Asymmetric dynamics of adaptation after onset and offset of flicker.
J Vis
; 4(1): 1-12, 2004 Jan 16.
Article
en En
| MEDLINE
| ID: mdl-14995894
ABSTRACT
We measured human psychophysical detection thresholds for test pulses which are superimposed on spatially homogeneous backgrounds that have abrupt onsets and offsets of high-contrast 25 Hz flicker. After the onset of the background flicker, test thresholds reach their steady-state levels within 20-60 ms. After the offset of the background flicker, test thresholds remain elevated above their steady-state level for much longer durations. Adaptation after onsets and offsets of background flicker is modeled with a divisive gain control that is activated by temporal contrast. We show that a feedback structure for the gain control can explain the asymmetric dynamics observed after onsets and offsets of the background contrast. Finally, we measure detection thresholds for tests presented on steadily flickering backgrounds as a function of the contrast of the background flicker. We show that the divisive feedback model for contrast gain control can describe these results as well.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Umbral Sensorial
/
Adaptación Ocular
/
Sensibilidad de Contraste
Límite:
Adult
/
Female
/
Humans
/
Male
Idioma:
En
Revista:
J Vis
Asunto de la revista:
OFTALMOLOGIA
Año:
2004
Tipo del documento:
Article
País de afiliación:
Países Bajos