Volitional Modulation of Temporal Spiking Patterns Uncovers the Ability of Temporal Coding in Abstract Skills Learning.

The ability to learn various kinds of skills, whether it is motor, sensory or cognitive, is pivotal to animal’s survival through evolution. Multiple coding schemes may be involved to encode information needed in learning. Among them, temporal coding is able to provide expanded bandwidth which renders more information to be encoded. Thus, we were motivated to inspect whether animal have the capability of encoding information in temporal precision to acquire skills. In this study, we adopted the brain-machine interfaces (BMIs) to investigate whether the precise spiking patterns can be directly reinforced and volitionally modulated. Rats were trained to learn to control the pitch of an auditory cursor to achieve rewards by volitionally modulating the number of concurrent spiking pairs between two selected units. We found that, performance in the task improved over sessions with successful modulation of relative timing of firings between two selected units to a short interval within 15ms, which indicated that temporal coding can play a part in abstract skill learning. Moreover, the fine temporal structure of neural activity and the yielding behavioral outcomes involved in learning was able to be unified under one experimental framework and robustly controlled for further studies. Successful conditioning of temporal spike patterns also revealed the great potential for high-resolution BMIs and clinical applications.