1. The impulse activity of single neurones in the motor cortex (MC) was recorded extracellularly, using movable varnish-insulated tungsten microelectrodes, six adult, freely moving cats. Neuronal while cats walked on a flat floor, as they stepped over series barriers, and rungs horizontal ladder. mean discharge rate (mR) depth frequency modulation (dM) each cell were estimated 10-100 steps. 2. ninety-eight MC cells (Including thirteen pyramidal tract (PTNs)) during stepping barriers 25 cm...

Swadlow, Harvey A., Irina N. Beloozerova, and Mikhail G. Sirota. Sharp, local synchrony among putative feed-forward inhibitory interneurons of rabbit somatosensory cortex. J. Neurophysiol. 79: 567–582, 1998. Many suspected (SINs) primary cortex (S1) receive a potent monosynaptic thalamic input (thalamocortical SINs, SINstc). It has been proposed that nearly all such SINstc S1 barrel column (BC) excitatory synaptic from each member subpopulation neurons within the topographically aligned...

This study examines the activity of different classes neurons motor cortex in rabbit during two locomotion tasks: a simple (on flat surface) and complex (overstepping series barriers) locomotion. Four efferent were studied: corticocortical (CC) with ipsilateral projection (CCIs), those contralateral (CCCs), descending corticofugal layer V (CF5s), VI (CF6s). In addition, one class inhibitory interneurons (SINs) was investigated. CF5 SINs only groups that strongly active most these clear-cut...

The dorsal side-up body orientation in quadrupeds is maintained by a postural system that driven sensory feedback signals. spinal cord, brainstem, and cerebellum play essential roles control, whereas the role of forebrain unclear. In present study we investigated whether motor cortex involved maintenance orientation. We recorded activity neurons awake rabbits while animals balance on platform periodically tilting frontal plane. tilts evoked corrections, i.e., extension limbs side moving down...

What are the differences in mechanics, muscle, and motor cortex activity between accurate nonaccurate movements? We addressed this question relation to walking. assessed full-body mechanics (229 variables), of 8 limb muscles, 63 neurons from forelimb representation during well-trained locomotion with different demands on accuracy paw placement cats: a continuous surface along horizontal ladders crosspieces widths. found that increasing demands, cats assumed more bent-forward posture (by...

The dorsal side-up body orientation in quadrupeds is maintained by a postural control system. We investigated participation of the motor cortex this system recording activity pyramidal tract neurons (PTNs) from limb representations during corrections. cat was standing on platform periodically tilting frontal plane, and equilibrium at different configurations: with head directed forward (symmetrically alternating loading left right fore limbs), or voluntary turned to (asymmetrical loading)....

The parietal cortex receives both visual- and motor-related information is believed to be one of the sites visuo-motor coordination. This study for first time characterizes integration visual motor in activity neurons area 5 during locomotion under conditions that require was recorded cats walking on a flat surface—a task with no coordination required (flat locomotion), along horizontal ladder or series barriers—a requiring an accurate foot placement surface heterogeneous direction...

Biomechanical and neural mechanisms of balance control during walking are still poorly understood. In this study, we examined the body dynamic stability, activity limb muscles, motor cortex neurons [primarily pyramidal tract (PTNs)] in cat unconstrained with a wide base support (wide-stance walking). By recording three-dimensional full-body kinematics found for first time that is dynamically unstable forward direction stride phases when only two diagonal limbs body. contrast to standing, an...

A deviation from the dorsal-side-up body posture in quadrupeds activates mechanisms for postural corrections. Operation of these was studied rabbit maintaining balance on a platform periodically tilted frontal plane. First, we characterized kinematics and electromyographic (EMG) patterns responses to tilts. It found that reaction tilt includes an extension limbs side moving down flexion opposite side. These limb movements are primarily due modulation activity extensor muscles. Second, it...

Recent progress in the understanding of motor cortex function has been achieved primarily by simultaneously recording neuron activity and movement kinematics corresponding limb. We have expanded this approach combining high-quality cortical single-unit recordings with synchronized full-body kinetics freely behaving cat. The method is illustrated selected results obtained from two cats tested while walking on a flat surface. Using method, 43 pyramidal tract neurons (PTNs) was recorded,...

We studied the flow of corticothalamic (CT) information from motor cortex cat during two types locomotion: visually guided (cortex dependent) and unguided. Spike trains CT neurons in layers V (CT5s) VI (CT6s) were examined. All CT5s had fast-conducting axons (<2 ms conduction time), nearly all showed step-phase-related activity (94%), sensory receptive fields (100%), spontaneous (100%). In contrast, times along CT6 much slower, with bimodal peaks occurring at 6 32 ms. Remarkably, almost...

1. The impulse activity of single neurones in the motor cortex (MC) was recorded extracellularly using movable varnish‐insulated tungsten microelectrodes four adult freely moving cats. cats walked inside experimental box with various loadings swing or stance phases step cycle. mean discharge rate (mR) and depth frequency modulation (dM) each neurone were estimated over 10‐100 steps. 2. thirty‐one cells (including eighteen pyramidal tract (PTNs)) during uphill walking on a 10 deg inclined...

The dorsal-side-up body posture in standing quadrupeds is maintained by the postural system, which includes spinal and supraspinal mechanisms driven somatosensory inputs from limbs. A number of descending tracts can transmit commands for corrections. first aim this study was to understand whether rubrospinal tract participates their transmission. We recorded activity red nucleus neurons (RNNs) cat maintaining balance on periodically tilting platform. Most were identified as ones. It found...

The activity of the motor cortex during locomotion is profoundly modulated in rhythm strides. source modulation not known. In this study we examined one major sources afferent input to cortex, ventrolateral thalamus (VL). Experiments were conducted chronically implanted cats with an extracellular single-neuron recording technique. VL neurons projecting identified by antidromic responses. During locomotion, 92% was strides; 67% cells discharged burst per stride, a pattern typical for cortex....

This study examined the burst firing of neurons in motor sector thalamic reticular nucleus (RE) cat. These are inhibitory cells that project to thalamus. The activity RE was studied during four behaviors: sleep, standing, walking on a flat surface, and accurate stepping crosspieces horizontal ladder. Extracellularly recorded analyzed 58 were identified according their receptive fields contralateral forelimb. All generated bursts spikes half one-third walking. majority sequences with an...

Extracellular responses from single horizontal semicircular canal afferents in two rhesus monkeys were studied after recovery a 14-day biosatellite (COSMOS 2044) orbital spaceflight. On the 1st postflight day, mean gain for 9 different afferents, tested using one or several passive yaw rotation waveforms, was nearly twice that 20 similarly during preflight and control studies. Adaptation of afferent response to on day also greater. These results suggest at least component vestibular end...