Controlling the Brain with Light (preview)

Every day as a practicing psychiatrist, I confront my field’s limitations. Despite the noble efforts of clinicians and researchers, our limited insight into the roots of psychiatric disease hinders the search for cures and contributes to the stigmatization of this enormous problem, the leading cause worldwide of years lost to death or disability. Clearly, we need new answers in psychiatry. But as philosopher of science Karl Popper might have said, before we can find the answers, we need the power to ask new questions. In other words, we need new technology.

Developing appropriate techniques is difficult, however, because the mammalian brain is beyond compare in its complexity. It is an intricate system in which tens of billions of intertwined neurons--with multitudinous distinct characteristics and wiring patterns--exchange precisely timed, millisecond-scale electrical signals and a rich diversity of biochemical messengers. Because of that complexity, neuroscientists lack a deep grasp of what the brain is really doing--of how specific activity patterns within specific brain cells ultimately give rise to thoughts, memories, sensations and feelings. By extension, we also do not know how the brain’s physical failures produce distinct psychiatric disorders such as depression or schizophrenia. The ruling paradigm of psychiatric disorders--casting them in terms of chemical imbalances and altered levels of neurotransmitters--does not do justice to the brain’s high-speed electrical neural circuitry. Psychiatric treatments are thus essentially serendipitous: helpful for many but rarely illuminating.

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