Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “range adaptation”

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 271 records · Page 15Linked to original sources
PubMed1969

Changes in the maintained discharge with adaptation level in the cat retina.

1. The mean rate, impulse interval distribution, and pulse number distribution of the maintained discharge of ganglion cells in the retina of the cat have been studied after prolonged adaptation at different luminance levels.2. From a state of complete dark adaptation up to a luminance of about 5 x 10(-3) cd/m(2) (viewed through a 7 mm(2) pupil) the mean rate of on-centre units increases. From darkness up to a somewhat higher luminance the mean rate of some off-centre units decreases, but others show little change.3. Above 10(-2) cd/m(2) the mean rate ceases to show a regular relation with adaptation level. On units often decrease and then increase again at a higher level. Rhythmical fluctuations are common near 10(-2) cd/m(2), especially if the retina is not in first class condition. Mean rates above 70/sec and below 1/sec are very rare at any adaptation level.4. Over the range where mean rate increases monotonically with adaptation level, it is shown that the surround of on-centre units does not inhibit and off responses cannot be elicited. When the monotonic increase is slowed or reversed it becomes possible to elicit responses from the surround. We suspect that the surround exerts a sustained, tonic, inhibiting effect at higher adaptation levels, thus holding down the maintained discharge.5. There are rare units, forming less than 1% of those isolated, that show a regularly increasing frequency with increase of adaptation level above 10(-2) cd/m(2). These units have concentric ;on' and ;off' zones in their receptive fields, but the responses to rapidly changing stimuli are sluggish and they have an unusually regular maintained discharge. They have been tentatively called ;luminance units'.6. The impulse-interval and pulse-number distributions of on-centre units change predictably with adaptation level; the variance of the pulse number distribution is usually several times the mean at very low adaptation levels, but only a fraction of the mean at high levels. Off-centre units do not show predictable changes. Luminance units fire more regularly, and have narrower pulse-number and impulse interval distributions than other concentric units.7. A simple model is proposed to account for the statistical characteristics of the maintained discharge of on-centre units.

Action Potentials↗
PubMed1998

Echolocation range of captive and free-ranging baiji (Lipotes vexillifer), finless porpoise (Neophocaena phocaenoides), and bottlenose dolphin (Tursiops truncatus).

The interclick intervals of captive dolphins are known to be longer than the two-way transit time between the dolphin and a target. In the present study, the interclick intervals of free-ranging baiji, finless porpoises, and bottlenose dolphins in the wild and in captivity were compared. The click intervals in open waters ranged up to 100-200 ms, whereas the click intervals in captivity were in the order of 4-28 ms. Echolocation of free-ranging dolphins appears to adapt to various distance in navigation or ranging, sometimes up to 140 m. Additionally, the difference of waveform characteristics of clicks between species was recognized in the frequency of maximum energy and the click duration.

Animals↗
PubMed1998

Development of an economic model for the management of upper gastrointestinal disease in primary care. Preliminary findings.

Health economic models for identifying therapeutic options that maximise health benefits from limited healthcare resources are being developed in a number of therapeutic areas. The development of such a model for upper gastrointestinal (UGI) symptoms to support decision-making by primary care clinicians is of particular importance, given the prevalence of this symptomatology. This economic model was based upon the clinical guidelines aimed at improving the management of UGI disorders at the primary care level that were developed by the International Gastro Primary Care Group. This paper discusses the derivation, methodology and results of the economic model developed to assess the resource implications arising from these clinical guidelines. In order to construct the economic model, it was necessary to identify the following: every therapeutic pathway followed by patients resource use along each pathway the probabilities of following alternative pathways. One crucial factor underlying the interpretation of results obtained from any economic model is the time period covered by the model. The model presented here analysed the initial 12-month treatment period of 'new' patients presenting with UGI symptoms. In order to test the implications of a longer term perspective, the model is currently being developed to analyse resource use over a 24-month period. The model demonstrates that utilising the predominant symptom approach to the diagnosis and treatment of patients with UGI disorders appears to provide significant benefits in terms of patient management and effective resource use. This factor, together with the more intensive use of Helicobacter pylori eradication therapy, provides the potential to reduce the cost of drugs for the treatment of UGI disorders by approximately 15% in the UK. A major strength of the model is its adaptability to a wide range of clinical and cost scenarios. Such adaptability enables the model to effectively reflect the potential resource implications in countries exhibiting significantly different levels of cost and patient management. In this manner, the model provides one valuable method by which clinicians can be supported in optimising the management of UGI disorders within current resource constraints.

Cost-Benefit Analysis↗
PubMed1977

Cytochrome f and plastocyanin kinetics in Chlorella pyrenoidosa. II. Reduction kinetics and electric field increase in the 10 ms range.

On dark-adapted Chlorella, after one flash, plastocyanin (PC) undergoes reduction with a half-time of 7 ms. After 4 or 5 flashes, the reduction of PC+ in the 10 ms range is suppressed, and the level of oxidized plastocyanin increases during the next few flashes before reaching a stationary value. Cytochrome f exhibits approximately the same pattern. The reduction of PC+ and cytochrome f+ in the 10 ms range is correlated with an increase of the electrice field named phase b (Joliot, P. and Delosme, R., Biochim. Biophys. Acta 357 (1974) 267-284). Both need the presence of a compound R' in the reduced state. A dark electron transfer involving a carrier of electrons across the membrane, a proton carrier, R' as terminal reducant, PC+ and cytochrome f+ as terminal oxidants, would account for this field generation. Cooperation between the electron transfer chains is implied at the level of plastocyanin oxidation. An equilibrium constant of about 2 is observed between cytochrome f and plastocyanin before 1 ms and after 500 ms after the photochemical reactions. We observe that cytochrome f and plastocyanin are not connected from 1 to 100 ms after a photochemical reaction. The equilibrium constant between plastocyanin and P-700 remains large [20] under these conditions.

Chlorella↗
PubMed1988

Spatial vision of the achromat: spatial frequency and orientation-specific adaptation.

1. The psychophysical technique of selective adaptation to stationary sine-wave gratings of varying spatial frequency and orientation was used to investigate the central processing of spatial information in the visual system of the complete achromat. 2. For adapting spatial frequencies of 1 and 2 cycles/deg, the spatial frequency and orientation selectivity of contrast threshold elevation is similar for achromatic and trichromatic vision. 3. For adapting frequencies below 1 cycle/deg, the achromat shows threshold elevations of normal magnitude with symmetrical spatial frequency and orientation tuning for adapting frequencies as low as 0.09 cycles/deg with 'bandwidth' estimates similar to those found at high frequencies in the trichromat. Below 0.66 cycles/deg no after-effect could be obtained in the trichromat, and the frequency tuning at 0.66 cycles/deg was skewed towards higher frequencies. 4. The interocular transfer of low-frequency adaptation in the achromat was 50%, which is the same value obtained at higher frequencies. 5. The time course of the decay of low spatial frequency adaptation in the achromat was similar to that found at higher frequencies. 6. Control experiments show no low-frequency adaptation in peripheral vision or in central vision in the dark-adapted trichromat indicating that low spatial frequency adaptation cannot be elicited through the rod system of the trichromat. 7. It is proposed that the observed range shift of adaptable spatial frequency mechanisms in the achromat's visual cortex is the result of an arrest at an early stage of sensory development. The visual cortex of the achromat is comparable, with respect to spatial processing, to that of the young, visually normal human infant.

Adaptation, Ocular↗
PubMed2006

Multiple time scales of temporal response in pyramidal and fast spiking cortical neurons.

Neural dynamic processes correlated over several time scales are found in vivo, in stimulus-evoked as well as spontaneous activity, and are thought to affect the way sensory stimulation is processed. Despite their potential computational consequences, a systematic description of the presence of multiple time scales in single cortical neurons is lacking. In this study, we injected fast spiking and pyramidal (PYR) neurons in vitro with long-lasting episodes of step-like and noisy, in-vivo-like current. Several processes shaped the time course of the instantaneous spike frequency, which could be reduced to a small number (1-4) of phenomenological mechanisms, either reducing (adapting) or increasing (facilitating) the neuron's firing rate over time. The different adaptation/facilitation processes cover a wide range of time scales, ranging from initial adaptation (<10 ms, PYR neurons only), to fast adaptation (<300 ms), early facilitation (0.5-1 s, PYR only), and slow (or late) adaptation (order of seconds). These processes are characterized by broad distributions of their magnitudes and time constants across cells, showing that multiple time scales are at play in cortical neurons, even in response to stationary stimuli and in the presence of input fluctuations. These processes might be part of a cascade of processes responsible for the power-law behavior of adaptation observed in several preparations, and may have far-reaching computational consequences that have been recently described.

Adaptation, Physiological↗
PubMed1996

Neuropsychiatry of 18q- syndrome.

Our understanding of neuropsychiatric abnormalities in patients with deletions of the long arm of chromosome 18 (18q- syndrome) is based mainly on sporadic case reports. We characterized the neuropsychiatric phenotype in 27 patients across a wide age range (2-47 years) with breakpoints ranging from 18q22.3-18q21.2. Adaptive behavior scores (Vineland Composite) were significantly higher in females than in males (62 +/- 5 vs. 43 +/- 3). Intelligence ranged from borderline to severely deficient (IQ, 73- < 40), with academic achievement similarly impaired. Performance in specific neuropsychological functions, including attention, novel problem solving, memory, language, visuomotor integration, and fine motor dexterity, was consistently in the moderately-to-severely impaired range. Behavioral problems were common in both sexes, including aggressivity, hyperactivity, and temper tantrums. Contrary to the few previous reports, we found no evidence of psychosis in any patients. In a subset of patients selected on the basis of no prior knowledge of behavioral problems, 1 of 16 patients (6%) had autism, as defined by the Autistic Diagnostic Interview--Revised (ADI-R) [Lord et al., 1994: J Autism Dev Disord 24:659-685]. Thus, the prevalence of autism in 18q- syndrome is probably no greater than that in other developmental disabilities with a similar level of cognitive impairment. In contrast to what has been believed since 18q- was first described 30 years ago, we found no relationship between chromosome deletion size and any measure of cognition or behavior; nor were there any correlations between any of these measures with the presence or absence of abnormalities on MRI or somatosensory-evoked potentials.

Adaptation, Psychological↗
PubMed2002

ACTIVE-EYES: an adaptive pixel-by-pixel image-segmentation sensor architecture for high-dynamic-range hyperspectral imaging.

The ACTIVE-EYES (adaptive control for thermal imagers via electro-optic elements to yield an enhanced sensor) architecture, an adaptive image-segmentation and processing architecture, based on digital micromirror (DMD) array technology, is described. The concept provides efficient front-end processing of multispectral image data by adaptively segmenting and routing portions of the scene data concurrently to an imager and a spectrometer. The goal is to provide a large reduction in the amount of data required to be sensed in a multispectral imager by means of preprocessing the data to extract the most useful spatial and spectral information during detection. The DMD array provides the flexibility to perform a wide range of spatial and spectral analyses on the scene data. The spatial and spectral processing for different portions of the input scene can be tailored in real time to achieve a variety of preprocessing functions. Since the detected intensity of individual pixels may be controlled, the spatial image can be analyzed with gain varied on a pixel-by-pixel basis to enhance dynamic range. Coarse or fine spectral resolution can be achieved in the spectrometer by use of dynamically controllable or addressable dispersion elements. An experimental prototype, which demonstrated the segmentation between an imager and a grating spectrometer, was demonstrated and shown to achieve programmable pixelated intensity control. An information theoretic analysis of the dynamic-range control aspect was conducted to predict the performance enhancements that might be achieved with this architecture. The results indicate that, with a properly configured algorithm, the concept achieves the greatest relative information recovery from a detected image when the scene is made up of a relatively large area of moderate-dynamic-range pixels and a relatively smaller area of strong pixels that would tend to saturate a conventional sensor.

Journal Article↗
PubMed2006

Regulation of immediate early gene expression by exercise: short cuts for the adaptation of immune function.

Onset of physical activity induces a wide variety of rapid biophysical and biochemical responses that act on cells and lead to a wide range of phenotypic adaptations. Here we elucidate the role of immediate early gene (IEG) expression as a first line of transcriptional response that mediates protein neosynthesis and leads to adaptation of immune function. New posttranscriptional mechanisms have been described that speed up transcriptional responses. These include RNA-RNA interactions such as those exploited by miRNAs and stimulus-dependent cytoplasmic polyadenylation. We describe these shortcuts that modulate expression and discuss the challenges of accurately measuring them using various transcriptomic screening and quantification approaches. Although there is high complexity of the upstream as well as the downstream pathways that lead to IEG expression, IEG expression itself may only show a limited number of response patterns. Focusing transcriptomic approaches in exercise immunology at the IEG-level may facilitate the discovery of exercise-specific transcriptional signatures.

Adaptation, Physiological↗
PubMed1981

Activity of warm receptors in Boa constrictor raised at various temperatures.

Nine young specimens of Boa constrictor were raised for 4 years in a climatic chamber at an ambient temperature of 30 degrees C under artificial illumination. Seven boas were raised at 23 degrees C under the same conditions. At the end of the adaptation period, mean body weight of the warm adapted boas was 9.6 +/- 0.8 kg and that of the cold adapted ones 5.9 +/- 0.3 kg. Static and dynamic activities of single specific trigeminal warm fibers were recorded when applying static temperatures of 20, 23, 26, 29, 32, 35 and 38 degrees C and dynamic warming steps of 3 degrees C, the initial temperatures being 20, 23, 26, 29, 32 and 35 degrees C. Eighty-nine warm fibers were examined in the warm adapted and 62 fibers in the cold adapted group. The average static frequencies between 29 and 35 degrees C were higher in the warm adapted animals, the respective values for both groups at 32 degrees C being 16.5 and 12 s-1. The average peak frequencies for dynamic warming were 80 s-1 for both groups, but the temperature of the dynamic maximum was shifted from 32 degrees C in the warm adapted to 26 degrees C in the cold adapted boas. At 32 and 35 degrees C the average peak frequencies were higher in the warm adapted animals. The whole fiber population contained various groups with static maxima between 23 and 35 degrees C. Long-term adaptation modified mainly the static and dynamic discharge of the low-temperature fibers. The fiber group with a static maximum at 29 degrees C showed a crossing of the static and dynamic frequency-temperature curves. In the higher temperature range the warm adapted animals had a higher and in the lower temperature range a lower static and dynamic frequency.

Acclimatization↗
PubMed1990

[Oscillation of impulse discharges of Pacinian corpuscles of cat mesentery to external stimulation].

A sensory unit with one or two Pacinian corpuscles was isolated from cat mesentery and square wave mechanical stimulation (duration 5-10 sec), sinusoidal frequency stimulation (duration 4-130 sec, frequency 0.06-300 Hz) and ramp mechanical stimulation (duration 5-10 sec) were applied to the Pacinian corpuscles. When the temperature exceeded 27 degrees C, the sensory unit caused a sustained discharge after on-response to the square wave stimulation. The sustained discharge lasted until the off-response. The sustained discharge was considered to be generated by an oscillation of the receptor potential in the Pacinian corpuscles. The results were as follows: 1. Sensory units with two Pacini corpuscles of cats from young (20 days after birth) to adult were found to respond with both fast-adapting and apparent slow-adapting responses at room temperature (27 degrees C). 2. The two Pacini corpuscles showed the characteristics of fast-adapting mechanoreceptor and vibrator. It was confirmed that the apparent slow-adapting responses from the sensory units were not artifacts induced by vibration from the stimulating bar or experimental table or experimental room, but were originated by an unknown mechanism in the corpuscles. 3. Some sensory units with two Pacinian corpuscles also responded with both fast-adapting and apparent slow-adapting responses in the range of 27-29 degrees C. The apparent slow-adapting responses were caused by pressure and vibratory stimulations above a strength level, but not by dumping of the stimulating bar. 4. The sensory unit evoked only the fast-adapting discharges near the threshold level of stimulus strength at less than 27 degrees C. In the temperature range of 27-40 degrees C, the sensory unit showed an increase in frequency of the apparent slow-adapting discharge by increased displacement and velocity of the stimulus. 5. The sensory unit responded with repeated firing to low-frequency stimulation (0.1-0.06 Hz) at the temperature range and the impulse number was increased by increased strength of the low-frequency stimulation. 6. At the 27-40 degrees C, the sensory units with Pacinian corpuscles evoked after discharge and spontaneous discharges and the impulse number was increased by increased displacement, velocity and frequency of the mechanical stimulus. Thus it is difficult to call the response of Pacinian corpuscles observed at more than 27 degrees C a slow-adapting one, judging from the duration of the receptor potential. We considered that these discharge responses resulted from an electrical oscillation of the receptor potential in the corpuscles.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Cold adaptation in marine organisms.

Animals from polar seas exhibit numerous so called resistance adaptations that serve to maintain homeostasis at low temperature and prevent lethal freezing injury. Specialization to temperatures at or below 0 degrees C is associated with an inability to survive at temperatures above 3-8 degrees C. Polar fish synthesize various types of glycoproteins or peptides to lower the freezing point of most extracellular fluid compartments in a non-colligative manner. Antifreeze production is seasonal in boreal species and is often initiated by environmental cues other than low temperature, particularly short day lengths. Most of the adaptations that enable intertidal invertebrates to survive freezing are associated with their ability to withstand ariel exposure. Unique adaptations for freezing avoidance include the synthesis of low molecular mass ice-nucleating proteins that control and induce extracellular ice-formation. Marine poikilotherms also exhibit a range of capacity adaptations that increase the rate of some physiological processes so as to partially compensate for the effects of low temperature. However, the rate of embryonic development in a diverse range of marine organisms shows no evidence of temperature compensation. This results in a significant lengthening of the time from fertilization to hatching in polar, relative to temperate, species. Some aspects of the physiology of polar marine species, such as low metabolic and slow growth rates, probably result from a combination of low temperature and other factors such as the highly seasonal nature of food supplies. Although neuromuscular function shows a partial capacity adaptation in Antarctic fish, maximum swimming speeds are lower than for temperate and tropical species, particularly for early stages in the life history.

Adaptation, Physiological↗
PubMed2006

Molecular cloning of growth hormone from silver sea bream: effects of abiotic and biotic stress on transcriptional and translational expression.

The pituitary growth hormone (GH) gene of silver sea bream (Sparus sarba) was cloned and characterized and found to be 615 base pairs encoding a protein of 204 amino acids. Using a bacterial expression system, recombinant protein was prepared and rabbit polyclonal antibody was raised. Transcript and protein amounts of GH were measured in fish that were adapted to a range of salinities, acclimated to different temperatures, or undergoing a natural time course of Vibrio alginolyticus infection. Isoosmotic salinity (12 ppt) adaptation resulted in increased GH transcript and protein in comparison to freshwater (0 ppt) and seawater (33 ppt) adapted fish. It was also found that cold temperature (12 degrees C) acclimated sea bream had higher amounts of pituitary GH transcript and protein when compared to warm temperature (25 degrees C) acclimated fish. Finally, the amounts of GH transcript and protein were found to be rapidly downregulated from an early stage of disease. The results from the present study demonstrate how GH can be modulated during both abiotic and biotic stress in fish.

Adaptation, Physiological↗
PubMed2006

Local and global costs of adaptive plasticity to density in Arabidopsis thaliana.

Although phenotypic plasticity is demonstrably adaptive in a range of settings, organisms are not perfectly plastic. Costs of plasticity comprise one factor predicted to counter the evolution of this adaptive strategy, yet evidence of costs is rare. Here, we test the fitness effects of plastic life-history and morphological responses to density and costs of this plasticity in recombinant inbred lines of Arabidopsis thaliana. Several costs of plasticity and homeostasis were detected. Of particular relevance, there was a significant cost of plasticity to active stem-elongation responses, an adaptive trait in many species. There was also a cost of plasticity to apical branch production at both high and low density, which resulted from the greater suppression of basal branching in genotypes with plastic apical branch production relative to genotypes with fixed apical branch production. The presence of a cost in multiple environments (i.e., a global cost) is predicted to counter the evolution of plasticity. Experimental segregating progenies such as the one used here are expected to have higher genetic costs of plasticity than arrays of genotypes sampled from natural populations because selection should remove genotypes with costs resulting from linkage disequilibrium or epistasis. The use of experimental progeny arrays therefore increases the ability to evaluate genetic costs.

Adaptation, Physiological↗
PubMedDate not supplied

[Theoretical and experimental approach to the problem of changes in functional capability of cells under the effects of adaptive doses of ionizing radiation].

It is concluded that a dose range from background dose to several cGy may be separated into two parts: a) first--the interval of small doses limited from above by D* which is determined from (1 g (D*/Doc)) < -0.51 g (n/2)), where Dse is an average dose of a single event, n--quantity of irradiated cells; in this interval only one track intersects a sensitive volume; b) second--the interval of low doses, in which in average one track intersects the volume and which is ranged from top D* to bottom Dse. Because events in this region qualitatively are similar to background events, cells in the dose range b) may be adapted to the influence of radiation. The first stage of the adaptive response of cells is associated with chromosome loci (centromere) movement in a cell nucleus and as we suggest the latter is the fundamental mechanism for repairing DSB DNA and switching of gene transcription. Because the movement of chromosome loci both in the resting cells under the adapting doses and in the normal dividing cells is much the same (but the latter lose their function characteristic for differentiated resting cells), it could be assumed that the resting cells under the adapting doses also lose their functional parameters. Under chronic exposure to low doses this functional changes can be principal for discussion on the influence of low doses on health.

Adaptation, Physiological↗
PubMed1999

Multiple immediate-early gene expression during physiological and endocrine adaptation to repeated stress.

This study had three objectives: (i) to determine whether there were individual differences in the activation and adaptation of a range of immediate-early genes to repeated restraint stress, (ii) to monitor physiological responses (endocrine, cardiovascular and core temperature) and their adaptation with repeated presentations of the stressor, and (iii) to determine whether any of these indices were altered by dehydroepiandrosterone, an anti-glucocorticoid steroid known to be reduced in humans by stress. Four groups of male rats were implanted subcutaneously with either dehydroepiandrosterone or control (paraffin) pellets. They were then subjected to either a single or 14 days of restraint (60 min/day) or transferred to the testing room (unstressed). Repeatedly stressed animals and their controls were also implanted with intra-abdominal telemetric transmitters to record heart rate and core temperature. Protein products for c-fos,fos-b, c-jun and jun-b were displayed by immunocytochemistry. Areas examined included the ventrolateral septum, hypothalamic paraventricular nucleus, amygdala, locus coeruleus and nucleus of the solitary tract. Acute restraint increased Fos immunoreactivity in all of the areas examined, with the exception of the medial amygdala. The pattern of induction for Fos-B and Jun-B was similar, while c-Jun was only increased in the septum (though constitutive levels were high in most structures compared to the other proteins examined). After 14 days of restraint, immediate-early gene immunostaining was reduced in all of the areas examined, though the extent of adaptation depended on the area and immediate-early gene. In the forebrain, Fos expression adapted in the paraventricular nucleus, amygdala and septum, whereas Fos-B and c-Jun adapted incompletely in the septum. In contrast, Jun-B behaved like Fos. In the brainstem, Fos, Fos-B and Jun-B expression adapted in the nucleus of the solitary tract (but not the locus coeruleus). Corticosterone levels were still raised above baseline, but the response was blunted compared to acute stress. There was marked stress-induced hypothermia which did not adapt during the restraint session, but this returned to baseline during restraint after about five days. In contrast, stress-induced tachycardia did not change during repeated restraint. Dehydroepiandrosterone implants had no clear-cut effects on any immunostaining following acute stress, though there was a trend towards lessened adaptation of the Fos response in the septum after steroid treatment. Dehydroepiandrosterone also did not affect the cardiovascular or endocrine responses to repeated restraint. These experiments show that adaptation of the expression of multiple immediate-early genes occurs during repeated restraint, but in a site-specific pattern in the brains of male rats.

Adaptation, Physiological↗
PubMed1992

Light adaptation and the luminance-response function of the cone electroretinogram.

Cone electroretinograms are typically isolated by presenting stimulus flashes against rod-desensitizing adapting fields. To investigate the manner in which adapting-field luminance affects cone electroretinogram response properties, we measured cone electroretinogram luminance-response functions of two normal subjects, with stimuli presented against adapting fields that ranged in luminance from -1.2 to 2.1 log cd/m2. A flicker rate of 31.1 Hz was used to isolate cone electroretinograms under all adaptation conditions. A hyperbolic equation of the form (R/Rmax) = Ln/(Ln + Kn) was fitted to each luminance-response function by a least-squares criterion. As adapting field luminance increased, the best-fit values of the variables K and n increased, which is in general agreement with results of electrophysiologic studies of light adaptation in retinal neurons. However, Rmax values also increased with adapting field luminance. The change in all three of these variables with adapting field luminance must be considered in the interpretation of cone electroretinogram luminance-response functions from patients with retinal disorders.

Adaptation, Ocular↗