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.