A functional neurosurgery fellow at Toronto Western Hospital, Strauss wants to know whether mild electrical pulses administered to a brain structure called the fornix improves memory circuits in people with mild Alzheimer’s disease.
The fornix is made up of axons, which are long fibres that extend from brain cells and carry outgoing messages. The fornix acts as a one-way link from the hippocampus to the rest of the brain. The hippocampus plays an important role in helping us consolidate short and long term memory and in spatial memory.
“We think that by charging the fornix, we might be able augment memory circuits in the brain” says Strauss, whose study is funded by the Alzheimer Society of Ontario and the Firefly Foundation.
While scientists don’t completely understand the mechanism, 20 years of deep brain stimulation in those with Parkinson’s disease shows it helps control the shaking associated with the illness. It also shows promise as a treatment for those with severe depression.
“Now we are trying it with Alzheimer’s disease,” says Strauss. His study is part of a larger international project on deep brain stimulation led by Dr. Andres Lozano at Toronto’s University Health Network.
“it could have huge implications.”
Strauss will test brain function in 20 participants implanted with a pacemaker-like battery beneath the skin of their chest. Two attached wires running under the skin behind the ears will deliver electrical pulses directly to the fornix. The devices will stay in their brains for the rest of the lives.
Ten of the participants will have device turned on immediately. The other 10 will have it turned on after 12 months. Neither the participants nor the research team know whose device is live and whose isn’t.
Before the devices are implanted, Strauss will use functional MRI scans to measure brain activity during memory exercises in which participants are asked to remember a series of faces and names. After a full year of living with the implants, participants will return to Strauss for a second assessment.
Strauss says he should know in about a year whether activity in the brain’s memory circuits are enhanced for those with live devices.
“Depending on what we find, it could have huge implications, not only for those with Alzheimer’s disease, but also for understanding memory networks,” says Strauss.
spark award: $51,500
The neuromodulatory effect of deep brain stimulation of the fornix on memory networks in Alzheimer’s disease
This study aims to explore the functional organization of memory related neural networks, and by doing so improve our understanding of how memories are encoded and how the process can be influenced by Deep Brain Stimulation (DBS) strategy in Alzheimer’s patients. Alzheimer’s disease is a progressive neurodegenerative disorder characterized by the gradual deterioration of affected individuals’ memory, intellect, and autonomy. A novel intervention consists of the implantation of Deep Brain Stimulation (DBS) electrodes of the fornix is currently taking place at the Toronto Western Hospital. The present study aims to evaluate the potential neuromodulatory effect of DBS stimulation of the fornix on memory performance in these patients and characterize the underlying neural changes. To accomplish this aim, patients will undergo a functional magnetic resonance imaging (fMRI) exam before and 12 months after the surgery. In each session the neural responses during an intentional formation of memories task will be tracked.