How Does Threat Affect Checking Behavior in OCD?

What you need to know

• This study used a rodent model to examine how perceived threat and punishment affect checking behaviors relevant to OCD.
• Functional checking increased in all animals under conditions of uncertainty and threat, but dysfunctional checking was elevated specifically in “sign-tracking” animals prone to attributing motivational value to environmental cues.
• The results suggest functional and dysfunctional checking rely on different motivational systems, with implications for understanding OCD.

Studying checking behavior in rats

Excessive checking is a common symptom of obsessive-compulsive disorder (OCD). However, some degree of checking behavior is normal and adaptive. To better understand the mechanisms underlying functional versus dysfunctional checking, researchers developed a rodent model called the observing response task (ORT).

In this task, rats can press a lever to “check” which of two other levers will provide a food reward. Pressing the checking lever turns on a light indicating which lever is currently active. The researchers measured two types of checking behavior:

1. Functional checking: Pressing the checking lever when the light is off to gain useful information.

2. Dysfunctional checking: Repeatedly pressing the checking lever when the light is already on, which provides no additional information.

This allowed the researchers to examine functional and dysfunctional checking separately in response to different manipulations.

Individual differences in cue sensitivity

The researchers were particularly interested in how individual differences might affect checking behavior. They classified the rats into two groups based on their tendency to approach reward cues:

• “Sign-trackers”: Rats that tended to approach and interact with a cue predicting reward. These animals are thought to attribute greater motivational value to environmental cues.

• “Goal-trackers”: Rats that tended to approach the location of reward delivery when cues were presented. These animals are thought to be less sensitive to the motivational properties of cues.

The researchers hypothesized that sign-trackers might show more dysfunctional checking behavior due to their greater sensitivity to environmental cues.

Effects of uncertainty and threat

The study examined how different manipulations affected checking behavior:

1. Uncertainty: Making the task less predictable increased functional checking in all animals. However, dysfunctional checking increased specifically in sign-trackers.

2. Perceived threat: Presenting contextual cues previously associated with mild electric shocks increased functional checking, but only in goal-trackers.

3. Actual punishment: Delivering mild shocks for incorrect responses increased functional checking in all animals. However, when punishment was removed, only sign-trackers continued to show elevated checking.

Implications for understanding OCD

The results suggest that functional and dysfunctional checking rely on different motivational systems:

• Functional checking appears to be driven by an “aversive” or threat-avoidance system. It increases adaptively in response to uncertainty and threat.

• Dysfunctional checking may be more closely related to an “appetitive” or reward-seeking system. It was elevated specifically in sign-tracking animals that are more sensitive to reward-related cues.

This distinction could help explain why checking becomes excessive and maladaptive in OCD. Patients may develop an “incentive habit” of checking that becomes detached from actual threat or uncertainty.

The findings also highlight how individual differences in cue sensitivity could influence vulnerability to developing compulsive checking. People who are more prone to attributing motivational significance to environmental cues may be at higher risk.

Conclusions

• Functional and dysfunctional checking appear to rely on separate motivational systems in the brain.
• Individual differences in sensitivity to environmental cues may influence vulnerability to compulsive checking.
• Treatments for OCD may need to target both threat-avoidance and reward-related motivational processes underlying checking behaviors.

While this research was conducted in rodents, it provides insights that could inform our understanding of human OCD and guide development of new treatments. Further research is needed to determine if similar processes occur in humans with OCD.