Eric T. Carlson

Multiple personality and hypnosis: The first one hundred years

The Enlightenment brought with it a greater scientific interest in and attention to a wider range of human behavior. In 1789, there emerged during the French Revolution a case of what would be today called multiple personality disorder which came under the care of a local physician, Dr. Eberhard Gmelin. Gmelin had only recently become interested in mesmerism and tried this procedure with this patient. So started an ongoing and gradually increasing exploration of the role of hypnosis in multiple personalities. This paper contributes to the historical background of such psychodynamic concepts as dissociation, splitting, repression, consciousness, subconscious, and unconscious.

A system for optically controlling neural circuits with very high spatial and temporal resolution

Optogenetics offers a powerful new approach for controlling neural circuits. It has a vast array of applications in both basic and clinical science. For basic science, it opens the door to unraveling circuit operations, since one can perturb specific circuit components with high spatial (single cell) and high temporal (millisecond) resolution. For clinical applications, it allows new kinds of selective treatments, because it provides a method to inactivate or activate specific components in a malfunctioning circuit and bring it back into a normal operating range [1-3]. To harness the power of optogenetics, though, one needs stimulating tools that work with the same high spatial and temporal resolution as the molecules themselves, the channelrhodopsins. To date, most stimulating tools require a tradeoff between spatial and temporal precision and are prohibitively expensive to integrate into a stimulating/recording setup in a laboratory or a device in a clinical setting [4, 5]. Here we describe a Digital Light Processing (DLP)-based system capable of extremely high temporal resolution (sub-millisecond), without sacrificing spatial resolution. Furthermore, it is constructed using off-the-shelf components, making it feasible for a broad range of biology and bioengineering labs. Using transgenic mice that express channelrhodopsin-2 (ChR2), we demonstrate the systems capability for stimulating channelrhodopsin-expressing neurons in tissue with single cell and sub-millisecond precision.