A novel role for the rat retrosplenial cortex in cognitive control

Andrew J.D Nelson,Emma L Hindley,Seralynne D Vann,John P Aggleton,Josephine E Haddon

doi:10.1101/lm.032136.113

Abstract

By virtue of its frontal and hippocampal connections, the retrosplenial cortex is uniquely placed to support cognition. Here, we tested whether the retrosplenial cortex is required for frontal tasks analogous to the Stroop Test, i.e., for the ability to select between conflicting responses and inhibit responding to task-irrelevant cues. Rats first acquired two instrumental conditional discriminations, one auditory and one visual, set in two distinct contexts. As a result, rats were rewarded for pressing either the right or left lever when a particular auditory or visual signal was present. In extinction, rats received compound stimuli that either comprised the auditory and visual elements that signaled the same lever response (congruent) or signaled different lever responses (incongruent) during training. On conflict (incongruent) trials, lever selection by sham-operated animals followed the stimulus element that had previously been trained in that same test context, whereas animals with retrosplenial cortex lesions failed to disambiguate the conflicting response cues. Subsequent experiments demonstrated that this abnormality on conflict trials was not due to a failure in distinguishing the contexts. Rather, these data reveal the selective involvement of the rat retrosplenial cortex in response conflict, and so extend the frontal system underlying cognitive control.

Highlights

The retrosplenial cortex is important for a range of spatial and mnemonic functions (Maguire 2001; Vann et al 2009), the impact of retrosplenial damage upon decision making and response conflict has received scant attention
Conflict control was taxed by simultaneously presenting pairs of stimuli that had individually elicited opposing (“incongruent”) responses due to their initial conditional discrimination training in different contexts (Experiment 1a)
Rats with retrosplenial cortex lesions successfully learnt the initial conditional tasks, these animals failed to use tasksetting cues provided by the contexts to help select between the context-appropriate and context-inappropriate levers during incongruent trials

Summary

Introduction

The retrosplenial cortex is important for a range of spatial and mnemonic functions (Maguire 2001; Vann et al 2009), the impact of retrosplenial damage upon decision making and response conflict has received scant attention. Incorrect contextual cues to disambiguate the conflicting response information, and so responded according to the stimulus element that had previously been trained in that same test context (Fig. 3D).

Results

Conclusion