Studied by 9 peopleaction selection, energization
deciding what is worth doing
reinforcement learning
doing something based on what has worked before
where do dopamine cells tend to live?
midbrain
input nucleus
striatum
output nucleus
SNr
obsessions
recurrent and persistent thoughts, urges
compulsions
repetitive behaviors or mental acts
disorder
time-consuming or clinically significant distress or functional impairment
cortico-basal ganglia circuit
connects cortex with basal ganglia and thalamus with cortex; is refined by rewards
locus of arbitration
cortico-basal ganglia circuit
process in cortico-basal ganglia circuit
proposal → vote → accept/reject
what refines arbitration?
rewards
which neurotransmitter controls 100% of plasticity in the striatum?
dopamine
flexible behaviors
meet demands of a changing world, learn how world changes, perform/execute knowledge one has about world
key roles of cortico-basal-ganglia
reward learning, decision making, movement, motivation/effort, executive functions, working memory, cognitive effort/focus
disorders cortico-basal-ganglia is implicated in
addiction, gambling, binge-eating, Parkinson’s, depression, schizophrenia, bipolar disorders, OCD, ADHD
when does the cortico-basal-ganglia flag and use a corrective action?
catching errors online or learning from errors
hierarchy
circuits identify errors in elementary circuits
procedural memory examples
baking, biking
obsession role in cortico-basal-ganglia
error detection mechanism, flag
compulsion role in cortico-basal-ganglia
error resolution mechanism, corrective action
caudal (direction)
forward
medial (direction)
middle
dorsal (direction)
up
lateral (direction)
away from middle
brain regions are implicated in OCD
dorsal-lateral prefrontal cortex, orbito frontal cortex, anterior cingulate cortex (all in a loop with cortico-basal ganglia), and caudate (dorsal-medial-striatum; deep brain structure that receives inputs from cortical areas)
dorsal-lateral prefrontal cortex (DLPFC) roles
domain-general executive control, operator or planner/schedule, planning, task-switching, task-set reconfiguration, inhibitory control, working memory regulation and load management
how does the dorsal-lateral prefrontal cortex (DLPFC) perform its roles?
tracks sequence “order” and “hierarchy” of events, tracks progress in this order/hierarchy
orbito frontal cortex (OFC) roles
rule book, stores causal structures of task space, cognitive map of ‘what if’ trajectories (rules), helps refine ‘plans’ of what to do next
how does the orbito frontal cortex (OFC) perform its roles?
learns transition probability of world, especially when conditioned on my actions
anterior cingulate cortex (ACC) roles
error detector, conflict/error monitoring, compare what happened w/ plan, affects motivation to perform/continue plan, strong coupling w/ amygdala (anxiety) and ventral striatum (motivation to correct behavior)
how does the anterior cingulate cortex (ACC) perform its roles?
computes ‘expected value of control (EVC)’, forecasts what plan achieves (rewards?) and costs of plans
caudate (dorsal-medial-striatum) roles
integrator, stores casual associations (a→b→c etc.), stores agency (how do I affect the world?), ‘procedural’ memory
how does the caudate (dorsal-medial-striatum) perform its roles?
arbitrates cortical proposal related to its roles, sequences plans to pursue goals (goal directed behaviors)
how do genome wide association studies (GWAS) find any patterns of variation in genes that could explain OCD diagnosis or traits?
assess heritable single nucleotide polymorphisms (SNPs; change in gene locations)
which neurotransmitters are associated with variations in genes related to OCD?
serotonin, dopamine, glutamate
how is optogenetic stimulation of lateral orbito fronto striatal pathway used to treat OCD?
suppresses compulsive behaviors
role of selective serotonin reuptake inhibitors (SSRIs) in treating OCD
increases serotonin levels, takes weeks for therapeutic function, unknown mechanism of action but many guesses
Brain Locked-Unlocked method of treating OCD
cognitive behavioral therapy with two steps
relabel the problem (there is a problem, but that is my OCD)
refocus the problem (do something else rewarding)
how is exposure used to treat OCD?
immerse person in fear to create response prevention
transcranial magnetic stimulation (TMS)
a method to affect electrical activity in the brain using alternating electro-magnetic fields
deep brain stimulation (DBS)
a method to affect electrical activity in the brain using implanted electrodes and programmed stimulator
Note
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