Research

Brain-state dependence of cortical population dynamics

Although the classical approach in Neuroscience has been to establish neural correlates of sensory or action-related variables, which are measurable and to a large extent controllable by the experimenter, the activity of neurons in many brain areas, including the cortex, is strongly dependent on global internal variables that modulate the organism as a whole, such as arousal, motivation, etc. Such variables, which determine what is typically referred to as brain-state, depend on the action of neuro-modulatory systems and, due to their global nature, have a very large impact on patterns of neural activity at the population level. We are interested in characterizing how the dynamics of populations of neurons in (sensory) cortex depend on brain-state, focusing on states of activation or desynchronization, typical of attentive wakefulness, but which can also be generated pharmacologically under anesthesia. We study the statistical structure and functional role of spontaneous activity fluctuations in cortical populations and their relationship with evoked sensory responses, in order to get a better understanding of the nature of neural variability and its impact on behaviour.

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Colaborators: Jaime de la Rocha & Albert Compte (IDIBAPS, Spain)

Circuit basis of simple auditory judgements

We are using auditory discrimination tasks in rodents, together with large-scale cortical population recordings and theory, in order to study the circuit basis of simple sensory judgements. We focus on several aspects of this problem, such as the population structure of trial-to-trial variability in auditory cortex and its relationship to behavioral accuracy, the way in which external sensory evidence is combined with prior expectations in local auditory cortical circuits, the role of different, genetically-identified cell types, in shaping the overall dynamics of spontaneous activity and evoked auditory responses, and the functional role of such dynamical, time-varying activity patterns in the context of auditory categorizations.

 

The dynamical basis of working memory

In order to guide behaviour, it is sometimes necessary to actively maintain or manipulate information which has been previously experienced, but is no longer present in the environment – an ability referred to as Working Memory. The prefrontal cortex has been identified as a key brain area in this process, and recent work is suggesting an important role for sensory areas in working memory as well.
In this project we are interested in characterising the structure of working memory representations at the population level, in quantifying their dynamical stability, and in investigating the contribution of sensory and frontal areas to working memory function in mice. Our goal is to combine careful behavioural analysis, electrophysiology, optogenetics and modeling to provide a dynamical foundation for this important cognitive ability.

Colaborators: Paul Chadderton (Imperial College, London) and Sebastian Royer (Center for Functional Connectomics, Seoul)

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