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Temporal dynamics of visuo-tactile extinction within and between hemispaces
Marcello Costantini1, Domenica Bueti, Mariella Pazzaglia
1Dipartimento di Scienze Cliniche e Bioimmagini, Universita G. D'Annunzio, Chieti, Italy. marcello.costantini@unich.it
Neuropsychology
|April 4, 2007
Summary
Patients with right brain damage (RBD) show tactile extinction, failing to detect left-sided tactile stimuli even when visual stimuli are present. This extinction occurs within the same visual field, suggesting visual attention inhibits tactile processing.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Clinical Neurology
Background:
- Right brain damage (RBD) can cause visual and tactile extinction.
- Extinction is the inability to perceive a stimulus in the presence of another.
- The interaction between visual and tactile processing in extinction is not fully understood.
Purpose of the Study:
- To investigate tactile detection in patients with visual and tactile extinction.
- To examine how cross-modal interactions influence extinction.
- To determine if extinction occurs within a single hemispace for tactile stimuli.
Main Methods:
- Compared left-sided visual and tactile stimulus detection in RBD patients and controls.
- Used single and double stimuli, including cross-modal (visual-tactile) pairs.
- Varied stimulus presentation across hemispaces and within the same hemispace.
- Manipulated stimulus onset asynchrony (SOA) between 105 ms and 905 ms.
Main Results:
- Healthy controls detected all stimuli.
- RBD patients exhibited classical extinction of contralesional tactile stimuli in bilateral trials.
- RBD patients also omitted contralesional tactile stimuli in unilateral left-sided trials (within hemispace).
- Extinction rates decreased with longer SOAs for both across- and within-hemispace conditions.
Conclusions:
- Visual stimulus processing can inhibit tactile stimulus processing, even within the same hemispace.
- Attentional mechanisms are involved in cross-modal interactions during extinction.
- Findings suggest a shared or interacting attentional network for visual and tactile stimuli in the contralesional space.
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