Optogenetics is a new and rapidly evolving gene and neuroengineering technology that allows optical control of specific populations of neurons without affecting other neurons in the brain at high temporal and spatial resolution. By heterologous expression of the light-sensitive membrane proteins, cell type-specific depolarization or hyperpolarization can be optically induced on a millisecond time scale. Optogenetics has the higher selectivity and specificity compared to traditional electrophysiological techniques and pharmaceutical methods. It has been a novel promising tool for medical research. Because of easy handling, high temporal and spatial precision, optogenetics has been applied to many aspects of nervous system research, such as tactual neural circuit, visual neural circuit, auditory neural circuit and olfactory neural circuit, as well as research of some neurological diseases. The review highlights the recent advances of optogenetics in medical study.
AIM: To investigate inhibitory γ-aminobutyric acid (GABA) ergic postsynaptic currents (IPSCs) and postsynaptic currents (PSCs) in layer IV of the rat visual cortex during the critical period and when plasticity was extended through dissolution of the perineuronal nets (PNNs). METHODS: We employed 24 normal Long-Evans rats to study GABA A-PSC characteristics of neurons within layer IV of the visual cortex during development. The animals were divided into six groups of four rats according to ages at recording: PW3 (P21 -23d), PW4 (P28 -30d), PW5 (P35-37d), PW6 (P42-44d), PW7 (P49-51d), and PW8 (56-58d). An additional 24 chondroitin sulfate proteoglycan (CSPG) degradation rats (also Long-Evans) were generated by making a pattern of injections of chondroitinase ABC (chABC) into the visual cortex 1 week prior to recording at PW3, PW4, PW5, PW6, PW7, and PW8. Immunohistochemistry was used to identify the effect of chABC injection on CSPGs. PSCs were detected with whole-cell patch recordings, and GABA A receptor-mediated IPSCs were pharmacologically isolated. RESULTS: IPSC peak current showed a strong rise in the age-matched control group, peaked at PW5 and were maintained at a roughly constant value thereafter. Although there was a small increase in peak current for the chABC group with age, the peak currents continued to decrease with the delayed highest value at PW6, resulting in significantly different week-by-week com-parison with normal development. IPSC decay time continued to increase until PW7 in the control group, while those in the chABC group were maintained at astable level after an initial increase at PW4. Compared with normal rats, the decay times recorded in the chABC rats were always shorter, which differed significantly at each age. We did not observe any differences in IPSC properties between the age-matched control and penicillinase (P-ase) group. However, the change in IPSCs after chABC treatment was not reflected in the total PSCs or in basic membrane properties in layer IV of the rat visual corte
AIM: To construct a new visual acuity measuring function for congenital nystagmus(CN) patients by studying the relationships between acuity,velocities and positions of the eye. ·METHODS: After assessing the relationship between acuity,movement velocities and positions of the eye separately,a new function,which we call the automated nystagmus acuity function(ANAF),was constructed to measure the visual acuity of CN patients. Using a high-speed digital video system working at 500 frames per second,each eye was calibrated during monocular fixation. Twenty-six recorded nystagmus data were selected randomly. Using nystagmus waveforms,the best vision position(foveation period) and visual acuity were analyzed in three groups of subjects,and then all outputs were compared with the well-known expanded nystagmus acuity function(NAFX) and ANAF. Standard descriptive statistics were used to summarize the outputs of the two programs. ·RESULTS: Foveation periods were brief intervals in the CN waveform when the image was on or near the fovea and eye velocity was relatively slow. Results showed good visual acuity happened during the period when velocity was low and the eye position was near the zero position,which fitted the foveation periods. The data analyzed with NAFX and ANAF had a correlation coefficient of 0.934276,with an average error of-0.00973. · CONCLUSION: The results from ANAF and NAFX analyses showed no significant difference. The NAFX manually identifies foveation eye positions and produces accurate measurements. The ANAF,however,can be calculated simply using the factors eye position andvelocity,and it automatically calculates the ANAF without the need to manually identify foveation eye positions.
