Material below is adapted from the SfN Short Course Local Circuit Analysis With Integrated Large-Scale Recording of Neuronal Activity and Optogenics, by György Buzsáki, PhD. Short Courses are daylong scientific trainings on emerging neuroscience topics and research techniques held the day before SfN’s annual meeting.

Understanding all the parts of a neuronal circuit will ultimately help explain how the circuit — and the brain — gives rise to behavior. To investigate how a circuit functions, different types of neurons spread across the brain need to be monitored simultaneously, and the contribution of each neuron determined. This requires hardware capable of recording many individual neurons, methods to separate spikes, and a way to identify different neuronal types.

Material below summarizes the article Optogentetic Activation of Non-nociceptive Aβ Fibers Induces Neuropathic Pain-Like Sensory and Emotional Behaviors After Nerve Injury in Rats, published on February 5, 2018, in eNeuro and authored by Ryoichi Tashima, Keisuke Koga, Misuzu Sekine, Kensho Kanehisa, Yuta Kohro, Keiko Tominaga, Katsuyuki Matshushita, Hidetoshi Tozaki-Saitoh, Yugo Fukazawa, Kazuhid Inoue, Hiromu Yawo, Hidemasa Furue, and Makoto Tsuda.

Somatosensory information from the periphery is conveyed to the spinal dorsal horn (SDH) via primary afferent sensory neurons. The incoming sensory information is processed by complex circuits in the SDH, integrated to projection neurons relaying to several regions of the brain.

Primary afferents are broadly divided into two classes: nociceptive (mainly unmyelinated C, and thinly myelinated alpha delta (Aδ) fibers), and non-nociceptive (myelinated alpha beta (Aβ) fibers), which respond to noxious and innocuous stimuli, respectively.

Read the latest research on the use of optogenetics in interrogating neural circuits.