Studied by 4 PeopleTags & Description
What is neuroscience
multidisciplinary science that studies the nervous system (brain and spinal cord) and how it functions
different themes
What is mental illness
Reduces ability to function for prolonged periods
significant levels of distress
changes in mood, behaviour, thinking
feelings of sadness and loneliness
feeling disconnected
What are the causes of psychiatric disease
Genetics, early life experience (trauma, abuse) stressful life event (death, loss of job), epigenetics (role of environment), environmental influences on fetus (drug or alcohol abuse)
What is the biopsychosocial model
Model that attributes mental illness to multiple factors
biological
psychological
social factors
Medical model of psychiatric disease
mental illness comes from various underlyine factors (physiological, biological or genetic)
psychological issues are classified under biological disease or abnormalities in brain function
Etiology
What causes it?
Prognosis
What is it?
What are the short/long term consequences?
Epidemiology/Prevalence
How common is it?
What does RDoC stand for?
Research Domain Criteria Initiative
Dorsal
Directional term for the to of the brain (surface)
Ventral
bottom of the brain
anterior
front of the brain
posterior
back of the brain
medial
middle of the brain
lateral
sides of the brain
coronal section
view from dorsal to ventral
Horizontal section
lateral to lateral
Saggital section
anterior to posterior view
Cerebrum
Major component. Made up of both hemispheres.
Cerebral cortex
Outermost layer of gray matter
Cerebellum
Motor coordination. (w/ balance and fine motor control) and mental processes
Brain stem
connects brain to spinal cord.
Responsible for basic instinctual functions
Spinal cord
carries nerve signals throughout your body
Gyrus
bumps and ridges on your brain
Sulcus
grooves that complement the gyrus
Efferent nerves
Exit.
Connect CNS to skeletal muscles and motor nerves
Afferent Nerves
arrive.
Carries info into the CNS
Parasympathetic syst.
rest and digest
sympathetic syst.
fight or flight.
right hemisphere
controls emotion, creativity, spatial ability, artistic and musical skills
left hemisphere
speech and language control center. Arithmetic and writing.
cerebral hemisphere
groove in the middle of both hemispheres that connects the two.
frontal lobe
reasoning and decision making. Motor and executive function (planning, organization, initiation in order to achieve a goal.)
Central sulcus
separates the lobes
Parietal lobe
tactile functions, sense of self in space, somatic sensory
Occipital lobe
visual processing (real and hallucinatory)
Temporal lobe
visual, auditory and gustotory functions
corpus callosum
White matter made up of axons that connects and communicates between the two hemispheres.
Components of the brain stem
Diencephalon
Midbrain
Hindbrain
Components of the diencephalon
Thalamus and hypothalamus
Thalamus
integrate sensory info in and then divide out the info to different parts to process
hypothalamus
main region involved in homeostasis
midbrain
key cells involved in the reward circuit.
Secretes dopamine
Hindbrain
Pons : connects cerebellum to brain stem. involved in sleep
Medulla: controls breathing and HR. connects brain and spinal cord
ventricular syst.
cerebral spinal fluid circulates in the ventricles in order to cushion the brain.
ventricles
four interconnected hollow spaces in the brain that circulates cerebral spinal fluid (CSF)
cerebral spinal fluid
fills ventricles, similar density to brain.
Meningeal layers + functions
dura mater: thickest
arachnoid: looks like spiderwebs in which CSF circulates
pia mater: delicate inner layer.
blood brain barrier
tighter endothelial junctions
endothelial cells line the inside of the blood vessels. Very small gaps to protect brain from toxins.
ex. area postrema that activates the vomit reflex
neuron
basic information processing units that communicate between each other
glial cells
support and regulate neural activities.
form = function
form myelin sheaths that insulate axons and allow for faster communications
Anatomy of the neuron
Dendrites - cell body - axon hillock - axon - terminal button
(very organized, oriented and layered)
Dendrites
gathers info. collects and integrates into the cell body
cell body of neuron
contains nucleus and DNA
axon hillock
where action potential begins.
Axon
passes down the depolarization to terminal buttons
terminal buttons
conveys info to other neurons through their dendrites.
myelination of axons
myelin = fatty white substance produced by glial cells
oligodendrocyte = (CNS) myelinates multiple axons
schwann cells = (PNS) myelinates one axon
grey matter
cell bodies and blood vessels
white matter
rich in myelinated axons. highways of the brain
Tracts
bundles of axons in CNS
connect nuclei to each other
mostly white myelinated matter
nerves
bundles of axons in PNS
nuclei
clusters of cell bodies that form a functional group w/ specific function.
clusters working together = circuit
Action potential
message travelling from axon hillock to axon terminals
flows in orthodromic direction
short term change in membrane polarity that transmits electrical signal
Takes place in ion channels in the neuron membrane. starts at -70mV
sodium channels open at -50mV. sodium rushes in and depolarizes.
followed by hyperpolarization to not trigger another action potential right away.
positive feedback loop that moves it down the axon.
synapse
point of connection between two neurons. site of inter-neuron info transfer
components of synapse
presynaptic neuron - synaptic cleft - post synaptic neuron
(vesicles that each contain a quanta of neurotransmitters)
steps of synaptic transfer
Neurotransmitters are synthesized and transported down to terminal buttons where they’re stores in vesicles.
action potential changes charge, calcium flows in that releases NT
NT bind to respecctive receptors in the post-synaptic membrane
Receptors are coupled to ion channels that opens when boound. influx of ions. causes post-synaptic potential (PSP)
Excitatoy PSP
depolarizing event. positively charged cations flows in. Increases likelihood of another action potential.
Inhibitory PSP
Hyperpolarizing event. Anions flow in. decreases likelihood of another action potential.
Temporal summation
Multiple impulses received together will trigger an action potential when alone they wouldn’t have been able too.
Major classes of neurotransmitters
Amino acids
Monoamines
Peptides
Other
Ligands
molecules that bind to and activate receptors.
NT and hormones are ligands to their respective receptor.
Ligand that binds + opens = agonist
Ligand that binds + prevents from opening = antagonist
Deactivation of neurotransmitters
Diffusion
Degradation (via enzyme)
Reuptake proteins (reabsorbs into the cell that just released it)
Glial cells
Hormones
Specific chemicals released by one cell group in an endocrine gland that travel through the blood stream in order to act on targets in the body
HPA axis
hypothalamic - pituitary- adrenal axis
Hypothalamus releases CRH (corticotropin-releasing hormone). Acts on anterior pituitary
Pituitary releases ACTH (adrenocorticotropic releasing hormone) acts on the adrenal gland
Adrenal: releases glucocorticoids (cortisol)
stress
effect of the stressor.
Stressor
Perceived threat to the body /body’s homeostasis that provokes a response
Either psychological or physical
Stress response
body’s response to stressor.
physiological and/or behavioral changes to cope with/escape stressor
General adaptation syndrome
Alarm: initial fight/flight
Resistance: physiological adaptation to cope with the stressor.
Exhaustion: Physiological resources depleted. Unable to cope. Disease.
SAM axis
Sympatho-adrenomedullary axis
fast pathway.
Hypothalamus projects to spinal cord to synapse with SNS neurons. Project to adrenal medulla which releases catecholamines
Catecholamines
Epinephrine and norepinephrine which bind to adregenic receptors throught the body
Cortisol
Steroid hormone. Glucocorticoid.
Ligand for:
Mineralocorticoid receptors (MR)
Glucocorticoid receptors (GR)
Activated by elevated cortisol levels.
Transcription factor type receptors
goes into DNA and changes how genes are expressed.
Effects of cortisol
Inhibits immune syst.
Metabolic effects
↓ bone and connective tissue formation
↑ breakdown of lean body mass
↑ blood sugar levels
Altered sensitivity of tissue to other hormones.
Impact of stress on cognition
impairs higher level reasoning, flexible thinking and memory
Prefrontal cortex (main planning, decision maker)
recent brain structure that inhibits lower brains structures (less adapted to today’s world). Stress inhibits the PFC and the lower structures are dominant (basal ganglia and amygdala)
