Gamma Frequency Activation of Inhibitory Neurons in the Acute Phase after Stroke Attenuates Vascular and Behavioural Dysfunction
This week, we profile a recent publication in Cell Reports from Drs. Matilde Balbi (pictured, fourth from left)
and Tim Murphy (fifth from left) at the Djavad Mowafaghian Centre for Brain Health at UBC.
The Murphy lab at UBC’s Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry lab develops approaches that have parallels to human brain imaging and stimulation tools but are applied in mouse experimental models. In developing these tools, the laboratory participates in the Canadian Neurophotonics Platform and leads UBC’s Dynamic Brain Circuits in Health and Disease Cluster which actively seeks to articulate new optical methods that are applied to questions related to diseases of the nervous system such as changes in brain function after stroke. By understanding the stroke recovery process on a circuit level, the lab hopes to advance patient translatable brain stimulation or other plasticity-inducing treatments.
In our recent publication, we show that entraining brain electrical rhythmic activity at 40 Hz leads to a reduction in stroke damage. This work is significant because it indicates that in addition to clot-busting, altering patterns of brain activity using optogenetics (genetically engineered neurons that can respond to light stimulation) within the first hours after stroke can have a positive effect on recovery in a mouse model. In our mouse model, these 40 Hz brain oscillations lead to better blood flow and brain tissue as well as functional recovery. While our work employed optogenetic stimulation that is not available in humans, it is possible that analogous forms of brain activity entrainment could be performed using sound stimulation or flashing lights.
Next steps for the research include trying to substitute optogenetic stimulation with light, sound, or tactile stimulation that activates the brain in a similar manner. If this can be done with other forms of sensory stimulation, stroke patients could undergo early interventions, which would entrain brain activity at 40 Hertz or similar frequencies leading to better long-term recovery. In fact, work in Alzheimer’s disease model mice suggests that flashing lights or sounds that help entrain 40 Hz activity can reduce the number of amyloid plaques.
We are grateful to our funding sources including the Canadian Institutes for Health Research, the Canadian Partnership for Stroke Recovery, Michael Smith Foundation for Health Research trainee program, and the Leducq Foundation. Dr. Balbi, the lead author, has taken up a position at the University of Queensland Australia and will continue similar research directions. Dr. Murphy is also continuing work on brain activity entrainment and stroke and will also begin to examine Alzheimer’s disease models.