Deforest Mellon

Primary Appointment

  • Professor, Biology

Contact

Research Interest(s)

Sensory System Organization and Development

Research Description

The major thrust of my research is the exploration of nerve cell dendritic function. Dendrites are the input processes of neurons and in most central nerve cells they receive the majority of excitatory and inhibitory synaptic contacts from other cells. Recent work has revealed an enormous functional complexity to dendritic action, based upon a diversity of ion channel types that are differentially expressed in different regions of thedendritic tree. This diversity of spatially segregated ion channels within the dendrites embues these structures with an array of mechanisms that modulate the electrical signalling properties of the neuron as a whole, i.e., its input/output relations. We are studying the dendritic properties of parasol cells within the higher central olfactory pathway of the freshwater crayfish. These unresting, local forebrain interneurons are large collector' multimodal sensory nerve cells with extensive and functionally complex dendritic arbors that receive olfactory, photic, and tactile input from various parts of the crayfish body. The parasol cells serve as a model cellular system for the exploration of questions about dendritic function: how is sensory input to the parasol cells modified by different types of electrical activity (eg, impulse bursts) within the dendritic branches ? What are the consequences to the input/output properties of parasol cells of the synchronous periodic depolarizations that impinge upon them from oscillator centers in other parts of the brain? Elucidation of the role of complex dendritic properties will continue to be a crucial step in comprehending how the brains of animals perceive the physical world and generate appropriate behaviors.

Figure Legend: Single parasol cell in the crayfish brain filled with an Alexa fluorescent dye. The heavy dendritic trunk and 3-4 basal branches can be readily identified. Dendritic geometry plays a major role in determining how action potentials are propagated throughout the neuron.

Selected Publications

  • Smelling, feeling, tasting and touching: behavioral and neural integration of antennular chemosensory and mechanosensory inputs in the crayfish. The Journal of experimental biology. 2012;215 2163-72. PMID: 22675176
  • Mellon D, Hamid O. Identified antennular near-field receptors trigger reflex flicking in the crayfish. The Journal of experimental biology. 2012;215 1559-66. PMID: 22496293
  • Not-so-simple setae. The Journal of experimental biology. 2011;214 871; author reply 872. PMID: 21307075
  • Mellon D, King S, Kim J, Reid J, Orr-Ewing A. Measurements of extinction by aerosol particles in the near-infrared using continuous wave cavity ring-down spectroscopy. The journal of physical chemistry. A. 2011;115(5): 774-83. PMID: 21204532
  • Butler T, Mellon D, Kim J, Litman J, Orr-Ewing A. Optical-feedback cavity ring-down spectroscopy measurements of extinction by aerosol particles. The journal of physical chemistry. A. 2009;113(16): 3963-72. PMID: 19249854
  • Mellon D, Christison-Lagay K. A mechanism for neuronal coincidence revealed in the crayfish antennule. Proceedings of the National Academy of Sciences of the United States of America. 2008;105(38): 14626-31. PMID: 18794524 | PMCID: PMC2567177