Early diabetes impairs visual function in mice through altering neuronal activity in the primary visual cortex.

Area of Science:

• Neuroscience
• Ophthalmology
• Diabetology

Background:

• Diabetes mellitus is known to cause visual impairments, including retinopathy.
• Central visual system dysfunction, affecting directional selectivity and color vision, can occur even without retinopathy.
• Contrast sensitivity (CS) is crucial for visual perception, enabling the differentiation of objects from their backgrounds.

Purpose of the Study:

• To investigate the effects of early-stage diabetes on the contrast sensitivity function of primary visual cortex (V1) neurons.
• To determine if visual processing deficits occur in V1 before the onset of observable retinopathy.

Main Methods:

• Diabetic mice models were utilized to examine visual cortex function.
• Multichannel electrophysiological recordings were performed on V1 neurons.
• Interneuronal correlation analysis and funduscopic examinations were conducted.

Main Results:

• V1 neurons in diabetic mice showed significantly reduced contrast sensitivity compared to control groups.
• Neuronal responses exhibited decreased signal-to-noise ratios and increased variability.
• Elevated noise correlation in the V1 of diabetic mice was observed, suggesting impaired population neuronal coding.

Conclusions:

• Significant alterations in V1 neuronal contrast sensitivity function occur in early diabetes, preceding funduscopic lesions.
• Disruption of the excitatory/inhibitory balance contributes to the observed neuronal dysfunction.
• These findings indicate a diminished coding capacity in V1 neurons during the early stages of diabetes, impacting visual perception.