Cog Neuro- Executive function

Has white matter or grey matter expanded more in humans

white matter (axons)

What do PFC patients look like?

generally typical when it comes to motor actions, speech, semantics, longterm memory, and intelligence. closer look shows apathy, distractibility, impulsivity, perseverative behavior, shift from goal-directed to stimulus driven behavior

Components of executive control

goal directed vs. automatic behavior

task switching

working memory

decision-making and impulsivity

goal-planning and filtering

Anterior Cingulate Cortex (ACC) is inolved in

executive function such as motivation, decision making, learning, cost-benefit calculation, as well as conflict and error monitoring

Where is the ACC hypoactive

in schizophrenia and opiate addiction

When is the ACC hyperactive

OCD

How do prefrontal lesions effect monkey’s performances on a delayed-response task (blank cards vs. with symbols)

disrupt performance in working memory task, but not in the associative memory task (cards with symbols rather than blank)

What does working memory accomplish for an organism?

1. access information

2. keep information safe

What areas of information processing in the brain connect back to the prefrontal cortex? What does this mean?

Parietal cortex (location), inferiotemporal (shape), tempo-occipital (color), suggests prefrontal cortex’s implication in working memory

Recency memory

ability to organize events within memory

Source memory

ability to recall where you learned a particular item

Deficits in recency and source memory are often due to

Frontal cortical lesions

N-back task

Participants are presented with a sequence of stimuli and must respond when the current stimulus matches the one presented 'n' positions back in the sequence

As the difficulty of an N-back task increases, activity in what area increases and in what direction

Activity in the PFC increases in a further anterior position with each increase

Damage to what area causes struggle in N-back tasks

PFC

Patients learned a series of obscure facts in one session, brought back after a week and asked about the words. How did frontal lobe patients perform?

Just as good as controls for accuracy of recall, but struggled to remember the source of their knowledge

Bird pecking

more target pecking with a higher probability of a reward, less target pecking with a delay

Patients with lesions to which area would rather $50 now over $100 in 3 days

orbitofrontal cortex

Patients with lesions to which area have a lack of functional fixedness and do better on atypical problems such as VI = VI + VI rather than easier problems such as VI = VII + I

lateral prefrontal patients

Which prefrontal control system supports goal oriented behavior such as planning, simulating consequences, and initiating, inhibiting, and shifting behavior.

LPFC, OFC, and FP (Frontal Pole)

Which control system plays an essential role in guiding and monitoring behavior

Medial Frontal Cortex (MFC)

Do frontal lobe lesions cause organisms to exhibit goal-directed or stimulus driven behavior?

Stimulus driven

Utilization behavior

extreme dependency on prototypical responses for guiding behavior (ex. hammer + nail + picture = hang the picture on the wall), regardless of the context of the situation

Habit

an action that is no longer under the control of a reward, but is stimulus driven; as such, we can consider it automatic

What area of the brain is implicated in working memory?

prefrontal cortex

Cells in the LPFC exhibit which type of selectivity

task-specific (what and where)

the goal representation hypothesis

Working memory is information formed by the combination of a task goal and the perceptual and long-term knowledge relevant for achieving that goal.

What is the posterior prefrontal cortex associated with

sensory and simple working memory tasks

What is the anterior prefrontal cortex associated with

more challenging working memory tasks

Lateral-medial gradient of the PFC

information in the environment (more lateral) or information related to personal history and emotional states (more medial).

Neurons in the PFC of monkeys show sustained activity throughout the delay period in delayed-response tasks. What do these cells depict?

A neural correlate for keeping a representation active after the triggering stimulus is no longer visible.

Normative decision theories vs descriptive decision theories

how people ought to make decisions that yield the optimal choice vs what people actually do

model-based vs model-free decisions

Model-based methods explicitly learn a model of the environment, allowing for planning and prediction, while model-free methods learn directly from experiences without needing a model

primary vs secondary reinforcers

direct benefit for survival (food, water, sex) vs. no intrinsic value themselves, but become rewarding through their association with other forms of reinforcement. (money, status)

Which neurons fired most for probability, payoff, and cost

ACC: all three

LPFC: probability

OFC: payoff

Which cortex is involved in modulating self-control

LPFC

Two of the primary loci of dopaminergic neurons

the substantia nigra pars compacta (SNc) and the ventral tegmental area (VTA)

Dopaminergic neurons that originate in the VTA project through two pathways:

the mesolimbic pathway travels to structures important to emotional processing, and the mesocortical pathway travels to the neocortex

When in a reward test is there more activation of dopaminergic neurons?

when the reward is unexpected

reward prediction error (RPE)

a signal that represents the difference between the obtained reward and the expected reward.

Habenula

Structure located within the dorsal thalamus, represents emotional and motivational events

When did Hebenula neurons become active in a test of monkeys’ saccade to fixation points

Habenula neurons became active when the saccade was to the no-reward side and were suppressed if the saccade was to the reward side.

Where are gains and losses encoded in the ventral striatum?

Gains were encoded in the more anterior regions, and losses in the more posterior regions

What does Kent Berridge suggest about the role of dopamine in learning?

dopamine release is the result, not the cause, of learning.

Berridge describes a reward as made up of what three dissociable components? Which component does dopamine mediate

wanting, learning, and liking. Dopamine mediates only the “wanting” component.

What are the two classes of responses in DA neurons in the brainstem?

Valence and salience

Neurons that respond to valence

these cells increased their firing rate to stimuli that were predictive of reward and decreased their firing rate to aversive stimuli

Neurons that respond to salience

respond to the increased likelihood of any reinforcement, independent of whether it was a reward or a punishment, and especially when it was unpredictable

Where are valence neurons located

ventromedially in the substantia nigra and VTA

Where are salience neurons located

dorsolaterally in the substantia nigra

Damage in the dopamine system can be associated with

behavioral changes related to motivation, learning, reward, and emotion.

The subjective value of an item is made up of what variables?

payoff amount, context, probability, cost, temporal discounting, and preference

What areas are implicated in value representations

frontal regions, including the OFC

selection

the ability to focus attention on perceptual features or information in memory.

What does prefrontal activation in semantic tasks do

filtering

Successful execution of an action plan involves three components:

1. identifying the goal and developing subgoals

2. anticipating consequences when choosing among goals

3. determining what is required to achieve the goals.

How does the brain allow for “multitasking”

the brain develops connectivity patterns that enable people to efficiently shift between different goals.

Inhibitory control (AKA response inhibition)

the ability to suppress strong impulses or behaviors and instead engage in more appropriate responses.

where are the fusiform face area (FFA) and parahippocampal place area (PPA) located

inferior temporal lobe

The effects of aging on the prefrontal cortex impacts what function

inhibition

Lesions in which area effect inhibitory control

right inferior frontal gyrus

which area is implicated in response initiation

basal ganglia

While DBS can help parkinsons patients with motor movements, it comes with a cost of increasing

impulsivity