Le 01/12/2022 de 15:00 à 16:30
Analyse par neuroimagerie structurelle du sens de la verticalité après AVC hémisphérique en phase subaigue : rôle majeur du planum temporale et de ses connexions
celine Piscicelli (GRENOBLE, France), Shenhao Dai (GRENOBLE, France), Camille Lemaire (GRENOBLE, France), Christophe Lopez (Marseille, France), Julien Barra (Chambéry, France), Olivier Detante (Grenoble, France), Alexandre Krainik (Grenoble, France), Michel Thiebaut de Schotten (Bordeaux, France), Dominic Pérennou (GRENOBLE, France)
Objective : The sense of upright is fundamental for bipedal behaviour. Here, we reveal the neural bases supporting the integration between the upright of the environment (visual vertical,VV) and that of the body (postural vertical,PV) by means of lesion and disconnectome symptoms mapping in stroke.
Material / Patients and Methods : We tested 116 individuals, 58 with a first right hemisphere stroke (RHS) and 58 with a left (LHS), matched in age and lesion volume. Brain areas damaged by the stroke and consequent anatomical disconnections were investigated by means of advanced structural neuroimaging methods for PV and VV.
Results : After RHS, tilts in vertical estimates were more frequent both for PV (32/58 vs 7/58,p<10-5) and VV (30/58 vs 17/58,p<0.01) and also more severe both for PV (-3.4°vs 0°; p<10-4,r=0.5) and VV (-4° vs -0.9°;p=0.001,r=0.2). Lateropulsion was also more frequent after RHS (30/58 vs 6/58;p<10-6,r=0.4). No structure or tracts was found in the LH. In the right hemisphere, the sense of upright was altered by a lesion of the planum temporale or a disconnection involving the cortico-pontocerebellar tract, the posterior thalamic peduncle and the inferior longitudinal fasciculus. In addition to this core and its connections, specific neural areas and pathways supported PV and VV, mainly parietal for the former and temporal for the latter.
Discussion - Conclusion : The sense of upright is a primary property of the right hemisphere, as well as its corollary the active body orientation with respect to gravity. The right planum temporale and its white matter tracts are the core polymodal neural pathway underpinning the human sense of upright.
Keywords : Sense of upright, Postural Vertical, Visual Vertical, Stroke