Even though retinal images of objects change their locations following each eye movement, we perceive a stable and continuous world. One possible mechanism by which the brain achieves such visual stability is to construct a craniotopic coordinate by integrating retinal and extraretinal information. There have been several proposals on how this may be done, including eye-position modulation (gain fields) of retinotopic receptive fields (RFs) and craniotopic RFs. In the present study, we investigated coordinate systems used by RFs in the lateral intraparietal (LIP) cortex and frontal eye fields (FEF) and compared the two areas. We mapped the two-dimensional RFs of neurons in detail under two eye fixations and analyzed how the RF of a given neuron changes with eye position to determine its coordinate representation. The same recording and analysis procedures were applied to the two brain areas. We found that, in both areas, RFs were distributed from retinotopic to craniotopic representations. There was no significant difference between the distributions in the LIP and FEF. Only a small fraction of neurons was fully craniotopic, whereas most neurons were between the retinotopic and craniotopic representations. The distributions were strongly biased toward the retinotopic side but with significant craniotopic shifts. These results suggest that there is only weak evidence for craniotopic RFs in the LIP and FEF, and that transformation from retinotopic to craniotopic coordinates in these areas must rely on other factors such as gain fields.
Animals ; Macaca ; Visual Fields ; Frontal Lobe/physiology* ; Eye Movements ; Brain

To investigate the effect of illumination on visual acuity and visual field in eyes with multifocal intraocular lens (IOL), the near and far visual acuity of the eyes with multifocal implants were compared to those of the eyes with monofocal implants in the diminished illumination, and the visual fields of two groups were also compared by the different target size and intensity. The near and far visual acuity of the eyes with multifocal implants were significantly decreased as compared to those of the eyes with monofocal implants under diminished illumination, and the visual field of the multifocal implanted eyes also significantly decreased as compared to that of the monofocal implanted eyes by the reduction of spot size and intensity. From the above results, it is assumed that the bifocal separation of incident light to two simultaneous focal points in the multifocal implants causes more decreased visual acuity and narrower visual field in the diminished illumination as compared to that of the eyes with monofocal implants.
Adult ; Cataract Extraction ; Female ; Humans ; *Lenses, Intraocular ; Light ; *Lighting ; Male ; Visual Acuity/*physiology ; Visual Fields/*physiology

OBJECTIVE: To compare pattern-pulse multifocal visual evoked potential (PPmfVEP) with pattern-reversal multifocal visual evoked potential (PRmfVEP), and to investigate the symmetry of mfVEP between both eyes in normal individuals. METHODS: The multifocal Vision Monitor was used to observe the mfVEP. T-test and ANOVA were used to analyze P1 wave, amplitude and signal noise ratios (SNR) of two mfVEPs. RESULTS: The SNR and the P1 amplitude reached the maximum at the central visual field and decreased with the increase of eccentricity, and then decreased slowly. The amplitude of the PPmfVEP was significantly smaller than the PRmfVEP in the central retina, while in the peripheral retina the result was exactly the opposite. SNR and amplitude of the PRmfVEP showed no statistical difference in both eyes (P > 0.05). The variance of the amplitude at the same side of visual field was larger than that at the symmetrical visual quadrant. CONCLUSION mfVEP can reflect the visual function in different parts of retina objectively and exactly. PPmfVEP reflect the vision function of the central retina better than PRmfVEP. The stability of PPmfVEP is better than PRmfVEP in the central retina, while the result is opposite in the peripheral retina. The mfVEP is symmetrical in both eyes of the same individual.
Evoked Potentials, Visual/physiology* ; Humans ; Neurologic Examination ; Reference Values ; Retina ; Sensitivity and Specificity ; Visual Fields/physiology*

OBJECTIVE: To study the character of the PRVEPs evoked by different stimulation fields in normal-vision subjects and its value in forensic medicine. METHODS: The PRVEPs were evoked by full-field, central-field and peripheral-field respectively in 30 subjects (60 eyes) and the latency and amplitude of N1 and P1 were analyzed. RESULTS: There was no statistically significant difference in the latency and amplitude of PRVEPs between right and left eyes. The appearance probability of all the waves was 100% at the different stimulations but that of N1 was 36.77% at the central-field. There was statistically significant difference in the latency of N1 at the full field and peripheral field stimulations and there was no statistically significant difference in the amplitude. There was statistically significant difference in the latency and amplitude of P1 at the full field, central field and peripheral field stimulation. CONCLUSION The PRVEPs evoked by different field stimulations can be used to evaluate the functions of the different area retina and can be used to identify the exaggerated or pretended visual dysfunction.
Adult ; Evoked Potentials, Visual/physiology* ; Female ; Forensic Medicine ; Humans ; Male ; Photic Stimulation ; Retina/physiology* ; Visual Fields/physiology* ; Young Adult

Active exploratory behaviors have often been associated with theta oscillations in rodents, while theta oscillations during active exploration in non-human primates are still not well understood. We recorded neural activities in the frontal eye field (FEF) and V4 simultaneously when monkeys performed a free-gaze visual search task. Saccades were strongly phase-locked to theta oscillations of V4 and FEF local field potentials, and the phase-locking was dependent on saccade direction. The spiking probability of V4 and FEF units was significantly modulated by the theta phase in addition to the time-locked modulation associated with the evoked response. V4 and FEF units showed significantly stronger responses following saccades initiated at their preferred phases. Granger causality and ridge regression analysis showed modulatory effects of theta oscillations on saccade timing. Together, our study suggests phase-locking of saccades to the theta modulation of neural activity in visual and oculomotor cortical areas, in addition to the theta phase locking caused by saccade-triggered responses.
Animals ; Frontal Lobe/physiology* ; Macaca mulatta ; Neurons/physiology* ; Saccades ; Theta Rhythm ; Visual Fields

Event-related potentials (ERP) is a good temporal resolution method to study the mechanism of visual field in brain. With the development of technique of high-density recording and brain imaging, the ERP is widely used in the location of the brain function. This article reviews the methods, results and primary conclusions in the field, and suggests several perspectives for the future research and application of ERP in the forensic science.
Attention/physiology* ; Brain/physiology* ; Evoked Potentials/physiology* ; Forensic Medicine ; Humans ; Photic Stimulation/methods* ; Space Perception/physiology* ; Visual Fields/physiology* ; Visual Perception

OBJECTIVE: To study the variation of latency and amplitude of the event related potential (ERP) and its distribution in human scalp when the normal subjects were stimulated with different visual fields. METHODS: The ERP recorded in scalp with the stimulation of 10 degrees visual field and 60 degrees visual field respectively in 20 healthy volunteers with normal visual function. RESULTS: Two different visual field stimulation may evoke the different exogenous components P1 (70-125 ms), N1 (90-170 ms), P2 (140-220 ms) and endogenous components N2 (190-280 ms) and P3 (290-430 ms). The latencies of all the components evoked by 10 degrees visual field were shorter than that of the 60 degrees visual field while the amplitudes of N1 and N2 were lower and appeared over the extensive encephalic region; and the amplitudes of the P1, P2 and P3 were higher and appeared in occipitotemporal, prefrontal and occipital region, respectively. CONCLUSION Two different visual field stimulation may evoke all the ERP components with significant differences in the latency, amplitude and distribution. The differences may reflect the different visual information integration and processing in human brain during the different visual field stimulation.
Adult ; Brain/physiology* ; Electroencephalography/methods* ; Electrooculography ; Evoked Potentials, Visual/physiology* ; Female ; Humans ; Male ; Photic Stimulation ; Reaction Time/physiology* ; Reference Values ; Scalp/physiology* ; Visual Field Tests/methods* ; Visual Fields/physiology* ; Visual Perception/physiology* ; Young Adult

The relationship between visual acuity, the level of visual field impairment, visual functioning, and the quality of life was evaluated in Korean patients with glaucoma. Forty-three consecutive glaucoma patients from the glaucoma service at Severance Eye and Ear Hospital were included in this study. Each subject underwent a vision-specific functional status questionnaire (VF-14), a modified VF-14 (VF'-14) and general quality-of-life questionnaires of the Medical Outcomes Study 36-Items Short Form Health Survey (SF-36). The visual acuity and visual field measurements with a Humphrey automated perimeter were taken within one month of the initial visit. The mean age of the subjects was 57.9 +/- 17.8. Among these patients, there were 23 males and 20 females. The mean deviation (MD) and the corrected pattern standard deviation (CPSD) by the automated perimeter in the eye with the better visual acuity were -5.87 +/- 5.16 dB and 3.92 +/- 2.74 dB respectively. The VF-14 and SF-36 scores were 41.28 +/- 14.56 and 52.39 +/- 6.61 respectively. There were significant correlations between the VF-14, VF'-14, and the MD of the better eye (p < 0.05). In Korean patients with glaucoma, the VF-14 and VF'-14 have significant relationship with the MD of the better eye in the visual field.
Female ; Glaucoma/physiopathology/*psychology ; Health Surveys ; Human ; Korea ; Male ; Middle Aged ; Quality of Life/*psychology ; Questionnaires ; Visual Acuity/*physiology ; Visual Fields

We quantitatively analyzed the changes of the (retinal) threshold sensitivities between normal status and dilated emmetropic status, and between dilated emmetropic status and -1.0D induced myopic status. Three consecutive visual field examinations by Humphrey Field Analyzer C-30-2 threshold test and STATPAC program were performed in 36 eyes of 21 normal subjects who ranged in age from 23 to 40 years. The results were as follows: 1) There was a statistically significant decrease (0.87 +/- 0.91dB)in the mean threshold sensitivity within the central 30 degrees at the dilated emmetropic status (27.90dB) as compared with the normal status (28.77dB)(p = 0.0001). 2) There was a statistically significant decrease(0.99 +/- 0.61dB) at -1.0D induced myopic status(26.91dB) as compared with the dilated emmetropic status(27.90dB)(p = 0.0001). 3) After dilation, the mean threshold sensitivity between 20 and 30 degrees of field showed statistically significant decrease as compared with those within the central 20 degrees of visual field(p < 0.05). In case of -1.0D induced myopia, there were uniform decreases in the mean threshold sensitivities within the central 30 degrees of visual field (p > 0.05). Therefore, we emphasize the importance of consistent pupillary size and correct refractive state in performing the serial automated visual field tests.
Adult ; Female ; Humans ; Male ; Myopia/etiology/*physiopathology ; Pupil/drug effects ; Pupil Disorders/chemically induced/*physiopathology ; Retina/physiology ; Sensory Thresholds/*physiology ; Tropicamide/pharmacology ; Visual Field Tests ; Visual Fields/*physiology

In this paper the event-related potential (ERP) of selective attention to the left and right visual field is investigated with 3D tomography technique. The results show that compared with the scalp surface ERP data, the current source intensity derived from tomography can better reflect the enhanced effect of P1 and N1, especially N1. Moreover, C1 component can be observed in the results, which cannot be identified in the scalp data.
Adult ; Attention ; physiology ; Electroencephalography ; methods ; Event-Related Potentials, P300 ; Evoked Potentials, Visual ; physiology ; Female ; Humans ; Imaging, Three-Dimensional ; Male ; Tomography ; methods ; Visual Fields ; physiology