Reliability of P50 suppression is vastly improved via dipole modeling

1992 ◽  
Vol 31 (5) ◽  
pp. 146-147
2020 ◽  
Vol 34 (3) ◽  
pp. 171-178
Author(s):  
Samantha Major ◽  
Kimberly Carpenter ◽  
Logan Beyer ◽  
Hannah Kwak ◽  
Geraldine Dawson ◽  
...  

Abstract. Auditory sensory gating is commonly assessed using the Paired-Click Paradigm (PCP), an electroencephalography (EEG) task in which two identical sounds are presented sequentially and the brain’s inhibitory response to the second sound is measured. Many clinical populations demonstrate reduced P50 and/or N100 suppression. Testing sensory gating in children may help to identify individuals at risk for neurodevelopmental disorders earlier, including autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), which could lead to more optimal outcomes. Minimal research has been done with children because of the difficulty of performing lengthy EEG experiments with young children, requiring them to sit still for long periods of time. We designed a modified, potentially child-friendly version of the PCP and evaluated it in typically developing adults. The PCP was administered twice, once in a traditional silent room (silent movie condition) and once with an audible movie playing (audible movie condition) to minimize boredom and enhance behavioral compliance. We tested whether P50 and N100 suppression were influenced by the presence of the auditory background noise from the movie. N100 suppression was observed in both hemispheres in the silent movie condition and in the left hemisphere only during the audible movie condition, though suppression was attenuated in the audible movie condition. P50 suppression was not observed in either condition. N100 sensory gating was successfully elicited with an audible movie playing during the PCP, supporting the use of the modified task for future research in both children and adults.


2020 ◽  
pp. 155005942097112
Author(s):  
Robert D. Melara ◽  
James C. Root ◽  
Raquel Bibi ◽  
Tim A. Ahles

Survivors of breast and other cancers often report protracted difficulty in performing tasks involving concentration and memory, even years after the completion of treatment. The current study investigated whether cancer and treatment history is associated with deficits in sensory filtering (gating out) and sensory memory (gating in), early processes in stimulus processing that may contribute to difficulties in later remembering. A group of breast cancer survivors and age-matched healthy control participants (mean age 54 years) underwent testing with paired-click and oddball tasks while electroencephalographic (EEG) signals were recorded. The survivors showed relatively poor inhibition of redundant sensory stimulation (P50 suppression). Dipole source analysis localized the survivors’ impairment to the hippocampus, with preservation of function in gating mechanisms of the frontal lobe and auditory cortex. Survivors also showed disruption to sensory memory processes needed to register novel information in an otherwise uniform auditory environment (mismatch negativity). The findings suggest that survivors experience deficits in early, automatic mechanisms of sensory gating, which may trigger a cascade of later perceived attentional and memory deficits. If our account is accurate, ideal therapies might aim to restore early inhibitory processes, such as those gauged by P50 suppression.


Author(s):  
Wei-Ta Chen ◽  
Yu-Chieh Ko ◽  
Kwong-Kum Liao ◽  
Jen-Chuen Hsieh ◽  
Tzu-Chen Yeh ◽  
...  

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.


1998 ◽  
Vol 155 (12) ◽  
pp. 1691-1694 ◽  
Author(s):  
Brett A. Clementz ◽  
Mark A. Geyer ◽  
David L. Braff
Keyword(s):  

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