Inhibitory influence of the ipsilateral motor cortex on responses to stimulation of the human cortex and pyramidal tract

We used microstimulation to examine the contribution of the motor cortex to the structure and timing of the hindlimb step cycle during locomotion in the intact cat. Stimulation was applied to the hindlimb representation of the motor cortex in 34 sites in three cats using either standard glass-insulated microelectrodes (16 sites in 1 cat) or chronically implanted microwire electrodes (18 sites in 2 cats). Stimulation at just suprathreshold intensities with the cat at rest produced multijoint movements at a majority of sites (21/34, 62%) but evoked responses restricted to a single joint, normally the ankle, at the other 13/34 (38%) sites. Stimulation during locomotion generally evoked larger responses than the same stimulation at rest and frequently activated additional muscles. Stimulation at all 34 sites evoked phase-dependent responses in which stimulation in swing produced transient increases in activity in flexor muscles while stimulation during stance produced transient decreases in activity in extensors. Stimulation with long (200 ms) trains of stimuli in swing produced an increased level of activity and duration of flexor muscles without producing changes in cycle duration. In contrast, stimulation during stance decreased the duration of the extensor muscle activity and initiated a new and premature period of swing, resetting the step cycle. Stimulation of the pyramidal tract in two of these three cats as well as in two additional ones produced similar effects. The results show that the motor cortex is capable of influencing hindlimb activity during locomotion in a similar manner to that seen for the forelimb.

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Activity of the Motor Cortex During Scratching

Journal of Neurophysiology ◽

10.1152/jn.00050.2005 ◽

2006 ◽

Vol 95 (2) ◽

pp. 753-765 ◽

Cited By ~ 1

Author(s):

Mikhail G. Sirota ◽

Galina A. Pavlova ◽

Irina N. Beloozerova

Keyword(s):

Motor Cortex ◽

Hind Limb ◽

Pyramidal Tract ◽

Average Depth ◽

Simple Correlation ◽

Population Activity ◽

Ankle Muscles ◽

Pyramidal Tract Neurons ◽

Awake Cats ◽

Stimulation Of

In awake cats sitting with the head restrained, scratching was evoked using stimulation of the ear. Cats scratched the shoulder area, consistently failing to reach the ear. Kinematics of the hind limb movements and the activity of ankle muscles, however, were similar to those reported earlier in unrestrained cats. The activity of single neurons in the hind limb representation of the motor cortex, including pyramidal tract neurons (PTNs), was examined. During the protraction stage of the scratch response, the activity in 35% of the neurons increased and in 50% decreased compared with rest. During the rhythmic stage, the motor cortex population activity was approximately two times higher compared with rest, because the activity of 53% of neurons increased and that of 33% decreased in this stage. The activity of 61% of neurons was modulated in the scratching rhythm. The average depth of frequency modulation was 12.1 ± 5.3%, similar to that reported earlier for locomotion. The phases of activity of different neurons were approximately evenly distributed over the scratch cycle. There was no simple correlation between resting receptive field properties and the activity of neurons during the scratch response. We conclude that the motor cortex participates in both the protraction and the rhythmic stages of the scratch response.

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High-Frequency Stimulation of the Subthalamic Nucleus Activates Motor Cortex Pyramidal Tract Neurons by a Process Involving Local Glutamate, GABA and Dopamine Receptors in Hemi-Parkinsonian Rats

The Chinese Journal of Physiology ◽

10.4077/cjp.2018.bag561 ◽

2018 ◽

Vol 61 (2) ◽

pp. 92-105 ◽

Cited By ~ 1

Author(s):

Chi-Fen Chuang

Keyword(s):

Motor Cortex ◽

Dopamine Receptors ◽

Subthalamic Nucleus ◽

High Frequency ◽

Pyramidal Tract ◽

High Frequency Stimulation ◽

Pyramidal Tract Neurons ◽

Frequency Stimulation ◽

Stimulation Of

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Focal Increases of White Matter Glucose Utilization Produced by Electrical Stimulation of Rat Motor Cortex

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.1983.8 ◽

1983 ◽

Vol 3 (1) ◽

pp. 67-70 ◽

Cited By ~ 6

Author(s):

Frank R. Sharp ◽

Sherzad Bzorgchami ◽

Thomas Kilduff

Keyword(s):

Electrical Stimulation ◽

White Matter ◽

Motor Cortex ◽

Glucose Utilization ◽

Pyramidal Tract ◽

Internal Capsule ◽

Local Cerebral Glucose Utilization ◽

The Right ◽

Deoxyglucose Method ◽

Stimulation Of

The right motor cortex was electrically stimulated in adult, awake rats for 45 min. Local cerebral glucose utilization (LCGU) was measured in white matter pathways with the (14C)-2-deoxyglucose method. Stimulation increased LCGU in focal regions of the right internal capsule to 51.3 μmol/100 g/min, compared to 39.8 on the control left side. Stimulation also increased LCGU in the right, medial pontine pyramidal tract to 36.2 μmol/100 g/min, compared with 27.3 on the control left side. The data demonstrate that electrical stimulation of motor cortex neurons increases LCGU 30 to 40% in the efferent myelinated axons of those neurons.

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Electrophysiological characterization of different types of neurons recorded in vivo in the motor cortex of the cat. I. Patterns of firing activity and synaptic responses

Journal of Neurophysiology ◽

10.1152/jn.1993.69.6.1850 ◽

1993 ◽

Vol 69 (6) ◽

pp. 1850-1864 ◽

Cited By ~ 41

Author(s):

A. Baranyi ◽

M. B. Szente ◽

C. D. Woody

Keyword(s):

Motor Cortex ◽

Action Potentials ◽

Pyramidal Tract ◽

Class Iii ◽

Firing Activity ◽

Electrophysiological Properties ◽

Antidromic Response ◽

Stimulation Of ◽

Synaptic Responses

1. Patterns of firing activity and characteristics of antidromic and synaptic responses to stimulation of the pyramidal tract at peduncular level [peduncular pyramidal tract (PP)] and the ventrolateral thalamic nucleus (VL) were studied in neurons of area 4 gamma of the motor cortex of awake, chronic cats using intracellular microelectrode techniques. The results offer a new functional classification of neocortical neurons based on electrophysiological properties of the 640 recorded cells. 2. Four classes of neurons were distinguished: (class i) inactivating bursting (ib) neurons (n = 60) including fast antidromic response PP (fPP) (n = 0), slow antidromic response PP (sPP) (n = 11), and no antidromic response PP cells (nPP) (n = 49); (class ii) noninactivating bursting (nib) neurons (n = 79), including fPP (n = 23), sPP (n = 0), and nPP cells (n = 56); (class iii) fast-spiking (fsp) neurons (n = 56), including fPP (n = 0), sPP (n = 0), and nPP cells (n = 56); and (class iv) regular-spiking (rsp) neurons (n = 445), including fPP (n = 96), sPP (n = 38), and nPP cells (n = 311). (Neurons in each classification were further separated by their antidromic responses to PP stimulation: fast PP (fPP) slow PP (sPP), or nPP cells, the latter not responding antidromically to electrical stimulation of the peduncle.) 3. Recurrent monosynaptic excitatory postsynaptic potentials (EPSPs) followed antidromic spikes elicited by PP stimulation in most (96%) fPP but much fewer (24%) sPP cells. In fPP cells, it was possible to separate the PP EPSPs into two monosynaptic EPSP components that were generated by other fPP and sPP cells, respectively. VL stimulation evoked monosynaptic EPSPs in 100% of fPP cells (vs. 63% of sPP cells) and antidromic action potentials in 16% of fPP cells (vs. 12% of sPP cells). 4. Firing activity consisted of single spike discharges in most PP cells; however, noninactivating bursting was observed in 19% of fPP cells, and inactivating bursting was observed in 23% of sPP cells (see below). In 18% of ib and 11% of nib/nPP neurons, VL stimulation elicited antidromic action potentials. Other bursting neurons proved to be PP cells with characteristic differences in axonal conduction velocity (see above). All PP cells among the nib cells were fPP, and all PP cells among the ib cells were sPP cells. All fsp neurons were found to be nPP cells, and none could be activated antidromically by VL stimulation. Thus the fsp pattern of discharge distinguished a unique class of nPP cells.(ABSTRACT TRUNCATED AT 400 WORDS)

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