title: Spatially precise visual gain control mediated by a cholinergic circuit in the midbrain attention network.
abstract: A primary function of the midbrain stimulus selection network is to compute the highest-priority location for attention and gaze. Here we report the contribution of a specific cholinergic circuit to this computation. We functionally disconnected the tegmental cholinergic nucleus isthmi pars parvocellularis (Ipc) from the optic tectum (OT) in barn owls by reversibly blocking excitatory transmission in the Ipc. Focal blockade in the Ipc decreases the gain and spatial discrimination of OT units specifically for the locations represented by the visual receptive fields (VRFs) of the disconnected Ipc units, and causes OT VRFs to shift away from that location. The results demonstrate mechanisms by which this cholinergic circuit controls bottom-up stimulus competition and by which top-down signals can bias this competition, and they establish causal linkages between a particular circuit, gain control and dynamic shifts of VRFs. This circuit may perform the same function in all vertebrate species.
authors.affiliation: Department of Neurobiology, Stanford University School of Medicine, Stanford, California 94305, USA.|Visuo-Motor Laboratory, Rayan Center for Neuroscience and Behavior, Ferdowsi University of Mashhad, Mashhad 9177948974, Iran.|Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad 9177948974, Iran.
authors.forename: Ali
authors.identifier: http://orcid.org/0000-0002-7915-6846
authors.initials: A
authors.lastname: Asadollahi
authors.affiliation: Department of Neurobiology, Stanford University School of Medicine, Stanford, California 94305, USA.
authors.forename: Eric I
authors.initials: EI
authors.lastname: Knudsen
mesh_terms: D000109:Acetylcholine / Q000378:metabolism*; D000161:Acoustic Stimulation / Q000379:methods; D000818:Animals; D001288:Attention; D001931:Brain Mapping / Q000379:methods; D002799:Cholinergic Fibers / Q000502:physiology*; D008636:Mesencephalon / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D009899:Optic Lobe, Nonmammalian / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D020305:Strigiformes; D014795:Visual Pathways / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
chemical_list: D000109:Acetylcholine