scholarly journals Effect of eye movements on the magnitude of functional magnetic resonance imaging responses in extrastriate cortex during visual motion perception

1998 ◽  
Vol 119 (4) ◽  
pp. 409-414 ◽  
Author(s):  
P. Freitag ◽  
M. W. Greenlee ◽  
T. Lacina ◽  
K. Scheffler ◽  
E. W. Radü
Keyword(s):  
Magnetic Resonance Imaging ◽  
Eye Movements ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Motion Perception ◽  
Visual Motion ◽  
Extrastriate Cortex ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Visual Motion Perception

scholarly journals Event-Related Functional Magnetic Resonance Imaging Study of the Extrastriate Cortex Response to a Categorically Ambiguous Stimulus Primed by Letters and Familiar Geometric Figures

2001 ◽  
Vol 21 (11) ◽  
pp. 1330-1341 ◽  
Author(s):  
Hélène Gros ◽  
Kader Boulanouar ◽  
Gérard Viallard ◽  
Emmanuelle Cassol ◽  
Pierre Celsis
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Right Hemisphere ◽  
Extrastriate Cortex ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Ambiguous Stimulus ◽  
Form Processing ◽  
Geometric Figures

Functional neuroimaging studies have suggested a specific role of the extrastriate cortex in letter string and visual word form processing. However, this region has been shown to be involved in object recognition and its specificity for the processing of linguistic stimuli may be questioned. The authors used an event-related functional magnetic resonance imaging design with category priming to record the response elicited by the passive viewing of single letters, geometric figures, and of the categorically ambiguous stimulus “O” that pertains to both sets of familiar symbols. Bilateral activations in the extrastriate cortex were found, with a left predominance particularly pronounced for the ambiguous stimulus. Individual analysis of spatial extent and signal intensity showed a priming × stimulus × hemisphere interaction. When primed by the congruous categoric set, a bilateral decrease in activation was observed for letters and geometric figures. The ambiguous stimulus behaved as a letter for the left hemisphere, with decreased activation when primed by letters, whereas in the right hemisphere, an adaptation effect occurred when primed by geometric figures. These priming effects suggest that, for the ambiguous stimulus, letter processing was systematically involved in the left extrastriate cortex. The current results support the existence of a neural substrate for the abstract category of letters.

scholarly journals Interictal abnormal fMRI activation of visual areas during a motor task cued by visual stimuli in migraine

2017 ◽  
Vol 15 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Adriana Bastos Conforto ◽  
Khallil Taverna Chaim ◽  
Mario Fernando Prieto Peres ◽  
André Leite Gonçalves ◽  
Inara Laurindo Siqueira ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Light Exposure ◽  
Visual Stimuli ◽  
Extrastriate Cortex ◽  
Light Deprivation ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Significant Group

ABSTRACT Objective To assess changes in blood-oxygen-level-dependent activity after light deprivation compared to regular light exposure in subjects with migraine in the interictal state and in controls. Methods Ten subjects with migraine and ten controls participated in two sessions of functional magnetic resonance imaging. In each session, they performed a finger-tapping task with the right hand, cued by visual stimuli. They were scanned before and after 30 minutes of light deprivation or light exposure. In subjects with migraine, functional magnetic resonance imaging was performed interictally. Analysis of variance was made with the factors time (before or after), session (light deprivation or exposure), and group (migraine or control). Results There were significant “group” effects in a cluster in the bilateral cuneus encompassing the superior border of the calcarine sulcus and extrastriate cortex. There were no significant effects of “time”, “session”, or interactions between these factors. Conclusion The main result of this study is consistent with aberrant interictal processing of visual information in migraine. Light deprivation did not modulate functional magnetic resonance imaging activity in subjects with or without migraine.

Visual motion aftereffect in human cortical area MT revealed by functional magnetic resonance imaging

Nature ◽  
1995 ◽  
Vol 375 (6527) ◽  
pp. 139-141 ◽  
Author(s):  
Roger B. H. Tootell ◽  
John B. Reppas ◽  
Anders M. Dale ◽  
Rodney B. Look ◽  
Martin I. Sereno ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Functional Magnetic Resonance Imaging ◽  
Cortical Area ◽  
Visual Motion ◽  
Motion Aftereffect ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Area Mt
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