Diaschisis in the human brain reveals specificity of cerebrocerebellar connections

• Published in: Journal of comparative neurology (1911) 2023-12, Vol.531 (18), p.2185-2193
• Main Authors: Guell, Xavier, Schmahmann, Jeremy D.
• Format: Article
• Language: English
• Subjects: Animals; Brain; Brain architecture; Cerebellar Vermis; Cerebellum; Cerebellum - diagnostic imaging; Cerebral hemispheres; Cognitive ability; Diaschisis; Epilepsy; Hemispheric laterality; Humans; Magnetic Resonance Imaging; Neural networks; Neuroimaging; Sensorimotor Cortex; Sensorimotor integration; Sensorimotor system; Topography
• ISSN: 0021-9967; 1096-9861
• DOI: 10.1002/cne.25534

Anatomical studies in animals and imaging studies in humans show that cerebral sensorimotor areas map onto corresponding cerebellar sensorimotor areas and that cerebral association areas map onto cerebellar posterior lobe regions designated as the representation of the association (cognitive and limbic) cerebellum. We report a patient with unilateral left hemispheric status epilepticus, whose brain MRI revealed diffuse unihemispheric cerebral cortical FLAIR and diffusion signal hyperintensity but spared primary motor, somatosensory, visual, and to lesser extent auditory cerebral cortices. Crossed cerebellar diaschisis (dysfunction at a site remote from, but connected to, the location of the primary lesion) showed signal hyperintensity in the right cerebellar posterior lobe and lobule IX, with sparing of the anterior lobe, and lobule VIII. This unique topographic pattern of involvement and sparing of cerebral and cerebellar cortical areas matches the anatomical and functional connectivity specialization in the cerebrocerebellar circuit. This first demonstration of within‐hemispheric specificity in the areas affected and spared by cerebrocerebellar diaschisis provides further confirmation in the human brain for topographic organization of connections between the cerebral hemispheres and the cerebellum. Brain magnetic resonance imaging and positron emission tomography following unilateral status epilepticus revealed abnormalities in cerebral association areas and contralateral cerebellar cognitive posterior lobe regions, with sparing of primary sensory and motor areas in cerebral cortex and cerebellum. This unique observation provides confirmation in the human brain of anatomical‐functional specialization in cerebrocerebellar circuits.