Humans ; Pruritus ; Somatosensory Cortex ; Spinal Cord

Hemichorea is caused by various diseases but stroke is the most common cause. The usual lesions of the stroke related hemichorea are the contralateral subthalamus or basal ganglia. Few cases with cortical lesion have been reported. But hemichorea with primary somatosensory cortical lesion has not yet been reported. We report a case with hemichorea after acute infarction of the contralateral primary somatosensory cortex.
Basal Ganglia ; Cerebral Infarction ; Chorea ; Infarction ; Somatosensory Cortex ; Stroke ; Subthalamus

Neural network plasticity is fundamental for learning and memory. Its abnormal change underlies some neural diseases. Measurement of the plasticity of cortex can help understand the mechanism of plasticity, and provide a quantitative way to observe the neural process of natural aging and neurodegenerative diseases, which may lead to a new approach for evaluation of anti-aging drugs and new medical treatments for neurodegenerative diseases. In this study, a systematic method was established based on whisker pairing (WP) experiment to measure the network plasticity in the barrel cortex in rat. WP experiment is a classical experiment to study the effect of innocuous bias of the flow of sensory activity from the whiskers for certain periods in awake and behaving rats on the receptive field organization in S1 barrel cortex neurons. In the experiment, one pair of adjacent whiskers D2 and D3 remained intact while others were being trimmed throughout a certain period. After that, receptive fields of single cells in the contralateral barrel were analyzed by post-stimulus time histogram after certain days of WP and compared with the controls. In the control group, response magnitudes to surrounding whiskers D1 and D3 deflection were not significantly different. However, after WP, a bias occurred in response to paired surrounding whisker D3 relative to the opposite trimmed surrounding whisker D1. In this study, by comparing the bias degree in rats in different groups after WP, a quantitative method was established to compare cortical plasticity. Example of corical plasticity comparison between adolescent and mature rats was employed in this paper to illustrate our method. The key techniques of this method such as the identification of D2 barrels, supragranular (L2-3) and barrel layer (L4) in real-time were described in details. The feasibility of this approach was further verified by compendious report of results and our previous study regarding cortical plasticity comparison between adolescent and mature rats.
Animals ; Neuronal Plasticity ; Rats ; Somatosensory Cortex ; physiology ; Vibrissae

This study was aimed to clarify the change of neuropeptide Y -immunoreactive (NPY -IR) and NADPH -diaphorase (NADPH -d)-positive neurons associated with aging of ICR and C57Bl/6 mice. To verify the effect of aging on NPY and NADPH -d neurons in the cerebral cortex, the tissues were stained by the immunohistochemical and histochemical method. The coexistence of NADPH -d and NPY was found in the cerebral cortex of the ICR and C57Bl/6 mice. The 30 -week -old ICR mice showed a significant increase in the number of NPY - IR neurons in comparison with the 5 -week -old mice in primary motor, secondary somatosensory, ectorhinal, auditory and visual cortex. In the 30 -week -old C57Bl/6 mice, the number of NPY -IR neurons was significantly increased in primary and secondary somatosensory cortex, decreased in retrosplenial and visual cortex compared to the 5 -week -old group. However, the number of NPY -IR/NADPH -d positive neurons of ICR mice was no significant changes in most cerebral cortical areas except insular and perirhinal cortex in the 30 week -old group in comparison with 5 -week -old group of both mice group. The number of coexisted neurons of 30 -week -old C57Bl/6 mice was significantly decreased in primary motor and auditory cortex compared to the 5 -week - old group. These results provides the morphological evidence for the change of NPY -IR neurons that do not contain NADPH -d may be more susceptible to age -related change than NADPH -d -containing neurons in the cerebral cortex of mice.
Aging ; Animals ; Auditory Cortex ; Cerebral Cortex* ; Mice* ; Mice, Inbred ICR ; NADP ; Neurons* ; Neuropeptide Y ; Neuropeptides* ; Somatosensory Cortex ; Visual Cortex

PURPOSE: Prenatal environmental conditions affect the development of the fetus. In the present study, we investigated the effects of exposure to music and noise during pregnancy on neurogenesis and thickness in the motor and somatosensory cortex of rat pups. METHODS: The pregnant rats in the music-applied group were exposed to 65 dB of comfortable music for 1 hour, once per day, from the 15th day of pregnancy until delivery. The pregnant rats in the noise-applied group were exposed to 95 dB of sound from a supersonic sound machine for 1 hour, once per day, from the 15th day of pregnancy until delivery. After birth, the offspring were left undisturbed together with their mother. The rat pups were sacrificed at 21 days after birth. RESULTS: Exposure to music during pregnancy increased neurogenesis in the motor and somatosensory cortex of rat pups. In contrast, rat pups exposed to noise during pregnancy showed decreased neurogenesis and thickness in the motor and somatosensory cortex. CONCLUSIONS: Our study suggests that music and noise during the developmental period are important factors influencing brain development and urogenital disorders.
Animals ; Brain ; Fetus ; Humans ; Mothers ; Motor Cortex ; Music ; Neurogenesis ; Noise ; Parturition ; Pregnancy ; Rats ; Somatosensory Cortex

Absence seizures (AS) are generalized non-convulsive seizures characterized by a brief loss of consciousness and spike-and-wave discharges (SWD) in an electroencephalogram (EEG). A number of animal models have been developed to explain the mechanisms of AS, and thalamo-cortical networks are considered to be involved. However, the cortical foci have not been well described in mouse models of AS. This study aims to use a high density EEG in pathophysiologically different AS models to compare the spatiotemporal patterns of SWDs. We used two AS models: a pharmacologically induced model (gamma-hydroxybutyric acid, GHB model) and a transgenic model (phospholipase beta4 knock-out, PLCβ4 model). The occurrences of SWDs were confirmed by thalamic recordings. The topographical analysis of SWDs showed that the onset and propagation patterns were markedly distinguishable between the two models. In the PLCβ4 model, the foci were located within the somatosensory cortex followed by propagation to the frontal cortex, whereas in the GHB model, a majority of SWDs was initiated in the prefrontal cortex followed by propagation to the posterior cortex. In addition, in the GHB model, foci were also observed in other cortical areas. This observation indicates that different cortical networks are involved in the generation of SWDs across the two models.
Animals ; Electroencephalography ; Epilepsy, Absence ; Frontal Lobe ; Mice ; Models, Animal ; Prefrontal Cortex ; Seizures ; Somatosensory Cortex ; Unconsciousness

Adult ; Aged ; Aging ; physiology ; Evoked Potentials, Somatosensory ; physiology ; High-Frequency Ventilation ; Humans ; Middle Aged ; Somatosensory Cortex ; physiology

Nitric oxide is synthesized by cells containing the nitric oxide synthase (NOS), and NADPH-diaphorase (NADPH-d) is a selective histochemical marker for the NOS in the brain. The influence of feeding rats only half the amount of their normal daily intake of a purified diet on NOS was measured in the cerebral cortex by immunohistochemistry and NADPH-d histochemistry. iNOS was not detected in the cerebral cortex of control group. iNOS-positive neurons were induced in the cerebral cortex at 1 week after food restriction and found in specific cortical areas, such as primary motor cortex, secondary motor cortex, primary somatosensory cortex, secondary somatosensory cortex, parietal association cortex, auditory cortex, visual cortex, temporal association cortex and retrosplenial cortex. At 2 weeks after food restriction, iNOS-positive neurons were not found in all cortical areas. At 4 weeks after food restriction, iNOS-positive neurons were found in ectorhinal cortex and perirhinal cortex. In samples obtained 3 days after food restriction, the staining intensity of NADPH-d-positive neurons was decreased in most cortrical regions compared to the control group. At 1 week after food restriction, the staining intensity of NADPH-d was significantly increased in isocortical regions compared to the control group. At 9 weeks after food restriction, the staining intensity of NADPH-d was significantly decreased in all cortical regions. NO, a free radical synthesized in the brain by NOS, is a messenger molecule that mediates vascular dilatation and neural transmission. Therefore, neurons showing induced iNOS-positivity and upregulated NADPH-d-positive neurons may affect the neuronal activity in the cerebral cortex after food restriction.
Animals ; Auditory Cortex ; Brain ; Cerebral Cortex* ; Diet ; Dilatation ; Immunohistochemistry ; Motor Cortex ; Neurons* ; Nitric Oxide Synthase ; Nitric Oxide* ; Rabeprazole ; Rats* ; Somatosensory Cortex ; Synaptic Transmission ; Visual Cortex

PURPOSE: The ascending reticular activating system (ARAS) is responsible for regulation of consciousness. In this study, using diffusion tensor imaging (DTI), we attempted to reconstruct the thalamocortical projections between the intralaminar thalamic nuclei and the frontoparietal cortex in normal subjects. METHODS: DTI data were acquired in 24 healthy subjects and eight kinds of thalamocortical projections were reconstructed: the seed region of interest (ROI) - the intralaminar thalamic nuclei and the eight target ROIs - the medial prefrontal cortex, dorsolateral prefrontal cortex, ventrolateral prefrontal cortex, orbitofrontal cortex, premotor cortex, primary motor cortex, primary somatosensory cortex, and posterior parietal cortex. RESULTS: The eight thalamocortical projections were reconstructed in each hemisphere and the pathways were visualized: projections to the prefrontal cortex ascended through the anterior limb and genu of the internal capsule and anterior corona radiata. Projections to the premotor cortex passed through the genu and posterior limb of the internal capsule and middle corona radiata; in contrast, projections to the primary motor cortex, primary somatosensory cortex, and posterior parietal cortex ascended through the posterior limb of the internal capsule. No significant difference in fractional anisotropy, mean diffusivity, and fiber volume of all reconstructed thalamocortical projections was observed between the right and left hemispheres (p>0.05). CONCLUSION: We reconstructed the thalamocortical projections between the intralaminar thalamic nuclei and the frontoparietal cortex in normal subjects. We believe that our findings would be useful to clinicians involved in the care of patients with impaired consciousness and for researchers in studies of the ARAS.
Anisotropy ; Brain* ; Cerebral Cortex* ; Consciousness ; Diffusion Tensor Imaging ; Extremities ; Healthy Volunteers ; Humans* ; Internal Capsule ; Intralaminar Thalamic Nuclei* ; Motor Cortex ; Parietal Lobe ; Prefrontal Cortex ; Somatosensory Cortex ; Thalamus

OBJECTIVETo investigate the change of behavior, as well as the plasticity of somatosensory cortex after whisker trimming.

METHODSSD rats were divided into 4 groups. Group A is the normal control group; group B: bilateral vibrissotomy on the second postnatal day; group C: unilateral right vibrissotomy on the second postnatal day; group D: right unilateral whisker trimmed during 1-5 days after birth, and leave untreated after the 5th postnatal day. Their body weight, length of the left D2 whiskers was measured on the 30th postnatal day. At the same time, the changes of their behavior (including the slit-detection test, the home exploring behavior and thigmotaxis test) were also recorded on the 30th postnatal day. Cytochrome oxydase histochemistry (CO reaction)was applied to study the development and arrangement of barrel cortex.

RESULTSIn the slit-detection test, control rats could find and get into the right slit very quickly. The rats in group B could get into the slit only if their noses touched the slit. The rats in group C couldn't identify the slit by right face, but if they turned their body and touched the slit with the left whiskers, they could get into the slit very quickly. The behavior of rats in group D was similar to that in group C. The time spent for finding out the right slit of the rats in group A, B, C was obviously longer than that of group A (P < 0.01, P < 0.05, P < 0.01). In the exploring behavior and thigmotaxis test, the time for left thigmotaxis, right thigmotaxis and total thigmotaxis of rats in group B was longer than that of control animals. The time for right thigmotaxis of group C was significantly shorter than that of group A (P < 0.05). Both the weight of the rats and the length of left D2 whiskers of rats in all the four groups had no significant difference. CO reaction showed that the barrels became smaller, the septum was not clear, the arrangement of the barrels was not tidy in the mice whose right whiskers were trimmed from 2-30 days after birth.

CONCLUSIONDeafferentation doesn't change the body weight and length of the whiskers left. But the stimulation of whiskers is important for rodent especially in thigmotaxis and exploring behavior. Deafferentation can also induce the plastic change of barrel cortex.

Animals ; Animals, Newborn ; Cerebral Cortex ; physiology ; Male ; Neuronal Plasticity ; Physical Stimulation ; Rats ; Rats, Sprague-Dawley ; Somatosensory Cortex ; physiology ; Vibrissae