title: Emergence of an abstract categorical code enabling the discrimination of temporally structured tactile stimuli.
abstract: The problem of neural coding in perceptual decision making revolves around two fundamental questions: (i) How are the neural representations of sensory stimuli related to perception, and (ii) what attributes of these neural responses are relevant for downstream networks, and how do they influence decision making? We studied these two questions by recording neurons in primary somatosensory (S1) and dorsal premotor (DPC) cortex while trained monkeys reported whether the temporal pattern structure of two sequential vibrotactile stimuli (of equal mean frequency) was the same or different. We found that S1 neurons coded the temporal patterns in a literal way and only during the stimulation periods and did not reflect the monkeys' decisions. In contrast, DPC neurons coded the stimulus patterns as broader categories and signaled them during the working memory, comparison, and decision periods. These results show that the initial sensory representation is transformed into an intermediate, more abstract categorical code that combines past and present information to ultimately generate a perceptually informed choice.
authors.affiliation: Instituto de Fisiología Celular ─ Neurociencias, Universidad Nacional Autónoma de México, 04510 Mexico City, Mexico.
authors.forename: Román
authors.initials: R
authors.lastname: Rossi-Pool
authors.affiliation: Department of Neurobiology & Anatomy, Wake Forest School of Medicine, Winston-Salem, NC 27157.
authors.forename: Emilio
authors.initials: E
authors.lastname: Salinas
authors.affiliation: Instituto de Fisiología Celular ─ Neurociencias, Universidad Nacional Autónoma de México, 04510 Mexico City, Mexico.
authors.forename: Antonio
authors.initials: A
authors.lastname: Zainos
authors.affiliation: Instituto de Fisiología Celular ─ Neurociencias, Universidad Nacional Autónoma de México, 04510 Mexico City, Mexico.
authors.forename: Manuel
authors.initials: M
authors.lastname: Alvarez
authors.affiliation: Instituto de Fisiología Celular ─ Neurociencias, Universidad Nacional Autónoma de México, 04510 Mexico City, Mexico.
authors.forename: José
authors.initials: J
authors.lastname: Vergara
authors.affiliation: Departamento de Física Teórica, Universidad Autónoma de Madrid, 28049 Cantoblanco, Madrid, Spain.
authors.forename: Néstor
authors.initials: N
authors.lastname: Parga
authors.affiliation: Instituto de Fisiología Celular ─ Neurociencias, Universidad Nacional Autónoma de México, 04510 Mexico City, Mexico; rromo@ifc.unam.mx.|El Colegio Nacional, 06020 Mexico City, Mexico.
authors.forename: Ranulfo
authors.initials: R
authors.lastname: Romo
mesh_terms: D000818:Animals; D003657:Decision Making / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology*; D007600:Judgment; D008253:Macaca mulatta; D008568:Memory / Q000502:physiology; D009044:Motor Cortex / Q000502:physiology*; D046709:Pattern Recognition, Physiological; D011930:Reaction Time; D059010:Single-Cell Analysis; D013003:Somatosensory Cortex / Q000502:physiology*
keywords: behaving monkeys; categorical code; dorsal premotor cortex; pattern discrimination; somatosensory cortex