TY - JOUR T1 - Unique Configurations of Compression and Truncation of Neuronal Activity Underlie L-DOPA-Induced Selection of Motor Patterns in <em>Aplysia</em> JF - eneuro JO - eNeuro DO - 10.1523/ENEURO.0206-17.2017 SP - ENEURO.0206-17.2017 AU - Curtis L. Neveu AU - Renan M. Costa AU - Ryota Homma AU - Shin Nagayama AU - Douglas A. Baxter AU - John H. Byrne Y1 - 2017/10/06 UR - http://www.eneuro.org/content/early/2017/10/06/ENEURO.0206-17.2017.abstract N2 - A key issue in neuroscience is understanding the ways in which neuromodulators such as dopamine modify neuronal activity to mediate selection of distinct motor patterns. We addressed this issue by applying either low or high concentrations of L-DOPA (40 or 250 μM) and then monitoring activity of up to 130 neurons simultaneously in the feeding circuitry of Aplysia using a voltage-sensitive dye (RH-155). L-DOPA selected one of two distinct buccal motor patterns (BMPs): intermediate (low L-DOPA) or bite patterns (high L-DOPA). The selection of intermediate BMPs was associated with shortening of the second phase of the BMP (retraction), whereas the selection of bite BMPs was associated with shortening of both phases of the BMP (protraction and retraction). Selection of intermediate BMPs was also associated with truncation of individual neuron spike activity (decreased burst duration but no change in spike frequency or burst latency) in neurons active during retraction. In contrast, selection of bite BMPs was associated with compression of spike activity (decreased burst latency and duration, and increased spike frequency) in neurons projecting through specific nerves, as well as increased spike frequency of protraction neurons. Finally, the large-scale VSD recordings delineated the spatial distribution of neurons active during BMPs and the modification of that distribution by the two concentrations of L-DOPA.Significance Statement A key issue in neuroscience is understanding the ways in which neuromodulators such as dopamine (DA) modify neuronal activity to mediate selection of distinct motor patterns. We examined DA modulation of the Aplysia feeding motor network using L-DOPA to activate DA pathways and a voltage-sensitive dye to record activity in up to 130 neurons per preparation. L-DOPA biased selection toward distinct motor patterns and differentially modified neuronal activity in a concentration-dependent manner. DA modulation of the Aplysia feeding central pattern generating network may help to understand DA modulation of more complex networks in the vertebrate CNS. ER -