Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “AFTERIMAGE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 811 records · Page 45Linked to original sources
PubMed2001

Electrophysiological correlates of the visual after effect by means of visual evoked potentials.

An attempt was made to determine whether changes of electrical activity could be seen in the posterior cortex during an after image of high frequency luminance gratings. Steady state visual evoked potentials were recorded (midoccipital, right and left temporo-occipital sites) immediately after a period of visual adaptation (15 min) to the stimulus, while the subjects experienced the after image. During this illusion, frequencies of the fast Fourier transform spectra linked to the stimulation differed from the noise and were larger at temporo-occipital sites than at the midoccipital one. In view of these results, the hypothesis that the after effect represents a short term storage of the temporal characteristics of the stimulus is evoked.

Adaptation, Physiological↗
PubMed2004

Prism aftereffects disrupt interlimb rhythmic coordination.

The authors examined effects of prism-induced proprioceptive aftereffects on coordination of 95 participants and compared interlimb rhythmic coordination performed before versus after exposure to prisms of varying optical displacements. The observed steady states of relative phase for postprism exposure coordination were shifted by a small but significant amount, but not across all prism conditions. Phase-shift direction was not specific to the direction of optical displacement and was not, across all conditions, proportional to the magnitude of optical displacement. Prism exposure was associated with increased relative phase variability for all prism conditions. A no-prism control group showed no changes in interlimb rhythmic coordination. The results suggest that prism-induced proprioceptive aftereffects have general, disruptive effects on interlimb rhythmic coordination.

Adaptation, Physiological↗
PubMed1998

The indirect McCollough effect: an examination of an associative account.

It has been found that viewing, for example, a red-and-black vertical grating alternating with a green homogeneous field produces a color aftereffect--a McCollough effect--on a black-and-white vertical grating (i.e., green). Viewing such colored patterns also produces an aftereffect on a noninduced horizontal grating (i.e., pink)--the indirect McCollough effect. Humphrey, Dodwell, and Emerson (1989) argued that the indirect McCollough effect is caused by opponent properties of the visual system that organize the processing of contour and color along contrasting, probably orthogonal, dimensions. Recently, however, their interpretation of the indirect McCollough effect has been challenged by some findings of Eissenberg, Allan, Siegel, and Petrov (1995). These researchers have proposed that the indirect McCollough effect, like the McCollough effect, can be explained by associative principles. The results reported here question crucial aspects of the hypothesis of Eissenberg et al.

Afterimage↗
PubMed1991

Visible persistence following a brief increment in stimulus luminance.

In previous studies, it has been demonstrated that visible persistence--the period for which the perceived duration of a stimulus exceeds its physical duration--can be extended by briefly incrementing the luminance of the stimulus immediately prior to offset. Using a two-component pattern integration task, we show that this effect is not an artifact of change in the total luminous flux within the stimulus. Visible persistence was unaffected by overall luminance of the stimulus. It was also time-locked to the luminance increment. Visible persistence is seen to result from a process that is initiated by stimulus onset and that can be either wholly or partially reinitiated by the onset of the luminance increment. The duration of this process (which determines the duration of stimulus visibility) can be modified in a graded fashion by stimulus events that occur after its initiation. We outline a single-process inhibitory feedback model of the persistence mechanism that accounts for the present findings.

Afterimage↗