Event

Bioengineering Seminar Series: Andrea Meredith

Wednesday, October 10, 2007
11:00 a.m.
2108 Chemical and Nuclear Engineering Building
J. Helim Aranda-Espinoza
(301) 405-8250
helim@umd.edu

Molecular Mechanisms of Circadian Rhythms in Neuronal Activity

Presented by Andrea Meredith
University of Maryland School of Medicine

Circadian physiology is an ideal model system for studying basic neurobiology. Daily behavioral rhythms (~24 hrs) are a universal trait of animals, vital for adaptation to their environment and overall fitness, but the mechanistic basis for this fundamental behavior is largely unknown. In mammals, lesion and transplantation studies have localized the principal circadian pacemaker to the suprachiasmatic nucleus (SCN) of the hypothalamus, identifying a discrete neural substrate for a complex behavior. Subsequently, several "clock genes" involved in a cell-autonomous transcriptional feedback loop were discovered to underlie the pacemaking mechanism within individual cells, but our knowledge of how these SCN-level rhythms are generated and convey circadian timing to behaviors remains limited.

One link between the molecular clockwork and circadian behavioral rhythms is expressed at the level of neuronal activity. Individual SCN neurons exhibit daily oscillations in spontaneous action potential activity, and action potentials in the SCN are necessary for normal circadian timing of behavior. We recently identified an ion channel, the BK Ca²⁺-activated K⁺ channel, as a critical regulator of both SCN neuronal firing rate and circadian behavioral rhythms. Through these studies, the focus of my lab is to determine how the daily variation in spontaneous firing rate is generated and how patterns of SCN activity confer circadian timing to behaviors.

Audience: Graduate  Undergraduate  Faculty  Post-Docs