Expression of brain-derived neurotrophic factor in the lateral geniculate body of monocular form deprivation amblyopic kittens

Purpose: The present study compared the expression of brain-derived neurotrophic factor (BDNF) in the lateral geniculate body between form deprivation amblyopia kittens and normal kittens to examine the significance of BDNF in the lateral geniculate body in the pathogenesis of amblyopia. Methods: Twenty kittens were divided into control group ( n = 10) and deprivation group ( n = 10). A black opaque eye mask was placed to cover the right eye of the deprivation group. Pattern visual-evoked potentials (PVEPs) were detected weekly in all kittens .After the kittens in the deprivation group developed monocular amblyopia, the lateral geniculate bodies of all kittens were removed. The expression of BDNF in the lateral geniculate body of the two groups was compared by immunohistochemistry and Western blotting. Results: The latency of the P100 wave in the right eye of the deprivation group was longer than that of the left eye and that of the right eye of the control group ( p < 0.05), and the amplitude decreased ( p < 0.05). The number and average optical density of BDNF-positive cells in the deprivation group were lower than those in the control group ( p < 0.05), and the expression of BDNF in the deprivation group was lower than that in the control group ( p < 0.05). Conclusions: The expression of BDNF in the lateral geniculate body of the amblyopic kittens decreased, and the decrease in BDNF promoted the development of amblyopia. These results demonstrate that BDNF in the lateral geniculate body plays an important role in visual development.

Reference values of pattern reversal visual evoked potentials in Bulgarian population

Aims: The aim of this study is to evaluate pattern visual evoked potentials as an objective electrophysiological method and to create reference values for Bulgarian population. Methods and Materials: Standardized four-channel equipment ‘Neuro-MEP 4’ produced by ‘Neurosoft’ Company was used. A group of 47 healthy individuals (94 eyes) was studied. The stimulation was monocular, with a contrast-reversing pattern from black to white and vice versa. The investigation was performed with a three-channel recording with equipment adjustments according to the latest published ISCEV standard for pattern visual evoked potentials (2016). Based on a comprehensive overview of the available literature, a protocol of stimulating, amplifying and recording the obtained potentials has been created. The values of pattern visual evoked potential wave components, P50, N75, P100, N145 and P200, were measured. Results: Based on a created protocol, latency and amplitudes of the individual wave components of pattern visual evoked potentials were obtained. The results were statistically processed to create reference values of all pattern visual evoked potentials components, which are used as reference of the laboratory for the Bulgarian population. Conclusion: Pattern visual evoked potentials are objective electrophysiological method which is used to diagnose and monitor numerous ophthalmological and neurological diseases as well as for objective study of visual acuity and visual field in children and aggravation. The creation of pattern visual evoked potentials reference values for the Bulgarian population and its implementation in clinical practice are of particular importance for studying the visual analyser function.