Graduate Program in Neuroscience

Jeff Riffell

riffell-jeffPhone: 206-616-5682
Dept.: Assistant Professor, Department of Biology
Neuroscience Focus Groups:
Lab Link


Sensory perception of chemical signals strongly influences reproduction, habitat selection, as well as cellular navigation and motility. Indeed, a variety of physiological processes and behaviors are critically dependent on chemosensory signaling mechanisms. Despite the complexity of these processes, the functional principle is the same: detection of chemical stimuli is transduced\ via biochemical signaling cascades, and further processed in the brain. The main goal of my lab’s research, therefore, is to understand these signaling mechanisms on a cellular level, and at the level of neuronal processing in the brain.

Olfactory processing of complex odor stimuli

An ‘odor’ is composed by a complex mixture of different molecules at various concentrations. In the brain, this information is encoded by spatial (and temporal) activity patterns of distinct neuron populations within the antennal (olfactory) lobe. Our research indicates that the temporal activity of the insect antennal lobe (AL) neurons, similar to that which occurs in the visual system, acts to ‘bind’ the complex mixture representation into a single odor percept. Using multi-electrode extracellular recordings of AL output neurons and behavioral assays, we aim to analyze the neural basis of behavior and neuronal network activity in the AL.

Chemotactic signaling in single cells

At a much smaller scale, we examine chemical communication processes at the level of the single cell where the basic molecular and cellular mechanisms underlying chemotaxis are far less understood. We recently found that members of the odorant receptor (OR) family are key mediators of sperm chemotaxis, and in parallel studies with invertebrates, that egg-derived chemical attractants increase sperm-egg encounters and fertilization success. We are currently examining the contribution ORs in mediating chemotactic behaviors and the molecular basis of this process.