title: Somatosensory dynamic gamma-band synchrony: a neural code of sensorimotor dexterity.
abstract: To investigate neural coding characteristics in the human primary somatosensory cortex, two fingers with different levels of functional skill were studied. Their dexterity was scored by the Fingertip writing test. Each finger was separately provided by a passive simple sensory stimulation and the responsiveness of each finger cortical representation was studied by a novel source extraction method applied to magnetoencephalographic signals recorded in a 14 healthy right handed subject cohort. In the two hemispheres, neural oscillatory activity synchronization was analysed in the three characteristic alpha, beta and gamma frequency bands by two dynamic measures, one isolating the phase locking between neural network components, the other reflecting the total number of synchronous recruited neurons. In the dominant hemisphere, the gamma band phase locking was higher for the thumb than for the little finger and it correlated with the contra-lateral finger dexterity. Neither in the dominant nor in the non-dominant hemisphere, any effect was observed in the alpha and beta bands. In the gamma band, the amplitude showed similar tendency to the phase locking, without reaching statistical significance. These findings suggest the dynamic gamma band phase locking as a code for finger dexterity, in addition to the magnification of somatotopic central maps.
authors.affiliation: ISTC-CNR, Unità MEG, Fatebenefratelli Hospital, Isola Tiberina, Roma, Italy. franca.tecchio@istc.cnr.it <franca.tecchio@istc.cnr.it>
authors.forename: Franca
authors.initials: F
authors.lastname: Tecchio
authors.forename: Sara
authors.initials: S
authors.lastname: Graziadio
authors.forename: Giulia
authors.initials: G
authors.lastname: Barbati
authors.forename: Roberto
authors.initials: R
authors.lastname: Sigismondi
authors.forename: Filippo
authors.initials: F
authors.lastname: Zappasodi
authors.forename: Camillo
authors.initials: C
authors.lastname: Porcaro
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Valente
authors.forename: Marco
authors.initials: M
authors.lastname: Balsi
authors.forename: Paolo Maria
authors.initials: PM
authors.lastname: Rossini
mesh_terms: D000328:Adult; D000465:Algorithms; D003071:Cognition / Q000502:physiology; D003344:Cortical Synchronization; D004569:Electroencephalography; D005260:Female; D005385:Fingers / Q000033:anatomy & histology / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D009048:Motor Skills / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D013003:Somatosensory Cortex / Q000502:physiology*