title: Age-related audiovisual interactions in the superior colliculus of the rat.
abstract: It is well established that multisensory integration is a functional characteristic of the superior colliculus that disambiguates external stimuli and therefore reduces the reaction times toward simple audiovisual targets in space. However, in a condition where a complex audiovisual stimulus is used, such as the optical flow in the presence of modulated audio signals, little is known about the processing of the multisensory integration in the superior colliculus. Furthermore, since visual and auditory deficits constitute hallmark signs during aging, we sought to gain some insight on whether audiovisual processes in the superior colliculus are altered with age. Extracellular single-unit recordings were conducted in the superior colliculus of anesthetized Sprague-Dawley adult (10-12 months) and aged (21-22 months) rats. Looming circular concentric sinusoidal (CCS) gratings were presented alone and in the presence of sinusoidally amplitude modulated white noise. In both groups of rats, two different audiovisual response interactions were encountered in the spatial domain: superadditive, and suppressive. In contrast, additive audiovisual interactions were found only in adult rats. Hence, superior colliculus audiovisual interactions were more numerous in adult rats (38%) than in aged rats (8%). These results suggest that intersensory interactions in the superior colliculus play an essential role in space processing toward audiovisual moving objects during self-motion. Moreover, aging has a deleterious effect on complex audiovisual interactions.
authors: Centre de Recherche en Neuropsychologie et Cognition, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, QC H3C 3J7, Canada.
authors: M
authors: M
authors: Costa
authors: Centre de Recherche en Neuropsychologie et Cognition, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, QC H3C 3J7, Canada; Université du Québec à Trois-Rivières, Trois-Rivières, QC G9A 5H7, Canada.
authors: M
authors: M
authors: Piché
authors: Centre de Recherche en Neuropsychologie et Cognition, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, QC H3C 3J7, Canada.
authors: F
authors: F
authors: Lepore
authors: Centre de Recherche en Neuropsychologie et Cognition, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, QC H3C 3J7, Canada. Electronic address: jean-paul.guillemot@umontreal.ca.
authors: J-P
authors: JP
authors: Guillemot
mesh_terms: D000161:Acoustic Stimulation; D000375:Aging / Q000502:physiology*; D000818:Animals; D001288:Attention / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D005260:Female; D008297:Male; D018408:Patch-Clamp Techniques; D010775:Photic Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013477:Superior Colliculi / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
keywords: aging; audiovisual integration; auditory; concentric spatial frequency; optic flow; vision