PubMed · 6740116
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A Mathis, A M Bourdiol, J M Muratet, P Bec. [Visual potentials evoked by pattern reversal].. https://pubmed.ncbi.nlm.nih.gov/6740116/
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The hemodynamic response to functional activation can be regarded as the convolution of the neuronal response with an unknown kernel. As such, it introduces an intrinsic blurring that limits the attainable temporal resolution of functional magnetic resonance (fMR) techniques. This study demonstrates that by measurement of displacements in activation onsets between different types of trial, it is nevertheless possible to obtain a subsecond temporal accuracy in fMR. A single trial stimulation paradigm was adopted: a simple search task embedded in a longer period of visual flicker stimulation that produced reliable activations in the primary visual cortex and supplementary motor area. Data were acquired from both of these regions using double voxel functional spectroscopy.
A 50-year-old woman with human T-lymphotropic virus type 1-associated myelopathy developed sudden loss of vision in her left eye. The patient had a relative afferent pupillary defect and a large central scotoma on visual field examination, but no abnormal findings were apparent upon slitlamp microscopy and funduscopic examination. A diagnosis of retrobulbar optic neuritis was made. We discuss the possible association of human T-lymphotropic virus type 1 infection.
Retrobulbar neuritis is a common clinical manifestation of multiple sclerosis. We evaluated and compared the results of visual field and fundus examinations, visual evoked response and nuclear magnetic resonance of the brain in 37 patients with the diagnosis of multiple sclerosis and retrobulbar neuritis. Diffuse, peripheral scotomas seemed to be the most often found scotomas on perimetry in these patients. In contrary, central scotomas formed just a little part of the visual field defects. Each threshold increasing of 0.10 log. units on perimetry was followed by increased latencies of 2.5 ms. Each other central scotoma on perimetry decreased the visual acuity of the patient for 1.6 lines on the Snellen chart. The central visual field examination without periphery in the patients with multiple sclerosis and retrobulbar neuritis seems to give false negative results.