title: Coding sound direction in noisy environment in the superior colliculus of the rat.
abstract: The aim of the present study was to evaluate the effect of background noise on the directional sensitivity of neurons in the deep layers of the superior colliculus. Extra-cellular recordings were carried out in anaesthetized adult Long Evans rats. When stimulated in a noisy environment, most of the neurons remained sensitive to sound direction and only a few changed their optimal direction by more than 15 degrees. When stimulated at their optimal direction in the presence of background noise, a majority of neurons did not modify their response rate, whereas a limited proportion of neurons showed either a significant drop or facilitation of their response rate. Moreover, the neurons' receptive fields showed significant tuning modifications in the presence of background noise. In a noisy environment, the larger receptive fields became narrower, whereas the sharply tuned receptive fields got broader.
authors.affiliation: Centre de Recherche en Neuropsychologie et Cognition, Département de Psychologie, Université de Montréal, C.P. 6128, Succ. Centre-Ville, Montréal, Québec, Canada.
authors.forename: Alex
authors.initials: A
authors.lastname: Martin
authors.forename: Etienne
authors.initials: E
authors.lastname: Vachon-Presseau
authors.forename: Christine
authors.initials: C
authors.lastname: Pageau
authors.forename: Franco
authors.initials: F
authors.lastname: Lepore
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Guillemot
mesh_terms: D000161:Acoustic Stimulation; D000200:Action Potentials; D000704:Analysis of Variance; D000818:Animals; D004777:Environment; D008839:Microelectrodes; D009473:Neuronal Plasticity / Q000502:physiology; D009474:Neurons / Q000502:physiology*; D009622:Noise; D016011:Normal Distribution; D051381:Rats; D020318:Rats, Long-Evans; D013017:Sound Localization / Q000502:physiology*; D013477:Superior Colliculi / Q000502:physiology*