Pyramidal tract neurons receptive to different forelimb joints act differently during locomotion

Stout, Erik E.; Beloozerova, Irina N.

doi:10.1152/jn.00650.2011

Cited by 17 publications

(30 citation statements)

References 72 publications

(78 reference statements)

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“…10C). A similar finding was also reported in our other recent studies (Armer et al 2013;Stout and Beloozerova 2012). In addition, we have previously found that, among all forelimbrelated neurons, fast-conducting PTNs as a group have the highest preference to discharge during the swing phase (Stout and Beloozerova 2013).…”

Section: Activity Of Motor Cortex Neurons During Wide-stance Walkingsupporting

confidence: 91%

Body stability and muscle and motor cortex activity during walking with wide stance

Farrell

Bulgakova

Beloozerova

et al. 2014

Journal of Neurophysiology

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Farrell BJ, Bulgakova MA, Beloozerova IN, Sirota MG, Prilutsky BI. Body stability and muscle and motor cortex activity during walking with wide stance. J Neurophysiol 112: 504 -524, 2014. First published April 30, 2014 doi:10.1152/jn.00064.2014.-Biomechanical and neural mechanisms of balance control during walking are still poorly understood. In this study, we examined the body dynamic stability, activity of limb muscles, and activity of motor cortex neurons [primarily pyramidal tract neurons (PTNs)] in the cat during unconstrained walking and walking with a wide base of support (wide-stance walking). By recording three-dimensional full-body kinematics we found for the first time that during unconstrained walking the cat is dynamically unstable in the forward direction during stride phases when only two diagonal limbs support the body. In contrast to standing, an increased lateral between-paw distance during walking dramatically decreased the cat's body dynamic stability in doublesupport phases and prompted the cat to spend more time in threelegged support phases. Muscles contributing to abduction-adduction actions had higher activity during stance, while flexor muscles had higher activity during swing of wide-stance walking. The overwhelming majority of neurons in layer V of the motor cortex, 82% and 83% in the forelimb and hindlimb representation areas, respectively, were active differently during wide-stance walking compared with unconstrained condition, most often by having a different depth of striderelated frequency modulation along with a different mean discharge rate and/or preferred activity phase. Upon transition from unconstrained to wide-stance walking, proximal limb-related neuronal groups subtly but statistically significantly shifted their activity toward the swing phase, the stride phase where most of body instability occurs during this task. The data suggest that the motor cortex participates in maintenance of body dynamic stability during locomotion.body dynamic stability; motor cortex activity; pyramidal tract neurons; locomotion; cat THE ABILITY TO CONTROL body balance and stability during locomotion is essential to prevent falls and recover from perturbations. Maintenance of stable standing and locomotion is complicated by injury (Day et al. 2012;Duong et al. 2004;Holder-Powell and Rutherford 2000), aging (Schrager et al. 2008), fear of falling (Chamberlin et al. 2005;Dunlap et al. 2012), and other factors. Several motor strategies have been found to help maintain stability while walking on complex terrain. They include 1) reducing walking velocity (Chamberlin et al. 2005;Dingwell et al. 2000;Gálvez-López et al. 2011; Maki 1997), 2) reducing stride length and increasing stance width (Dunlap et al. 2012; Maki 1997;Misiaszek 2006), and 3) lowering the center of mass (Gálvez-López et al. 2011;Schmidt and Fischer 2010) and prolonging the double-support phase (Chamberlin et al. 2005; Maki 1997). While stability of the human body during locomotion has been analyzed in detail, little is known ab...

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Section: Activity Of Motor Cortex Neurons During Wide-stance Walkingsupporting

confidence: 91%

Body stability and muscle and motor cortex activity during walking with wide stance

Farrell

Bulgakova

Beloozerova

et al. 2014

Journal of Neurophysiology

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“…PTN does not respond (arrowhead 3) because in 0.7 ms its spontaneous spike was still en route to the site of stimulation in the pyramidal tract, and thus collision/nullification of spontaneous and evoked spikes occurred. (Adapted with modifications from Stout and Beloozerova, 2012). …”

Section: Characteristics Of Neurons Included In This Reviewmentioning

confidence: 99%

“…Instead, each of the motor centers contains a variety of neurons that differ in the phases of their discharges during the stride, in the number of PEFs they produce per cycle, in the manner by which they respond to the accuracy demand imposed by the ladder, and other parameters. We did our best to describe these different cell types in our original research reports (Marlinski et al, 2012a,b; Stout and Beloozerova, 2012). In Figure 7 we show neurons with shoulder-related receptive fields that belong to the most populous group of cells: those that discharge a single PEF per cycle and respond to accuracy demand on stepping by increasing the magnitude of their stride-related modulation and by shortening the PEF.…”

Section: Examples Of Locomotion-related Activity Of Neurons Across Thmentioning

confidence: 99%

“…Original data on biomechanics of ladder locomotion were published in Beloozerova et al (2010); on the activity of the MC – in Stout and Beloozerova (2012); on the activity of the VL – in Marlinski et al (2012a); and on the activity of the RE – in Marlinski et al (2012b). Data on biomechanics and the activity of the MC, VL, and RE were all obtained in identical experiments although conducted on different sets of cats.…”

Section: Introductionmentioning

confidence: 99%

“…Data on biomechanics and the activity of the MC, VL, and RE were all obtained in identical experiments although conducted on different sets of cats. Methods of data collection and spike trains analysis have been described earlier (Beloozerova and Sirota, 1993a; Prilutsky et al, 2005; Beloozerova et al, 2010; Marlinski et al, 2012a,b; Stout and Beloozerova, 2012) and will be briefly outlined below when necessary. All experiments were conducted in accordance with NIH guidelines and with the approval of the Barrow Neurological Institute Animal Care and Use Committee.…”

Section: Introductionmentioning

confidence: 99%

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Distinct Thalamo-Cortical Controls for Shoulder, Elbow, and Wrist during Locomotion

Beloozerova

Stout

Sirota

2013

Front. Comput. Neurosci.

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Recent data from this laboratory on differential controls for the shoulder, elbow, and wrist exerted by the thalamo-cortical network during locomotion is presented, based on experiments involving chronically instrumented cats walking on a flat surface and along a horizontal ladder. The activity of the following three groups of neurons is characterized: (1) neurons of the motor cortex that project to the pyramidal tract (PTNs), (2) neurons of the ventrolateral thalamus (VL), many identified as projecting to the motor cortex (thalamo-cortical neurons, TCs), and (3) neurons of the reticular nucleus of thalamus (RE), which inhibit TCs. Neurons were grouped according to their receptive field into shoulder-, elbow-, and wrist/paw-related categories. During simple locomotion, shoulder-related PTNs were most active in the late stance and early swing, and on the ladder, often increased activity and stride-related modulation while reducing discharge duration. Elbow-related PTNs were most active during late swing/early stance and typically remained similar on the ladder. Wrist-related PTNs were most active during swing, and on the ladder often decreased activity and increased modulation while reducing discharge duration. In the VL, shoulder-related neurons were more active during the transition from swing-to-stance. Elbow-related cells tended to be more active during the transition from stance-to-swing and on the ladder often decreased their activity and increased modulation. Wrist-related neurons were more active throughout the stance phase. In the RE, shoulder-related cells had low discharge rates and depths of modulation and long periods of activity distributed evenly across the cycle. In sharp contrast, wrist/paw-related cells discharged synchronously during the end of stance and swing with short periods of high activity, high modulation, and frequent sleep-type bursting. We conclude that thalamo-cortical network processes information related to different segments of the forelimb differently and exerts distinct controls over the shoulder, elbow, and wrist during locomotion.

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Cortically Controlled Electrical Stimulation for Locomotion of the Spinal Cord Injured

Alam

2013

Biosystems &Amp; Biorobotics

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Pyramidal tract neurons receptive to different forelimb joints act differently during locomotion

Cited by 17 publications

References 72 publications

Body stability and muscle and motor cortex activity during walking with wide stance

Body stability and muscle and motor cortex activity during walking with wide stance

Distinct Thalamo-Cortical Controls for Shoulder, Elbow, and Wrist during Locomotion

Cortically Controlled Electrical Stimulation for Locomotion of the Spinal Cord Injured

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