, 2005 and Kahn-Kirby et al., 2004). For instance, exogenous serotonin is required for OSM-9-dependent, touch-evoked Ca2+ transients in ASH (Hilliard et al., 2005). Finally, can we extend these findings to mammalian nociceptors? Polymodal afferents express an array of DEG/ENaCs and TRP channels, and respond to many of the same stimuli as ASH neurons (Figure 1D). Genetic ablations of acid sensing ion channels, mammalian DEG/ENaC homologs, result in only mild changes in touch sensitivity, so the jury is still out on their function in cutaneous senses (Arnadóttir and Chalfie, 2010). Given the rapidly
expanding list of mechanosensory transduction channels in the worm’s “simple” nervous system,
mechanisms that underlie touch, pain, and hearing are likely Epigenetics inhibitor to be just as diverse in vertebrate mechanosensory cells. The search continues. The authors are supported by NIH R01AR051219 and R01NS073119. “
“The functional synchronization of neuronal activity in a normal brain has been compared to the coordination of instruments in an orchestra. The ultimate output of these neuronal interactions, in this analogy, Y27632 could be compared to a symphony. For a symphony to be harmonious, each musician in the orchestra needs to play his or her part in tune with the rhythm, synchrony, and tone of the rest of the participants. In an analogous manner, for the brain to function properly, the right speed, volume, rhythm, and synchronization
of information flow within circuits is crucial. In healthy individuals, synchrony across groups of neurons is required to accurately analyze and propagate the information in a reliable manner. In contrast, synchronization across large populations of neurons is sometimes the hallmark of dysfunction in the central nervous Calpain system. Indeed, in Parkinson’s disease (PD), synchrony between large populations of medium spiny neurons (MSNs) in the dorsal striatum can underlie striatal dysfunction that interferes with proper signal propagation throughout the basal ganglia. Two distinct pathways connect the striatum to the basal ganglia output structures, the direct and the indirect pathways (Figure 1). The direct pathway striatal neurons derive their name because they synapse directly onto output neurons in the globus pallidus internal segment (GPi)/substantia nigra reticulata (SNr), whereas the indirect pathway neurons synapse on the external globus pallidus (GPe) and the subthalamic nucleus (STN) before innervating these output nuclei. As such, these pathways act in opposite manners, with direct pathway neurons facilitating movement, whereas the indirect pathway neurons decrease movement. MSNs that project in the direct pathway express D1-receptors and MSN projecting in the indirect pathway express D2-receptors.