PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 2771340

Retinal adaptation effects on the patterned VEP and ERG.

M M Spafford·S L Lu
View original source ↗Export metadata ↓

Abstract

The patterned visually evoked potential (pVEP) and patterned electroretinogram (pERG) after light and dark adaptation were investigated in 10 visually normal human observers. The influence of retinal preadaptation on the pVEP appeared to be dependent on the stimulus field size. With a 6 degree field size retinal adaptation effects were not apparent, but with a 12 degree field size the amplitudes of the dark-adapted steady-state pVEP (ssVEP) and transient pVEP (tVEP) were significantly larger than the light-adapted amplitudes. Similarly pERG's elicited by a 12 degree field size produced larger amplitude dark-adapted results. The implications of these findings are discussed. Monitoring the temporal changes in the pVEP subsequent to different retinal preadaptation levels proved to be inconclusive for the conditions studied.

Explore related subjects

Adaptation, OcularAdultDark AdaptationElectroretinographyEvoked Potentials, VisualHumansRetinaTime FactorsVision TestsComparative StudyJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

M M Spafford, S L Lu. 1989. Retinal adaptation effects on the patterned VEP and ERG.. https://doi.org/10.1097/00006324-198908000-00003

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Phototransduction in mouse rods and cones.

Phototransduction is the process by which light triggers an electrical signal in a photoreceptor cell. Image-forming vision in vertebrates is mediated by two types of photoreceptors: the rods and the cones. In this review, we provide a summary of the success in which the mouse has served as a vertebrate model for studying rod phototransduction, with respect to both the activation and termination steps. Cones are still not as well-understood as rods partly because it is difficult to work with mouse cones due to their scarcity and fragility. The situation may change, however.

Adaptation, Ocular↗
PubMed2007

Oculomotor plasticity: are mechanisms of adaptation for reactive and voluntary saccades separate?

Saccadic eye movements are permanently controlled and their accuracy maintained by adaptive mechanisms that compensate for physiological or pathological perturbations. In contrast to the adaptation of reactive saccades (RS) which are automatically triggered by the sudden appearance of a single target, little is known about the adaptation of voluntary saccades which allow us to intentionally scan our environment in nearly all our daily activities. In this study, we addressed this issue in human subjects by determining the properties of adaptation of scanning voluntary saccades (SVS) and comparing these features to those of RS. We also tested the reciprocal transfers of adaptation between the two saccade types. Our results revealed that SVS and RS adaptations disclosed similar adaptation fields, time course and recovery levels, with only a slightly lower after-effect for SVS. Moreover, RS and SVS main sequences both remained unaffected after adaptation. Finally and quite unexpectedly, the pattern of adaptation transfers was asymmetrical, with a much stronger transfer from SVS to RS (79%) than in the reverse direction (22%). These data demonstrate that adaptations of RS and SVS share several behavioural properties but at the same time rely on partially distinct processes. Based on these findings, it is proposed that adaptations of RS and SVS may involve a neural network including both a common site and two separate sites specifically recruited for each saccade type.

Adaptation, Ocular↗
PubMed2006

Remote facilitation in the Fourier domain.

To explore spatial interactions between visual mechanisms in the Fourier domain we measured detection thresholds for vertical and horizontal sine-wave gratings (4.4 deg diameter) over a range of spatial frequencies (0.5-23 c/deg) in the presence of grating and plaid masks with component contrasts of 8%, orientations of +/-45 degrees and a spatial frequency of 1c/deg. The mask suppressed the target grating over a range of +/-1 octave, and the plaid produced more suppression than the grating, consistent with summation of mask components in a broadly tuned contrast gain pool. At greater differences in spatial frequency ( approximately 3 octaves), the plaid and grating masks both produced about 3 dB of facilitation (they reduced detection thresholds by a factor of about square root 2). At yet further distances ( approximately 4 octaves) the masks had no effect. The facilitation cannot be attributed to a reduction of uncertainty by the mask because (a) it occurs for mask components that have very different spatial frequencies and orientations from the test and (b) the large stimulus size and central fixation point mean there was no spatial uncertainty that could be reduced. We suggest the results are due to long-range sensory interactions (in the Fourier domain) between mask and test-channels. The effects could be due to either direct facilitation or disinhibition.

Adaptation, Ocular↗