Inhibition of cortical evoked potentials and sensation by self-initiated movement in man

Sensorimotor adaptation changes the neural coding of somatosensory stimuli

“…Transient reductions in SEPs have been reported previously in conjunction with finger and limb movement (Papakostopoulos et al 1975;Rushton et al 1981;Starr and Cohen 1985). The reduction has been attributed to the idea that the nervous system suppresses sensory inflow associated with self-initiated movement.…”

Selectivity of attenuation (i.e., gating) of somatosensory potentials during voluntary movement in humans

“…Electrical stimulation of the me&an and ulnar nerves at the wrist evoked similar latency SEP (Fig 1) 'thalamocortical" N20 peaked at 18 4 ± 1 2 msec and 18 8 + 1 2 msec respectively, cortical P27 peaked at 22 7+18 msec and 22 4+13 msec respectively (see Emerson and Pedley 1984 for a dxscussxon of origins of these components) Electrical sumulauon of digits 1-2 and 5 evoked the same sequence of components but at approximately 3 msec longer latencles, N20 peaked at 21 8 _+ 0 8 msec and 21 7 ± 0 8 msec respectively, P27 peaked at 25 3 ± 1 7 msec and 25 2+ 1 3 msec respectively The peripheral nerve afferent volleys and N20 components to the different stimuli figure) and ulnar (bottom half of figure) nerve stimulation The thalamocortlcal N20 and cortical P27 components are labeled Note that the P27 component of SEP to me&an nerve sumulatlon was attenuated dunng digit 1 movement (upper traces) whereas the P27 component of the SEP to ulnar nerve stimulation was most attenuated during dig~t 5 movement (lov~er traces) The peripheral nerve potentials evoked by these stimuli did not change dunng these movements The bar graphs plot the attenuation of the P27 component dunng median nerve stimulation (upper portion) and ulnar nerve stimulation (lower portion) a, a funcuon of the finger that x~as moxed did not significantly change dunng any movement condition (Tables I and II) In contrast, the P27 component was attenuated dunng certain combinations of movements and nerve stimulation Opposition of the thumb towards digit 5 was accompanied by attenuation of potentials evoked by both median nerve and &git 1-2 stimulation (P27 dlrmnlshed to 35 67 ± 27 10% and to 44 75_+ 10 50% respectively, P < 0 01 Fig 1 top section, digit 1 movement, and Table I left-hand columns) In contrast, potentials evoked by both ulnar ~erve and digit 5 stimulation were not significantly affected during thas same digit 1 movement (Fig 1 bottom section, Table I right-hand columns) Abduction of the fifth finger was accompanied by attenuation of potentials evoked by both ulnar nerve and digit 5 stimulauon (P27 dxlmmshed to 31 80+7 29% and to 37 00± 12 36% respectively, P < 0 01, Fig 1 bottom section, digit 5 movement, and Table II right-hand columns) In contrast, potentials evoked by both median nerve and dtgits 1-2 stimulation were not significantly affected dunng this fifth digit movement (Fig 1 top section and Table II left columns) Attenuation of SEP IS not due to changes in subject vigI- lance and attention since the alterations in SEP were speofic only for certain combinations of nerve stimulation and movement conditions Moreover, the earhest task-related change in SEP that has been reported affects those components with latencles longer than 55 msec (Desmedt and Robertson 1977) Discussion It has been amply demonstrated that there is an attenuauon of SEP during movement of the stimulated limb in both animals and humans (Ghez and Plsa 1972, Papakostopoulos et al 1975…”

“…Modification of central sensory processes dunng motor activity l~ referred to as 'gating' and has been described for somatosensory (Papakostopoulos et al 1975, Rushton et al 1981, an&tory (Start 1964, Hazemann et al 1975 and visual inputs (Volkmann 1962, Adey andNoda 1973) In the somatosensory system 'gating' begins even before movement onset, during the precontractlon penod (Coulter 1974, Starr andCohen 1985) lmphcatmg the action of central efferent systems m the modulation of sensory reformation Asanuma (1981) suggested that activity of the pyramidal tract may influence the transmission of afferent impulses to higher centers including the motor cortex However, details as to the relationship between the types of movement and the selectivity of afferent input modification are not known This report utilizes scalp recordings of somatosensory evoked potentials m humans to demonstrate that somatosensory evoked potentials derived from stimulating a particular peripheral nerve are modified specifically for movements Involving the body parts Innervated by that particular nerve…”

Sensory perception during movement in man

“…The amplitude of evoked potentials in the lemniscal system decreases prior to and during voluntary limb movements in cats (Ghez and Lenzi 1971;Ghez and Pisa 1972;Coulter 1974), monkeys (Dyhre-Poulson 1978;Chapman et al 1984) and man Offprint requests to: C.E. Chapman, Centre de Recherche en Sciences Neurologiques, Universit6 de Montr6al, PO Box 6128, Station A, Montrral, Qu6bec, H3C 3J7, Canada (Giblin 1964;Coquery and Vitton 1972;Lee and White 1974;Hazemann et al 1975;Papakostopoulos et al 1975;Rushton et al 1981;Starr and Cohen 1985). In keeping with these findings, psychophysical experiments have shown that the threshold for detecting cutaneous stimuli rises when the stimulated area is actively moved (Coquery et al 1971;Garland and Angel 1974;Dyhre-Poulson 1978;Angel and Malenka 1982) and this change can precede the onset of movement (Coquery 1978).…”