Ans: b (Cog wheel rigidity) Ref: Harrison, 16th ed, p. 144Cog wheel rigidity is a feature of extra pyramidal tract lesion--ParkinsonismMajor Brain stem stroke syndromesName of syndromeSiteSymptomsWeberAnterior cerebral peduncle (mid-brain)Ipsilateral 3rd palsy ,contralateral hemiparesisBenedict's syndromeUpper red nucleusIpsilateral 3rd nerve palsy with tremors,chorea, and athetosis on opposite sideNothnagel syndromeSuperior cerebellar peduncleIpsilateral 3rd nerve palsy and contralateral cerebellar ataxiaClaude syndromeSuperior cerebellar peduncle+Red nucleusFeatures of both Benedict and Nothnagel syndromeParinaud syndromeDorsal mid-brain(tectum)Vertical gaze palsyConvergence disordersConvergence retraction nystagmusPupillary and lid disordersW allenberg syndromeLateral medulla(Due to occlusion of any of the following vessels-vertbral artery, PICA, or superior, middle, or inferior lateral medullary arteries.)Ipsilateral 5th,,9th, 10th 11th palsyIpsilateral Horner's syndromeIpsilateral cerebellar signsContralateral spinothalamic sensory lossVestibular disturbancePontine syndromesMillard Gubler syndromeVentral pontine syndrome, caused by paramedian infarction of ponsIpsilateral paresis of lateral rectus with diplopiaIpsilateral paresis of upper and lower face (damage to 7th cranial nerve)Contralateral hemiplegia with sparing of contralateral faceFoville syndromeLower dorsal pontine syndromeCaused by lesion to dorsal tegmentum of lower ponsIpsilateral horizontal gaze palsy (damage to nucleus of abducent nerve and paramedian pontine reticular formation)Ipsilateral paresis of whole face(damage to nucleus and fibres of 7th nerve)Contralateral hemiplegia with sparing of contralateral face(damage to corticospinal tract)Raymond Ceston syndromeUpper dorsal pontine syndromeIpsilateral ataxia and coarse intention tremorIpsilateral paralysis of muscles of masticationContralateral loss of sensory modalities in the bodyContralateral hemiparesis of face and bodyHorizontal gaze palsy may occur