[The preliminary study of stimulus input temporal changes on the visual cortex of rats at different ages]

Objective: To observe the impact of the input temporal changes on visual cortex of rats cells and the change of the synaptic efficacy, for the study of visual developmental plasticity mechanism. Methods: Experimental research. The brain slice of ten 14d healthy Wistar rats and ten 21d healthy Wistar rats were recorded with whole cell recording technique, using single stimulation and combined stimulate model, to observe the visual cortex of rats neurons changes in synaptic activity. Change the stimulus input sequence, and observe the visual cortex of rats changes of synaptic efficacy. Using the paired t test to compare the change of excitatory postsynaptic potential (EPSC) of visual cortex. Result: The difference between single stimulation and combined stimulate about EPSC was statistically significant, which was decreased (14.3±7.4) % (n=15) in single stimulation and (53.4±17.5) % (n=20) in combined stimulation for P14 rats which were long-term depression (t_s2=3.9, t_s1+s2=2.2; P<0.05) , and was increased (27.5±11.4) % (n=16) in single stimulation and (34.6±10.3) % (n=10) in combined stimulation for P20 rats which were long-term potentiation (t_s2=2.3, t_s1+s2=3.5; P<0.05) . Rats in different development period have a specific time window for input temporal changes. Combined stimulation patterns produced by the neuron cell reaction were not just an accumulation of simple response caused by single stimulation. For P14 rats, its time window was of about ±0.5ms. However, for P20 rats, scope of time window reduced to ±0.1ms. Conclusions: Different development period of rats, change the stimulation pattern can cause the change of the visual cortex synapses reaction, and stimulate the temporal change within a specific time window to producenonlinear results. (Chin J Ophthalmol, 2016, 52: 936-940).