posterior circulation infarct posterior circulation infarct posterior circulation infarct (poci) is a type of cerebral infarction affecting the posterior circulation supplying one side of the brain. posterior circulation infarctdiagram of the arterial circulation at the base of the brain (inferior view). posterior circulation represented by bottom half of diagram.specialtyneurology posterior circulation stroke syndrome (pocs) refers to the symptoms of a patient who clinically appears to have had a posterior circulation infarct, but who has not yet had any diagnostic imaging (e.g. ct scan) to confirm the diagnosis. it can cause the following symptoms: cranial nerve palsy and contralateral motor/sensory defect bilateral motor or sensory defect eye movement problems (e.g.nystagmus) cerebellar dysfunction isolated homonymous hemianopia vertigo it has also been associated with deafness.