Neural oscillations as important information carrier in the brain, are increasingly interpreted as transient bursts rather than as sustained oscillations. Short (<150 ms) bursts of beta-waves (15-30 Hz) have been documented in humans, monkeys, and mice. These events were correlated with memory, movement and perception, and were even suggested as the primary ingredient of all beta-band activity. However, a method to measure these short-lived events in real-time and to investigate their causal impact on behaviour and overall oscillatory power is missing. Here we present a real-time data analysis system, capable to detect short and narrowband bursts. The system is associated with an operant conditioning apparatus for rodents, thus enabling closing the loop between oscillatory events and behaviour (neurofeedback). We successfully trained 3 rats to increase the beta event rate in motor cortex, and indeed observed an overall increase in beta-power, supporting the critical role of events on beta-band activity. The increase in beta could be linked to behaviour, as a machine learning algorithm could reliably predict occurrences of beta events based on the rats' movements. Our results demonstrate the potency and flexibility of the real-time neurofeedback system in a freely moving rodent as well as the impact of transient bursts on global oscillatory power. Our approach can be a starting point for a plethora of studies targeted at understanding the causal role of oscillatory bursts. For example, instead of artificial external stimuli, real-time burst-triggered stimulus presentations could be combined with behavioural and electrophysiological measurements, thereby allowing to probe the intrinsic function of oscillatory bursts. Furthermore, neurofeedback has been clinically used for decades without a clear understanding of the underlying neural mechanisms. As our tool is ideally suited for rodents, it can be combined with additional invasive or non-invasive treatments and post-mortem histology, thereby providing a new testbed with high relevance for future clinical developments.

Real-time detection of neural oscillation bursts allows behaviourally relevant neurofeedback