fast eye movements (vision)
and the auditory pathway
what does the tegmentum (part of the mesencephalon) have a role in
motor movement
what are the pons involved in
sleep & arousal
what is the cerebellum involved in
motor co-ordination & smooth execution of movement
what does the mylecephalon contain and what does this make it involved in
the medulla oblongata. basic life functions (breathing, swallowing etc) and sleep wake cycles
what roots carry sensory info to the CNS
dorsal (afferent)
what roots carry motor info away from the CNS, towards the effector
ventral (efferent)
how many pairs of afferent and efferent nerves do we have in the spinal cord
31
how many sets of cranial nerves do we have
12
which nervous system is responsible for ‘fight or flight’ functions
sympathetic
which nervous system is used for ‘rest and restore’ functions
parasympathetic
what do motor neurons do
control muscle contraction and gland secretion
what do sensory neurons do
detect changes in external and internal environment
which type of neuron is ONLY in the CNS and are involved in cognition
interneurons (both Sensory and motor neurons are in both PNS &CNS )
what is the difference between a unipolar, bipolar and multipolar neuron
Multipolar neuron – one axon and many dendrites attached to soma.
Bipolar Neuron – one axon and one dendrite attached to soma.
Unipolar Neuron – one axon attached to soma; axon divides, one branch receiving sensory information - other sending the information into CNS
what type of glial cell acts as an immune cell
microglia
what do astrocytes do
Provide physical support to neurons
Provide nourishment
Clean up debris and form scar tissue when neurons die
what do oligodendrocytes do
-support axons and produce the myelin sheath - insulation lipids
what do oligodendrocytes do
-support axons and produce the myelin sheath - insulation lipids
what is the blood brain barrier
semipermeable barrier between the CNS and circulatory system which helps regulate the flow of nutrient rich fluid into the brain
what is the area postrema and why is it bad
- region of medulla where blood- brain barrier is weak - allows toxins in blood to stimulate this area which initiates vomiting, poison expelled from the body
in a sodium potassium pump, what goes in and out and how many go in and out
3 sodium in per 2 potassium out
in an action potential, what channels open and close in what order
Sodium channels open when threshold is reached
Potassium channels open in rising phase
Sodium channels close at peak
potassium channels start to close as resting potential is reached
what is the all or none law
when an action potential occurs, it happens in full
what is rate law
variations in intensity of stimulus are seen in variations in rate at which the axon fires
what happens in saltatory conduction
AP’s are conducted along myelinated axons and the AP seems to jump from one node of ranvier to the next
What is EPSP and what would cause it to occur
excitatory depolarization of the postsynaptic membrane. Likely to be caused by sodium channels opening
what is IPSP and what would lead to it occuring
inhibitory hyperpolarization of the postsynaptic membrane. Caused by opening of chloride or potassium channels
what is neuronal intergration
the process where inhibitory & excitatory postsynaptic potentials summate & control rate of firing of a neuron
what is psychopharmacology
the study of the effects of drugs on the nervous system & on behaviour
what is the nocebo effect
people feeling worse after an intervention that should have no ill effects
what neurotransmitter typically causes depolarisation/ an excitatory response
glutamate or norepinephrine
what neurotransmitter(s) typically cause an inhibitory response
GABA, glycine or opiods
what neurotransmitters can exhibit either an excitatory or inhibitory response
acetylcholine, dopamine and serotonin
what type of receptors does ACh bind to
nAChR, mAChR
what kind of receptors does GABA bind to
GABA1, GABA2
what kind of receptors does glutamate bind to
NMDA, AMPA
what kind of receptors does serotonin bind to
5-HT receptor (serotonin aka 5-HT)
What happens at a cholinergic synapse
Voltage gated calcium channels open, leads to release of ACh vesicles into synapse. ACh binds to postsynaptic receptors, leads to sodium channel opening & thus depolarisation.
AChE(enzyme) breaks down ACh and its reuptaken
what kind of receptor is a nicotinic receptor , what is it stimulated by and what is it blocked by
ionotropic, stimulated by nicotine, blocked by curare
what kind of receptor is a muscarinic receptor, what is it stimulated by and what is it blocked by
metabotropic, muscarine, blocked by atropine
what is botulinium toxin
ACh antagonists, prevents release
what is black widow spider venom
ACh agonist, triggers release, causes convulsions
Which neurotransmitters are monoamines
dopamine, norepinephrine, epinephrine, serotonin
what is a tolerance
A state in which organism no longer responds to a drug * A higher dose is required to achieve the same effect
what is dependence
a state in which an organism functions normally only in the presence of a drug
what neurotransmitter is involved in addiction and regulating control of attention
dopamine
what is the nigrostriatal system and can be caused by its degeneration
it starts in the substania nigra and ends in the basal ganlia, it plays a role in the control of movement. Parkinson’s is caused by the degeneration of this system
what does cocaine do to the brain
inhibits dopamine uptake from the synapse, causing an increased activation fo the reward system
how does serotonin move around the brain
via the raphe nuclei
what are the effects of ecstasy on serotonin
blocks the reuptake of serotonin, bringing more of it to the synapse
what does ecstasy cause
neurotoxcity which causes nerve terminal degeneration & possibly memory impairment
what are the most common neurotransmitters in the CNS
GABA, glutamate, glycine
what is the most important excitatory neurotransmitter in the brain
glutamate
what is the most important inhibitory neurotransmitter in the brain
GABA
What are some physical changes stress brings to the body
changes in breathing
exacerbate existing mental health conditions
changes in eating
diarrhoea/constipation
what are some of the results of chronic stress
hypertension/ heart attack
headache and migraines
In the everson-rose study in 2014, they did a multi-ethnic study of atherscelorsis and measured stress as burden in 5 domains. What did they find
chronic stress at baselines was predicted an increased likelihood of stroke over the follow up period (even after accounting for extraneous variables)
who coined the fight or flight term
walter cannon
what is a cause of acute physical stress
injury
what is a cause of acute psychological stress
a deadline
what is a cause of acute social stress
humiliation
what is a cause of chronic physical stress
hunger/cancer
what is a cause of chronic psychological stress
chronic work pressure
what is a cause of chronic social stress
chronic isolation
what structures are involved in the HPA axis
hypothalamus, anterior pituitary gland & adrenal cortex
what neurotransmitters/hormones are involved in the HPA axis
Cortisol, ACTH (adrenocorticotropic hormone) and CRH (corticotropin releasing hormone)
what does the adrenal gland release
cortisol & epinephrine
what does too much cortisol cause
cushings syndrome
what does too little cortisol cause
addisons disease
what were the 3 stages stressors lead to in Seyle’s animal experiments
Alarm, resistance, exhaustion
In Berns experiment in which participants experienced 100% of a voltage at the start of the experiment, what were the resulting choices of the participants.
Extreme dreaders chose to experience more voltage immediately (e.g 90% in 3 seconds) than less voltage for a longer time (e.g 60% for 27 seconds)
what can dwarfism be caused by
stress
what hormone can directly suppress the activity of the immune system
cortisol
kiecolt-glaser experiment featuring 13 caregivers and 13 controls.
What was the observed affect of stress on the caregivers
wounds take longer to heal in caregivers
what did glaser find out in their study featuring 40 1st year med students during exam season
their immune responses weakened and they had increased risk of epstein barr virus
What are some psychological modifiers of stress
(name at least 3)
- Outlets of frustration
- sense of predictability
- perception of life improving
- sense of control
- social support
what is stress reactivity
the way in which we respond to stress
when is the lowest amount of noradrenaline released
during sleep
when is the highest amount of noradrenaline released
during stress
An observed cohort of people have increased risk of heart disease and type 2 diabetes at age 50 due to what kind of stress
Prenatal stress
What is metabolic imprinting and what effect does it have
the foetus learning food is ‘scarce’ so it becomes good at storing consumed food and retaining salt.
Kajante et al 2002 study on men with recorded birthweights and size.
what was the relationship found between birthweight and basal cortisol levels during adulthood
the lower the birthweight, the higher the basal cortisol levels in adulthood
what effects are seen in rats when the mothers underwent prenatal stress
- evidence of greater anxiety- freezing in bright lights, difficulties learning,
*amygdala shows greater glucocorticoid receptors
what was seen in rats with postnatal stress (maternal seperation)
showed increased glucocorticoid response to stress (more fearful)
lower adult height
study regarding a romanian orphanage
what were the differences in cortisol levels between the canadian kids, the kids adopted early and the kids left in the orphanage for over 8 months
The kids left in the orphanage showed significantly higher cortisol levels. The other 2 groups had similar cortisol levels
Vuilleumier fMRI study on distinguishing houses and faces.
When faces were fearful, what affect did this have on judging houses
it took longer for the P’s to process them
Vuilleumier fMRI study on distinguishing houses and faces.
What brain areas had more activation when viewing faces
Fusiform gyrus has increased activity when responding to faces
Amygdala was more active when incidentally viewing fearful faces
what area of the brain is seen to conduct bottom-up signalling to indicate threats in the environment
amygdala
what regions of the brain are responsible for top down regulation to prevent the triggering of constant stress responses
medial prefrontal cortex & anterior cingulate cortex
Outline some types of substance use disorders.
Reinforcement
Craving and relapse
Different types of substances (opiates, stimulants, nicotine, alcohol, and cannabis)
Hereditary elements
What is substance abuse?
Is a pattern of drug use in which people rely on a drug chronically and excessively and not for therapeutic reasons.
What is addiction or dependence?
Refers to being physically dependent on a drug in addition to abusing it.
What is the risk of cocaine abuse disorder?
Psychotic behaviour, brain damage, death.
What is the risk of designer drug abuse disorder?
Untested, potentially contaminated
What is the risk of intravenous drug abuse disorders?
Risk of contracting infectious diseases, overdose and death, harm caused to individual’s life
What is the risk of alcohol abuse disorder?
Cirrhosis of the liver, increased risk of heart disease and stroke, korakoff’s syndrome.
What is the risk of smoking?
Increased risk of many cancers, heart disease, stroke etc.
What is the importance of positive reinforcement in regards to substance abuse?
Positive reinforcement:
- The addition of a reinforcing stimulus following a behaviour that makes it more likely that the behaviour will occur again in the future.
Taking substances that give a positive effect, this will reinforce the behaviour of taking the drug.
Outline the relationship of timing and reinforcing stimuli in drug abuse.
Reinforcing stimuli have a greater effect if it occurs immediately after the behaviour.
What are some neural mechanisms of positive reinforcement in drug abuse?
Drugs trigger the release of dopamine in the nucleus accumbens (NAC)
Process of addiction begins in the mesolimbic dopaminergic system.
Produce long term changes in other brain regions - starting with the ventral tegmental area (VTA)
What is the nucleus accumbens (NAC) associated with?
It triggers the release of dopamine as a neural mechanism of positive reinforcement.
Where does the process of addiction start?
In the mesolimbic dopaminergic system.
Where do long term changes in the brain start in relation to positive reinforcement (in drug use)?
Starting with the ventral tegmental area (VTA).
Saal et al. (2003) did a study administering an addictive drug on mice, what did they find in relation to drug abuse?
there was increased strength of the excitatory synapses on dopaminergic neurons in the Ventral tegemental Area after a single administration