Recent sensory history plays a critical role in the perception of event duration. For example, repetitive exposure to a particular duration leads to the distortion of subsequent duration perception. This phenomenon, termed duration adaptation, induces a robust repulsive duration aftereffect. In particular, adaptation to relatively long sensory events shortens the perceived duration of a subsequent event, while adaptation to relatively short sensory events lengthens the perception of subsequent event durations. This phenomenon implies the plasticity of duration perception and offers important clues for revealing the cognitive neural mechanism of duration perception. Duration aftereffect has received more and more attention in recent years. In this review, we introduce recent research advances in our understanding of duration aftereffect, especially with regards to its manifestations, origin, and cognitive neural mechanisms. We also propose possible directions for future research. In sum, we posit that studies on the duration aftereffect phenomenon are helpful in understanding general duration perception, and as such, should receive more attention in future.
Figural Aftereffect ; Humans ; Motion Perception ; Visual Perception

In order to investigate the effect of head mounted display (HMD) on the human eye, the authors performed ophthalmologic examination on normal persons, dry eye patients and strabismus patients before and after use of Glastron, i-glasses, LGHMD(PT),LGHMD10 for two hours once or for five consecutive days, respectively. There were no substantial changes in visual acuity, color vision, intraocu-lar pressure, and tear secretion before and after use of HMD. There were transient changes in terms of corneal curvature, refraction, stereopsis, the angle of strabismus, and accommodation. There existed no difference according to the kinds of HMD. In conclusion, there was no permanent ocular changes with use of four kinds of HMD for two hours once or for five consecutive days.
Color Vision ; Depth Perception ; Head* ; Humans* ; Strabismus ; Tears ; Visual Acuity

We performed Farnsworth-Munsell 100-hue test in pseudophakic eyes and phakic eyes to detect the abnormal color perception suggested in pseudophakic eyes compared with phakic eyes. But there were no significant differences in total error scores and mean error scores at four individual boxes between two groups. The results suggest that there were no differences in color perception between pseudophakic and phakic eyes by Farnsworth-Munsell 100-hue test.
Color Perception

This study was for investigating relations between distributions of monoamines-norepinephrine, serotonin, and dopamine-on the visual system and their functions. Distributions of these monoamines in the lateral geniculate body, pulvinar, lateral posterior nucleus, and suprachiasmatic nucleus were investigated. Brain of a squirrel monkey was removed and frozen sectioned. Immunocytochemical study was performed for the tissue of the brain. Results showed that the anterior part of the lateral geniculate body contained more monoamines than the posterior part. More serotonins were distrbuted at the magnocellular part, and more dopamines were found at the parvocellular part. In pulvinar, more norepinephrines were distributed at the medial part, while serotonins were evenly distributed at all parts. In lateral posterior nucleus and suprachiasmatic nucleus, three kinds of monoamines were distributed with high density. Among the three, density of the serotonin showed the highest value. The lateral geniculate body relates with visual perception such as visual acuity, form and color perception, and stereopsis, while the pulvinar relates with visual functions, such as visual attention, sensory integration, and differentiation. Since norepinephrine and serotonine are distributed with high density in the pulvinar than in the lateral geniculate body those two monoamines are expected to playa major role for visual functions. Inferior part of the pulvinar relates with visual imagination, and the lateral posterior nucleus relates with integration of visual sensory. Relatively high distribution of dopamine in these two parts means that dopamine may playa major role for visual imagination and integration. As suprachiasmatic nucleus relates with controlling biorhythm, dense distribution of monoamines in suprachiasmatic nucleus implies that the monoamines may work for controlling biorhythm.
Brain ; Color Perception ; Depth Perception ; Dopamine ; Geniculate Bodies ; Imagination ; Lateral Thalamic Nuclei ; Norepinephrine ; Periodicity ; Pulvinar ; Saimiri* ; Sciuridae* ; Serotonin ; Suprachiasmatic Nucleus ; Visual Acuity ; Visual Perception

Visual conditions such as anisometropia, monovision and monocular undercorrection affect the combination of visual input from both eyes. This study investigated the effects of monocular blur, in binocularly normal participants, on stereoacuity and binocular contrast sensitivity. Fifteen young adults (age range between 19 and 23 years old) with normal visual acuity and binocular vision participated in this study. Stereopsis was measured using the TNO test with a series of positive spherical lenses placed before the dominant eye. The procedure was repeated using the Titmus Stereotest on five participants as a control experiment. Monocular and binocular contrast sensitivities were also measured using the Pelli-Robson Contrast Sensitivity Chart. Blur was induced monocularly with a series of positive spherical lenses placed before the dominant eye and binocular contrast sensitivity was re-measured. Stereopsis scores decreased significantly when monocular blur was imposed. Across blur levels, absolute stereopsis scores measured with TNO test were worse than those measured with Titmus stereotest (all p < 0.05). However, the ratio of scores obtained without blur and under monocular blur appeared to be similar for both tests. Stereopsis without blur was between 6.82× to 8× better than that obtained with the highest level of imposed monocular blur. Binocular contrast sensitivity score decreased significantly with increasing level of monocular blur (p < 0.01). Binocular contrast sensitivity score without blur was 1.62× better than that obtained under binocular viewing with highest level of imposed blur. Stereopsis tests are more sensitive than measurements of binocular contrast sensitivity as an indicator of interocular acuity discrepancies which could occur in anisometropic or monovision patients. However, the choice of stereopsis test is crucial, as the TNO test appears to be more sensitive to monocular blur than the Titmus stereostest.
Depth Perception

124 cases with congenital red-green color defects were examined using hahn`s color vision test, double 15 hue test, and Nagel`s anomaloscope. In the Neitz anomaloscope test, 5 cases(4%) showed protanomaly, 1 case(1%) extreme protanomaly, 16 cases (13%) protanopia, 45 cases(36%) deuteranomaly, 52 cases(42%) deuteranopia, and 5 cases (4%) normal state. 5 cases(4%) of protan was classified by degree of color defects, 1 case with mild defect, 1 case with moderate defect, and 3 cases with severe defect by the Hahn`s color vision test. 14 cases (10.4%) of deutan eye the following:5 cases in mild, 6 cases in noderate, and 3 cases in severe defect. 105 cases (85.6%) were the unclassified type. In comparision with Hahn`s color vision test and anomaloscope, the concordance rate was 57.1%(8/14) in only mild and severe color defect of deutan. In the Double 15 hue test, 29 cases (23%) showed in 60.9%(25/41) in deutan. By the degree of color defect, 6 cases showed medium response, 23 cases strong response in protan. 4 cases showed medium, 37 cases strong response in deutan. The concordance rates are 57%(13/23) in protan and 68%(25/37) in deutan in strong response. We conclude that Neitz anomaloscope test is better method than Hahn`s color vision test and double 15 hue test in qualitative and qualntitative dignosis of cogenital red-green color defects.
Color Perception Tests* ; Color Perception* ; Color Vision

In order to explore the possible mechanisms by which ethologically relevant sounds can be extracted from complex auditory environments, this study examined the effects of weak noise on the rate-intensity functions (RIFs) of neurons responding to tone burst in the inferior colliculus (IC) of nine mice (Mus musculus Km). Under free field stimuli conditions, a total of 112 IC neurons were recorded. RIFs with and without simultaneous presentation of weak noise, of which the intensity was relative to 5 dB below minimum threshold of tone burst, were measured in 44 IC neurons. By means of evaluating the changes of dynamic range (DR), slope of RIFs, and percent inhibition at different tone burst intensities evoked by the weak noise, three types of variations in RIFs were observed, i. e., inhibition (39/44, 88.6%), facilitation (2/44, 4.6%), and no effectiveness (3/44, 6.8%). Statistical analysis indicated that only inhibitory effect of weak noise was significant (P< 0.001, n = 39). The inhibitory effect of weak noise was greater at lower stimulus intensity of tone burst but decreased significantly with increased stimulus intensity (P< 0.0001, n = 39). In addition, the DR and slope of RIFs became narrower and steeper with weak noise presentation, respectively (P< 0.01, n = 31). The results from the present study suggest that weak noise exerts a dynamic modulatory action on acoustical intensity sensitivity of IC neurons, which possibly leads to a better understanding of neural mechanisms underlying the extraction of sound signals from natural auditory scenes.
Acoustic Stimulation ; Animals ; Auditory Perception ; physiology ; Auditory Threshold ; physiology ; Inferior Colliculi ; physiology ; Mice ; Neurons ; physiology ; Noise

BACKGROUND AND OBJECTIVES: Deficits of the aging auditory system negatively affect older listeners in terms of speech communication, resulting in limitations to their social lives. To improve their perceptual skills, the goal of this study was to investigate the effects of time alteration, selective word stress, and varying sentence lengths on the speech perception of older listeners. SUBJECTS AND METHODS: Seventeen older people with normal hearing were tested for seven conditions of different time-altered sentences (i.e., +/-60%, +/-40%, +/-20%, 0%), two conditions of selective word stress (i.e., no-stress and stress), and three different lengths of sentences (i.e., short, medium, and long) at the most comfortable level for individuals in quiet circumstances. RESULTS: As time compression increased, sentence perception scores decreased statistically. Compared to a natural (or no stress) condition, the selectively stressed words significantly improved the perceptual scores of these older listeners. Long sentences yielded the worst scores under all time-altered conditions. Interestingly, there was a noticeable positive effect for the selective word stress at the 20% time compression. CONCLUSIONS: This pattern of results suggests that a combination of time compression and selective word stress is more effective for understanding speech in older listeners than using the time-expanded condition only.
Aging ; Auditory Perception ; Hearing ; Speech Perception*

PURPOSE: To study the effect of spherical lens induced aniseikonia on stereopsis and fusion. METHODS: One hundred subjects, with normal binocular function without any ophthalmic disease or surgery history, were examined. The aniseikonia was induced with spherical lenses in 1 diopter (D) stepwise manner from -2 D to +2 D. The amount of aniseikonia was measured by Awaya's New Aniseikonia Test. Stereopsis and fusion were determined with Titmus Stereo Test and fusion card of major amblyoscope respectively. RESULTS: As the amount of aniseikonia was increased, the stereopsis and fusion were decreased. The change was statistically significant (ANOVA, p<0.001). Aniseikonia was more correlated to fusion than stereopsis. A significant decline in the stereopsis was detected when the size of aniseikonia changed from 1% to 2%. A significant decline in fusion was noticed when aniseikonia changed from 2% to 3% (Independent t-test, p<0.01). CONCLUSIONS: Our study suggests that binocular function can be disturbed by experimentally induced aniseikonia in normal subjects and that stereoacuities and fusional amplitude can be decreased as the degree of aniseikonia becomes larger.
Aniseikonia* ; Depth Perception ; Telescopes*

The commonly used tests for stereopsis are Titmus-fly, Randot, and TNO tests. In this study, 50 normal subjects were tested with these tests in order to set a criterion for normal stereopsis. The value of mean, mode and 75% point of these three tests were derived and compared.These three tests were also performed in 23 intermittent exotropes and 32 accommodative esotropes who showed gross stereopsis in the range of 60 to 400 seconds of arc by Titmus-fly testing. The aim was to obtain standards for clinical applicability and accuracy of these tests.This study cincludes that the appropriate criteria for normal stereopsis are less than 60 seconds of arc for Titmus-fly or Randot test, and 120 seconds of arc fot TNO test. Accurate testing for stereopsis in patients with gross stereopsis requires both Titmus-fly and Randot tests together. TNO test was inferior to the other two tests in terms of the accuracy and clinical applicability.
Depth Perception ; Humans