The basis of processing and encoding the information signal in the nervous system is based on the firings (spikes) formed by the neurons. It is stated that the information encoding mechanism of neurons is strongly related to the spike time or rate. In addition, it has been shown that neurons benefit more efficiently from the synaptic connection with coding based on spikes timing than with coding based on spikes ratio. One of the information encodings based on spike time is the first firing time in neurons. In this context, the first spike dynamics of neurons have been extensively examined in both experimental and numerical studies. For example, it has been reported that noise with a certain level induces delays in the first spike time of neurons. On the other hand, bi-chromatic signals are widespread in the brain, considering burst-type neurons that can fire on two or more time scales. In recent years, the electrical dynamics of neurons under the influence of two different frequency signals, one low-frequency (LF) signal and the other high-frequency (HF) signal, have been analyzed in detail. Studies have shown that the coding performance of weak LF signals of neurons is optimized at a certain amplitude of YF signals. The dynamics of this phenomenon, known as vibrational resonance, have been extensively studied in the literature at the single neuron level and in various network schemes. However, the effects of HF signals on the first firing times of neurons, a crucial coding mechanism in the neuronal system, have not been addressed. With this motivation, the effects of HF signals on the first spike latency of Hodgkin-Huxley (H-H) neurons are investigated in this study. Prior findings show that HF signal at a particular amplitude induces significant delays in the first spike latencies of H-H neurons. It is observed that these delays become more pronounced at the frequencies at the boundaries separating the sub-threshold and the supra-threshold.
Anahtar Kelimeler: high-frequency signal, low-frequency signal, Hodgkin-Huxley neuron, first firing time.