title: A segregated neural pathway for prefrontal top-down control of tactile discrimination.
abstract: It has proven difficult to separate functional areas in the prefrontal cortex (PFC), an area implicated in attention, memory, and distraction handling. Here, we assessed in healthy human subjects whether PFC subareas have different roles in top-down regulation of sensory functions by determining how the neural links between the PFC and the primary somatosensory cortex (S1) modulate tactile perceptions. Anatomical connections between the S1 representation area of the cutaneous test site and the PFC were determined using probabilistic tractography. Single-pulse navigated transcranial magnetic stimulation of the middle frontal gyrus-S1 link, but not that of the superior frontal gyrus-S1 link, impaired the ability to discriminate between single and twin tactile pulses. The impairment occurred within a restricted time window and skin area. The spatially and temporally organized top-down control of tactile discrimination through a segregated PFC-S1 pathway suggests functional specialization of PFC subareas in fine-tuned regulation of information processing.
authors: Institute of Biomedicine/Physiology, University of Helsinki, Helsinki, Finland BioMag Laboratory, HUS Medical Imaging Center, Helsinki University Central Hospital, Helsinki, Finland.
authors: Juha
authors: J
authors: Gogulski
authors: Institute of Biomedicine/Physiology, University of Helsinki, Helsinki, Finland Brain Research Unit, O.V. Lounasmaa Laboratory AMI Centre, Aalto Neuroimaging, Aalto University School of Science, Espoo, Finland.
authors: Robert
authors: R
authors: Boldt
authors: Nexstim Ltd., Helsinki, Finland and.
authors: Petri
authors: P
authors: Savolainen
authors: Institute of Biomedicine/Physiology, University of Helsinki, Helsinki, Finland BioMag Laboratory, HUS Medical Imaging Center, Helsinki University Central Hospital, Helsinki, Finland.
authors: Jessica
authors: J
authors: Guzmán-López
authors: Institute of Biomedicine/Physiology, University of Helsinki, Helsinki, Finland Brain Research Unit, O.V. Lounasmaa Laboratory AMI Centre, Aalto Neuroimaging, Aalto University School of Science, Espoo, Finland Medical School, University of Tampere, Tampere, Finland.
authors: Synnöve
authors: S
authors: Carlson
authors: Institute of Biomedicine/Physiology, University of Helsinki, Helsinki, Finland.
authors: Antti
authors: A
authors: Pertovaara
mesh_terms: D000328:Adult; D004192:Discrimination, Psychological / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D017397:Prefrontal Cortex / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology*; D055698:Touch Perception / Q000502:physiology*; D050781:Transcranial Magnetic Stimulation; D055815:Young Adult
keywords: navigated transcranial magnetic stimulation; prefrontal cortex; tactile perception; top-down modulation; tractography