PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Sensorimotor Cortex”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources
PubMed2004

Multimodal functional mapping of sensorimotor cortex prior to resection of an epileptogenic perirolandic lesion.

The effects of chronic epileptogenic lesions on functional anatomy are under debate. Our recent experience during mapping and resection of a lesion in sensorimotor cortex supports the idea that epileptogenic lesions may prompt development of alternate cortical motor representations. Multimodal mapping may uncover alternate areas of functionality that make surgery feasible even when conventional neuroanatomy suggests otherwise. Newer methods such as electrocorticographic spectral analysis may complement traditional electrical cortical stimulation mapping.

Adolescent↗
PubMed1995

Presurgical integrated MRI/SPECT localization of the sensorimotor cortex in a patient with a low-grade astrocytoma in the rolandic area.

We describe the case of a young man who, despite the presence of a tumour in the left sensorimotor cortex, exhibited no motor deficit. Integrated MRI/SPECT-CBF study during motor activation was aimed at determining which cerebral areas were involved in movement execution in this patient and their relationship with the tumour. CBF changes during motor activation were located in two motor areas: anteriorly and medially to the tumour in the left frontal lobe (+29%) and in the right medial frontal cortex (+43%). Integrated MRI/SPECT images provided both an anatomical and functional definition of the motor areas in a patient with a rolandic tumour and could prove useful in determining preoperatively an appropriate surgical strategy.

Adolescent↗
PubMed2002

Serial fMRI of adaptive changes in primary sensorimotor cortex following thumb reconstruction.

Serial fMRI was performed in a patient who underwent transfer of the left great toe to the hand following amputation of the right thumb. Motor activation within the primary sensorimotor cortex (SMC) of both hemispheres was quantified over 2 years, showing a transient increase in contralateral but not ipsilateral primary SMC. The temporal pattern of motor cortical activation observed in this patient may represent a "signature" of good functional recovery.

Adult↗
PubMed1978

Characteristics of evoked potentials and single neuron responses in the cat sensorimotor cortex to sound stimuli with different frequencies.

The characteristics of the averaged evoked potentials (AEP) (experiments with awake non-paralysed animals), of the evoked potentials (EP) and of the responses of single sensorimotor cortical neurons (acute experiments) of cats to tone-bursts with frequencies within 0.1-6.0 kHz were studied. Response selectivity to the tone-burst frequencies which are energetically pronounced in some biologically significant sounds for the cat was observed. The averaged curve of the dependence of the amplitude of AEP in the somatosensory cortical region (S1) on the tone-burst frequency has reliable maximum values at the frequencies of 0.8, 1.6 and 2.0-3.0 kHz. Most pronounced changes in the heart rhythm were observed within the tone-burst frequency ranges in which the AEP of the highest amplitudes were recorded. The amplitude of the AEP was found to increase during the conditioned reflex elaboration. The curve of the dependence of the probability of the EP occurrence on the frequency at equal sound pressure levels had maximum values at the frequencies of 1.6 and 3.2 kHz. The highest amplitude values of EP were found at frequencies of 0.8, 1.6 and 3.2 kHz. More than half of the recorded neurons revealed the lowest values of the response thresholds and the maximum values of the occurrence probability under suprathreshold stimulation at frequencies close to 0.8, 1.6, and 3.2 kHz. It is supposed that the above mentioned feature of the input frequency organization in sensorimotor cortex is connected with the selectivity as to the biological significance of acoustic stimuli.

Acoustic Stimulation↗
PubMed1992

Localization of sensorimotor cortex: the influence of Sherrington and Cushing on the modern concept.

According to Penfield, the work of Charles Sherrington's laboratory forced a change from the long-held concept of a broad, overlapping sensorimotor cortex to the concept of a narrow, discrete pre-Rolandic motor cortex separate from the post-Rolandic sensory strip. Harvey Cushing, one of the founders of modern neurosurgery, coined the term narrow motor strip. Cushing also appears to have been the first to color the precentral gyrus in a mosaic pattern and to use red coloring for the motor cortex and blue for the sensory cortex. Cushing's red and blue color coding is still used in textbooks, nearly 100 years later. In this article, we review the historical evolution of and the evidence for the concept of narrow and discrete motor and sensory strips anterior and posterior to the Rolandic cortex. A review of the historical development of the concept and recent physiological studies reaffirms the proposition that the motor and sensory areas are much broader and more complex than they were thought to be in the classic teaching that originated with Sherrington and Cushing.

Animals↗
PubMedDate not supplied

[Effect of extirpation of the sensorimotor cortex on the formation of conditioned reflexes to a complex signal in the ontogeny of the cat].

In kittens of the age from 39 days to 4 months the influence was studied of the sensorimotor cortex (SMC) ablation on formation and preservation of previously elaborated reflex to a simultaneous complex stimulus (light + sound) with extinction of reaction to nonreinforced components of the complex signal. It is shown that SMC ablation in the age up to 2.5 months does not affect the formation or preservation of the conditioned reflex. The SMC ablation in preliminarily trained kittens in the age of 3.5 months and older leads to disinhibition of components differentiation with preservation of the positive conditioned reflex to the complex signal. In untrained kittens of the same age the SMC ablation leads to disability of animals to inhibit the motor reaction to differentiation signal. The question is discussed of SMC significance in the ontogenesis at formation of adequate forms of behaviour requiring heterosensory interaction.

Acoustic Stimulation↗
PubMed1992

Dopamine and skilled limb use in the rat: more severe bilateral impairments follow substantia nigra than sensorimotor cortex 6-hydroxydopamine injection.

The experiments examined the suggestion that the dopaminergic (DA) projection to the motor cortex are involved in the motor impairments that follow complete hemitelencephalic DA depletions. The neurotoxin, 6-hydroxydopamine (6-OHDA), was injected unilaterally into the sensorimotor cortex (MCtx), the ventral tegmental area (VTA), or into the substantia nigra pars compacta (SN) of rats trained to reach for food with either forelimb. The SN injections produced large (greater than 95%) unilateral striatal dopamine (DA) depletions and severe bilateral impairments in limb use. VTA and MCtx injections did not produce impairments in limb use or severe depletions of cortical DA. An effective test of the contribution of cortical DA to skilled limb use must await a more effective technique for producing selective cortical DA depletion. Nevertheless, the results suggest that the severe impairments of skilled forelimb use that follow hemitelencephalic DA depletions may stem primarily from depletion of the nigrostriatal DA projection.

Animals↗
PubMed1998

Adrenergic modulation of GABAA receptor-mediated inhibition in rat sensorimotor cortex.

The effect of adrenoceptor activation on pharmacologically isolated monosynaptic inhibitory postsynaptic currents (IPSCs) detected in layer V pyramidal neurons was examined by using whole cell voltage-clamp in a slice preparation of rat sensorimotor cortex. Epinephrine (EPI; 10 muM) reversibly altered the amplitude of evoked IPSCs (eIPSCs) in slices from postnatal day 9-12 (P9-12) and P15-18 rats. The effects of EPI were heterogeneous in both age groups, and in individual cases an enhancement, a depression or no effect of eIPSCs was observed, although depression was observed more commonly in the younger age group. The effects of EPI on eIPSC amplitude were likely mediated through presynaptic mechanisms because they occurred in the absence of any alteration in the current produced by direct application of gamma-aminobutyric acid (GABA), or in input resistance. EPI always elicited an increase in the frequency of spontaneous IPSCs (sIPSCs) irrespective of whether or not it induced any change in the amplitude of eIPSCs in the same neuron. The increase in sIPSC frequency was blocked by phentolamine (10 muM) but not by propranolol (10 muM), supporting the conclusion that EPI-mediated effects on sIPSC frequency result from activation of alpha-adrenoceptors located on presynaptic inhibitory interneurons. In a subpopulation of neurons (3/9) from P15-18 rats, EPI increased both the amplitude and frequency of miniature IPSCs (mIPSCs) recorded in the presence of tetrodotoxin (TTX) and under conditions where postsynaptic EPI effects were blocked, suggesting activation of adrenoceptors on presynaptic terminals in these cells. Results of these experiments are consistent with an action of EPI at adrenoceptors located on presynaptic GABAergic interneurons. Adrenergic activation thus has multiple and complex influences on excitability in cortical circuits, some of which are a consequence of interactions that regulate the strength of GABAergic inhibition.

Adrenergic alpha-Antagonists↗
PubMed1981

[Comparison of the developing temporal neocortex with the sensorimotor cortex in rats (author's transl)].

The development of the cortical thickness, the length of apical dendrites and the total amount of apical dendrite spines of layer V pyramidal neurons in albino rat temporal and sensorimotor cortex in Golgi-Cox preparations is related to another during the first 3 postnatal months. The graphs demonstrate the relative growth of the features. The allometries are discussed in relation to general organizational processes during the postnatal rat ontogenesis (hearing, transition period with weaning and period of primary socialization according to Scott et al. 1974).

Animals↗
PubMed2005

Extradural compression of the sensorimotor cortex delays the acquisition but not the recalling of a lever-pressing task in Wistar rats.

The learning and recalling of a lever-press task (LPT) after brief unilateral extradural compression (EC) of the right sensorimotor cortex was studied in Wistar rats. All rats, regardless of the time-point for EC, were trained to lever press for food from D(day)1 to D6. On D8, the position of the active lever was changed to the right side of the operant box and performance was tested until D14. Total and active lever presses, as well as % errors were used to analyse the performance. Rats submitted to EC 24 h before initiating the LPT schedule (naïve-compressed group) showed delayed task acquisition and impaired performance until D10. No significant impairments were detected by D3 on a beam-walking test, excluding paresis as the cause to the delay. Rats submitted to EC after they learned the LPT (trained-compressed group) showed only mildly impaired post-compression performance with no effects on the recalling of the task. Using a progressive ratio LPT, the maximum number of presses to obtain a food-pellet (breaking point) was significantly reduced 24h after EC suggesting reduced motivation for the task early after brain injury. The delayed acquisition of the LPT in naïve-compressed rats was accompanied by consistent cortical, striatal and thalamic degeneration detected by Fluoro-Jade and anti-glial fibrillary acidic protein (GFAP) staining, whereas the improvement in the performance of this group was accompanied by a reduction of the cortical damage on D10. Recall of the LPT in trained-compressed rats was not altered by EC, suggesting the contribution of compensatory mechanisms.

Analysis of Variance↗
PubMed1990

[The influence of lesion of different areas of sensorimotor cortex on effects of EA on NRM neurons].

The purpose of the experiment was to study whether the effects of electroacupuncture (EA) on neurons in nucleus raphe magnus (NRM) were influenced by lesion of different areas of sensorimotor cortex (SM) in rats. Unit discharges of NRM and their nociceptive response to stimulation of tail tip were recorded extracellularly with glass microelectrode. The excitatory type neurons of NRM were selected using of the experiments. 1. The effects of bilateral "Zusanli" point on 31 NRM neurons were observed in control group. EA had a tendency to activate NRM neurons, but obviously inhibited nociceptive response of the neurons in 0-30 minutes (P less than 0.01). 2. After resection of bilateral hindlimb areas of SM, the effects of EA on 31 units in NRM were observed. EA could obviously activate NRM neurons, increasing spontaneous firing rates to 115.3 +/- 20.3% in 0 minute (P less than 0.001) and could still inhibit nociceptive response of the neurons (P less than 0.01). Compared with the EA control group, lesion of hindlimb areas of SM could obviously increase the effect of EA activating NRM neurons, but had no influence on the effect of EA inhibiting nociceptive responses. 3. After lesion of bilateral larger areas of SM, the effects of EA on 14 neurons in NRM did not show activation of NRM neurons, but EA could still inhibit their nociceptive responses of the neurons in 5-25 minutes (P less than 0.01).

Acupuncture Analgesia↗
PubMedDate not supplied

[The time distribution of the spike train activity of the neurons in the rabbit sensorimotor cortex during a rhythmic motor dominant].

A stationary excitation focus produced in rabbit cortex by rhythmical electrodermal paw stimulation was revealed by presentation of testing sound stimuli, which were earlier indifferent for an animal. The multiunit activity in the sensorimotor cortex was recorded. The neuronal pairs were detected with correlated discharges. Analysis of discharges in such pairs revealed the dominant incidence of conjugated impulses with the interval equal or close to 2 s, if the focus had been created by stimulation with the rhythmic interval 2 s. The dominant interval between discharges in a conjugated pair of neurons was equal of close to 3 s, if the rhythmic stimuli positions had been spaced 3 s. It was shown that the rhythmical nature of the dominant focus was maintained at the level of neuronal interactions, i.e., was of a systemic character. The acquired rhythm in conjugated cell activity was observed not only during summation in the moment of excitation transmission to the effector (i.e., when the dominant realized itself in the motor reaction), but within the periods between the testing stimuli.

Animals↗
PubMed2005

Impaired long-term habituation is dissociated from increased locomotor activity after sensorimotor cortex compression.

Behavioural habituation to a novel environment is a simple form of learning in rodents. We studied the habituation and locomotor activity (LMA) of Wistar rats subjected to unilateral, transient (30min) extradural compression (EC) of the right sensorimotor cortex. One group of rats was tested every 24h during the first 5 days (D1-D5) post-EC. Two other groups were tested for the first time in the LMA boxes on D3 and D6 post-EC and their performance was compared with the group tested on D1 (activity in a novel environment). Total and center locomotion, vertical activity and time spent in the center of the LMA box were reduced on D1 post-EC and normalized by D2. The EC-induced motor paresis was undetectable on the rotarod by D2 and on the beam-walking by D3. Total locomotion, vertical activity and time spent in the center of EC-rats significantly increased from D1 to D3. EC caused neurodegeneration in the cortex, caudate putamen and thalamus as detected by Fluoro-Jade staining. The size of the cortical damage decreased from D2 to D5 in the medial and caudal regions of the compressed hemisphere, in accordance with recovery of motor function. LMA provided additional information in the follow-up of recovery from brain injury and habituation to the environment. Thus, long-term, inter-session habituation was impaired from D1 to D3 but dissociated from increased LMA intra-session on D3, when the motor deficits provoked by EC were already undetectable in the rotarod and beam-walking tests.

Analysis of Variance↗
PubMed2003

Hemodynamic evoked response of the sensorimotor cortex measured noninvasively with near-infrared optical imaging.

We have performed a noninvasive bilateral optical imaging study of the hemodynamic evoked response to unilateral finger opposition task, finger tactile, and electrical median nerve stimulation in the human sensorimotor cortex. This optical study shows the hemoglobin-evoked response to voluntary and nonvoluntary stimuli. We performed measurements on 10 healthy volunteers using block paradigms for motor, sensory, and electrical stimulations of the right and left hands separately. We analyzed the spatial/temporal features and the amplitude of the optical signal induced by cerebral activation during these three paradigms. We consistently found an increase (decrease) in the cerebral concentration of oxy-hemoglobin (deoxy-hemoglobin) at the cortical side contralateral to the stimulated side. We observed an optical response to activation that was larger in size and amplitude during voluntary motor task compared to the other two stimulations. The ipsilateral response was consistently smaller than the contralateral response, and even reversed (i.e., a decrease in oxy-hemoglobin, and an increase in deoxy-hemoglobin) in the case of the electrical stimulation. We observed a systemic contribution to the optical signal from the increase in the heart rate increase during stimulation, and we made a first attempt to subtract it from the evoked hemoglobin signal. Our findings based on optical imaging are in agreement with results in the literature obtained with positron emission tomography and functional magnetic resonance imaging.

Adult↗
PubMedDate not supplied

Pharmacological analysis of conditioning in sensorimotor cortex neurons in a model.

In awake mobile rabbits, with electrodes implanted in the medial lemniscus, midbrain tegmental reticular nucleus, and pyramidal tract, combined stimulation of two brain of two brain structures resulted in elaboration of conditional connections in sensorimotor cortex neuronal populations. The main criterion of the conditioning was the appearance of changes in the neuronal activity on omission of the second stimulus. These changes represented a complex of electrical events, some of which were similar to and others different from the evoked responses to the second stimulus. Application of atropine, sulfate, chlorpromazine hydrochloride, serotonin creatinine sulfate, and gamma-aminobutyric acid (GABA) to the cortex at the site of the recording exerted a modulating effect on the conditional neuronal activity patterns. Of the above substances, GABA and atropine had the most pronounced effect. The GABA removed the short-latency components of the conditional changes which were similar to evoked responses. The atropine abolished the long-latency changes which differed from evoked responses.

Animals↗
PubMed1978

The concept of a sensorimotor cortex: its early history, with especial emphasis on two early experimental contributions by W. Bechterew.

A brief account has been given of the events during the last quarter of the nineteenth century which led to the concept of the sensorimotor cortex. An early review by Frederick Mott has served as a useful guide. Particular attention has been paid to two early startlingly prescient papers by W. Bechterew. Since, however, Bechterew changed his views in subsequent publications, he forfeited a major claim for priority, and his early papers were forgotten.

Animals↗