Activity of Pyramidal Tract Neurons in the Cat During Postural Corrections

2005 ◽  
Vol 93 (4) ◽  
pp. 1831-1844 ◽  
Author(s):  
I. N. Beloozerova ◽  
M. G. Sirota ◽  
G. N. Orlovsky ◽  
T. G. Deliagina
Keyword(s):  
Motor Cortex ◽  
Pyramidal Tract ◽  
Frontal Plane ◽  
Dorsal Side ◽  
The Body ◽  
Contact Forces ◽  
Postural Control System ◽  
Pyramidal Tract Neurons ◽  
The Right

The dorsal side-up body orientation in quadrupeds is maintained by a postural control system. We investigated participation of the motor cortex in this system by recording activity of pyramidal tract neurons (PTNs) from limb representations of the motor cortex during postural corrections. The cat was standing on the platform periodically tilting in the frontal plane, and maintained equilibrium at different body configurations: with the head directed forward (symmetrically alternating loading of the left and right fore limbs), or with the head voluntary turned to the right or to the left (asymmetrical loading). We found that postural corrective responses to tilts included an increase of the contact forces and activity of limb extensors on the side moving down, and their decrease on the opposite side. The activity of PTNs was strongly modulated in relation to the tilt cycle. Phases of activity of individual PTNs were distributed over the cycle. Thus the cortical output mediated by PTNs appeared closely related to a highly automatic motor activity, the maintenance of the body posture. An asymmetrical loading of limbs, caused by head turns, resulted in the corresponding changes of motor responses to tilts. These voluntary postural modifications were also well reflected in the PTNs' activity. The activity of a part of PTNs correlated well with contact forces, in some others with the limb muscle activity; in still others no correlation with these variables was observed. This heterogeneity of the PTNs population suggests a different functional role of individual PTNs.

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

2012 ◽  
Vol 107 (7) ◽  
pp. 1890-1903 ◽  
Author(s):  
Erik E. Stout ◽  
Irina N. Beloozerova
Keyword(s):  
Motor Cortex ◽  
Cortical Neurons ◽  
Pyramidal Tract ◽  
Receptive Fields ◽  
Close Relation ◽  
Afferent Input ◽  
The Body ◽  
Pyramidal Tract Neurons ◽  
Discharge Duration ◽  
Increased Activity

During locomotion, motor cortical neurons projecting to the pyramidal tract (PTNs) discharge in close relation to strides. How their discharges vary based on the part of the body they influence is not well understood. We addressed this question with regard to joints of the forelimb in the cat. During simple and ladder locomotion, we compared the activity of four groups of PTNs with somatosensory receptive fields involving different forelimb joints: 1) 45 PTNs receptive to movements of shoulder, 2) 30 PTNs receptive to movements of elbow, 3) 40 PTNs receptive to movements of wrist, and 4) 30 nonresponsive PTNs. In the motor cortex, a relationship exists between the location of the source of afferent input and the target for motor output. On the basis of this relationship, we inferred the forelimb joint that a PTN influences from its somatosensory receptive field. We found that different PTNs tended to discharge differently during locomotion. During simple locomotion shoulder-related PTNs were most active during late stance/early swing, and upon transition from simple to ladder locomotion they often increased activity and stride-related modulation while reducing discharge duration. Elbow-related PTNs were most active during late swing/early stance and typically did not change activity, modulation, or discharge duration on the ladder. Wrist-related PTNs were most active during swing and upon transition to the ladder often decreased activity and increased modulation while reducing discharge duration. These data suggest that during locomotion the motor cortex uses distinct mechanisms to control the shoulder, elbow, and wrist.

The Role of Spices with reference Novel Coronavirus Covid 19

2020 ◽  
Vol 11 (SPL1) ◽  
pp. 1655-1661
Author(s):  
Roshna Sukheoji Bhutada ◽  
Kritika Umate
Keyword(s):  
Viral Infections ◽  
The Body ◽  
Common People ◽  
Supplementary Food ◽  
Long Time ◽  
Novel Coronavirus ◽  
The Right ◽  
Common Spices ◽  
Physiological Reactions

The need of the day is a brisk lift to the resistant framework to keep it fit, battling today pandemic infections, for example, Covid — 19. One should get the right amount of nutrients from the diet, supplementation regimen to boost the immune system. These spices are always there to make tasty food as well as to protect the body from infectious diseases by building the immunity strong Ayurveda approaches to develop physiological reactions to facilitate immunity. Planning of diet is most important to boost immunity. As per many types of research to provide supplementary food which contains Zinc, Vitamin C, Vitamin D and immunity boosting food such as dealing with plenty of spices for a very long time. These spices include some rare to very common spices which we can found near us. The concern is that these viral infections are very prone to attack weak immunity and take the chance to affect the country to the globe. So the very common spices available will be always helpful to get through this Regular use of a few spices in the very simple form proves its importance as a medicine. In this article a review of spices is done which we are available near us, we are using it in our daily life and we are getting the benefit of these which a common people might not be fully aware of about role of immunity building of the body. 

scholarly journals Slowly-conducting pyramidal tract neurons in macaque and rat

2019 ◽  
Author(s):  
A Kraskov ◽  
D Soteropoulos ◽  
I Glover ◽  
RN Lemon ◽  
SN Baker
Keyword(s):  
Motor Cortex ◽  
Pyramidal Tract ◽  
Recurrent Inhibition ◽  
Anatomical Studies ◽  
Slow Conduction ◽  
Pyramidal Tract Neurons ◽  
Conduction Velocities ◽  
Myelinated Fibres ◽  
Anaesthetised Rats

SummaryAnatomical studies report a large proportion of fine myelinated fibres in the primate pyramidal tract (PT), while very few pyramidal tract neurons (PTNs) with slow conduction velocities (CV) (< ∼10 m/s) are reported electrophysiologically. This discrepancy might reflect recording bias towards fast PTNs or prevention of antidromic invasion by recurrent inhibition of slow PTNs from faster axons. We investigated these factors in recordings made with a polyprobe (32 closely-spaced contacts) from motor cortex of anaesthetised rats (n=2) and macaques (n=3), concentrating our search on PTNs with long antidromic latencies. We identified 21 rat PTNs with antidromic latencies > 2.6 ms and estimated CV 3-8 m/s, and 67 macaque PTNs (> 3.9ms, CV 6-12 m/s). Spikes of most slow PTNs were small and present on only some recording contacts, while spikes from simultaneously recorded fast-conducting PTNs were large and appeared on all contacts. Antidromic thresholds were similar for fast and slow PTNS, while spike duration was considerably longer in slow PTNs. Most slow PTNs showed no signs of failure to respond antidromically. A number of tests, including intracortical microinjection of bicuculline (GABAA antagonist), failed to provide any evidence that recurrent inhibition prevented antidromic invasion of slow PTNs. Our results suggest that recording bias is the main reason why previous studies were dominated by fast PTNs.

Ionic changes induced by excitatory amino acids in the rat cerebral cortex

1987 ◽  
Vol 65 (5) ◽  
pp. 1067-1077 ◽  
Author(s):  
R. Pumain ◽  
I. Kurcewicz ◽  
J. Louvel
Keyword(s):  
Amino Acids ◽  
Motor Cortex ◽  
Nmda Receptors ◽  
Excitatory Amino Acids ◽  
Pyramidal Tract ◽  
Potassium Ions ◽  
Channel Blockers ◽  
Pyramidal Tract Neurons ◽  
Ionic Mechanisms ◽  
Inward Currents

The ionic mechanisms underlying the action of excitatory amino acids were investigated in the rat motor cortex. Ion-selective microelectrodes were attached to micropipettes such that their tips were very close and local changes in extracellular concentration of sodium, calcium, and potassium ions elicited through ionophoretic applications of glutamate (Glu) and of its agonists N-methyl-D-aspartate (NMDA), quisqualate (Quis), and kainate (Ka) were measured. These agents produced moderate increases in [K+]o (up to 13 mM) but, in contrast, substantial tetrodotoxin-insensitive decreases in [Na+]o (maximally of 60 mM). NMDA-induced sodium responses could be blocked by manganese, while the Quis- and Ka-induced responses were not. Quis and Ka produced increases in [Ca2+]o or biphasic responses while NMDA, even with small doses, induced each time drastic decreases in [Ca2+]o (maximally of 1.15 mM), which could be attenuated or blocked by manganese but not by organic calcium channel blockers. NMDA responses could be abolished by reduced doses of 2-amino-phosphonovaierate. The largest Glu- and NMDA-induced calcium responses were observed in the superficial cortical layers, but such maxima disappeared after selective degeneration of pyramidal tract neurons. All amino acids produced sizeable reductions in the extracellular space volume. The following can be concluded. (i) All the excitatory amino acids tested induce an increased permeability to sodium and potassium ions. (ii) In addition, the NMDA-operated channels have specifically a large permeability for calcium, although calcium ions contribute only by less than 10% to the NMDA-induced inward currents, (iii) Glu-induced calcium responses are due to the activation by Glu of NMDA receptors. (iv) In the motor cortex, the largest density of NMDA receptors is found on apical dendrites of pyramidal tract neurons.

Activity of the Motor Cortex During Scratching

2006 ◽  
Vol 95 (2) ◽  
pp. 753-765 ◽  
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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