Lesions of the Orbitofrontal but Not Medial Prefrontal Cortex Affect Cognitive Judgment Bias in Rats.

Joanna Golebiowska,Rafal Rygula

doi:10.3389/fnbeh.2017.00051

Abstract

Neuroimaging studies in humans have recently shown that the prefrontal cortex (PFC) and orbitofrontal cortex (OFC) mediate bias in the judgment of forthcoming events. In the present study, we sought to determine whether cognitive judgment bias (CJB) is also dependent on these prefrontal regions in non-human animals. For this, we trained a cohort of rats in the ambiguous-cue interpretation (ACI) paradigm, subjected them to excitotoxic lesions in the medial PFC (mPFC) and OFC, and tested the effects of neuronal loss within these regions on CJB. Comparison of the lesions’ behavioral effects in the ACI paradigm revealed that neuronal loss within the OFC but not within the mPFC influences the interpretation of ambiguous cues by animals. Our findings demonstrate the specific involvement of the OFC in CJB in rats.

Highlights

The glass is always half empty, while for others, it is always half full
Three animals from the orbitofrontal cortex (OFC) lesion group and three from the medial prefrontal cortex (mPFC) lesion group were excluded because the lesions could not be localized
After the surgery and recovery period, the CJB index (CJBI) was significantly lower in animals with excitotoxic lesions within the OFC than in SHAM-operated controls (p = 0.016) or at baseline (p = 0.002)

Summary

Introduction

The glass is always half empty, while for others, it is always half full These biases in cognitive judgment, termed pessimism and optimism, respectively, influence many aspects of human life and have been implicated in the etiology and maintenance of several psychiatric disorders, including depression and mania (Brittlebank et al, 1993; Nygren et al, 1996; Murphy et al, 1999). Very few studies to date have attempted to characterize the potential neurochemical and neuroanatomical correlates of optimistic or pessimistic cognitive judgment bias (CJB). Sharot et al (2012) demonstrated that administration of a drug that enhances dopaminergic function (dihydroxy-L-phenylalanine; L-DOPA) increases optimism in humans by reducing negative expectations regarding the future. Using functional magnetic resonance imaging (fMRI), the same authors found increased activation

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Discussion

Conclusion