Brain Rhythms Lab

Our laboratory studies the dynamics of collective activity in the nervous system as expressed by the different temporal and spatial patterns of oscillatory synchronization that are evident in the EEG across behavioural states.

Why are we interested in collective activity?
Collections (or ensembles) of nerve cells (and not just single neurons) are likely to underlie the brain’s representation of both simple and complex environmental stimuli. Thus, studying ensemble activity is the way to understand the operation of the nervous system.

Why might synchrony be important?
Synchrony is an activity-dependent way by which ensembles of neurons could be bound together into a representation. As a perceptual example, think about the salience of synchronously flashing or moving lights in a marquee display (like the teletype displays common for stock trading). You tend to see these displays as coherent moving groups of letters or images and not simply random flashing dots. In the nervous system, synchrony in groups of neurons might be read (i.e., perceived) in a similar fashion. Indeed, through a synchronous associative and activity dependent process, these representations might also be stored (i.e., learned and memorized).

Why would oscillations be important?
The elicitation of de novo synchronization is costly in terms of energy requirements. A more efficient synchronization method would be to exploit an already oscillatory process. As an example, think about when you are a member of a group of people helping to push a car out of a snow bank (a fairly frequent activity for Canadians). In order to coordinate activity, a preliminary count-down is given (usually a cycle count of three: 1, 2, 3, …) during which you (and the others) rhythmically tone your muscles in tempo with each count. This culminates in a highly coordinated push on the final count of four. Think of how difficult this synchronization would be to achieve if you didn’t have a oscillatory cycling (the rhythmic count) to coordinate the final push. Spontaneous oscillatory processes in single neurons and local networks could be exploited in the same fashion in the nervous system.

Brain Rhythms as Differential Processing States.
In the brain, different patterns of synchronized and coordinated oscillations could operate as different forms of processing or computational routines which could differentially bias inputs and outputs. Our lab is interested in both the mechanisms AND the functional relevance of these different rhythmic states.