We are interested in the relationship between the dynamics of neural networks and animal behavior. Our research focuses on the integrative processes by which the brain corresponds ongoing sensory signals with proceeding motor actions. Our goal is to identify the neural representations and computational principles occurring in interacting populations of neurons during sensorimotor tasks. In addition, we aim to describe the mechanisms by which these neural circuit computations emerge from the biophysical properties of neurons and synapses.
With only about 100,000 neurons, the brain of Drosophila melanogaster produces rather sophisticated orientation behaviors. The balance between brain numerical simplicity and behavioral complexity makes Drosophila an attractive experimental system to investigate how visually guided behaviors are implemented by small neural networks. We use novel methods that allow us to record the activity of neurons in a behaving fly during locomotion.

Our Projects

Sensory processing and motor actions are intimately linked in many aspects of brain function. Examples include active sensing, goal-directed locomotion and motor learning. We use these behavioral contexts to investigate the underlying operational principles of sensorimotor processing.
Our projects are divided in three inter-related lines of research:

Development of behavioral paradigms to study sensorimotor integration

We are currently developing “freely moving” and “tethered” behavioral paradigms in virtual reality-like worlds designed to probe the computational capacities of the fly’s brain during visually guided orientation behaviors. These shall form a platform for studying: a) how the fly uses its own movements and the generated visual motion cues to explore an environment, b) how her brain incorporates sensory signals to correct locomotion during orientation towards objects, and c) how do past experiences inform ongoing behavior.

Colaborators: Gonçalo Lopez, José Cruz and Matthieu Pasquet

Identification of neurons and circuits involved in sensorimotor processing

The aim of this project is to understand how components in the circuit are linked and how the activity patterns of neurons arise from their synaptic connectivity. We identify neuronal components of a network using behavioral, physiological and anatomical methods. We then map connectivity among candidate neurons by combining chemical, optical and electrical techniques. Importantly, in the brain of the fruitfly it is possible to systematically identify the same class of neurons across different individuals. This allows investigating variability in synaptic connectivity and circuit function across different flies.

Probing neural processing during sensorimotor tasks

In simultaneous with head-fixed, tethered locomotion, we use electrophysiological and imaging techniques to monitor the activity dynamics of populations of genetically- or anatomically-defined groups of neurons. We apply quantitative analytical tools to correlate neural population activity with the behaviors described above, and to make predictions about the contribution of different groups of neurons to such behaviors. We examine the roles of different groups of neurons in the circuit by precise manipulations of their activity with genetic and optical techniques. These experiments are aimed at defining the functional logic of the circuitry in the context of a specific behavior. By comparing different visual-motor tasks, our research attempts to identify common principles of visual-motor transformations.

Eugenia Chiappe, PhD
Principal Investigator
eugenia.chiappe@neuro.fchampalimaud.org

Francisco Semedo
Lab Manager
francisco.semedo@neuro.fchampalimaud.org

Tomás Cruz
Masters Student
tomas.cruz@neuro.fchampalimaud.org

Tuthill JC, Chiappe ME, Reiser MB (2011) Neural correlates of illusory motion perception in Drosophila. Proc. Natl. Acad. Sci. U.S.A. 108 (23), 9685-9690 (doi:10.1073/pnas.1100062108)

Seelig JD, Chiappe ME, Lott GK, Dutta A, Osborne JE, Reiser MB, Jayaraman V (2011) Two-photon calcium imaging from head-fixed Drosophila during optomotor walking behavior. Nat. Methods 7 (7), 535-534 (doi:10.1038/nmeth.1468)

Chiappe ME, Seelig JD, Reiser MB, Jayaraman V (2010) Walking Modulates Speed Sensitivity in Drosophila Motion Vision. Curr. Biol. 20 (16), 1470-1475 (doi:10.1016/j.cub.2010.06.072)

Tian L, Hires SA, Mao T, Huber D, Chiappe ME, Chalasani SH, Petreanu L, Akerboom J, McKinney SA, Schreiter ER, Bargmann CI, Jayaraman V, Svoboda K and Looger LL (2009) Imaging neural activity in worms, flies and mice with improved GCaMP calcium indicators. Nat. Methods 6 , 875 - 881 (doi:doi:10.1038/nmeth.1398 )

Chiappe ME, Kozlov AS and Hudspeth AJ (2007) The Structural and Functional Differentiation of Hair Cells in a Lizard's Basilar Papilla Suggests an Operational Principle of Amniote Cochleas. J. Neurosci. 27 (44), 11978-11985 (doi:10.1523/JNEUROSCI.3679-07.2007)

Larsson MC, Domingos AI, Jones WD, Chiappe ME, Amrein H, Vosshall LB. (2004) Or83b encodes a broadly expressed odorant receptor essential for Drosophila olfaction. Neuron 43 (5), 703-714 (doi:10.1016/j.neuron.2004.08.019)

Chiappe ME, Lattanzi ML, Colman-Lerner AA, Barañao JL, Saragüeta P (2002) Expression of 3 beta-hydroxysteroid dehydrogenase in early bovine embryo development. Mol. Reprod. Dev. 61 (2), 135-141 (doi:10.1002/mrd.1140)

Lerner AA, Salamone DF, Chiappe ME, Barañao JL (1995) Comparative studies between freshly isolated and spontaneously immortalized bovine granulosa cells: protein secretion, steroid metabolism, and responsiveness to growth factors. J. Cell. Physiol. 164 (2), 395-403 (doi:10.1002/jcp.1041640220)