Pharmacological Inhibition of Spermine Oxidase Reduces Neurodegeneration and Improves Retinal Function in Diabetic Mice.

Diabetic retinopathy (DR) is a significant cause of blindness in working-age adults worldwide. Lack of effective strategies to prevent or reduce vision loss is a major problem. Since the degeneration of retinal neurons is an early event in the diabetic retina, studies to characterize the molecular mechanisms of diabetes-induced retinal neuronal damage and dysfunction are of high significance.

Detailed electroretinographic findings in rd8 mice.

Purpose: Previous work has suggested that the retinal degeneration mutant rd8 mouse lacks an electroretinographic (ERG) phenotype until about 9 months of age. We evaluated the ERG phenotype of these mice by measuring both conventional ERG responses and scotopic threshold responses.

Methods: Groups of 4-month-old wild-type (WT) and mutant (rd8) mice were anesthetized and tested for mass retinal responses (ERGs) to several types of visual stimuli.

Multifocal Electroretinography in the Presence of Temporal and Spatial Correlations and Eye Movements.

Releasing patients from the fixation task, and permitting them to view natural stimuli such as movies, would provide increased comfort, and potentially additional signs of retinal function, when recording multifocal electroretinograms (mfERGs). Techniques must be developed to handle the difficulties that arise from these alternative stimulation strategies. Multifocal stimuli were presented to volunteer human subjects with and without fixation.

Effects of fixational saccades on response timing in macaque lateral geniculate nucleus.

Even during active fixation, small eye movements persist that might be expected to interfere with vision. Numerous brain mechanisms probably contribute to discounting this jitter. Changes in the timing of responses in the visual thalamus associated with fixational saccades are considered in this study.

Lagged cells in alert monkey lateral geniculate nucleus.

Five lagged cells were recognized by extracellular recording in the lateral geniculate nucleus of an awake, behaving macaque monkey. Previous reports of lagged cells were all in the anesthetized cat. Both parvocellular and magnocellular lagged cells were observed.

Lagged cells.

The timing of the retinal input to the lateral geniculate nucleus is highly modified in lagged cells. Evidence is reviewed for how the responses of these cells are generated, how their structure and function differs from their nonlagged neighbors, and what their projections to cortex might do.

Temporal receptive field estimation using wavelets.

A standard goal of many neurophysiological investigations is to obtain enough insight into a neuron's behavior that it becomes possible to predict responses to arbitrary stimuli. Techniques have been developed to solve this system identification problem, and the numerical method presented here adds to this toolbox. Stimuli and responses, beginning as functions of time, are transformed to complex-valued functions of both time and temporal frequency, giving amplitude and phase at each frequency and time point.

Temporal properties of inputs to direction-selective neurons in monkey V1.

Motion in the visual scene is processed by direction-selective neurons in primary visual cortex. These cells receive inputs that differ in space and time. What are these inputs? A previous single-unit recording study in anesthetized monkey V1 proposed that the two major streams arising in the primate retina, the M and P pathways, differed in space and time as required to create direction selectivity.

Development of response timing and direction selectivity in cat visual thalamus and cortex.

Single-unit recordings were made in the dorsal lateral geniculate nucleus (LGN) and visual cortex of kittens that were 4-13 weeks of age. Responses to visual stimuli were analyzed to determine the relationship between two related facets of the behaviors of the cells: direction selectivity (DS) and timing. DS depends on timing differences within the receptive field.