Modulating mood with transcranial direct current stimulation: basic research and clinical applications for treating depression

Approximately 8 per cent of all Canadian adults will experience at least one major episode of depression during their lifetimes, and up to 6.5 per cent of Canadian children currently meet the criteria for clinical depression. Efforts to understand the neural mechanisms underlying depression and to develop new treatment methods for the mood disorder have the potential to facilitate improvements in quality of life for people throughout Canada and around the world. Neuroimaging studies show that negative mood and depression are associated with increased activity in the right prefrontal cortex and decreased neural activity in the left prefrontal cortex. Dr. Bradley Vines is examining how changes in neural activity in the prefrontal cortex influence mood. He is also exploring the therapeutic potential of transcranial direct current stimulation (TDCS) as a treatment for clinical depression. TDCS is a safe, painless, and non-invasive brain stimulation technique that modulates neural activity in targeted brain areas. It has been shown to significantly influence behavioural and cognitive performance. The technique involves running a low-level direct current between two electrodes placed on a person's scalp. The neurons underneath the positively-charged anode fire more rapidly, whereas the neurons underneath the negatively-charged cathode become less active. Using tDCS, it would be possible to simultaneously increase neural activity in the left prefrontal cortex and decrease activity in the right prefrontal cortex – potentially correcting the neural imbalance that is characteristic of depression. Vines’ research promises to advance our understanding of how the prefrontal cortex contributes to emotional states and mood disorders, and to determine the viability of using tDCS as a therapy for depression.