Disordered Brain Exam 2 - CS OCD

What is OCD characterized by?

Obsessions and compulsions. Essentially, OCD people have uncontrollable intrusive thoughts or impulses (obsessions) that can only be alleviated by patterns of rigid or ceremonial behavior.

For the MIDT, what are the key findings? Interpretations?

For reward anticipation, OCD patients have hypo-reactivity of the VS and insula. For reward outcomes, not really found!

Interpretation: Lack of ability to update based on environmental contingencies/deficit with learning?!

What does the Incentive Flanker Task test? Explain it?

Ability to inhibit prepotent response.

There are 3 types of trials, gain, loss, and neutral. Task involves showing a series of letters and you press a button with regard to what letter is in the middle. Incentive is flanked by other stimuli, making it hard to press button correctly. There are varying levels of interference: high if flankers are diff button, low if flankers is same button as the target.

When people make mistakes on the Incentive Flanker Task, (most likely during high interference trials), what are the brain responses for OCD patients compared to healthy controls? What is the interpretation?

For both, ACC is highly activated!

For the OFC, there is hyper-reactivity compared to controls, because it isn’t hypo-reacting like normal!

Interpretation is that there is dysfunction with subjective evaluation of error/correct responses. The OFC is hypo-reactive to correct evaluations, essentially not reacting normally to correct/rewarding situations. Correct response is not being subjectively logged.

When people make mistakes on the Incentive Flanker Task for LOSS TRIALS, what are the brain responses for OCD patients compared to healthy controls? What is the interpretation?

When patients with OCD make an error on a loss trial, they have hyper-reactivity of the OFC compared to controls.

Explain the monitoring and interference study involving numbers in a row. When viewing interference trials (noncongruent), what in the CS is active, compared between OCD patients and healthy controls?

People see a 3 digit number, and the numbers that are a part of it range from 0 to 3. Congruent trials are ones in which the number corresponds to the position it is in. For example 3 at the unit place. Incongruent is when a diff number is there like 1 at unit place. They are asked to press the number of the ________ digit. Congruent trials are more frequent than incongruent trials and so they train you to get used to making that prepotent response.

ACC is highly activated in the incongruent trials for both, but it is hyper-reactive for OCD patients!

OCD patients make ___________ errors compared to controls for the incongruent trials involving numbers in row. When people make errors in this task, what are levels of activation for CS circuit for OCD compared to controls?

more.

OCD patients have hyper-reactivity of the vmPFC/OFC for errors compared to controls. (similar results to the study done with incentive flanker task)

ACC and vmPFC/OFC activity is __________________ among patients with OCD, while it is ________________ among controls for incongruent trials.

positive correlated

negatively correlated

Explain the task switching experimental paradigm. For these experiments, what is the brain activity for CS during task switching?

You are asked to identify a face or house. Shown a face or house, chosen to press button for face. But then switches to press for house. The stimuli is slightly ambiguous for house and face (they don’t look too diff).

For task switching trials, OCD patients have hypoactivity of the ACC, OFC, vmPFC, and DS.

People with OCD have ______________ of the amygdala in response to symptoms that provoke them (what their OCD is about) and general aversive stimuli

hyper-reactivity

Ventral striatum is ___________ coupled with the vmPFC in OCD. The putamen is ____________ coupled with the vmPFC in OCD.

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