Research

Social organization requires communication, and the complexity of a society is often reflected in the complexity of its signals. My research focuses on how social structure influences the development of communication, on the level of groups, individuals, and neuronal circuits. Understanding these processes can lead to insights into the evolution of social behavior and the mechanisms underlying speech learning in humans.

Vocal Communication in Social Songbirds

Oscine songbirds, parrots, hummingbirds, cetaceans, and humans learn many of their vocalizations from other animals of their species. This permits the development of highly complex signals that can communicate identity, territory boundaries, danger, aggressive intentions, and desire, to name just a few.

I am interested in how vocalizations are used by songbirds with affiliative social behaviors. In collaboration with Dustin Rubenstein, I am studying the vocal behavior of the superb starling (Lamprotornis superbus), a coopertively breeding African starling. We are recording the songs and calls of a marked population of starlings, and examining how call structure differs as a function of genetic and social relatedness, and how the vocal behavior of individuals and groups changes as a result of immigration and intergroup interactions.

Auditory Pattern Learning

I also work with European starlings, an extremely successful species from the Eurasian branch of the Sturnidae. European starlings live in very large groups, with a complex fission-fusion social structure and a particularly rich vocal behavior. Their songs consist of long sequences of temporally discrete segments called motifs, which are about a second long. Individual birds have unique repertoires of 10 to 90 motifs, and starlings can learn to recognize the songs of specific individuals.

In the lab of Daniel Margoliash at the University of Chicago, I am combining behavioral and neurophysiological approaches to examine how starlings learn to recognize the songs of individual conspecifics. We ask two related questions: how are the features of learned songs represented in the starling auditory pathway, and how do those representations change when birds learn to recognize new songs?

A high-level auditory forebrain nucleus, the caudomedial mesopallium (CMM), contains neurons that respond selectively to motifs the bird learns during training tasks. This high degree of selectivity does not depend on simple spectrotemporal properties of the stimuli, suggesting an analogy with higher order recognition areas like the fusiform facial area in human and primate cortex. We disassembled starling motifs into component notes and found that, in contrast to the highly nonlinear spectrotemporal tuning found in CMM, neurons responded robustly and linearly to combinations of the component notes, suggesting that motif identity is encoded as a combination of basic vocal gestures.

I am now examining how these representations change as a function of experience, in experiments that will combine behavioral measures of song discrimination with neuronal measurements of responses in CMM. I hope to extend these experiments to look at top-down influences from social context.

This work is supported by a Ruth L Kirschstein National Research Service Award grant from the National Institutes for Deafness and Communicative Disorders (National Institutes of Health).

Selected Publications

Meliza, C.D., Chi Z., and Margoliash D. Representations of Conspecific Song by Starling Secondary Forebrain Auditory Neurons: Toward a Hierarchical Framework. J Neurophys 2010, 103 1195-1208. [link]

Meliza, C.D. and Dan, Y. Receptive-Field Modification in Rat Visual Cortex Induced by Paired Visual Stimulation and Single-Cell Spiking. Neuron, 2006, 49, 183-189. [pdf]