corticostriatal anatomy

describe motivation

what we need, want, and like

describe action

coordinates how we achieve our goals

describe learning

what predicts and what works

what do motivation, action & learning help us with?

help us anticipate and proactively respond to the world to maximize reward

describe liking

actual pleasure component or hedonic impact of a reward

describe wanting

motivation for reward which includes incentive salience ‘wanting’ processes, and conscious desires for incentives or cognitive goals

describe learning

associations, representations, and predictions about future rewards based on past experiences which includes explicit and cognitive predictions, and associative conditioning

what is the hub for the corticostriatal circuit?

striatum

describe substantia nigra

where dopaminergic neurons originate

what is this structure?

basal ganglia

where does the ventral striatum project to in the PFC?

vmPFC and orbital PFC

describe the loop created through projections between ventral striatum and PFC

motivational loop, wanting and desire to pursue a goal

what makes up the dorsal striatum and their relative positions in the brain?

caudate and putamen

caudate: medial

putamen: lateral

describe the caudate

goal directed planning and behavior modification when we do not receive the reward we hoped to achieve

to which structure(s) does the caudate project to?

dlPFC and dorsal anterior cingulate cortex (dACC)

describe the loop created from the projections from the caudate

executive, higher order, planning loop

describe to which area(s) the putamen is connected/projected to

supplementary motor area and motor cortex

describe the loop between the putamen and its connections

reward related motor movement (including planning movements)

identify the white structure

internal capsule

describe the ic (internal capsule)

white matter connections/tracks that convey informations to & from the body to the brain

why should we think of the VS as a gate?

opens to generate motivation for pleasure and pursue a reward

the opening of the VS gate is dependent on what?

intrinsic and extrinsic cues

what cause the VS gates to remain closed

closed by the amygdala if there is a signal of danger in the environment even with present reward signals

the corticostriatal circuit is associated with what behaviors?

basic signs of pleasure, either immediate or long-term

describe VS dysregulation

overactive striatum: impulsive-like behaviors

underactive: anhedonic-like behaviors

to which area(s) does the BLC directly project to?

ventral striatum

what kind of information is projected from the BLC?

sensory information

what way(s) does sensory information get into the circuit?

only through the BLC

describe the transfer of sensory information out of the VS and to other structures

VS → outputs through ventral pallidum →

caudate & putanem→ outputs through dorsal pallidum →

→→ thalamus → mPFC, lPFC, singulate

does sensory information directly or indirectly leave the striatum?

indirectly since it first sends outputs to the pallidum

which structure has dense collections of opioid receptors?

ventral pallidum

describe how information leaves the PFC to the striatum

directly to striatum or through the thalamus to striatum

identify the following structures

identify the following structure

thalamus

how are the thalamus and striatum receiving sensory information?

the amygdala → thalamus → striatum

the thalamus is a hub for getting information ___ of the ___ and ___ the ___

the thalamus is a hub for getting information out of the striatum and into the PFC

describe how the pallidum is an intermediary

all the neurons from the VS and DS stop by the pallidum before going to the thalamus

what happens when the ventral pallidum is stimulated form the striatum?

generates a hedonic liking response

VS projects to which pallidum?

ventral pallidum

DS projects to which pallidum?

dorsal pallidum

identify the following structure

amygdala

describe the amygdala in relation to the corticostriatal circuit

BLC projects all of the sensory information to VS

contributes to learning cues in the environment that predict satisfaction

describe the optogenetic study

• used optogenetics to stimulate and inhibit glutamatergic neurons projected from BLC into VS

  • the animal could stimulate the neuron itself by putting its nose through a hole which would activate the circuit

  • frequency of behavior (nose pokes) increased greatly compared to the the control group

• they then conditioned animals to a cue and a reward and transiently inhibited projections from the BLC to the VS

  • in the control: animals learned the association and started licking when the cue was present

  • but in the group where they inhibit processing from BLC to VS right when the cue is presented, the animals do no learn the association between cue and reward

  • conditioned group showed increased lick rate of consumption over time whereas the inhibitory group does not

identify the following structure

hippocampus

describe the hippocampus

provides contextual information: who, what, where, when

learning of the context in which a specific action satisfies a specific motivation (with context facilitating or inhibiting opening of VS gate)

what is argued with rapid development of limbic regions but more slowly developing PFC?

brain more vulnerable to developing psychopathology especially in adolescence

how does sensory information get to VS?

BLC

how does context get to VS?

through hippocampus (both stimulatory of reward in appropriate context or inhibitory in an inappropriate context)

how does PFC regulation get to VS?

indirectly and directly through thalamus

identify the following structure

hypothalamus

describe the hypothalamus

a region that secretes hormones that regulate food and se_

what other structure is interconnected with the hypothalamus thats leads to secretion of hormones

striatum

describe orbitofrontal cortex

subjective evaluation of how rewarding something is or even how much we desire something

describe the mPFC

• integrates bottom-up and top-down processing

• for adaptive responses to environment

describe how the vmPFC is an integretory hub

where sensory info (thalamus & cortex), interoceptive info (insula), and contextual info (hippocampus) becomes integrated with motivational info from the VS

what happens to sensory information in the vmPFC after it becomes integrated with motivation info from the VS?

translated locally (along w/ projections to OFC) into subjective valuation of what we find pleasurable

the vmPFC allow you to become ___and form ___ ___ for ___

the vmPFC allow you to become aware and form subjective value for importance

where is info projected to after the vmPFC?

dlPFC

describe the dlPFC

forms complex plans for satisfaction

to where does the dlPFC communicate its info to?

the VS through vmPFC

how does the dlPFC put plans into action?

from VS to DS to support motor and motor cortex

describe the dACC

• monitors conflict between expectations and actual outcomes

• helps correct (modify) actions to achieve desired effect (goal) by projecting to dlPFC

• monitors effectiveness of actions

identify the following structure

midbrain