Physiological properties of neurons projecting from area 3a to area 4 gamma of feline cerebral cortex

1982 ◽  
Vol 48 (4) ◽  
pp. 1048-1057 ◽  
Author(s):  
H. Asanuma ◽  
R. S. Waters ◽  
H. Yumiya

1. The corticocortical projection from area 3a to area 4 gamma was restudied using tranquilized cats. 2. Intracortical microstimulation (ICMS) of a given locus in area 3a produced effects on neurons in area 4 gamma that were located in a small area extending along the direction of the radial fibers constituting a columnar shape. 3. Cortical neurons in area 3a that projected to a particular neuron in area 4 gamma were located in a region that extended along the direction of the radial fibers and constituted a columnar shape. 4. Two-thirds of the projection neurons in area 3a had different receptive fields from those of neurons in the projected area in 4 gamma, thus suggesting that the 3a neurons are not simply transferring peripheral information to the 4 gamma neurons. 5. ICMS delivered to area 3a rarely excited 4 gamma neurons but rather facilitated their evoked discharges. 6. It is suggested that the activity of corticocortical projection from area 3a to 4 gamma can influence the activity of 4 gamma neurons only when combined with other inputs to the motor cortex.

1988 ◽  
Vol 59 (3) ◽  
pp. 796-818 ◽  
Author(s):  
C. S. Huang ◽  
M. A. Sirisko ◽  
H. Hiraba ◽  
G. M. Murray ◽  
B. J. Sessle

1. The technique of intracortical microstimulation (ICMS), supplemented by single-neuron recording, was used to carry out an extensive mapping of the face primary motor cortex. The ICMS study involved a total of 969 microelectrode penetrations carried out in 10 unanesthetized monkeys (Macaca fascicularis). 2. Monitoring of ICMS-evoked movements and associated electromyographic (EMG) activity revealed a general pattern of motor cortical organization. This was characterized by a representation of the facial musculature, which partially enclosed and overlapped the rostral, medial, and caudal borders of the more laterally located cortical regions representing the jaw and tongue musculatures. Responses were evoked at ICMS thresholds as low as 1 microA, and the latency of the suprathreshold EMG responses ranged from 10 to 45 ms. 3. Although contralateral movements predominated, a representation of ipsilateral movements was found, which was much more extensive than previously reported and which was intermingled with the contralateral representations in the anterior face motor cortex. 4. In examining the fine organizational pattern of the representations, we found clear evidence for multiple representation of a particular muscle, thus supporting other investigations of the motor cortex, which indicate that multiple, yet discrete, efferent microzones represent an essential organizational principle of the motor cortex. 5. The close interrelationship of the representations of all three muscle groups, as well as the presence of a considerable ipsilateral representation, may allow for the necessary integration of unilateral or bilateral activities of the numerous face, jaw, and tongue muscles, which is a feature of many of the movement patterns in which these various muscles participate. 6. In six of these same animals, plus an additional two animals, single-neuron recordings were made in the motor and adjacent sensory cortices in the anesthetized state. These neurons were electrophysiologically identified as corticobulbar projection neurons or as nonprojection neurons responsive to superficial or deep orofacial afferent inputs. The rostral, medial, lateral, and caudal borders of the face motor cortex were delineated with greater definition by ICMS and these electrophysiological procedures than by cytoarchitectonic features alone. We noted that there was an approximate fit in area 4 between the extent of projection neurons and field potentials anti-dromically evoked from the brain stem and the extent of positive ICMS sites.(ABSTRACT TRUNCATED AT 400 WORDS)


Author(s):  
M. Smith Allan ◽  
Dugas Clause ◽  
Fortier Pierre ◽  
Kalasha John ◽  
Picard Nathalie

ABSTRACT:The activity of single cells in the cerebellar and motor cortex of awake monkeys was recorded during separate studies of whole-arm reaching movements and during the application of force-pulse perturbations to handheld objects. Two general observations about the contribution of the cerebellum to the control of movement emerge from the data. The first, derived from the study of whole arm reaching, suggests that although both the motor cortex and cerebellum generate a signal related to movement direction, the cerebellar signal is less precise and varies from trial to trial even when the movement kinematics remain unchanged. The second observation, derived from the study of predictable perturbations of a hand-held object, indicates that cerebellar cortical neurons better reflect preparatory motor strategies formed from the anticipation of cutaneous and proprioceptive stimuli acquired by previous experience. In spite of strong relations to grip force and receptive fields stimulated by preparatory grip forces increase, the neurons of the percentral motor cortex showed very little anticipatory activity compared with either the premotor areas or the cerebellum.


Physiology ◽  
1993 ◽  
Vol 8 (6) ◽  
pp. 266-272 ◽  
Author(s):  
RT Robertson ◽  
J Yu

Patterns of intense acetylcholinesterase activity occur transiently in developing thalamocortical projection neurons and their terminal fields in sensory regions of cerebral cortex. These patterns correlate well with the time of ingrowth of thalamocortical axons and synaptogenesis with cortical neurons.


In the course of experiments in which the cerebral cortex of the monkey is stimulated, it is peculiarly noticeable that the activity of the cortex varies from time to time. That such variation should occur is by no means strange, in view of the difficulty of maintaining a constant depth of narcosis. But there are other variations which seemingly are not conditioned by variation of depth of narcosis. Thus it not rarely happens that, when the depth of narcosis is certainly a constant one, the motor cortex becomes suddenly inexcitable. This occurs, for instance, after a cortical discharge, which is followed by “ epileptic ” after-discharge. But it also occurs without any apparent preceding cause. Thus suddenly the cortical excitability becomes abolished—at any rate, to practicable strengths of stimulation. This sudden loss of cortical excitability is a phenomenon of interest. It is accompanied by two marked states. Of these, the first is an anæmia of the cortex ; the second is a maintained postural contraction of certain of the muscles of the limbs. The anæmia seems to occur over the whole of the small area of cortex—pre-central and post-central—usually exposed in these experiments. It causes a sudden change in appearance from the “raw ham” look of the cortex when it is in the most favourable condition for electrical stimulation to a pale “ dead ” look. The cortex blanches; it may be surmised that it faints.


2002 ◽  
Vol 88 (4) ◽  
pp. 1791-1814 ◽  
Author(s):  
Sylvain Lavoie ◽  
Trevor Drew

We have examined the contribution of the red nucleus to the control of locomotion in the cat. Neuronal activity was recorded from 157 rubral neurons, including identified rubrospinal neurons, in three cats trained to walk on a treadmill and to step over obstacles attached to the moving belt. Of 72 neurons with a receptive field confined to the contralateral forelimb, 66 were phasically active during unobstructed locomotion. The maximal activity of the majority of neurons (59/66) was centered around the swing phase of locomotion. Slightly more than half of the neurons (36/66) were phasically activity during both swing and stance. In addition, some rubral neurons (14/66) showed multiple periods of phasic activity within the swing phase of the locomotor cycle. Periods of phasic discharge temporally coincident with the swing phase of the ipsilateral limb were observed in 7/66 neurons. During voluntary gait modifications, most forelimb-related neurons (70/72) showed a significant increase in their discharge activity when the contralateral limb was the first to step over the obstacle (lead condition). Maximal activity in nearly all cells (63/70) was observed during the swing phase, and 23/63 rubral neurons exhibited multiple increases of activity during the modified swing phase. A number of cells (18/70) showed multiple periods of increased activity during swing and stance. Many of the neurons (35/63, 56%) showed an increase in activity at the end of the swing phase; this period of activity was temporally coincident with the period of activity in wrist dorsiflexors, such as the extensor digitorum communis. A smaller proportion of neurons with receptive fields restricted to the hindlimbs showed similar characteristics to those observed in the population of forelimb-related neurons. The overall characteristics of these rubral neurons are similar to those that we obtained previously from pyramidal tract neurons recorded from the motor cortex during an identical task. However, in contrast to the results obtained in the rubral neurons, most motor cortical neurons showed only one period of increased activity during the step cycle. We suggest that both structures contribute to the modifications of the pattern of EMG activity that are required to produce the change in limb trajectory needed to step over an obstacle. However, the results suggest an additional role for the red nucleus in regulating intra- and interlimb coordination.


1992 ◽  
Vol 67 (5) ◽  
pp. 1057-1070 ◽  
Author(s):  
G. H. Recanzone ◽  
M. M. Merzenich ◽  
W. M. Jenkins

1. The responses of cortical neurons evoked by cutaneous stimulation were investigated in the hand representation of cortical area 3a in adult owl monkeys that had been trained in a tactile frequency discrimination task. Cortical representations of the hands in these experimental hemispheres were compared with those representing the opposite, untrained hand, as well as with those representing a passively stimulated hand in a second class of control monkeys. 2. A large cutaneous representation of the hairy and glabrous skin surfaces of the hand emerged in area 3a in each trained hemisphere. 3. With the emergence of cutaneous responses recorded for neurons at many area 3a locations, the normally recorded deep receptor inputs were no longer evident at most of these locations. 4. There was a greater territory of representation of the small area of skin that was stimulated in the behavioral task in trained monkeys, when compared with the representations of corresponding skin sites in the opposite hemisphere of the same monkeys, or to the representations of equivalent skin sites stimulated in passively stimulated control monkeys. 5. There was great variability in the receptive-field properties of neurons responsive to cutaneous inputs among trained monkeys. In most recording sites within the representations of the behaviorally engaged hands, the cutaneous receptive fields were large, extending over a significant part of the glabrous or hairy surfaces of the hand. However, in one monkey, very small, topographically ordered cutaneous receptive fields were recorded over a wide zone of area 3a. 6. The physiologically defined borders between areas 3a and 3b were in register with the cytoarchitectonically defined borders between these two cortical areas in trained and in control monkeys. 7. This study demonstrates that there is a reorganization of the cutaneous and "deep" representation of hand in cortical area 3a, with the main change being an emergence of a large cutaneous representation and the parallel disappearance of a large part of the normal deep representation in this field. These changes are discussed in light of the possible functional roles of cortical area 3a.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adel Parvizi-Fard ◽  
Mahmood Amiri ◽  
Deepesh Kumar ◽  
Mark M. Iskarous ◽  
Nitish V. Thakor

AbstractTo obtain deeper insights into the tactile processing pathway from a population-level point of view, we have modeled three stages of the tactile pathway from the periphery to the cortex in response to indentation and scanned edge stimuli at different orientations. Three stages in the tactile pathway are, (1) the first-order neurons which innervate the cutaneous mechanoreceptors, (2) the cuneate nucleus in the midbrain and (3) the cortical neurons of the somatosensory area. In the proposed network, the first layer mimics the spiking patterns generated by the primary afferents. These afferents have complex skin receptive fields. In the second layer, the role of lateral inhibition on projection neurons in the cuneate nucleus is investigated. The third layer acts as a biomimetic decoder consisting of pyramidal and cortical interneurons that correspond to heterogeneous receptive fields with excitatory and inhibitory sub-regions on the skin. In this way, the activity of pyramidal neurons is tuned to the specific edge orientations. By modifying afferent receptive field size, it is observed that the larger receptive fields convey more information about edge orientation in the first spikes of cortical neurons when edge orientation stimuli move across the patch of skin. In addition, the proposed spiking neural model can detect edge orientation at any location on the simulated mechanoreceptor grid with high accuracy. The results of this research advance our knowledge about tactile information processing and can be employed in prosthetic and bio-robotic applications.


2012 ◽  
Vol 107 (7) ◽  
pp. 1890-1903 ◽  
Author(s):  
Erik E. Stout ◽  
Irina N. Beloozerova

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.


2020 ◽  
Vol 123 (5) ◽  
pp. 1944-1954 ◽  
Author(s):  
Sergey G. Khasabov ◽  
Hai Truong ◽  
Victoria M. Rogness ◽  
Kevin D. Alloway ◽  
Donald A. Simone ◽  
...  

Processing of information related to itch sensation at the level of cerebral cortex is not well understood. In this first single-unit electrophysiological study of pruriceptive cortical neurons, we show that neurons responsive to noxious and pruritic stimulation of the cheek of the face are concentrated in a small area of the dysgranular cortex, indicating that these neurons encode information related to itch and pain.


Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Stefanie Nunez ◽  
Mary Teena Joy ◽  
Jason D Hinman

Introduction: Small vessel ischemic strokes account for 25% of strokes in the US. They often occur silently, increasing the prevalence 5-10 fold and are progressive with new strokes occurring adjacent to prior strokes. In this common form of stroke, there is a local injury damaging axons and white matter, and a distant injury damaging the neurons with axons affected by the stroke, leading to cortical thinning in the connected cortex. This selective neuronal loss contributes to minor stroke related cognitive dysfunction and disability yet the molecular response of neurons with stroke-injured axons remains challenging to study. Hypothesis: White matter stroke injures cortical projection neurons and triggers a unique molecular program that contributes to selective neuronal loss. Methods: To determine the neuronal effects of a white matter stroke, we produced a subcortical white matter stroke below the forelimb motor cortex in adult male C57/Bl6 mice resulting in a focal white matter lesion. Retrograde neuronal tracing identifies individual neurons damaged by the white matter stroke. Layer 5 cortical neurons were isolated by magnetic microbead separation of non-neuronal cells, followed by fluorescent-activated cell sorting (FACS) isolation of retrogradely-labeled cells. Results: Stereologic measurement of the neurons with stroke-injured axons co-labeled with the Layer 5 neuronal marker CTIP-2 reveals that focal white matter stroke selectively identifies between 15-25% of the Layer 5 cortical neurons in both sensory and motor cortex with spanning the cortical regions of interest, compared to only ∼3% in sham injured animals. Using FACS isolation, we compared the transcriptional profile of white matter stroke injured cortical projection neurons to uninjured Layer 5 neurons at one week after stroke. An average of 6,297 cells were collected per isolation, RNA isolated and analyzed by qPCR and RNA-seq. Conclusions: Bioinformatic analysis of differentially expressed genes indicates that white matter stroke activates both degenerative and regenerative pathways in stroke-induced axonally-injured neurons. These data can be harnessed to prevent selective neuronal loss after white matter stroke and induce neural repair after stroke.


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