Sensory System Abnormalities Research Articles

The role of sensory information in the pathophysiology of focal dystonias.

Over the past few decades, abnormalities in sensory functions, such as tactile, proprioceptive and nociceptive processing, have been increasingly recognized in patients with focal dystonias. In this Review, we ask whether sensory system abnormalities are specific to particular types of dystonia, whether a causal link exists between sensory alterations and dystonic motor activity and how mechanisms underlying the sensory abnormalities fit in with the proposed 'network model' of dystonia. We suggest that alterations in the various sensory modalities participate at three different levels in the pathophysiological cascade that leads to dystonia: a background level that predisposes individuals to dystonia, a disease-related level that is evident only when dystonia becomes manifest and a causative level that triggers dystonia. We conclude that it is crucial to study sensory as well as motor pathophysiology to fully understand focal dystonias.

SEM Study on Morphological Changes in <I>Metarhizium anisopliae</I> Infected <I>Aphis craccivora</I> Koch.

Morphological changes in Metarhizuim anisopliae (Metschnikoff) Sorokin infected cow pea aphid, Aphis craccivora Koch were studied by scanning electron microscope (SEM). Aphids were caged on paired lantern chimney over cowpea twigs dipped in conical flasks with water infected and inoculated with fungal propagules of M. anisopliae at the concentration of 1X10 6 spores /ml of water. Infected aphids were observed under SEM and it showed severe cuticular damage, abnormalities in sensory systems as well as deformation of all the body parts. The hydrophobic conidia of M. anisopliae were found to attach to all body regions. It was evident that mycelial growth and conidiophores with conidia of M. anisopliae covered the body surface and penetrates inside the body of infested aphid causing damage to the pest by disturbing its major physiological activities leading to its death.

SEM Study on Morphological Changes in <I>Metarhizium anisopliae</I> Infected <I>Aphis craccivora</I> Koch.

Morphological changes in <em>Metarhizuim anisopliae</em> (Metschnikoff) Sorokin infected cow pea aphid, <em>Aphis craccivora</em> Koch were studied by scanning electron microscope (SEM). Aphids were caged on paired lantern chimney over cowpea twigs dipped in conical flasks with water infected and inoculated with fungal propagules of <em>M. anisopliae</em> at the concentration of 1X10<sup>6</sup> spores /ml of water. Infected aphids were observed under SEM and it showed severe cuticular damage, abnormalities in sensory systems as well as deformation of all the body parts. The hydrophobic conidia of <em>M. anisopliae</em> were found to attach to all body regions. It was evident that mycelial growth and conidiophores with conidia of <em>M. anisopliae</em> covered the body surface and penetrates inside the body of infested aphid causing damage to the pest by disturbing its major physiological activities leading to its death.

Spectral domain optical coherence tomography for detection of foveal morphology in patients with nystagmus

To evaluate the feasibility of spectral domain optical coherence tomography (SD-OCT) macular scanning as a means of studying the afferent visual system in nystagmus patients. Nystagmus patients who underwent SD-OCT, clinical evaluation, and eye movement recordings were recruited for this prospective, single-center, noncomparative study. Three SD-OCT macular three-dimensional cube scans per eye (200 x 200 x 1024 samplings in a 6 x 6 mm region) were obtained for qualitative retinal morphology analysis. Nineteen patients (6-68 years; average, 19 years) were analyzed. Of these, 17 patients had infantile nystagmus syndrome, and 2 had fusion maldevelopment nystagmus; 17 patients (89%) had associated sensory system abnormalities, including 9 (47%) with albinism. Macular images were successfully obtained in all but 1 patient (95%). Of the 8 successfully imaged oculocutaneous patients, 7 patients demonstrated "fovea plana," and all demonstrated abnormal morphology. SD-OCT reliably provides detailed structural imaging of the fovea in nystagmus patients.

Trauma‐induced spinal vascular event producing hemipseudoathetosis

We report on a patient with spinal pseudoathetosis secondary to posterior column vascular incident and physical injury. This unusual case highlights sensory system abnormalities as a cause of movement disorders.

Sensory stimulation accelerates dopamine release in the basal ganglia

We report herein the modulation of dopamine release in the basal ganglia during peripheral electrical stimulation in animals. The endogenous dopamine release during electrical stimulation was measured in anesthetized cats by positron emission tomography (PET) using the D2 receptor agonist [ 11C]-raclopride. Binding potential (BP) parametric maps were calculated using a simplified reference region model. The regional dopamine release evoked by electrical stimulation was estimated both by region of interest (ROI) analysis and statistical parametric mapping (SPM 99). Both ROI analysis and statistical parametric mapping showed significant release of endogenous dopamine in the nucleus accumbens and the striatum contralateral to the stimulated side as compared to the resting condition as well as the ipsilateral side. Accordingly, we suggest that the activity of the dopaminergic neurons in the midbrain projecting to the nucleus accumbens and the striatum is modulated by the input from the afferent nerves. This provides an in vivo evidence for the importance of the basal ganglia in the processing of peripheral information required for normal movement. This may also explain the clinically observed sensory system abnormalities in patients with movement disorders.

Clinical and ocular motor analysis of congenital nystagmus in infancy

Purpose: The purpose of this study was to identify the clinical and ocular motility characteristics of congenital nystagmus and to establish the range of waveforms present in infancy. Background: The clinical condition of congenital nystagmus usually begins in infancy and may or may not be associated with visual sensory system abnormalities. Little is known about its specific waveforms in infancy or their relationship to the developing visual system. Methods: Forty-three infants with involuntary ocular oscillations typical of congenital nystagmus were included in this analysis. They were evaluated both clinically and with motility recordings. Eye movement analysis was performed off line from both chart recordings and computer analysis of digitized data. Variables analyzed included age, sex, vision, ocular abnormalities, head position, null-zone or neutral-zone characteristics, symmetry, conjugacy, waveforms, frequencies, foveation times, and responses to convergence and to monocular cover. Results: Patient ages ranged from 3 to 18 months (average, 9.2 months). Seventeen patients (40%) had abnormal vision, 3 had a positive family history of nystagmus, 11 had strabismus, 16 (37%) had a head posture, 26 (60%) had null and neutral positions, 14 (33%) had binocular asymmetry, and all were horizontally conjugate. Average binocular frequency was 2.8 Hz, and average monocular frequency was 4.6 Hz. The waveforms were both jerk and pendular; average foveation periods in patients with normal vision were more than twice as long as those in patients with abnormal vision. Conclusions: Common clinical characteristics and eye-movement waveforms of congenital nystagmus begin in infancy, and waveform analysis at this time helps with both diagnosis and visual status. (J AAPOS 1999;3:70-9)

Electrophysiological evidence of sensory system abnormalities in progressive spinal muscular atrophy (SMA): [formula omitted] and E. Orzeszko (EMG Lab. Child Health Centre, Warsaw, Poland)

Electrophysiological evidence of sensory system abnormalities in progressive spinal muscular atrophy (SMA): [formula omitted] and E. Orzeszko (EMG Lab. Child Health Centre, Warsaw, Poland)