Dr. Matthew W. Spitzer

Biography

Sc.B., Neural Sciences, Brown University, 1987

Ph.D., Anatomy and Neurobiology, University of California – Irvine, 1994

My research addresses the neural basis of perception and cognition. Current projects use the vocal communication of marmoset monkeys as a model to explore the information processing within the cerebral cortex that mediates perception of complex sounds in noisy, natural environments. Physiological mapping and anatomical methods are combined to examine the functional organization of auditory cortical areas involved in the recognition of species-specific vocalizations and in sound localization. Behavioural experiments utilize the marmoset’s innate social communication to identify the informational basis for recognition of individual voices and call types. An ultimate goal of these investigations is to examine the neuronal processing that underlies vocal perception by recording neuronal activity from freely moving monkeys involved in natural and simulated vocal exchanges.

Potential Student Projects

Collaborations

Brain mapping studies are conducted in collaboration with A. Prof. Marcello Rosa and Dr. James Bourne in the Department of Physiology and Prof. Dexter Irvine (Psychology).

Behavioural studies are conducted in collaboration with A. Prof. Rosa, Prof. Irvine.

Grant Support

Behavioural studies of vocal communication. Experiments exploit the marmoset's natural antiphonal calling behaviour (call and response) to identify the acoustic cues used to recognize calls from familiar individuals and to distinguish between species specific vocalizations and other sounds.

Mapping brain pathways involved in auditory perception. Neuronal tracing methods are used to identify the connections between brain areas that form specialized information processing pathways. Electrophysiological recordings from single neurons are used to map the functional topography of individual brain areas and to identify functional differences between areas.

Information processing by single neurons. Although specific regions of the non-primary auditory cortex are implicated in the perception of complex sounds, including speech, relatively little is known about the neuronal information processing within these areas. These experiments take advantage of the marmoset's call vocabulary to provide insight into what acoustic features are likely to be important. Electrophysiological recordings of responses of single neurons to natural and digitally modified vocalizations are used to examine the extraction of perceptually salient information, and the synthesis of perceptual representations of calls and voices.

Engineering projects. The behavioural projects provide two major technical challenges and provide ample scope for Engineering student projects. One project available in joint supervision by Mr. Brian Lithgow (Electrical and Computer Systems Engineering) involves development of miniaturized wireless systems for multi-channel neuronal recording. A second project, in collaboration with A. Prof. David Suter and Prof. Ray Jarvis (Centre for Intelligent Robotics Research) involves development of software for tracking the head orientation of marmosets from high speed stereo video inputs.

Publications

Spitzer M.W., Bala A.D.S., Takahashi T.T. (2004). A neuronal correlate of the precedence effect is associated with spatial selectivity in the barn owl's auditory midbrain. Journal of Neurophysiology. 92: 2051-2070.

Spitzer MW, Bala ADS, Takahashi TT. (2003). Auditory spatial discrimination by barn owls in simulated echoic conditions. The Journal of the Acoustical Society of America 113(3): 1631-1645.

Bala ADS, Spitzer MW, Takahashi TT. (2003). Prediction of auditory spatial acuity from neuronal images on the owl's auditory space map. Nature 424: 771-773.

Takahashi TT, Bala ADS, Spitzer MW, Euston DR, Spezio ML, Keller CH. (2003). The synthesis and use of the owl's auditory space map. Biological Cybernetics. 89: 378-387.

Spitzer MW, Clarey JC, Roe AW, Pettigrew JD, Calford MB. (2001). Spontaneous and stimulus-evoked intrinsic optical signals in primary auditory cortex of the cat. Journal of Neurophysiology. 85: 1283-1298.

Spitzer MW, Semple MN. (1991). Interaural phase coding in auditory midbrain: influence of dynamic stimulus features. Science 254:721-724.