title: A systematic analysis of neurons with large somatosensory receptive fields covering multiple body regions in the secondary somatosensory area of macaque monkeys.
abstract: Previous neurophysiological studies performed in macaque monkeys have revealed complex somatosensory responses in the secondary somatosensory area (SII), such as large receptive fields (RFs), as well as bilateral ones. However, systematic analyses of neurons with large RFs have not been performed. In the present study, we recorded single-unit activities in SII of awake macaque monkeys to investigate systematically large RFs by dividing the whole body into four body regions (head, trunk, forelimb, and hindlimb). Recorded neurons were classified into two types, according to whether the RFs were confined to one body region: single (n = 817) and combined (n = 282) body-region types. These two types were distinct in terms of the percentage of bilateral RFs: 55% in the single-region type and 90% in the combined type, demonstrating that two types of RF enlargement occur simultaneously in the combined type, namely, RF convergence from different body regions and RF convergence from both hemibodies. Among the combined-type RFs, two tendencies of RF convergence were found: 1) the distal parts of the limbs (i.e., hand and foot) and the mouth are interconnected, and 2) the trunk RFs extend continuously toward the distal parts of the limb and head to cover the entire body surface. Our distribution analysis on unfolded maps clarified that neurons having RFs with these two tendencies were distributed within specific subregions in SII.
authors: Department of Physiology, Toho University School of Medicine, Tokyo, Japan; mktaoka@brain.riken.jp.|Section of Cognitive Neurobiology, Department of Maxillofacial Biology, Tokyo Medical and Dental University, Tokyo, Japan; and.|Laboratory for Symbolic Cognitive Development, RIKEN Brain Science Institute, Wako, Saitama, Japan.
authors: M
authors: M
authors: Taoka
authors: Department of Physiology, Toho University School of Medicine, Tokyo, Japan.
authors: T
authors: T
authors: Toda
authors: Section of Cognitive Neurobiology, Department of Maxillofacial Biology, Tokyo Medical and Dental University, Tokyo, Japan; and.|Laboratory for Symbolic Cognitive Development, RIKEN Brain Science Institute, Wako, Saitama, Japan.
authors: S
authors: S
authors: Hihara
authors: Department of Physiology, Toho University School of Medicine, Tokyo, Japan.|Section of Cognitive Neurobiology, Department of Maxillofacial Biology, Tokyo Medical and Dental University, Tokyo, Japan; and.|Laboratory for Symbolic Cognitive Development, RIKEN Brain Science Institute, Wako, Saitama, Japan.
authors: M
authors: M
authors: Tanaka
authors: Department of Physiology, Toho University School of Medicine, Tokyo, Japan.|Section of Cognitive Neurobiology, Department of Maxillofacial Biology, Tokyo Medical and Dental University, Tokyo, Japan; and.|Laboratory for Symbolic Cognitive Development, RIKEN Brain Science Institute, Wako, Saitama, Japan.
authors: A
authors: A
authors: Iriki
authors: Department of Physiology, Toho University School of Medicine, Tokyo, Japan.
authors: Y
authors: Y
authors: Iwamura
mesh_terms: D000818:Animals; D001931:Brain Mapping / Q000379:methods*; D004567:Electrodes, Implanted; D005552:Forelimb / Q000502:physiology; D006257:Head / Q000502:physiology; D006614:Hindlimb / Q000502:physiology; D008251:Macaca; D008297:Male; D009474:Neurons / Q000502:physiology*; D010812:Physical Stimulation / Q000379:methods; D013003:Somatosensory Cortex / Q000502:physiology*; D060726:Torso / Q000502:physiology
keywords: awake macaque monkey; large receptive field; secondary somatosensory area; single-unit recording