Attentional competition between modalities: extinction between touch and vision after right hemisphere damage

Area of Science:

• Neuroscience
• Cognitive Psychology
• Clinical Neurology

Background:

• Unilateral brain damage often causes extinction, a failure to detect contralesional stimuli during simultaneous presentation.
• Current theories propose extinction results from attentional bias favoring ipsilesional stimuli.
• Extinction typically occurs within a single sensory modality (vision, audition, touch).

Purpose of the Study:

• To investigate whether extinction can manifest cross-modally between different sensory modalities.
• To determine if an ipsilesional stimulus can extinguish a contralesional stimulus in a separate sensory modality.

Main Methods:

• Three patients with right hemisphere damage and within-modality extinction were tested.
• Cross-modal extinction was assessed by presenting simultaneous visual and tactile stimuli.
• Stimuli were presented to ipsilesional and contralesional sides, including non-homologous locations.

Main Results:

• Patients exhibited significant cross-modal extinction.
• An ipsilesional tactile stimulus extinguished awareness of a simultaneous contralesional visual stimulus.
• Conversely, an ipsilesional visual stimulus extinguished a simultaneous contralesional tactile stimulus.

Conclusions:

• Unilateral brain damage leads to a competitive advantage for ipsilesional stimuli across sensory modalities.
• This cross-modal competition influences spatial attention.
• Findings support the role of competitive interactions between sensory modalities in spatial attention control.