Cognitive Neuroscience Quiz #5

cognitive control

the ability to focus on and select information that is currently relevant to a particular goal, while inhibiting information that is not relevant. Dependent on multiple executive functions, including working memory, inhibition, conflict monitoring, and has often been discussed in terms of facilitating flexible behavioral responses

Phineas Gage

25 year old rail road worker who had an iron bar go through his head. His case has been instrumental in understanding the role of the brain, particularly in the frontal lobe, in cognitive control and personality

Inhibition of gaze in hierarchical primates

in primates with stronger social hierarchical structure, gaze has more implications (eye contact as a threat for example). A subordinate monkey must track dominants covertly for safety, but they must inhibit by making eye contact.

Antisaccade

Making a movement in the opposite direction of the target. Cognitive control occurs at the fixation point, and they can deploy this prior to the task beginning.

go/no go task 

When there is a circle press the button, when there is a square INHIBIT and do not press the button. Cognitive control is deployed once the target appears. 

Countermanding task

Fixation point occurs a second time, the monkey has to inhibit and stop the initial movement towards the target. Cognitive control is deployed after the main target has been presented.

Antisaccade task

Human patients with damage to frontal lobe have difficulties suppressing the reflexive saccades (the tendency to look at the target) 

saccade neurons

Activity is greater in prosaccade than antisaccade trials. There is an inhibitory mechanism suppressing neuronal activity in the preparation of the antisaccade trial 

fixation neurons 

Activity is greater in an antisaccade than prosaccade trial and also suggests an inhibitory mechanism (opposite of saccade trials)

Activity during fixation is higher in saccade neurons…

For trials in which animal fails to inhibit the saccade. For trials in which the animal succeeds: the inhibitory mechanism fails before the trial even starts

SSRT

Stop signal reaction time. The time needed to cancel a saccade after a stop signal has been presented.

Neural recordings during countermanding task: saccade neurons

GO trials, the firing rate increases towards a threshold that when breached results in a saccade. in STOP trials the firing rate declines rapidly following the presentation of the STOP signal. This decline occurs within the SSRT. Firing rate is similar in GO trials and in STOP trials in which the animal failed to stop the saccade.

Neural recordings during countermanding task: fixation neurons 

firing rate declines in GO trials and sharply increase in STOP trials 

Race Models

Race between the system of neurons trying to inhibit the movement and the system of neurons that are trying to promote the movement

Activity in inferior frontal regions is greater in NoGO or GO trials in humans?

NoGO. This suggests that the inferior frontal cortex is exerting cognitive control by inhibiting movement.