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Visually evoked potential (VEP) measurement of neural suppression during dynamic accommodation
Author(s) -
Laird S. K.,
Mucke S.,
Manahilov V.,
Strang N. C.,
Seidel D.
Publication year - 2008
Publication title -
ophthalmic and physiological optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.147
H-Index - 66
eISSN - 1475-1313
pISSN - 0275-5408
DOI - 10.1111/j.1475-1313.2007.00530_5.x
Subject(s) - accommodation , amplitude , spatial frequency , latency (audio) , dynamic range , optics , computer science , physics , telecommunications
Purpose: Previous work using psychophysical procedures has found evidence of high spatial frequency suppression during step accommodation responses. In this experiment we use VEPs to provide an objective measure of this suppression. Method: VEPs to horizontal sinusoidal gratings were measured in one young subject in both dynamic and static conditions. The gratings were presented for 40 ms on a monitor placed at 1 m. In the dynamic mode the grating was presented at various time intervals over the course of an accommodation response (1–3D). These measures were compared with static VEP measures taken at defocus equivalent points across the accommodation response range. Results: The results show VEP amplitudes decreasing with defocus (due to accommodation) in both the static and the dynamic conditions. However, at the time of peak accommodation response acceleration, a decrease in amplitude is seen in the dynamic compared with static condition. The latency of both the dynamic and static recordings increased with the amount of defocus. Conclusion: The results support the suggestion that neural high spatial frequency suppression occurs during an accommodation step response.