Cortical synchronization and narrow-band oscillatory (ca. 18-45 Hz) responses to foveal pattern-reversal stimulation in man

1997 ◽  
Vol 103 (1) ◽  
pp. 145
Author(s):  
L Lopez
Keyword(s):  
Narrow Band ◽  
Pattern Reversal ◽  
Pattern Reversal Stimulation

Primary Presenile Dementia: The Use of the Visual Evoked Potential as a Diagnostic Indicator

1985 ◽  
Vol 147 (5) ◽  
pp. 532-539 ◽  
Author(s):  
Graham F. A. Harding ◽  
Christine E. Wright ◽  
Arnold Orwin
Keyword(s):  
Visual Evoked Potential ◽  
Evoked Potential ◽  
Cortical Atrophy ◽  
Control Group ◽  
Pattern Reversal ◽  
Presenile Dementia ◽  
The Difference ◽  
Pattern Reversal Stimulation ◽  
Diagnostic Indicator ◽  
Visual Evoked

The use of the flash and pattern reversal visual evoked potential (VEP) in the diagnosis of primary presenile dementia was investigated. The results from 20 patients with primary presenile dementia were compared with those from a control group of normals of equivalent age and from a control group of 20 patients with cortical atrophy but no dementia. Presenile dementia caused a slowing of the major positive (P2) component of the VEP to flash stimulation. However, the VEP to pattern reversal stimulation (P100) was of normal latency. The difference between these two latencies characterises this unusual combination of results and is found to be a more specific diagnostic indicator of primary presenile dementia than the EEG or CT scan.

scholarly journals Optimal Check Size and Reversal Rate to Elicit Pattern-reversal MEG Responses

2005 ◽  
Vol 32 (2) ◽  
pp. 218-224 ◽  
Author(s):  
Wei-Ta Chen ◽  
Yu-Chieh Ko ◽  
Kwong-Kum Liao ◽  
Jen-Chuen Hsieh ◽  
Tzu-Chen Yeh ◽  
...  
Keyword(s):  
Cortical Activation ◽  
Pattern Reversal ◽  
Check Size ◽  
Size Dependent ◽  
Visual Contrast ◽  
Single Dipole ◽  
Dipole Modeling ◽  
Pattern Reversal Stimulation ◽  
Visual Cortical ◽  
The Impact

ABSTRACT:Objective:To determine the impact of check size and interstimulus interval (ISI) on neuromagnetic visual cortical responses.Methods:We recorded visual evoked fields to pattern-reversal stimulation with central occlusion in ten subjects. The ~100 ms magnetic activation (P100m) was analyzed by single dipole modeling.Results:With 1 s ISI, P100m strengths increased as check size increased from 15' up to 120' of visual arc, and larger checks elicited less P100m activation. With 120' checks, we found no P100m attenuation as ISI decreased from 4 s to 0.16 s. P100m sources around the calcarine sulcus did not vary with check size or ISI.Conclusions:The magnitude of cortical activation during visual contrast processing is check size-dependent and the 120' checks are optimum for future studies on neuromagnetic visual cortical functions using central-occluded stimulation. The corresponding neuronal activation demonstrated a short refractory period less than 0.16 s. We also found significantly overlapping cortical representation areas for different check sizes or ISIs.

Visual evoked cortical magnetic fields to pattern reversal stimulation

1997 ◽  
Vol 6 (1) ◽  
pp. 9-22 ◽  
Author(s):  
Akinori Nakamura ◽  
Ryusuke Kakigi ◽  
Minoru Hoshiyama ◽  
Sachiko Koyama ◽  
Yoshihiro Kitamura ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Pattern Reversal ◽  
Pattern Reversal Stimulation ◽  
Visual Evoked
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