Chapter 20 A framework for the analysis of neuronal networks

Amjad, A.M.; Breeze, Peter; Conway, B.A.; Halliday, David M.; Rosenberg, J.R.

doi:10.1016/s0079-6123(08)62218-9

Cited by 14 publications

(10 citation statements)

References 18 publications

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“…Analog signals representing velocity, acceleration and EMG were handled as continuous processes with continuously changing values over time. Autospectra were computed by averaging the Fourier transforms of successive 1P28 s segments using the standard procedure appropriate for point processes (Bartlett, 1963;Amjad, Breeze, Conway, Halliday & ) and continuous processes (Bendat & Piersol, 1986), giving a frequency resolution of approximately 0-78 Hz. Cross-spectra between two processes were then calculated and normalized as the coherence spectrum, which is a function describing the linear correlation squared between the two signals at a given frequency on a scale from zero to one.…”

Section: Respectively Experimental Protocolmentioning

confidence: 99%

“…The splint was attached to an actuator device by means of a low-mass hinged bar. The actuator has been described previously (Al-Falahe & Vallbo, 1988 (Edin & Vallbo, 1987 The recorded afferents were classified on the basis of eight criteria using a Bayesian evaluation procedure as described by Edin & Vallbo (1987, 1990a (Bendat & Piersol, 1986 1P28 s segments using the standard procedure appropriate for point processes (Bartlett, 1963;Amjad, Breeze, Conway, Halliday & and continuous processes (Bendat & Piersol, 1986), giving a frequency resolution of approximately 0-78 Hz. Cross-spectra between two processes were then calculated and normalized as the coherence spectrum, which is a function describing the linear correlation squared between the two signals at a given frequency on a scale from zero to one.…”

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confidence: 99%

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Coding of pulsatile motor output by human muscle afferents during slow finger movements.

Wessberg

Vallbo

1995

The Journal of Physiology

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1. Impulse activities of thirty‐eight muscle spindle and tendon organ afferents from the finger extensor muscles were recorded in the radial nerve of human subjects while the subjects performed voluntary flexion and extension finger movements at a single metacarpophalangeal joint. 2. The afferent firing was analysed in relation to the 8‐10 Hz discontinuities which previously have been shown to characterize these movements. Spike‐triggered averaging and frequency domain analyses demonstrated that all Ia muscle spindle afferents and a large proportion of group II spindle afferents responded in close association with local peaks in the joint acceleration. During muscle lengthening the impulses appeared during phases of rapid muscle stretch, whereas they appeared during the phase of minimal speed during muscle shortening. 3. The Golgi tendon organ (Ib) afferents displayed a reverse pattern of activity in relation to the discontinuities, i.e. the impulses tended to appear in the phase of minimal speed during lengthening movements and close to maximal shortening speed during shortening movements. Hence, their firing often coincided with the phasic increases of the parent muscle activity which account for the 8‐10 Hz discontinuities. 4. A close analysis of the time relations between spindle firing and the kinematics of the 8‐10 Hz discontinuities revealed that the population spindle response was too delayed and too dispersed to support the hypothesis that the discontinuities are accounted for by the stretch reflex. 5. If, as suggested in a previous paper, the 8‐10 Hz discontinuities are produced by a pulsatile descending motor command, the coding of the periodic but tenuous kinematic events by the population of proprioceptors may have a role in relation to an alleged pulsatile command generator.

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Section: Respectively Experimental Protocolmentioning

confidence: 99%

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confidence: 99%

Coding of pulsatile motor output by human muscle afferents during slow finger movements.

Wessberg

Vallbo

1995

The Journal of Physiology

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“…For comparisons between subjects in the experimental recordings, the corticomuscular coherence values were z ‐transformed as described in (Rosenberg et al 1989; Amjad et al 1989).…”

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Linear transmission of cortical oscillations to the neural drive to muscles is mediated by common projections to populations of motoneurons in humans

Negro

Farina

2011

The Journal of Physiology

123

115

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Non-technical summary Since the human central nervous system controls muscle contraction through inputs to spinal motoneurons, oscillations recorded on the primary motor cortex during voluntary movements are correlated with the electrical activity produced on the surface of the muscles. We show through theoretical derivations and experimental recordings that cortical input is transmitted partly in a linear way to the population of motoneurons. The results demonstrate the effective spread of the cortical projections to the motoneuron pool to allow an efficient control of the muscle force output.Abstract Oscillations in the primary motor cortex are transmitted through the corticospinal tract to the motoneuron pool. This transmission has been previously investigated using coherence analysis between concurrent recordings of EEG and surface EMG signals. In this study we used a mathematical derivation and motor unit recordings in vivo to investigate the origin of linear transmission of cortical input to the motoneuron spike trains (neural drive to muscle). The theoretical derivation showed that a common input spread to a relatively small number of motoneurons is partly transmitted in a linear way, overcoming the interference signal generated by the non-linearity of the individual motoneurons. We further calculated the corticomuscular coherence between experimental EEG signals and the cumulative spike trains of motor units in the abductor digiti minimi muscle of seven healthy men. The experimental results indicated that, on average, only four to five motor units were sufficient to reach the same level of coherence as estimated from the surface EMG. The results demonstrate that linearity in the transmission of the cortical input to motoneurons through the corticospinal tract is achieved because (i) this input is largely common to all motoneurons, and (ii) its frequency content requires only a small fraction of active motoneurons to be accurately sampled. In this way, the central nervous system can directly transmit oscillations to the control signals to muscles for practically the entire range of functionally relevant forces.

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“…Coherence may be derived from the cross-and autocorrelograms by a linear process involving Fourier transformation to obtain cross-and autospectra (Amjad, Breeze, Conway, Halliday & Rosenberg, 1989). It is to be expected, therefore, that measures provided by correlograms and coherence spectra should be equally representative of the strength of association between two processes provided the appropriate time and frequency ranges are used.…”

Section: Association Between Y-motoneurone Dischargesmentioning

confidence: 99%

Organization of the sural cutaneous input regulating the discharge of triceps surae gamma‐motoneurones in the cat

Ellaway

Davey²,

Ljubisavljević³

1997

Experimental Physiology

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SUMMARYThe organization of the cutaneous afferent influence on the discharge of y-motoneurones has been investigated in the decerebrated, spinal cat. y-Motoneurone discharges were recorded from cut nerve filaments. Time and frequency domain analyses were used to reveal the strength of coupling between y-motoneurone discharge and cutaneous afferents excited by natural skin stimulation. Time domain analysis (cross-correlation) was also used to reveal the sign (facilitation or inhibition) and time course of the cutaneous influence on individual y-motoneurones. Mechanical stimulation of discrete areas of skin within the sural nerve field caused facilitation or inhibition of individual y-motoneurones supplying the gastrocnemius and soleus muscles. In a few cases, a y-motoneurone facilitated by stimulation at one site could be inhibited from another location. The effect of cutaneous afferent stimulation was not evident in the decerebrated cat with intact spinal cord. The intensity of facilitation and inhibition was mapped for the sural nerve field. Facilitation had a focus of highest intensity to stimulation applied between the calcaneum and lateral malleolus. The focus for inhibition was either the same as for facilitation or, more frequently, tended to be lateral and dorsal to the calcaneum at the edge of the sural field. Cutaneous stimulation at the edge of the sural field could also reduce the coherence between the discharges of y-motoneurones, particularly at low frequencies of association (1-5 Hz), indicating disfacilitation of other sources of afferent input. The results reveal a detailed pattern of cutaneous inputs to the fusimotor system that could participate in a wide range of behavioural adjustments to stretch or contact of the skin at the heel.

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Chapter 20 A framework for the analysis of neuronal networks

Cited by 14 publications

References 18 publications

Coding of pulsatile motor output by human muscle afferents during slow finger movements.

Coding of pulsatile motor output by human muscle afferents during slow finger movements.

Linear transmission of cortical oscillations to the neural drive to muscles is mediated by common projections to populations of motoneurons in humans

Organization of the sural cutaneous input regulating the discharge of triceps surae gamma‐motoneurones in the cat

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