Antidepressant effects of focused ultrasound induced blood-brain-barrier opening.

In many cases, hippocampal neurogenesis appears to be a hallmark of antidepressant treatments. One novel technique for inducing this type of neurogenesis is using focused ultrasound waves, in conjunction with circulating microbubbles, to open the blood-brain-barrier. The present experiment aimed to test whether this technique has antidepressant effects in a rodent model. Rats were subjected to 1, 2 or 3 weekly treatments of magnetic resonance-guided focused ultrasound in order to open the blood-brain-barrier in the hippocampal region. Before and after treatments, animals went through modified forced swim tests. 1 week after the final treatment, animals that received 2 weekly treatments showed antidepressant-like effects on behavioural measures in comparison to untreated controls. This was not the case for animals that received 1 or 3 weekly treatments. Effects had disappeared by 5 weeks following the first ultrasound treatment. These results suggest that focused ultrasound may be used for inducing short-term antidepressant effects.