The circuitry of abulia: Insights from functional connectivity MRI

• A method for single subject functional connectivity analysis is proposed.
• In a case study, resting state fcMRI identifies reproducible disruption that corresponds to clinical deficit.
• Damage to the anterior thalamus results in disrupted functional connectivity in the cingulate cortex.
• Abulia without frontal lesion shows disrupted functional connectivity in the cingulo-opercular and default mode networks.

BackgroundFunctional imaging and lesion studies have associated willed behavior with the anterior cingulate cortex (ACC). Abulia is a syndrome characterized by apathy and deficiency of motivated behavior. Abulia is most frequently associated with ACC damage, but also occurs following damage to subcortical nuclei (striatum, globus pallidus, thalamic nuclei). We present resting state functional connectivity MRI (fcMRI) data from an individual who suffered a stroke leading to abulia. We hypothesized that, although structural imaging revealed no damage to the patient's ACC, fcMRI would uncover aberrant function in this region and in the relevant cortical networks.MethodsResting state correlations in the patient's gray matter were compared to those of age-matched controls. Using a novel method to identify abnormal patterns of functional connectivity in single subjects, we identified areas and networks with aberrant connectivity.ResultsNetworks associated with memory (default mode network) and executive function (cingulo-opercular network) were abnormal. The patient's anterior cingulate was among the areas showing aberrant functional connectivity. In a rescan 3 years later, deficits remained stable and fcMRI findings were replicated.ConclusionsThese findings suggest that the aberrant functional connectivity mapping approach described may be useful for linking stroke symptoms to disrupted network connectivity.