Reevaluation of motor cortex and of sensorimotor overlap in cerebral cortex of albino rats

Sanderson, K. J.; Welker, Wally; Shambes, Georgia M.

doi:10.1016/0006-8993(84)90761-3

Cited by 170 publications

(87 citation statements)

References 31 publications

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“…This suggests their origin in the motor rather than the sensory cortex (Kuang and Kalil, 1990;Bareyre et al, 2002). A motor bias of the midlinecrossing CST is also demonstrated by the high proportion of neurons that originated from the RFA, which is suggested to be primarily motor (Neafsey and Sievert, 1982;Sanderson et al, 1984;Rouiller et al, 1993).…”

Section: Increase In Size Of Sensory Activation Map Of the Unimpairedmentioning

confidence: 95%

Functional and Anatomical Reorganization of the Sensory-Motor Cortex after Incomplete Spinal Cord Injury in Adult Rats

Ghosh¹,

Sydekum²,

Haiss³

et al. 2009

J. Neurosci.

157

112

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A lateral hemisection injury of the cervical spinal cord results in Brown-Séquard syndrome in humans and rats. The hands/forelimbs on the injured side are rendered permanently impaired, but the legs/hindlimbs recover locomotor functions. This is accompanied by increased use of the forelimb on the uninjured side. Nothing is known about the cortical circuits that correspond to these behavioral adaptations. In this study, on adult rats with cervical spinal cord lateral hemisection lesions (at segment C3/4), we explored the sensory representation and corticospinal projection of the intact (ipsilesional) cortex. Using blood oxygenation level-dependent functional magnetic resonance imaging and voltage-sensitive dye (VSD) imaging, we found that the cortex develops an enhanced representation of the unimpaired forepaw by 12 weeks after injury. VSD imaging also revealed the cortical spatio-temporal dynamics in response to electrical stimulation of the ipsilateral forepaw or hindpaw. Interestingly, stimulation of the ipsilesional hindpaw at 12 weeks showed a distinct activation of the hindlimb area in the intact, ipsilateral cortex, probably via the injury-spared spinothalamic pathway. Anterograde tracing of corticospinal axons from the intact cortex showed sprouting to recross the midline, innervating the spinal segments below the injury in both cervical and lumbar segments. Retrograde tracing of these midline-crossing axons from the cervical spinal cord (at segment C6/7) revealed the formation of a new ipsilateral forelimb representation in the cortex. Our results demonstrate profound reorganizations of the intact sensory-motor cortex after unilateral spinal cord injury. These changes may contribute to the behavioral adaptations, notably for the recovery of the ipsilesional hindlimb.

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Section: Increase In Size Of Sensory Activation Map Of the Unimpairedmentioning

confidence: 95%

Functional and Anatomical Reorganization of the Sensory-Motor Cortex after Incomplete Spinal Cord Injury in Adult Rats

Ghosh¹,

Sydekum²,

Haiss³

et al. 2009

J. Neurosci.

157

112

View full text Add to dashboard Cite

show abstract

“…The animal's rectal temperature was controlled automatically by a feedback circuit composed of a rectal probe and a heating pad and set to 35°C (Fine Science Tools, Heidelberg, Germany). For stimulation of the neocortex, animals were placed in a stereotaxic apparatus, and craniotomy was performed to gain access to wM1 according to coordinates given by Sanderson et al (1984). For acute experiments, the dura mater was removed, and a single electrode was lowered into the neocortex at a 90°angle with respect to its surface to a depth of 1300 m using a hydraulic micropositioner (Kopf 650; David Kopf Instruments, Tujunga, CA).…”

Section: Methodsmentioning

confidence: 99%

“…In seven animals, the focus was on quantitative assessment of whisker trajectories, and another four animals were mapped coarsely during surgery for chronic implantation. Sanderson et al (1984) reported that wM1 is divided into two subregions, a larger anterolateral one coding for retraction and a smaller posteromedial one coding for protraction, a finding that has never been confirmed since the initial report was published (Gioanni and Lamarche, 1985;Neafsey, 1990;Miyashita et al, 1994;Carvell et al, 1996;Franchi, 2000Franchi, , 2001). Our present experiments using short stimuli (five current pulses at intervals of 2.2 ms) validate the location of the subregions found by Sanderson et al (1984) and the qualitative findings of their study.…”

Section: Vibrissa Movement Evoked During Intracortical Microstimulatimentioning

confidence: 99%

“…Sanderson et al (1984) reported that wM1 is divided into two subregions, a larger anterolateral one coding for retraction and a smaller posteromedial one coding for protraction, a finding that has never been confirmed since the initial report was published (Gioanni and Lamarche, 1985;Neafsey, 1990;Miyashita et al, 1994;Carvell et al, 1996;Franchi, 2000Franchi, , 2001). Our present experiments using short stimuli (five current pulses at intervals of 2.2 ms) validate the location of the subregions found by Sanderson et al (1984) and the qualitative findings of their study. Stimulation of the anterolateral subregion [0.5-4.5 mm anteroposterior (A-P), 0.5-2.5 mm mediolateral (M-L) from bregma; tagged by us as the "retraction-face" region (RF) to describe the effects seen in the awake animal; see below] led to a twitch pulling all whiskers backward in all 15 animals studied ( Fig.…”

Section: Vibrissa Movement Evoked During Intracortical Microstimulatimentioning

confidence: 99%

“…Guided by previous results in anesthetized animals that suggested that there is a subdivision of protraction and retraction movements in rat wM1 (Sanderson et al, 1984), we decided to explore whether these two regions may correspond to spatially segregated regions controlling rhythmic whisking presumptively involving a subcortical CPG and nonrhythmic movements. Indeed, using long intracortical stimulation trains in awake animals, we found the hypothesized segregation demonstrating that representations of modes of control may be integrated into the somatotopic map of M1.…”

Section: Introductionmentioning

confidence: 99%

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Spatial Segregation of Different Modes of Movement Control in the Whisker Representation of Rat Primary Motor Cortex

Haiss¹,

Schwarz²

2005

J. Neurosci.

116

131

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What is mapped on the surface of the primary motor cortex (M1)? The classic somatotopic map holds true on the level of limb representations. However, on the small scale (at within-limb representations), neither somatotopy nor movement dynamics/kinematics seem to be organizational principles. We investigated the hypothesis that integrated into the body representation of M1 there may be separate representation of different modes of motor control, using different subcortical computations but sharing the same motor periphery. Using awake rats and long intracortical stimulation trains in M1 whisker representation (wM1) revealed that natural-like, rhythmic whisking (normally used for tactile exploration) can be evoked from a posteromedial subregion of wM1. Nonrhythmic whisker retraction, on the other hand, was evoked in an adjacent but more anterolaterally located region within wM1. Evoked whisker retraction was always accompanied by complex movements of the face, suggesting that the respective subregion is able to interact with other representations in specific behavioral contexts. Such associations were absent for evoked rhythmic whisking. The respective subregion rather seemed to activate a downstream central pattern generator, the oscillation frequency of which was dependent on the average evoked cortical activity. Nevertheless, joint stimulation of the two neighboring subregions demonstrated their potency to interact in a functionally useful way. Therefore, we suggest that the cause of cortical separation is the specific drive of subcortical structures needed to generate different types of movements rather than different behavioral contexts in which the movements are performed.

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Topography, architecture, and connections of somatosensory cortex in opossums: Evidence for five somatosensory areas

1996

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Microelectrode maps of somatosensory inputs were related to cortical architecture and patterns of cortical connections to provide evidence for five subdivisions of the somatosensory or sensorimotor cortex in North American opossums (Didelphis marsupialis). Microelectrode recordings revealed three systematic representations of the body surface. A large mediolaterally oriented representation was identified as the primary somatosensory area (S1) by its relative position, somatotopy, architecture, and connections. S1 represented the hindlimb, trunk, forelimb, and face in a mediolateral sequence. Two additional representations of cutaneous receptors were found caudolateral to S1, each with face representations adjacent to the border of lateral S1 and other body-part representations progressing more caudally toward the auditory cortex. We identified the more dorsal field as the second somatosensory area (S2) and the more ventral field as the parietal ventral area (PV). Tracers injected into S1 labeled neurons and terminals in architectonically distinct fields rostral and caudal to S1, the somatosensory caudal area (SC) and the somatosensory rostral area (SR). Movements could be evoked by microstimulation from sites scattered over S1, SR, and the frontal cortex, but thresholds were high and uncharacteristic of motor cortex. S2 and PV merged caudally with the cortex responsive to auditory stimuli, possibly A1, and neurons in some caudal recording sites in PV were activated by both auditory and cutaneous stimuli. Primary (V1) and secondary (V2) visual areas were also identified by microelectrode mapping, architecture, and connections. In addition, at least part of the cortex between V2 and the somatosensory cortex had visual connections. Thus, most of the dorsolateral cortex of opossums appears to be somatosensory, auditory, or visual.

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Reevaluation of motor cortex and of sensorimotor overlap in cerebral cortex of albino rats

Cited by 170 publications

References 31 publications

Functional and Anatomical Reorganization of the Sensory-Motor Cortex after Incomplete Spinal Cord Injury in Adult Rats

Functional and Anatomical Reorganization of the Sensory-Motor Cortex after Incomplete Spinal Cord Injury in Adult Rats

Spatial Segregation of Different Modes of Movement Control in the Whisker Representation of Rat Primary Motor Cortex

Topography, architecture, and connections of somatosensory cortex in opossums: Evidence for five somatosensory areas

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