Interactions between voluntary and postural mechanisms of thehuman motor system.

Die Rolle des Motorkortex beim motorischen Lernen

In this review, we review the legacy of Gerald (Gerry) Gottlieb in various fields related to the neural control of human movement. His studies on the myotatic (stretch) reflex and post-myotatic responses to ankle joint perturbations paved the way for current explorations of long-loop reflexes and their role in the control of movement. The dual-strategy hypothesis introduced order into a large body of literature on the tri-phasic muscle activation patterns seen over a variety of voluntary movements in healthy persons. The dual-strategy hypothesis continues to be important for understanding the performance of subjects with disordered motor control. The principle of linear synergy (co-variance of joint torques) was an attempt to solve one of the notorious problems of motor redundancy, which remains a hot topic in the field. Gerry's attitude towards the equilibrium-point hypothesis varied between rejection and using it to explore patterns of hypothetical control variables and movement variability. The discovery of reciprocal excitation in healthy neonates fostered other studies of changes in spinal cord physiology as motor skills develop. In addition, studies of patients with spasticity and the effects of treatment with intrathecal baclofen were crucial in demonstrating the possibility of unmasking voluntary movements after suppression of the hyperreflexia of spasticity. Gerry Gottlieb contributed a significant body of knowledge that formed a solid foundation from which to study a variety of neurological diseases and their treatments, and a more comprehensive and parsimonious foundation to describe the neural control of human movement.

The Legacy of Gerald L. Gottlieb in Human Movement Neuroscience.

Specific facilitation of the agonist motoneuron pool (pretibial muscle; TA) was investigated under the two different reaction time conditions, i, e, simple(S) and choice(C) reaction time tasks. The motor task was bilateral ankle dorsiflexion, and two different strengths of voluntary ankle dorsiflexion (25%, (S) and 50% (L) of maximum contraction force) were controlled by visually guided tracking. The excitability of the agonist motoneuron pool was investigated by the H-reflex method. As the differences between the EMG reaction times of TA on both sides were extremely small under both the S and C tasks, it might be reasonable to use the non-stimulated side as the onset of voluntary movement. Not only the onset of H-reflex facilitation with respect to EMG onset, but also the reaction times were significantly prolonged under the conditions of task C compared with those of task S. In addition, movement times were also prolonged and

Interactions between voluntary and postural mechanisms of thehuman motor system.

Citations

Die Rolle des Motorkortex beim motorischen Lernen

The Legacy of Gerald L. Gottlieb in Human Movement Neuroscience.

Modulation of specific h-reflex facilitation during simple and choice reaction time tasks

Spinal cord modulation associated with isometric contractions

Gain control in human motor system

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