Contralateral and long latency effects of human biceps brachii stretch reflex conditioning

1995 ◽  
Vol 107 (1) ◽  
Author(s):  
StevenL. Wolf ◽  
RichardL. Segal ◽  
NancyD. Heter ◽  
PamelaA. Catlin
Keyword(s):  
Stretch Reflex ◽  
Biceps Brachii ◽  
Long Latency

scholarly journals Motor learning and transfer: from feedback to feedforward control

2019 ◽  
Author(s):  
Rodrigo S. Maeda ◽  
Paul L. Gribble ◽  
J. Andrew Pruszynski
Keyword(s):  
Motor Learning ◽  
Muscle Activity ◽  
Shoulder Joint ◽  
Stretch Reflex ◽  
Feedforward Control ◽  
Motor Task ◽  
Joint Torques ◽  
Motor Commands ◽  
Shoulder Muscle ◽  
Long Latency

AbstractPrevious work has demonstrated that when learning a new motor task, the nervous system modifies feedforward (ie. voluntary) motor commands and that such learning transfers to fast feedback (ie. reflex) responses evoked by mechanical perturbations. Here we show the inverse, that learning new feedback responses transfers to feedforward motor commands. Sixty human participants (34 females) used a robotic exoskeleton and either 1) received short duration mechanical perturbations (20 ms) that created pure elbow rotation or 2) generated self-initiated pure elbow rotations. They did so with the shoulder joint free to rotate (normal arm dynamics) or locked (altered arm dynamics) by the robotic manipulandum. With the shoulder unlocked, the perturbation evoked clear shoulder muscle activity in the long-latency stretch reflex epoch (50-100ms post-perturbation), as required for countering the imposed joint torques, but little muscle activity thereafter in the so-called voluntary response. After locking the shoulder joint, which alters the required joint torques to counter pure elbow rotation, we found a reliable reduction in the long-latency stretch reflex over many trials. This reduction transferred to feedforward control as we observed 1) a reduction in shoulder muscle activity during self-initiated pure elbow rotation trials and 2) kinematic errors (ie. aftereffects) in the direction predicted when failing to compensate for normal arm dynamics, even though participants never practiced self-initiated movements with the shoulder locked. Taken together, our work shows that transfer between feedforward and feedback control is bidirectional, furthering the notion that these processes share common neural circuits that underlie motor learning and transfer.

Firing patterns of human flexor carpi radialis motor units during the stretch reflex

1985 ◽  
Vol 53 (5) ◽  
pp. 1179-1193 ◽  
Author(s):  
B. Calancie ◽  
P. Bawa
Keyword(s):  
Motor Unit ◽  
Stretch Reflex ◽  
Latency Period ◽  
Response Probability ◽  
Short Latency ◽  
Single Motor Unit ◽  
Single Motor ◽  
Motoneuron Pool ◽  
Long Latency ◽  
Long Latency Reflex

Single motor unit and gross surface electromyographic responses to torque motor-produced wrist extensions were studied in human flexor carpi radialis muscle. Surface EMG typically showed two "periods" of reflex activity, at a short and long latency following stretch, but both periods occurring before a subject's voluntary reaction to the stretch. The amplitude of EMG activity in both reflex periods increased monotonically with an increase in the torque load. The amplitude of the short-latency reflex response was very dependent on the motoneuron pool excitability, or preload. The amplitude of the long-latency reflex response also varied with the preload, but could, in addition, be modulated by the subject's preparatory set for a voluntary response to the imposed displacement. When a single motor unit that was not tonically active began to fire during the stretch reflex, it did so primarily during the long-latency period. When caused to fire repetitively by voluntary facilitation of the motoneuron pool, that same unit now showed activity during both periods of the stretch reflex. Further increases in either motoneuron pool facilitation or in perturbation strength resulted in a monotonic increase in response probability of a single motor unit during the short-latency period. However, the response probability of a single unit during the long-latency reflex period did not always vary in a monotonic way with increases in either torque load or motoneuron pool facilitation. For an additional series of experiments, the subject was instructed on how to respond voluntarily to the upcoming wrist perturbation. The three instructions to the subject had no effect on the response probability of a single motor unit during either the background or short-latency periods of the stretch reflex. However, prior instruction clearly affected a unit's response probability during the long-latency reflex period. Changes in the firing rate of motor units, and in the recruitment or derecruitment of nontonic units, contributed to this modulation of reflex activity during the long-latency period.

Evidence for a supraspinal contribution to the human quadriceps long-latency stretch reflex

2005 ◽  
Vol 168 (4) ◽  
pp. 529-540 ◽  
Author(s):  
N. Mrachacz-Kersting ◽  
M.J. Grey ◽  
T. Sinkjær
Keyword(s):  
Stretch Reflex ◽  
Long Latency

scholarly journals Instruction-dependent modulation of the long-latency stretch reflex is associated with indicators of startle

2013 ◽  
Vol 230 (1) ◽  
pp. 59-69 ◽  
Author(s):  
Vengateswaran J. Ravichandran ◽  
Claire F. Honeycutt ◽  
Jonathan Shemmell ◽  
Eric J. Perreault
Keyword(s):  
Stretch Reflex ◽  
Long Latency

scholarly journals Modulation of Stretch Reflexes of the Finger Flexors by Sensory Feedback From the Proximal Upper Limb Poststroke

2009 ◽  
Vol 102 (3) ◽  
pp. 1420-1429 ◽  
Author(s):  
Gilles Hoffmann ◽  
Derek G. Kamper ◽  
Jennifer H. Kahn ◽  
William Z. Rymer ◽  
Brian D. Schmit
Keyword(s):  
Upper Limb ◽  
Stretch Reflex ◽  
Sensory Input ◽  
Biceps Brachii ◽  
Elbow Flexion ◽  
Spinal Reflex ◽  
Reflex Response ◽  
Emg Activity ◽  
Triceps Brachii ◽  
Flexor Digitorum

Neural coupling of proximal and distal upper limb segments may have functional implications in the recovery of hemiparesis after stroke. The goal of the present study was to investigate whether the stretch reflex response magnitude of spastic finger flexor muscles poststroke is influenced by sensory input from the shoulder and the elbow and whether reflex coupling of muscles throughout the upper limb is altered in spastic stroke survivors. Through imposed extension of the metacarpophalangeal (MCP) joints, stretch of the relaxed finger flexors of the four fingers was imposed in 10 relaxed stroke subjects under different conditions of proximal sensory input, namely static arm posture (3 different shoulder/elbow postures) and electrical stimulation (surface stimulation of biceps brachii or triceps brachii, or none). Fast (300°/s) imposed stretch elicited stretch reflex flexion torque at the MCP joints and reflex electromyographic (EMG) activity in flexor digitorum superficialis. Both measures were greatest in an arm posture of 90° of elbow flexion and neutral shoulder position. Biceps stimulation resulted in greater MCP stretch reflex flexion torque. Fast imposed stretch also elicited reflex EMG activity in nonstretched heteronymous upper limb muscles, both proximal and distal. These results suggest that in the spastic hemiparetic upper limb poststroke, sensorimotor coupling of proximal and distal upper limb segments is involved in both the increased stretch reflex response of the finger flexors and an increased reflex coupling of heteronymous muscles. Both phenomena may be mediated through changes poststroke in the spinal reflex circuits and/or in the descending influence of supraspinal pathways.

Time and direction preparation of the long latency stretch reflex

2016 ◽  
Vol 47 ◽  
pp. 38-48 ◽  
Author(s):  
Yasutaka Nikaido ◽  
Ryota Hatanaka ◽  
Yasutomo Jono ◽  
Yoshifumi Nomura ◽  
Keisuke Tani ◽  
...  
Keyword(s):  
Stretch Reflex ◽  
Long Latency
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