Unilateral medial frontal cortex lesions cause a cognitive decision-making deficit in rats

Eur J Neurosci. 2014 Dec;40(12):3757-65. doi: 10.1111/ejn.12751. Epub 2014 Oct 27.


The medial frontal cortex (MFC) is critical for cost-benefit decision-making. Generally, cognitive and reward-based behaviour in rodents is not thought to be lateralised within the brain. In this study, however, we demonstrate that rats with unilateral MFC lesions show a profound change in decision-making on an effort-based decision-making task. Furthermore, unilateral MFC lesions have a greater effect when the rat has to choose to put in more effort for a higher reward when it is on the contralateral side of space to the lesion. Importantly, this could not be explained by motor impairments as these animals did not show a turning bias in separate experiments. In contrast, rats with unilateral dopaminergic midbrain lesions did exhibit a motoric turning bias, but were unimpaired on the effort-based decision-making task. This rare example of a cognitive deficit caused by a unilateral cortical lesion in the rat brain indicates that the MFC may have a specialised and lateralised role in evaluating the costs and benefits of actions directed to specific spatial locations.

Keywords: T-maze; decision; lesion; neglect; rat.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cognition Disorders / physiopathology*
  • Decision Making / physiology*
  • Dopamine / metabolism
  • Frontal Lobe / drug effects
  • Frontal Lobe / pathology
  • Frontal Lobe / physiopathology*
  • Functional Laterality / physiology*
  • Male
  • Mesencephalon / drug effects
  • Mesencephalon / pathology
  • Mesencephalon / physiopathology
  • Motor Activity / physiology
  • Neuropsychological Tests
  • Oxidopamine / toxicity
  • Photomicrography
  • Quinolinic Acid / toxicity
  • Rats
  • Reward


  • Oxidopamine
  • Quinolinic Acid
  • Dopamine