Why is calcium imaging done almost only in animals? · Grey Matter

It needs two things a person would have to consent to as a medical intervention: a gene for the indicator introduced into brain cells, usually by a viral vector, and an optical path to the cortex, a window in the skull or a lens pushed into the tissue.

Why is calcium imaging done almost only in animals?

It needs two things a person would have to consent to as a medical intervention: a gene for the indicator introduced into brain cells, usually by a viral vector, and an optical path to the cortex, a window in the skull or a lens pushed into the tissue. Gene delivery into the brain is permanent in practice and is offered in people only as a treatment for disease, so the risk is hard to justify for a recording that brings the participant no benefit. The method's insights reach people through animal studies, while human recordings rely on electrodes placed for clinical reasons.