Bit-mapped somatosensory evoked potentials and muscular reflex responses in man: comparative analysis in different experimental protocols.

Bit-colour maps of somatosensory evoked potentials (SEPs) and muscular responses from forearm and hand muscles were simultaneously recorded after median nerve stimulation. Subjects were asked either to relax totally (A), or to contract the examined muscle continuously and isometrically at 10-20% (B) and 80-100% (C) of the maximal strength. Isotonic contractions ipsilateral (D) and contralateral to the stimulus (E) were also examined. Both SEPs and EMG responses were elicited by individual near-motor threshold pulses delivered at 0.2/sec to the median nerve at the elbow. SEPs were maximal in amplitude during complete relaxation, whilst all the components following the parietal N20 were depressed by muscle contraction. Such decrements affected predominantly the parietal and frontal peaks of positive polarity during condition B, whilst the frontal negative component (wave N30) dropped remarkably in conditions C and D. Early EMG responses (V1 = spinal circuitry) were usually absent in condition A; they were present together with later components (= V2 possibly long-loop, transcortical circuitry) in C and D, whilst they were alone recordable in B and E. The amplitudes of the frontal wave N30 in SEPs and of V2 in LLRs were inversely correlated. This observation is consistent with the hypothesis that a change in the reactivity of the sensorimotor brain areas to afferent impulses is coupled to LLR elicitation in forearm and hand muscles.

[1]  S. Jones,et al.  An 'interference" approach to the study of somatosensory evoked potentials in man. , 1981, Electroencephalography and clinical neurophysiology.

[2]  S. Jones.  Short latency potentials recorded from the neck and scalp following median nerve stimulation in man. , 1977, Electroencephalography and clinical neurophysiology.

[3]  B. Bussel,et al.  Excitability of human motoneurones after discharge in a conditioning reflex. , 1976, Electroencephalography and clinical neurophysiology.

[4]  P. Matthews,et al.  Observations on the genesis of the stretch reflex in Parkinson's disease. , 1986, Brain : a journal of neurology.

[5]  P. M. Rossini,et al.  Simultaneous motor output and sensory input: Cortical interference site resolved in humans via neuromagnetic measurements , 1989, Neuroscience Letters.

[6]  T. Yamada,et al.  Topography of somatosensory evoked potentials after stimulation of the median nerve. , 1984, Electroencephalography and clinical neurophysiology.

[7]  R Porter,et al.  Corticocortical synaptic influences on morphologically identified pyramidal neurones in the motor cortex of the monkey. , 1988, The Journal of physiology.

[8]  M. Wiesendanger.  Experimental evidence for the existence of a proprioceptive transcortical loop. , 1986, Progress in brain research.

[9]  G Cheron,et al.  Specific gating of the early somatosensory evoked potentials during active movement. , 1987, Electroencephalography and clinical neurophysiology.

[10]  B. Cant,et al.  Conduction time in central somatosensory pathways in man. , 1978, Electroencephalography and clinical neurophysiology.

[11]  C. Marsden,et al.  Stretch reflex and servo action in a variety of human muscles. , 1976, The Journal of physiology.

[12]  G Cheron,et al.  Central somatosensory conduction in man: neural generators and interpeak latencies of the far-field components recorded from neck and right or left scalp and earlobes. , 1980, Electroencephalography and clinical neurophysiology.

[13]  C D Marsden,et al.  Is the human stretch reflex cortical rather than spinal? , 1973, Lancet.

[14]  Emanuel Donchin,et al.  Average evoked potentials - Methods, results, and evaluations , 1969 .

[15]  G. Cheron,et al.  Non-cephalic reference recording of early somatosensory potentials to finger stimulation in adult or aging normal man: differentiation of widespread N18 and contralateral N20 from the prerolandic P22 and N30 components. , 1981, Electroencephalography and clinical neurophysiology.

[16]  T Allison,et al.  SCALP AND CORTICAL RECORDINGS OF INITIAL SOMATOSENSORY CORTEX ACTIVITY TO MEDIAN NERVE STIMULATION IN MAN * , 1980, Annals of the New York Academy of Sciences.

[17]  L. Cohen,et al.  Localization, timing and specificity of gating of somatosensory evoked potentials during active movement in man. , 1987, Brain : a journal of neurology.

[18]  J. Rothwell,et al.  Gating of somatosensory evoked potentials during different kinds of movement in man. , 1981, Brain : a journal of neurology.

[19]  E. Favale,et al.  Conduction time of the lemniscal pathway in males and females , 1980, Acta neurologica Scandinavica.

[20]  T Allison,et al.  The scalp topography of human somatosensory and auditory evoked potentials. , 1977, Electroencephalography and clinical neurophysiology.

[21]  P. Matthews.  Evidence from the use of vibration that the human long‐latency stretch reflex depends upon spindle secondary afferents. , 1984, The Journal of physiology.

[22]  F Mauguière,et al.  Astereognosis and dissociated loss of frontal or parietal components of somatosensory evoked potentials in hemispheric lesions. Detailed correlations with clinical signs and computerized tomographic scanning. , 1983, Brain : a journal of neurology.

[23]  A. McComas,et al.  Potentiation of `late' responses evoked in muscles during effort , 1971, Journal of neurology, neurosurgery, and psychiatry.

[24]  Behaviour of short and long latency components of the stretch reflex in human muscle. , 1975, The Journal of physiology.

[25]  Bl Day,et al.  HABITUATION OF THE HUMAN LONG LATENCY STRETCH REFLEX , 1985 .

[26]  A Urbano,et al.  Abnormalities of short-latency somatosensory evoked potentials in parkinsonian patients. , 1989, Electroencephalography and clinical neurophysiology.

[27]  G. Eklund,et al.  The ‘late’ reflex responses to muscle stretch: the ‘resonance hypothesis’ versus the ‘long‐loop hypothesis’ , 1982, The Journal of physiology.

[28]  R. Cracco,et al.  Somatosensory evoked potential in man: far field potentials. , 1976, Electroencephalography and clinical neurophysiology.

[29]  J. Desmedt.  Cerebral motor control in man : long loop mechanisms , 1978 .

[30]  Hammond Ph,et al.  Involuntary activity in biceps following the sudden application of velocity to the abducted forearm. , 1955, The Journal of physiology.

[31]  B Conrad,et al.  Effects of voluntary isometric and isotonic activity on late transcortical reflex components in normal subjects and hemiparetic patients. , 1977, Electroencephalography and clinical neurophysiology.

[32]  M G Marciani,et al.  Non-invasive evaluation of input-output characteristics of sensorimotor cerebral areas in healthy humans. , 1987, Electroencephalography and clinical neurophysiology.

[33]  E. Stanley.  Reflexes evoked in human thenar muscles during voluntary activity and their conduction pathways. , 1978, Journal of neurology, neurosurgery, and psychiatry.

[34]  T. Yamada,et al.  Short- and long-latency median somatosensory evoked potentials. Findings in patients with localized neurological lesions. , 1983, Archives of neurology.

[35]  J. Noth,et al.  Long-loop reflexes in small hand muscles studied in normal subjects and in patients with Huntington's disease. , 1985, Brain : a journal of neurology.

[36]  P. Rossini,et al.  Monitoring of subcortical and cortical somatosensory evoked potentials during carotid endarterectomy: comparison with stump pressure levels. , 1987, Electroencephalography and clinical neurophysiology.

[37]  L. Cohen,et al.  ‘Gating’ of somatosensory evoked potentials begins before the onset of voluntary movement in man , 1985, Brain Research.