Purpose: To investigate how light stimulus conditions of varying spatial sizes affect components of the flash and long-flash electroretinogram (ERG) in normal subjects.
Method: Three stimulus conditions were generated by a Ganzfeld stimulator: a white flash on white background (WoW), a red flash on a blue background (RoB) and an L+M-cone isolating on-off (long flash) stimulus (Cone Iso). ERGs were recorded from six subjects (5 M, 1 F) with DTL electrodes to full-field (FF), 70°, 60°, 50°, 40°, 30° and 20° diameter circular stimuli. Amplitudes and peak times for a-, b-, d- and i-wave, and PhNR were examined. PhNR amplitudes were estimated in two different ways: from baseline (fB) and from preceding b-wave peak (fP).
Results: With decreasing stimulus size, amplitudes for all ERG waveform components attenuated and peak times increased, although the effect varied across different components. An exponential fit described the relationship between amplitudes and size of stimulated retinal area well for most components and conditions (R= 0.75-0.99), except for PhNR(fB) (R= - 0.16-0.88). For peak times, an exponential decay function also fitted the data well (R= 0.81-0.97), except in a few cases where the exponential constant was too small and a linear regression function was applied instead (a-wave Cone Iso, b- and i-wave WoW). The exponential constants for RoB amplitudes (b-wave, PhNR(fB), PhNR(fP)) were larger compared to their counterparts under WoW (p < 0.05), while there was no difference between the constants for a-wave amplitudes and peak times and for PhNR peak times. The exponential constants of amplitudes vs. area under WoW and Cone Iso were remarkably similar, while under RoB PhNR(fB) showed larger constants compared to either a- or b-wave (p < 0.05).
Conclusion: ERG components change in a predictable way with stimulus size and spectral characteristics of the stimulus under these conditions. This predictability could allow a modified version of these sets of stimuli to be tested for clinical applicability.
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http://dx.doi.org/10.1007/s10633-020-09797-6 | DOI Listing |
Int J Exerc Sci
December 2024
Rehabilitation and Modulation of Pain (RAMP) Lab, Institute of Exercise Physiology and Rehabilitation Science, University of Central Florida, Orlando, FL, USA.
This study assessed the effect of an eight-minute cycling intervention using varying intensities on exercise-induced hypoalgesia (EIH). The main objective of this study was to examine the effect of varying intensities on pressure pain threshold (PPT) and heat pain threshold (HPT) at the thigh and forearm, tested pre- and post-cycling intervention. Healthy male participants ( = 16) performed a graded exercise test on a cycle ergometer to establish their peak power output (PPO).
View Article and Find Full Text PDFJ Soc Cardiovasc Angiogr Interv
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Division of Cardiovascular Medicine, Sulpizio Cardiovascular Center, University of California San Diego, San Diego, California.
Background: A minimum threshold activated clotting time (ACT) to guide heparin dosing during percutaneous coronary intervention (PCI) is associated with lower ischemic complications. However, data are variable regarding the risk of high ACT levels. The aim of this study was to assess the impact of peak procedural ACT on complications and mortality for transfemoral and transradial access PCI.
View Article and Find Full Text PDFSoft Matter
January 2025
Faculty of Chemistry, Ho Chi Minh City University of Science, Vietnam National University, Ho Chi Minh City, 227 Nguyen Van Cu Street, Ward 4, District 5, Ho Chi Minh City 70000, Vietnam.
Surface-enhanced Raman spectroscopy (SERS) is a highly sensitive analytical technique with excellent molecular specificity. However, separate pristine nanoparticles produce relatively weak Raman signals. It is necessary to focus on increasing the "hot-spot" density generated at the nanogaps between the adjacent nanoparticles (second-generation SERS hotspot), thus significantly boosting the Raman signal by creating an electromagnetic field.
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Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
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BMC Ophthalmol
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Department of Ophthalmology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
Significance: Cataract surgery is one of the most performed surgical procedures worldwide. As a potential complication following cataract surgery, dry eye has the potential to impact visual outcomes, lower patient satisfaction, and be detrimental to quality of life.
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