Summary
Background: The clinical manifestations of an acute stroke could be well circumscribed and or widespread producing a number of variants. The clinical features could be diverse and complex depending
on the site, extent and location of the lesion. The possibility of frontal lobe disorder (or extensive behavioural dysfunction) in posterior cerebral artery territory infarction has often been overlooked
in most reports, probably because it does not fit well with the fact that the frontal lobe is typically spared in posterior cerebral artery infarction.
Case Report: This case study is about a 78- year- old right- handed man previously well who suffered a right posterior cerebral artery infarction. The first presenting symptoms were confusion, subtle weakness of the left side and contra- lateral homonymous hemianopia. This was followed a few days later by complex visual and auditory hallucinations, complex motor behaviour (environmental driven responses and utilization behaviours), disinhibition, aspontaniety, marked perseveration and visual agnosias for objects, colours and faces. At six months post-stroke he demonstrated aggressive and hostile behavior, restlessness and slept poorly consistent with mania and had memory problems. There are several lines of evidence to suggest the findings could be explained as an attentional disorder. The neuropsychological features declined over a period of 14 months from mild to severe dementia. The MRI showed involvement of the right temporo-occipital regions involving
the hippocampus, mesial temporal regions and extending to involve the thalamus and the retrospenial cortex.
Conclusions: The frontal-subcortical circuitry and the frontal diencephalic brain stem system provide a comprehensive framework for the understanding of the varied and complex neuropsychological
and neurobehavioral features associated with posterior cerebral artery infarction.

Keywords: Posterior cerebral artery infarction, frontal-subcortical circuitry, frontal diencephalic brain stem system, secondary mania