Marc F. Schmidt

faculty photo
Graduate Group Affiliations

Contact information
312 Leidy Laboratories
Philadelphia, PA 19104
Office: (215) 898-9375
Fax: (215) 898-8780
Permanent link

Description of Research Expertise

Encoding of complex motor behaviors; auditory/motor integration; neural basis of vocal learning

Birdsong; auditory gating; motor control; sensorimotor integration; vocal learning.

Chronic recording in awake, behaving songbirds; Single unit analysis; Intracellular recording from neurons in brain slices; behavioral analysis of bird songs.

The goal of our research is to understand the functional organization of the circuits that control vocal production, perception and learning. We study these questions in songbirds, which produce highly stereotyped songs that are learned within a restricted phase during the animal's juvenile stage. Our experiments are performed in both awake and anesthetized animals and can be divided into three broad areas.

a. Neural mechanisms of behavioral state-dependent auditory processing and perception
We have shown that auditory responses in forebrain song control nuclei are highly dependent on the animal's behavioral state with auditory responses varying from robust to non-existent depending on the animal's arousal or attentional state. We are presently characterizing the neural mechanism(s) underlying this modulation of auditory responsiveness. We are also combining behavioral experiments with neural recordings in order to characterize behavioral states that are optimal for auditory response tuning in the awake bird.

b. Neural encoding of forebrain vocal motor commands
We are using a combination of extracellular recording and stimulation in awake singing birds to perturb the bird's song output in order to understand the relationship between neural discharge patterns in higher-level forebrain song structures and the bird's vocal output.

c. Neural correlates of vocal ontogeny
Because young bird's can learn their song under carefully controlled tutoring conditions, we are studying the dynamic changes in neural tuning during acquisition of the song template. These studies are aimed both at understanding the mechanism of how the auditory template is stored in these song nuclei as well as how the network properties change during vocal learning.

Selected Publications

Cardin J.A. and M.F. Schmidt : Auditory responses in two sensorimotor forebrain song system nuclei are co-modulated by behavioral state. J. Neurophyiology 91: 2148-63, 2004.

Cardin J.A. and M.F. Schmidt: Noradrenergic Inputs Mediate State-Dependence of Auditory Responses in the Avian Song System. J. Neuroscience 2004 Notes: in press.

Cardin, J.A. and M. F. Schmidt : Song system auditory responses are stable and highly tuned during sedation, rapidly modulated and unselective during wakefulness, and suppressed by arousal. J. Neurophys. 90: 2884-99, 2003.

Schmidt M. F. : Pattern of interhemispheric synchronization in HVc during singing correlates with key transitions in the song pattern. J. Neurophyisology 90: 3931-49, 2003.

Nealen P. M. and M. F. Schmidt: Comparative Approaches to Avian Song System Function: Insights into Auditory and Motor Processing. J. Comp. Physiology 188: 929-41, 2002.

Dutar P., Petrozzino J. J., Vu H.M., Schmidt M.F. and D. J. Perkel: Slow Synaptic Inhibition Mediated by Metabotropic Glutamate Receptor Activation of GIRK Channels. J Neurophys. 84: 2284-2290, 2000.

Schmidt M. F. and M. Konishi : Gating of auditory responses in the song control system of awake songbirds. Nature Neuroscience 1: 513-18, 1998.

Vu E. T., Schmidt M. F. and M. E. Mazurek: Interhemispheric coordination of premotor neural activity during singing by zebra finches. J. Neurosci. 18(21): 9088-98, 1998.

back to top
Last updated: 09/08/2004
The Trustees of the University of Pennsylvania