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Results for “sensorimotor behavior”

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PubMed2006

A conditionally immortal clonal stem cell line from human cortical neuroepithelium for the treatment of ischemic stroke.

Transplantation of neural stem cells into the brain is a novel approach to the treatment of chronic stroke disability. For clinical application, safety and efficacy of defined, stable cell lines produced under GMP conditions are required. To this end, a human neural stem cell line, CTX0E03, was derived from human somatic stem cells following genetic modification with a conditional immortalizing gene, c-mycER(TAM). This transgene generates a fusion protein that stimulates cell proliferation in the presence of a synthetic drug 4-hydroxy-tamoxifen (4-OHT). The cell line is clonal, expands rapidly in culture (doubling time 50-60 h) and has a normal human karyotype (46 XY). In the absence of growth factors and 4-OHT, the cells undergo growth arrest and differentiate into neurons and astrocytes. Transplantation of CTX0E03 in a rat model of stroke (MCAo) caused statistically significant improvements in both sensorimotor function and gross motor asymmetry at 6-12 weeks post-grafting. In addition, cell migration and long-term survival in vivo were not associated with significant cell proliferation. These data indicate that CTX0E03 has the appropriate biological and manufacturing characteristics necessary for development as a therapeutic cell line.

Analysis of Variance↗
PubMedDate not supplied

Imaging of the 5-HT2A system: age-, gender-, and Alzheimer's disease-related findings.

Serotonin (5-HT) and more specifically the 5-HT(2A) receptor is involved in cognitive and non-cognitive behavior and plays an important role in Alzheimer's disease (AD). The objective was to assess the 5-HT(2A) binding potential (BP) in healthy volunteers and AD with SPECT and 123I-5-I-R91150, a selective radio-iodinated 5-HT(2A) receptor antagonist. Twenty-six controls and nine AD patients were included. A semiquantitive analysis with normalization on cerebellar uptake provided estimates of BP for 26 cortical regions of interest. An age-related decline of neocortical BP was found (11.6% per decade). Compared to age-matched controls, a generally decreased neocortical BP in AD was found with a significant regional reduction in the orbitofrontal, prefrontal, lateral frontal, cingulate, sensorimotor, parietal inferior, and occipital region. These results are in line with previous postmortem, in vitro, and PET findings. The age-related decline highlights the necessity for matched advanced age study samples. The fact that the 5-HT(2A) receptor is differentially affected in AD patients has implications for both the etiological basis and therapeutic management of AD.

Age Factors↗
PubMed2001

Event-related beta desynchronization indicates timing of response selection in a delayed-response paradigm in humans.

Voluntary movements are preceded by event-related desynchronization (ERD) of alpha and beta activity. The present study used magnetoencephalography to investigate the relationship between motor preparation and the time course of beta ERD in a delayed response paradigm. Depending on the task, the required response (left or right finger lifting) was cued either spatially by the lateralization of a sound at trial onset, or verbally by the content of a midline auditory event. Beta ERD appeared over sensorimotor regions contralaterally to the response side about 200 ms earlier for the spatial than the verbal cue task. This suggests a close relationship between the latency of beta ERD onset and the duration of cognitive processes involved in selecting a motor response.

Acoustic Stimulation↗
PubMed1999

Neuroacanthocytosis--the variability of presenting symptoms in two siblings.

Neuroacanthocytosis is a progressive multisystem disease with a wide range of symptoms. The involuntary movements mainly include chorea and orofaciolingual dyskinesias. The descriptive name of the disease refers to the presence of abnormal erythrocytes in peripheral blood. Two siblings are presented. One young female had dystonia, self-mutilating behaviour, lip biting and eating difficulties. Her brother had repeated generalized epileptic seizures several years before developing choreatic movements and neuropsychiatric symptoms. Both had clinical signs of sensorimotor axonal polyneuropathy. Fresh blood smears in each patient contained between 15 and 20% acanthocytes compared to less than 2% in normal controls. Neuroacanthocytosis must be kept in mind in young adult patients without heredity for Huntington's disease and the diagnosis is easily confirmed when making a fresh blood smear.

Acanthocytes↗
PubMed2006

Somatosensory cortical atrophy after spinal cord injury: a voxel-based morphometry study.

The authors used voxel-based morphometry to compare sensorimotor cortical gray and white matter volume on structural MR images of a group of 17 individuals with cervical spinal cord injury (SCI) and a group of 17 healthy subjects. SCI subjects had reduced gray matter volume bilaterally in primary somatosensory cortex (p < 0.001). These findings suggest that the somatosensory cortex of the human brain atrophies after SCI.

Adolescent↗
PubMed2005

Emerging patterns of neuronal responses in supplementary and primary motor areas during sensorimotor adaptation.

Acquisition and retention of sensorimotor skills have been extensively investigated psychophysically, but little is known about the underlying neuronal mechanisms. Here we examine the evolution of neural activity associated with adaptation to new kinematic tasks in two cortical areas: the caudal supplementary motor area (SMA proper), and the primary motor cortex (MI). We investigate the hypothesis that adaptation starts at premotor areas, i.e., higher in the hierarchy of computation, until a stable representation is formed in primary areas. In accordance with previous studies, we found that adaptation can be characterized by two phases: an early phase that is accompanied by fast and substantial reduction of errors, followed by a late phase with slower and more moderate improvements in behavior. We used unsupervised clustering to separate the activity of the single cells into groups of cells with similar response patterns, under the assumption that each such subpopulation forms a functional unit. We specifically observed the number of clusters in each cortical area during early and late phases of the adaptation and found that the number of clusters is higher in the SMA during early phases of adaptation. In contrast, a higher number of clusters was observed in MI only during late phases. Our results suggest a new approach to analyze responses of large populations of neurons and use it to show a hierarchy of dynamic reorganization of functional groups during adaptation.

Adaptation, Physiological↗
PubMedDate not supplied

[Functional role of the red nucleus in the cerebral cortex-cerebellum-spinal cord communication system].

Unilateral transection of the rubrospinal tract before lesion of the red nucleus or the ventrolateral thalamic nucleus has been shown to facilitate recovery of operantly conditioned reflexes and compensatory processes in rats. Such strengthening of the recovery plasticity and operantly conditioned was found when transection of the bulbar pyramide performed before ablation of the sensorimotor cortex. These influences are explained by activation of the rubroolivary projection, which is switching of descending cortico-rubrospinal system on the corticospinal system, and on the contrary. The general property of this phenomenon is that preliminary lesion of the peripheral part of the descending spinal projection to acquire a signal forestalling significance for mibilization of compensatory brain capacity in order to recovery the deficit of central link of the system.

Animals↗
PubMed2002

Practice-dependent modulation of neural activity during human sensorimotor coordination: a functional Magnetic Resonance Imaging study.

We investigated the degree to which differences in the pattern of blood oxygen level dependent activity (BOLD) between syncopated and synchronized coordination patterns are altered by practice. Baseline levels of BOLD activity were obtained from eight subjects while they syncopated or synchronized with an auditory metronome at 1.25 Hz. Subjects then practiced syncopation at the same rate for four consecutive sessions. Post practice scans of the two coordination patterns were then performed. Before practice, baseline syncopation activated a much broader network of both cortical and subcortical regions than synchronization that included Supplementary Motor Area (SMA), bilateral putamen, left thalamus, bilateral superior temporal gyrus as well as the vermis. This pattern of activity is hypothesized to reflect the extra timing and attention requirements of syncopation. After practice, activity in superior temporal gyrus and vermis were no longer observed during syncopation reflecting a reduction in the need for attention and the use of sensory feedback for guiding behavior. Surprisingly, post practice synchronization resulted in additional significant activations in SMA, inferior frontal gyrus and superior temporal gyrus as well as small activations in bilateral putamen. Practice with the more difficult syncopation task thus had a dual effect of decreasing the number of active regions during syncopation and increasing the number of active regions during synchronization. Since overt syncopation performance did not change significantly as a result of practice, these observed neural changes appear to be due to context- and history-dependent factors, rather than behavioral learning per se.

Adult↗
PubMed1996

The estrous cycle and the olivo-cerebellar circuit. I. Contrast enhancement of sensorimotor-correlated cerebellar discharge.

Neuromodulation of Purkinje (Pnj) cell responses by monoamines and estrous hormones is well characterized in the cerebellum at the cellular level, but not at the level of neuronal circuits in the awake behaving animal. In the present study, simultaneous recordings of up to 16 single neurons from within the olivo-cerebellar circuit were obtained through chronically implanted microwire electrode bundles: arrays of Pnj cell like neurons (Pnj cln) in the paravermal cerebellum and neurons within the afferent source of its climbing fiber input, the rostral dorsal accessory olive (rDAO), were recorded simultaneously across 3-20 consecutive estrous cycles during constant or variable speed treadmill locomotion performance tasks. Over 90% of Pnj cln recorded during treadmill locomotion exhibited significant increases (80%) or decreases (10%) in activity correlated with the stance phase of locomotion. In contrast, cells from the rDAO increased activity during speed changes or when the rat failed to maintain the treadmill speed (position slip). On the night of behavioral estrus, which is triggered by elevations in circulating levels of 17 beta-estradiol and progesterone, the magnitude of both increases and decreases in stance-correlated Pnj cln activity increased by 85-115%. These results are consistent with our previous findings that 17 beta-estradiol and progesterone enhance excitatory and inhibitory responses of single Pnj cells to locally applied glutamate and GABA, respectively. This dual enhancement of both excitatory and inhibitory effects, apparently paradoxical at the cellular level, produced a marked heightening of the contrast of the neural population "signal" at the neuronal ensemble level. Furthermore, the stance-correlated discharge of Pnj cln during estrus preceded that during diestrus by approximately 120 ms. Frame-by-frame video analysis also suggested that the swing phase of the step cycle was shortened on estrus compared with diestrus (low hormone state). In addition, rDAO discharge correlated with speed change or position slip was also significantly increased (P < 0.05) on the night of behavioral estrus versus diestrus. Thus, estrus was associated with changes in both the amplitude and the timing of Pnj cln and rDAO discharge correlated with specific behavioral events. These estrous-associated changes in Pnj cell activity were well correlated (r = 0.84) with faster responses to random changes in treadmill speed, a motor performance task. Together, these findings suggest that the increases in the contrast of stance-correlated Phj cln discharge observed following peak circulating levels of sex steroid hormones are associated with improved motor performance on a randomly moving treadmill.

Animals↗
PubMed1992

Kainic acid-induced thalamic seizure in cats--a possible model of petit mal seizure.

Bipolar depth electrodes were implanted stereotaxically in the thalamus, hippocampus and midbrain reticular formation of cats. Cortical screw electrodes were placed over the bilateral sensorimotor cortex. A guide cannula with an inner injection cannula was inserted unilaterally into the posterolateral ventral nuclei (VPL) of the thalamus. Eight days after the procedures, kainic acid (2.0 micrograms) was injected unilaterally into the VPL via the injection cannula in freely moving animals and electro-clinical observations were made. About 1 h after the kainic acid injection, multiple spikes were observed in the VPL (injection site), which propagated to the subcortical structures. These seizures finally propagated bilaterally to the cortex about 2 h after the injection. About 3-4 h after the injection, small spike and wave complexes repeatedly appeared for a short period of time in cortical leads and cats exhibited behavioral arrest with unresponsiveness during the seizures. About 24 h after the injection, generalized small spike and wave complexes were observed intermittently in cortical and subcortical structures. They persisted for 4-5 s and were associated with behavioral arrest and staring. The results demonstrate that a unilateral microinjection of kainic acid into VPL induced petit mal-like seizure, and suggest that VPL plays an important role in the generation or transfer of spike and wave complexes.

Animals↗
PubMed2001

Event-related dynamics of cortical rhythms: frequency-specific features and functional correlates.

Oscillations in the alpha and beta band (<35 Hz) display a dynamic behavior and show characteristic spatiotemporal patterns in sensory, motor and cognitive tasks. The event-related desynchronization (ERD) of alpha band and beta rhythms can be seen as a correlate of an activated cortical area with an increased excitability level of neurons. An event-related synchronization (ERS) of frequency components between 10 and 13 Hz may represent a deactivated cortical area or inhibited cortical network, at least under certain circumstances. It is hypothesized, that antagonistic ERD/ERS patterns, called 'focal ERD/surround ERS', may reflect a thalamo-cortical mechanism to enhance focal cortical activation by simultaneous inhibition of other cortical areas. Induced oscillations in the beta band (13-35 Hz, beta ERS) were found in sensorimotor areas after voluntary movement and after somatosensory stimulation. This may be interpreted as a state of 'inhibition' of neural circuitry in the primary motor cortex. Simultaneous activation of the motor cortex by e.g. motor imagery lead to an attenuation of the beta ERS. Moreover, there is evidence that the frequency of the induced beta oscillations represent a 'resonance-like frequency' of underlying cortical networks. However, further research is needed to investigate the functional meaning of bursts of beta oscillations below 35 Hz.

Alpha Rhythm↗
PubMed2007

Influence of body segment position during in-phase and antiphase hand and foot movements: a kinematic and functional MRI study.

Behavioral studies have provided important insights into the mechanisms governing interlimb coordination. In this study, we combined kinematic and functional magnetic resonance imaging (fMRI) analysis to investigate the brain cortical and subcortical areas involved in interlimb coordination and the influence of direction of movement and of body segment position on the activity of those areas. Fifteen right-handed healthy subjects were studied while performing cyclic in-phase and antiphase hand and foot movements with the dominant, right limbs, with the upper limb positioned either prone or supine, and in front or behind with respect to the trunk. When contrasting antiphase to in-phase movements, fMRI analysis demonstrated an increased recruitment of a widespread sensorimotor network (including regions in the frontal and parietal lobes, bilaterally, the cingulated motor area, the thalami, the visual cortex, and the cerebellum) considered to function in motor, sensory, and multimodal integration processing. When contrasting the anterior to the posterior position of the upper limb with respect to the trunk, we found different recruitment patterns in the frontal and parietal regions as well as the preferential recruitment of the basal ganglia, the insula, and the cerebellum during the first condition and of regions located in the temporal lobes during the second one. Different brain areas are engaged at a different extent during interlimb coordination. In addition to the relative difficulty of the movement, the different cognitive and sensorial loads needed to control and perform the motor act might be responsible for these findings.

Adult↗
PubMed1996

The septohippocampal system is involved in prepulse inhibition of the acoustic startle response in rats.

Prepulse inhibition (PPI) of the acoustic startle response (ASR) can be used as an operational measure for brain mechanisms that prevent disruption of ongoing stimulus processing routines by other stimuli and that thereby avoid behavioral interference. Deficient PPI has been observed in schizophrenics; therefore, much interest has been devoted to the understanding of the neural basis of PPI. This study investigated the role of the septohippocampal system in the modulation of PPI in rats. Stimulation of the medial septum by injection of the glutamate agonist kainate led to a profound disturbance of PPI and reduced the ASR amplitude. The PPI deficit induced by intraseptal kainate was attenuated by systemic or intrahippocampal administration of the acetylcholine antagonist scopolamine. Lesions of the medial septum, made by the neurotoxin AMPA, did not affect PPI. The present data indicate that activation of the septohippocampal system reduces PPI of the ASR, suggesting its role in sensorimotor gating.

Animals↗
PubMed1975

[Three basic kinds of behaviour, a scheme of their neurobiological correlates (author's transl)].

The psychic sphere is to be regarded as the source of meaningful behaviour, which is carried out in the service of the cell community that makes up our body. Three fundamental types of behaviour can be distinguished: the purely practical, the theoretical-practical, and the purely theoretical. These three types of behaviour have three different reasons: the first a determining reason, the second a motivating reason, and the third a supporting reason. The threefold nature of the reasons is related to the threefold needs of the cell community (in this context man is considered as an example of an animal). Possible neurobiological bases of human behaviour are depicted in a schematic figure showing the relation of cerebral centres and sensorimotor functions of the human face including eye movements. The psychic centre may be located in the thalamus, the areas of the central sulcus are regarded as an objectivation zone. This indicates that the motor zones of the cortex, including the frontal adversive fields, are intention zones, and the sensory zones reproduction, expectation, and recollection zones. A system so composed would render possible what we see in every animal being: decision-making, foresight, and learning.

Behavior↗
PubMed1996

Effect of intraventricular injections of dihydro-beta-erythroidine (DH beta E) on spatial memory in the rat.

The analysis of the behavioral effect of the nicotinic acetylcholine receptor (nAChR) antagonists has been generally based on drugs which act at the associated ion channel. In contrast dihydro-beta-erythroidine (DH beta E) is a competitive antagonist at the nAChR. Using rats, DH beta E was injected intraventricularly prior to training in two spatial tests, the Morris Water Maze and a Win-Stay radial maze. In addition DH beta E 300 nmol was used to reverse the effect of (-)-nicotine on locomotor activity. In the Morris Water Maze DH beta E (300 nmol) disrupted memory of the platform location as measured by crosses of the area in a probe trial. At 300 nmol DH beta E showed no sensorimotor effects in a visible platform test. In the Win-Stay task there was a significant, dose dependent disruption of spatial memory. A dissociation of nicotine's effects on locomotor activity was observed, in that DH beta E 300 nmol was able to significantly attenuate (-)-nicotine enhancement of horizontal motor activity, but did not affect the initial reduction of vertical activity. Nicotinic processing of memory appears to be involved in these tests of spatial memory.

Animals↗
PubMed2000

CNS plasticity and assessment of forelimb sensorimotor outcome in unilateral rat models of stroke, cortical ablation, parkinsonism and spinal cord injury.

We have reviewed a battery of useful tests for evaluating sensorimotor function and plasticity acutely and chronically in unilateral rat models of central nervous system injury. These tests include forelimb use for weight shifting during vertical exploration in a cylindrical enclosure, an adhesive removal test of sensory function, and forelimb placing. These tests monitor recovery of sensorimotor function independent of the extent of test experience. Data are presented for four models, including permanent focal ischemia, focal injury to the forelimb area of sensorimotor cortex, dopaminergic neurodegeneration of the nigrostriatal system, and cervical spinal cord injury. The effect of the dendrite growth promoting factor, Osteogenic Protein-1 (OP-1) on outcome following permanent middle cerebral artery (MCA) occlusion was used as an example to illustrate how the tests can be applied preclinically. OP-1 showed a beneficial effect on limb use asymmetry in the cylinder test.

Animals↗
PubMed1993

Non-organic failure to thrive: growth failure secondary to feeding-skills disorder.

In this article the authors propose that non-organic failure to thrive (FTT) is a growth failure secondary to feeding-skills disorder, and that this disorder is neurophysiological in origin. The symptoms of feeding-skills disorder were suggestive of an oral sensorimotor impairment which is usually present from birth or early life, but tends to go unrecognized. Data from 38 infants with non-organic and 22 infants with organic FTT demonstrated that early clinical symptoms of feeding impairment, and observed maternal and infant feeding behaviours and interactions, were similar for both groups, suggesting a need to redefine the term 'non-organic'.

Anthropometry↗
PubMed2004

A new model of sensorimotor coupling in the development of speech.

We present a computational model that learns a coupling between motor parameters and their sensory consequences in vocal production during a babbling phase. Based on the coupling, preferred motor parameters and prototypically perceived sounds develop concurrently. Exposure to an ambient language modifies perception to coincide with the sounds from the language. The model develops motor mirror neurons that are active when an external sound is perceived. An extension to visual mirror neurons for oral gestures is suggested.

Artificial Intelligence↗