Transcript Study 1
Valentina Moro, Cosimo Urgesi, Simone Pernigo, Paola Lanteri, Mariella Pazzaglia, and Salvatore Maria Aglioti 1. Single unit recording and fMRI in monkeys 2. Intracranial recordings in humans 3. Evoked potentials in humans 4. fMRI in humans 5. TMS in humans 6. Lesions in humans – this experiment Neurons in inferior temporal cortex (IT) respond selectively to human/monkey bodies and body parts. Other neurons in IT respond selectively to faces but not to hands. from Peelem & Downing, 2007 שיטות Extrastriate visual cortex N230 - hand selective from Peelem & Downing, 2007 שיטות N170 (face selective) and N190 (body selective) have distinct lateral occipitotemporal Sources (according to source localization) from Peelem & Downing, 2007 שיטות Extrastriate body area (EBA) - posterior inferior temporal sulcus/middle temporal gyrus - Body parts. Fusiform body area (FBA) – Whole bodies. from Peelem & Downing, 2007 שיטות EBA - 150–250 ms after stimulus onset - impaired performance on a delayed match-to-sample task involving images of body parts, but not face or motorcycle parts. Extrastriate body area (EBA) Static bodies Dynamic displays of bodies Body parts Body forms but not actions Not faces Fusiform body area (FBA) Whole body Body parts Ventral Premotor cortex (vPMc) Body actions but not form שיטות Patients with anterior (n=14) and posterior (n=14) lesions. No visual agnosia Study 1 – face parts vs. body parts vs. objects Study 2 – Body Form vs. Body Action Task: Two choice matching to sample visual discrimination *In a separate experiment with controls: inverted and upright stimuli inversion effect for faces only (configural processing for faces) Group (anterior, posterior, control) X Category (body, face, object) Posterior patients perform worse than controls and anterior patients in discriminating body and face parts. Body Face Relationship between injury and behavior on a voxel-by-voxel basis In this experiment: 1. For each patient T1 weighted MRI 2. Each lesion was superimposed onto a standard brain 3. To identify the voxels that are associated with the three categories, three VLSM analyses were conducted. The predictors were: % correct responses of the for body % correct responses for face % correct responses for object (Individual % CR of each category were entered) Impaired body discrimination – bilateral inferior and middle Occipitotmeporal & left STS lesions. EBA FBA Task: two choice matching to sample visual discrimination (action or form) Form discrimination: Different models, same action Action discrimination: Same model, different action. Group (anterior, posterior, control) X Type (action, form) Anterior patients – worse for actions Posterior patients – worse for form / identity Double dissociation between action & form and anterior posterior Independent from lateralization Predictors: % CR in Action/% CR in Form % CR in Form/% CR in Action Body form - Lateral occipitotemporal (bilatetral) - (BA 19,37) – EBA Left inferior occipital (BA 19). same size & location as in study 1 Body action – left vPMC, a little bit right as well. Selective deficits for bodies at the perceptual level Study 1: Body agnosia 1. Face & body - Ventromedial, occipitotemporal (FBA). 2. Body only - Extrastriate body area (EBA). Study 2: body form and body action agnosias. 3. Double dissociation: Body form - EBA & FBA Body action - ventral premotor cortex (vPMc). Selective deficits for bodies at the perceptual level Neural substrates for form and body action agnosias that are Double dissociated. Left and right ventral premotor are causatively associates with Action perception. Diagnostic tools for clinical assessment. 1. We need sensitive tests (The Posterior patients did not report having difficulties in recognizing bodies in daily life). 2. Body selective areas are small and sometimes overlap with object, face and motion areas. Maybe motion agnosia masks body agnosia? 3. Body deficits may be compensated by other body selective areas (ipsilateral or contralaetral)