As You Like It: A case study of damage to the anterior cingulate cortex

Abstract

Apathy is a frequent and debilitating consequence of traumatic brain injury associated with damage to the frontostriatal circuits involving the anterior cingulate. The patient examined sustained a severe traumatic brain injury with frontal contusions and extensive damage to the cingulate. After his injury, he showed a strong reduction in goal-directed behaviour in addition to emotional flatness and a cognitive profile characterized by problems with attention, psychomotor speed and executive function. Damage to the anterior cortex appears to affect the brain’s ability to sustain and concentrate effort in goal pursuit, disconnecting the individual’s perceptions of reward possibilities in the environment to mechanisms of implementation and arousal. The patient’s symptoms are interpreted as reflecting missing anterior cingulate input that would normally serve to sustain concentration and assign effort, as well as adjust arousal and thus emotional variance; this “effort” network of the brain, when disabled, leaves the executive network without input and the emotional system without a means of output. Classification systems, theories, and studies of the neuropsychological consequences of apathy are reviewed, and implications of this study for future research is discussed.