Dorsal and ventral stream contributions to form-from-motion perception in a patient with form-from motion deficit: a case report.
The main model of visual processing in primates proposes an anatomo-functional distinction between the dorsal stream, specialized in spatio-temporal information, and the ventral stream, processing essentially form information. However, these two pathways also communicate to share much visual information. These dorso-ventral interactions have been studied using form-from-motion (FfM) stimuli, revealing that FfM perception first activates dorsal regions (e.g., MT+/V5), followed by successive activations of ventral regions (e.g., LOC). However, relatively little is known about the implications of focal brain damage of visual areas on these dorso-ventral interactions. In the present case report, we investigated the dynamics of dorsal and ventral activations related to FfM perception (using topographical ERP analysis and electrical source imaging) in a patient suffering from a deficit in FfM perception due to right extrastriate brain damage in the ventral stream. Despite the patient's FfM impairment, both successful (observed for the highest level of FfM signal) and absent/failed FfM perception evoked the same temporal sequence of three processing states observed previously in healthy subjects. During the first period, brain source localization revealed cortical activations along the dorsal stream, currently associated with preserved elementary motion processing. During the latter two periods, the patterns of activity differed from normal subjects: activations were observed in the ventral stream (as reported for normal subjects), but also in the dorsal pathway, with the strongest and most sustained activity localized in the parieto-occipital regions. On the other hand, absent/failed FfM perception was characterized by weaker brain activity, restricted to the more lateral regions. This study shows that in the present case report, successful FfM perception, while following the same temporal sequence of processing steps as in normal subjects, evoked different patterns of brain activity. By revealing a brain circuit involving the most rostral part of the dorsal pathway, this study provides further support for neuro-imaging studies and brain lesion investigations that have suggested the existence of different brain circuits associated with different profiles of interaction between the dorsal and the ventral streams.
Laboratory of Cognitive Neuroscience, Brain-Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 19, 1015, Lausanne, Switzerland.|The Functional Brain Mapping Laboratory, Department of Neuroscience, University of Geneva, Geneva, Switzerland.|Department of Neurology, University Hospital, Geneva, Switzerland.|Centre de Recherche Cerveau et Cognition (CerCo), CNRS, UMR5549, Pavillon Baudot CHU Purpan, BP 25202, 31052, Toulouse Cedex, France.
Manuel R
MR
Mercier
Department of Fundamental Neuroscience, University of Geneva, Geneva, Switzerland.|Swiss Center for Affective Sciences, University of Geneva, Geneva, Switzerland.
Sophie
S
Schwartz
Department of Neurology, University Hospital, Geneva, Switzerland.
Laurent
L
Spinelli
The Functional Brain Mapping Laboratory, Department of Neuroscience, University of Geneva, Geneva, Switzerland.
Christoph M
CM
Michel
Laboratory of Cognitive Neuroscience, Brain-Mind Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 19, 1015, Lausanne, Switzerland. olaf.blanke@epfl.ch.|Department of Neurology, University Hospital, Geneva, Switzerland. olaf.blanke@epfl.ch.|Laboratory of Cognitive Neuroscience, Center for Neuroprosthetics and Brain Mind Institute, Swiss Federal Institute of Technology (EPFL), Chemin des Mines 9, 1202, Geneva, Switzerland. olaf.blanke@epfl.ch.
Olaf
O
Blanke
D000368:Aged; D004569:Electroencephalography; D005074:Evoked Potentials, Visual; D005260:Female; D005556:Form Perception / Q000502:physiology*; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009039:Motion Perception / Q000502:physiology*; D010468:Perceptual Disorders / Q000473:pathology / Q000503:physiopathology*; D010775:Photic Stimulation; D014793:Visual Cortex / Q000473:pathology / Q000503:physiopathology*; D014795:Visual Pathways / Q000473:pathology / Q000503:physiopathology
Brain lesion; EEG; Form-from-motion; Perceptual deficit