TY - JOUR T1 - QUANTITATIVE REEVALUATION OF THE EFFECTS OF SHORT- and LONG-TERM REMOVAL OF DESCENDING MODULATORY INPUTS ON THE PYLORIC RHYTHM OF THE CRAB, <em>CANCER BOREALIS</em> JF - eneuro JO - eneuro DO - 10.1523/ENEURO.0058-14.2015 SP - ENEURO.0058-14.2015 AU - Albert W. Hamood AU - Sara A. Haddad AU - Adriane G. Otopalik AU - Philipp Rosenbaum AU - Eve Marder Y1 - 2015/01/14 UR - http://www.eneuro.org/content/early/2015/01/14/ENEURO.0058-14.2015.abstract N2 - The crustacean stomatogastric ganglion (STG) receives descending neuromodulatory inputs from three anterior ganglia, the paired commissural ganglia (CoGs) and the single esophageal ganglion (OG). In this paper we provide the first detailed and quantitative analyses of the short- and long-term effects of removal of these descending inputs (decentralization) on the pyloric rhythm of the STG. Thirty minutes after decentralization, the mean frequency of the pyloric rhythm dropped from 1.20 Hz in control to 0.52 Hz. Whereas the relative phase of pyloric neuron activity was approximately constant across frequency in the controls, after decentralization this changed markedly. Nine control preparations kept for 5-6 days in vitro maintained pyloric rhythm frequencies close to their control values. Nineteen decentralized preparations kept for 5-6 days dropped slightly in frequency from those seen at 30 minutes after decentralization, but then displayed stable activity over 6 days. Bouts of higher frequency activity were intermittently seen in both control and decentralized preparations, but the bouts began earlier and were more frequent in the decentralized preparations. Although the bouts may indicate that the removal of the modulatory inputs triggered changes in neuronal excitability, these changes did not produce obvious long-lasting changes in the frequency of the decentralized preparations. Significance statement: Neuromodulatory inputs are known to strongly influence the intrinsic excitability of individual neurons and the networks in which the targets of modulation are found. It is therefore important to understand how nervous systems respond to altered neuromodulatory environments. We find that removal of neuromodulatory inputs from the stomatogastric ganglion of wild-caught Cancer borealis decreases frequency and alters phase relationships of the pyloric rhythm within 30 minutes, and that these changes persist across time. Previous reports from several species suggested that the pyloric rhythm of crustaceans compensates for this loss and recovers intact activity patterns; our dataset suggests that this perturbation is not compensated. Caution is necessary when interpreting results from wild-caught populations, which may be unstable over time. ER -