Stroke recovery in mice through light

Using something as simple and ubiquitous as light, medical research has made advances in neuroscientific research, and importantly, in stroke recovery treatments. After experiencing a stroke, the devastating consequences can be wide-ranging. This is due to the complexity of the brain, and the unique areas of function that work seamlessly together. Treatment options for strokes are very limited, as the affected areas become starved of vital oxygen and nutrients and therefore die (termed “necrotic”).

Many approaches are currently being developed, however one promising treatment involves the stimulation of brain areas adjacent to the necrotic tissue. This should allow for re-wiring of the synapses, making up for the damage and loss of specific brain functions. Studies pioneered at Stanford University in California, investigate the importance of targeting specific brain cells in this method, rather than the entire area.

The group used an exciting technique, known as optogenetic stimulation, to investigate which types of brain cells would lead to recovery after stroke. Specifically, a part of the cerebellum was targeted, due to its important neural connections to stroke-affected areas of the brain, such as the motor cortex, which controls movement, balance and coordination.

Optogenetic stimulation uses light to activate specific cells in genetically modified subjects. This can be thought of as a light-sensitive switches. In this particular case, mice were genetically engineered to have light-sensitive switches in specific cells in their cerebellum. These cells activate in response to light. Through this method, the scientists were able to stimulate these particular cells a few days after stroke was induced in the animals. The animals’ recovery after stroke was studied by observing the mice perform in various tests of movement, balance and coordination.

The group found that repeated stimulation of the targeted brain area promoted recovery after stroke, and the animals performed just as well as prior to the induced stroke. In addition to improving movement and behaviour, the group also found that the optogenetic stimulations promotes neuronal growth, thereby providing physiological evidence of recovery after stroke.

Naturally, the use of optogenetic techniques is, as yet, impossible in humans, however this research provides good evidence of brain areas that can be targeted for the development of stroke recovery drugs.

About Danny Schnitzler

Danny Schnitzler is working as research assistant at the University of Edinburgh, Scotland on the role of oxytocin in feeding behaviour, while applying for PhD funding. Her scientific passion is neuroendocrinology, which looks at the role of hormones in the brain. In particular, she has an interest in how sex hormones act on neurophysiolgy. Outside of the lab, Danny is involved in addressing the gender imbalance in many aspects of STEM, public engagement and science communication. She also does "normal" fun things like going for runs, reading books and petting dogs.

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