Welcome to the Schmidt Lab!
Our laboratory is interested in the neural mechanisms that underlie courtship display. Much of our current work is focused on studying courtship and social behavior in the brown-headed cowbird (Molothrus ater), a highly gregarious species whose complex social structure is necessary for group cohesion, mating and reproductive success. The overall approach of our work is highly integrative ranging from neural circuit tracing to wireless neural recording of individual birds interacting within a natural social group in a large “smart” aviary where we can quantify social network dynamics across the entire breeding season. By its nature, this work is highly interdisciplinary and we have close collaborations with several laboratories both at Penn. These include the Daniilidis lab (Penn Engineering) where we implement novel computer vision approaches for tracking birds in our “smart aviary”, the Balasubramanian lab (Penn Physics) where we develop novel techniques to integrate neural recordings with social network dynamics and the Aflatouni lab (Penn Electrical Engineering) where we implement novel non-invasive wireless neural recording devices for long term tracking of brain activity within a natural social context. We also continue our productive collaboration with the White lab (Wilfried Laurier University, Ontario, CA) where we can track longterm social behavior of cowbirds in large aviary across multiple years.
Our overall work can be divided into two primary areas:
- Neural circuit work: Here we use a combination of neuroanatomical, viral and neurophysiological approaches to test the hypothesis that the “song system”, a specialized neural circuit defined as critical for the production and learning of song, is also critical for coordinating non-vocal aspects of song. We use both male and females to test this hypothesis. In males, we test the role of the “song system” in coordinating song with the dramatic postural “wingspread” display that accompanies this display when song is directed to conspecific males. In females, we combine lesion, neural recording and anatomical tracing studies to evaluate the role of the song system in the production of Copulation Solicitation Displays (CSD) that females produce in response to potent songs. We also study the role of this circuit during the production of “wing strokes”, rapid courtship displays produced by females in response to male song. Much of our neural focus in these studies is on forebrain areas that form part of the “song system” as well as a the midbrain Peri-Acqueductal Gray (PAG) which we have recently proposed to be critical for the elaboration and evolution of courtship displays in vertebrates (Schwark, Fuxjager and Schmidt, eLife 2022).
- Tracking social behavior and its neural properties in a smart aviary: The neural and behavioral sciences are entering a phase where advances in technology, mathematics and engineering make it possible to quantify behaviors within complex naturalistic environments and relate them to underlying neural mechanisms. Because social animals have evolved to perceive and evaluate signals within a social context, the ability to link neural function with the precise social context that surrounds them promises to be transformative. We have assembled an interdisciplinary team of engineers, neurobiologists and computational scientists with the aim to create a platform to record and evaluate brain dynamics in individual birds within a complex social context over ethologically relevant timescales. Cowbird are particularly amenable for neurophysiological studies in complex social environments given their larger size (45 grams; finches weigh 15 grams) and their use of distinct, and quantifiable, vocal and non-vocal communication signals allowing for a quantitative description of their social network state, how its dynamics might change over time and how it may impact individual and group behavior. Numerous studies, including our own in songbirds, have shown that sensory neural processing and action selection are strongly dependent on an animal’s behavioral state and therefore likely modulated by social context. Little is known about how the brain integrates complex social information and how it might be encoded. The primary challenge is measuring and assessing the variables that determine social context and then linking the social network to precise neural events. Here, we aim to use our “smart aviary” equipped with arrays of cameras and microphones to develop novel non-invasive and fully automated approaches for tracking moment-to-moment behavioral events within a social group (with the Daniilidis group). Equipped with these data, we aim to generate fine-scale ethograms for each individual over the breeding season and propose to develop mathematical tools to represent the state of the social group and link social network context to recorded neural dynamics (with the Balasubramian group). Recording neural activity in birds operating within a 3D aviary without interfering with the normal behavior of the bird or its social group is challenging and has never been performed. We therefore are also developing a lightweight miniature wireless recording device specifically designed for cowbirds that can allow long term recording (with the Aflatouni group).