Bcl-2 is a cytoplasmic protein that blocks apoptosis in a wide variety of cell types. Here we report a novel role for Bcl-2 in the early stages of neuronal development. Shortly after differentiating from progenitor cells, sensory neurons undergo a distinct morphological change; initially they have small, spindle-shaped, phase-dark cell bodies that become large, spherical, and phase-bright. Earl...

Unlike the monosynaptic "stretch" reflex, the exact neuronal pathway for a simple cutaneous reflex has not yet been defined in any vertebrate. In young frog tadpoles, we made whole-cell recordings from pairs of spinal neurons. We found direct, excitatory, glutamatergic synapses from touch-sensitive skin-sensory neurons to sensory pathway interneurons, and then from these sensory interneurons to...

Pheromones are substances released from animals that, when detected by the vomeronasal organ of other individuals of the same species, affect their physiology and behavior. Pheromone binding to receptors on microvilli on the dendritic knobs of vomeronasal sensory neurons activates a second messenger cascade to produce an increase in intracellular Ca(2+) concentration. Here, we used whole-cell a...

The vertebrate diencephalic A11 system provides the sole dopaminergic innervation of hindbrain and spinal cord and has been implicated in modulation of locomotion and sensory processes. However, the exact contributions of sensory stimuli and motor behavior to A11 dopaminergic activity remain unclear. We recorded cellular calcium activity in four anatomically distinct posterior tubercular A11-ty...

The nonselective cation channel transient receptor potential ankyrin 1 (TRPA1) is known to be a key contributor to both somatosensation and pain. Recent studies have implicated TRPA1 in additional physiologic functions and have also suggested that TRPA1 is expressed in nonneuronal tissues. Thus, it has become necessary to resolve the importance of TRPA1 expressed in primary sensory neurons, par...

We have begun to analyze several elementary forms of learning in a simple preparation consisting of the isolated mantle organs and abdominal ganglion of Aplysia. Previous studies suggested that plasticity at siphon sensory neuron synapses contributes to habituation and dishabituation of the gill- and siphon-withdrawal reflex in this preparation. We next wished to identify the sensory neurons th...

The principle by which unmyelinated primary sensory neurons transducing thermal, itch and pain perception are specified in early development is unknown. These classes of sensory neurons diversify from a common population of late-born neurons, which initiate expression of Runt homology domain transcription factor RUNX1 and the nerve growth factor receptor TrkA. Here, we report that signals emana...

In the natural world, the statistics of sensory stimuli fluctuate across a wide range. In theory, the brain could maximize information recovery if sensory neurons adaptively rescale their sensitivity to the current range of inputs. Such adaptive coding has been observed in a variety of systems, but the premise that adaptation optimizes behaviour has not been tested. Here we show that adaptation...

The morphological consequences of long-term habituation and sensitization of the gill withdrawal reflex in Aplysia california were explored by examining the total number of presynaptic varicosities of single identified sensory neurons (a critical site of plasticity for the biochemical and biophysical changes that underlie both types of learning) in control and behaviorally trained animals. Sens...

Developmental neurite pruning is a process by which neurons selectively eliminate unnecessary processes of axons and/or dendrites without cell death, shapes the mature wiring nervous systems. In this sense, developmental requires spatiotemporally precise control local degradation cellular components including cytoskeletons and membranes. The Drosophila system undergoes large-scale remodeling, a...