| Different rhythms of brain electrical activity in humans are related to different consciousness states, while the specificity of different rhythms of neural signals in different states of other species such as birds is not yet clear. In this paper, we studied the rhythm specificity of neural activity in pigeons (Columba livia domestica) under different states of consciousness: anesthetic coma, consciously quiet, and freely exploring, by analyzing the local field potential (LPF) signals. Firstly, LPF signals in different states were collected. Then, five rhythms including delta (1﹣4 Hz), theta (4﹣8 Hz), alpha (8﹣12 Hz), beta (15﹣30 Hz) and gamma (30﹣60 Hz) were extracted.. Finally, time-frequency analysis was carried out by using wavelet transform, studying the characteristics of different rhythms by observation of statistical time-frequency diagram and statistical analysis of wavelet energy. We also analyzed the complexity of signals based on the Sample Entropy to explore the possible reasons for this rhythm specificity. The statistical hypothesis testing was carried out by Friedman test. Results showed that as the brain became clear and clear, the low-frequency rhythms delta, theta, and alpha, were significantly inhibited (P < 0.001, Fig. 3), while the activity of high-frequency rhythm, gamma was significantly enhanced (P < 0.001, Fig. 3). We then did statistical hypothesis testing for sample entropy of neural signal in different rhythms, and the results of Friedman test showed that the higher the rhythm frequency band, the greater the signal sample entropy (P < 0.001, Fig. 4), corresponding to the improvement of consciousness clarity from anesthesia, awakening to free exploring. The study on the rhythm specificity of neural electrical activity in pigeons under different conditions will make contribution to the understanding of the encoding mechanism of neural rhythm in different species. |
