The integration of sensory information
As most of the neurons located in sensory cortical areas are specifically tuned for a sensorial feature such as a shape, a tone or an odor, we usually assume that the role of sensory cortices is to produce a faithful representation of our surroundings.
The Polack Lab’s research aims to elucidate (1) how the neurons of the cerebral cortex integrate visual information when animals are actively processing images, and (2) how epileptic seizures are initiated and propagate into cortical networks. We use a wide range of electrophysiological, optogenetic and functional imaging techniques to record and manipulate the activity of dendrites, single neurons and neuronal populations in awake mice.
Understanding the Mechanisms of Perception
Sensory cortices integrate raw information provided by sensory organs. As most of the neurons located in sensory cortical areas are specifically tuned for a sensorial feature such as a shape, a tone or an odor, we usually assume that the role of sensory cortices is to produce a faithful representation of our surroundings. However, is this encoding really faithful? Recent studies suggest that higher brain functions such as attention, emotion, and memory actively influence the cortical processing of sensory information. Studies in primates have shown that some behavioral tasks can modulate the response of sensory cortical neurons to sensory stimulation. These results led to the hypothesis that sensory cortices are dynamic interfaces where features of the outer world are matched with inner expectations. It is possible that in neurological disorders such as autism, schizophrenia and Alzheimer’s disease, the poor performance of patients at tasks involving sensory processing such as face recognition, motion processing and visual attention results from a dysfunction of this interface.
To investigate how neurons of the mouse primary visual cortex integrate information during active visual processing, we perform two-photon targeted patch-clamp recordings, two-photon calcium imaging, voltage sensor imaging, as well as optogenic and pharmacological manipulations in the visual cortex. These techniques are used in awake mice while they are performing behavioral tasks involving visual perception or visual attention.
Understanding How Epileptic Seizures Start
Epilepsy is a group of neurological disorders characterized by the repetition of seizures. Epileptic seizures are brief episodes during which the activity of large neuronal populations is excessively synchronized. However, the mechanisms that trigger this sudden synchronization are unknown. We are interested in addressing this question in models of focal epilepsy by using functional imaging, whole cell recordings and optogenetic manipulations in awake mice.
Pierre-Olivier Polack studied veterinary medicine at the École Nationale Vétérinaire de Nantes (France) before starting a career in Neuroscience. During his Ph.D. at the College de France in Paris, he worked on the mechanisms of initiation and propagation of absence epilepsy seizures. During his postdoc at the University of Pennsylvania with Diego Contreras and his second postdoc at the University of California Los Angeles with Peyman Golshani, he developed different imaging and electrophysiological techniques to record the activity of neurons and neuronal networks in awake mice. He joined CMBN in September 2014.