State University of New York College of Optometry

About: State University of New York College of Optometry is a education organization based out in New York, New York, United States. It is known for research contribution in the topics: Population & Receptive field. The organization has 428 authors who have published 747 publications receiving 17653 citations. The organization is also known as: SUNY Optometry & State College of Optometry.

Temporal precision in the neural code and the timescales of natural vision

Abstract: In mammalian visual system, spikes evoked by visual stimuli have millisecond-scale timing even though the relevant timescales of visual processing themselves are much slower. It has therefore long been debated whether spike timing itself carries some form of the neural code. Now experiments in the lateral geniculate nucleus of cats, the part of the brain that is the primary processor of visual information, show that spike timing precision is not absolute for all classes of visual stimuli. Rather, the degree of precision is relative to the timescale of the stimulus, and this relatively high level of precision is required to construct an accurate representation of the stimulus. In the mammalian visual system, spikes evoked by visual stimuli have millisecond-scale timing, even though the relevant time scales of visual processing themselves are much slower. In cat lateral geniculate nucleus, spike timing precision is not absolute for all classes of visual stimuli, but is relative to the time scale of the stimulus. Further, it is demonstrated that this relatively high level of precision is required to construct an accurate representation of the stimulus. The timing of action potentials relative to sensory stimuli can be precise down to milliseconds in the visual system1,2,3,4,5,6,7, even though the relevant timescales of natural vision are much slower. The existence of such precision contributes to a fundamental debate over the basis of the neural code and, specifically, what timescales are important for neural computation8,9,10. Using recordings in the lateral geniculate nucleus, here we demonstrate that the relevant timescale of neuronal spike trains depends on the frequency content of the visual stimulus, and that ‘relative’, not absolute, precision is maintained both during spatially uniform white-noise visual stimuli and naturalistic movies. Using information-theoretic techniques, we demonstrate a clear role of relative precision, and show that the experimentally observed temporal structure in the neuronal response is necessary to represent accurately the more slowly changing visual world. By establishing a functional role of precision, we link visual neuron function on slow timescales to temporal structure in the response at faster timescales, and uncover a straightforward purpose of fine-timescale features of neuronal spike trains.

Corneal epithelial wound healing.

Abstract: One of the important functions of the cornea is to maintain normal vision by refracting light onto the lens and retina. This property is dependent in part on the ability of the corneal epithelium to undergo continuous renewal. Epithelial renewal is essential because it enables this tissue to act as a barrier that protects the corneal interior from becoming infected by noxious environmental agents. Furthermore, the smooth optical properties of the corneal epithelial surface are sustained through this renewal process. The rate of renewal is dependent on a highly integrated balance between the processes of corneal epithelial proliferation, differentiation, and cell death. One experimental approach to characterize these three aspects of the renewal process has been to study the kinetics and dynamics of corneal re-epithelialization in a wound-healing model. This effort has employed in vivo and in vitro studies. From such studies it is evident that the appropriate integration and coordination of corneal epithel...

Occurrence of Ocular Motor Dysfunction in Acquired Brain Injury: A Retrospective Analysis

Abstract: BACKGROUND The purpose of this retrospective study was to determine the frequency of occurrence of oculomotor dysfunctions in a sample of ambulatory outpatients who have acquired brain injury (ABI), either traumatic brain injury (TBI) or cerebrovascular accident (CVA), with associated vision symptoms. METHODS Medical records of 220 individuals with either TBI (n = 160) or CVA (n = 60) were reviewed retrospectively. This was determined by a computer-based query spanning the years 2000 through 2003, for the frequency of occurrence of oculomotor dysfunctions including accommodation, version, vergence, strabismus, and cranial nerve (CN) palsy. RESULTS The majority of individuals with either TBI (90%) or CVA (86.7%) manifested an oculomotor dysfunction. Accommodative and vergence deficits were most common in the TBI subgroup, whereas strabismus and CN palsy were most common in the CVA subgroup. The frequency of occurrence of versional deficits was similar in each diagnostic subgroup. CONCLUSION These new findings should alert the clinician to the higher frequency of occurrence of oculomotor dysfunctions in these populations and the associated therapeutic, rehabilitative, and quality-of-life implications.

Receptive field structure varies with layer in the primary visual cortex.

Abstract: Here we ask whether visual response pattern varies with position in the cortical microcircuit by comparing the structure of receptive fields recorded from the different layers of the cat's primary visual cortex. We used whole-cell recording in vivo to show the spatial distribution of visually evoked excitatory and inhibitory inputs and to stain individual neurons. We quantified the distribution of 'On' and 'Off' responses and the presence of spatially opponent excitation and inhibition within the receptive field. The thalamorecipient layers (4 and upper 6) were dominated by simple cells, as defined by two criteria: they had separated On and Off subregions, and they had push-pull responses (in a given subregion, stimuli of the opposite contrast evoked responses of the opposite sign). Other types of response profile correlated with laminar location as well. Thus, connections unique to each visual cortical layer are likely to serve distinct functions.