Search results for " Somatosensory"
showing 10 items of 71 documents
Abnormal Somatosensory Evoked Potentials Indicate Compressive Cervical Myelopathy in Mucopolysaccharidoses
2000
Compressive myelopathy at the cranio-cervical junction is a complication of mucopolysaccharidoses (MPS). To detect cervical myelopathy we recorded median and posterior tibial nerve SEPs in 15 patients aged 2.4 - 33.4 years (median 8.8 years) with MPS I-S (n = 3), MPS IVA (n = 8) and MPS VI (n = 4). In addition to the cortical waveforms we recorded the subcortical median nerve SEPs N13b and P13 generated near the cranio-cervical junction and the lemniscal P30 after posterior tibial nerve stimulation. MRI studies in 13 subjects revealed spinal cord compression at the cranio-cervical junction in 10 patients; 5 patients had an increased signal intensity on the T2-weighted initial MRI indicating…
DEGENERATIVE CERVICAL MYELOPATHY: REVIEW OF SURGICAL OUTCOME PREDICTORS AND NEED FOR MULTIMODAL APPROACH
2020
Degenerative cervical myelopathy is the most common cause of spinal cord injury in the elderly population in the developed world, and it significantly affects the quality of life of patients and their caregivers. Surgery remains the only treatment option able to halt disease progression and provide neurological recovery for most patients. Although it has remained challenging to predict exactly who will experience improvement after surgery, increasingly it has been shown that clinical, imaging, and electrophysiological factors can predict, with relatively good capacity, those more likely to benefit. Clinically, the baseline neurological impairment appears to be strongly related to the outcom…
Activity in the rabbit somatosensory cortex reflects the active procedural memory trace of a classically conditioned eyeblink response.
2003
Behavioral responses and neural responses in the somatosensory cortex were recorded in nine rabbits during the unpaired and paired treatments of classical eyeblink conditioning with a tone conditioned stimulus (CS) and an airpuff unconditioned stimulus. During the unpaired treatment, neither the behavioral nor neural responses to the CS were observed. During the paired treatment, behavioral conditioned response (CR), accompanied by neural activity, was developed. In well-trained animals occasional failures to elicit the CR were accompanied by an absence of neural responses. Nevertheless, the CS modified the behavioral unconditioned response in paired trials, implying that the CR-failures co…
Spinothalamic and thalamocortical nociceptive pathways
2002
The concept that the perception of a stimulus as being painful requires activity in parts of the cerebral cortex has gained universal recognition within the past 10 years. 28 The large number of functional imaging studies in humans, appearing during that period, have greatly contributed to this development by showing consistent evidence for activation of various cortical areas by painful stimuli, including the primary and secondary somatosensory cortex, the insula, the anterior cingulate gyrus, and prefrontal cortical areas. Thus, the sense of pain—like all other senses— has a representation within the cerebral cortex. These imaging studies, however, did not reveal the pathways by which a p…
Effects of a small acute subdural hematoma following traumatic brain injury on neuromonitoring, brain swelling and histology in pigs.
2011
An acute subdural hematoma (ASDH) induces pathomechanisms which worsen outcome after traumatic brain injury, even after a small hemorrhage. Synergistic effects of a small ASDH on brain damage are poorly understood, and were studied here using neuromonitoring for 10 h in an injury model of controlled cortical impact (CCI) and ASDH. Pigs (n = 32) were assigned to 4 groups: sham, CCI (2.5 m/s), ASDH (2 ml) and CCI + ASDH. Intracranial pressure was significantly increased above sham levels by all injuries with no difference between groups. CCI and ASDH reduced ptiO<sub>2</sub> by a maximum of 36 ± 9 and 26 ± 11%, respectively. The combination caused a 31 ± 11% drop. ASDH alone and i…
Magnetoencephalography Responses to Unpredictable and Predictable Rare Somatosensory Stimuli in Healthy Adult Humans
2021
Mismatch brain responses to unpredicted rare stimuli are suggested to be a neural indicator of prediction error, but this has rarely been studied in the somatosensory modality. Here, we investigated how the brain responds to unpredictable and predictable rare events. Magnetoencephalography responses were measured in adults frequently presented with somatosensory stimuli (FRE) that were occasionally replaced by two consecutively presented rare stimuli [unpredictable rare stimulus (UR) and predictable rare stimulus (PR); p = 0.1 for each]. The FRE and PR were electrical stimulations administered to either the little finger or the forefinger in a counterbalanced manner between the two conditio…
Bodily self-relatedness in vicarious touch is reflected at early cortical processing stages.
2019
Studies have suggested that there is a strong link between the bodily self and the mechanisms underlying vicarious representations. Here, we used somatosensory ERPs to investigate the temporal dynamics of vicarious touch for stimuli that are more or less related to one's own body (human hands vs. rubber gloves). We found that vicarious touch effects were restricted to self-relatable events (human hands) at early implicit stages of somatosensory processing (P45). At later more cognitive stages of processing (late positive complex, LPC), the vicarious touch effect was stronger for self-relatable events (touch on human hands) than nonself-relatable events (touch on rubber gloves) but present f…
Evoked potential study in facio-scapulo-humeral muscular dystrophy.
1997
Nerve conduction velocities (NCVs), somatosensory (SEPs) and auditory evoked potentials (BAEPs) were recorded in 9 patients with facio-scapulo-humeral dystrophy (FSHD) and in 20 age-matched controls. In FSHD patients a significant increase of the nerve distal sensory latencies and of the absolute SEP latencies revealed a subclinical involvement of the afferent sensory pathways, as well as the abnormal slowing of the later components of the BAEPs, pointed to a central auditory dysfunction. Moreover all patients underwent brain MRI that showed the presence of white matter hyperintense lesions in 4 of them (44%). No correlations were found between individual or total number of SEP and BAEP abn…
Cerebral activation in patients with somatoform pain disorder exposed to pain and stress: an fMRI study.
2006
Patients with somatoform pain disorders are supposed to suffer from an early acquired defect in stress regulation. In order to look for common alterations of the pain- and stress-responsive cortical areas, we prospectively recorded cerebral activations induced by pin-prick pain, by cognitive stress and emotional stress using functional magnetic resonance imaging (fMRI) in a group of 17 patients and an age-matched control group. In addition, the hippocampal volumes of both groups were measured. Patients showed increased activations of the known pain-processing areas (thalamus, basal ganglia, operculo-insular cortex), but also of some prefrontal, temporal and parietal regions during first pai…
Cortical representation of saccular vestibular stimulation: VEMPs in fMRI
2006
Short tone bursts trigger a vestibular evoked myogenic potential (VEMP), an inhibitory potential which reflects a component of the vestibulocollic reflex (VCR). These potentials arise as a result of activation of the sacculus and are expressed through the vestibulo-collic reflex (VCR). Up to now, the ascending projections of the sacculus are unknown in humans, only the representation of the semicircular canals or the entire vestibular nerve has been demonstrated. The aim of this study was to determine whether a sacculus stimulus that evoked VEMPs could activate vestibular cortical areas in fMRI. To determine this, we studied the differential effects of unilateral VEMP stimulation in 21 heal…