Period

~ Sept-Dec 2017

~ Jan-March 2018

~ April-June 2018

Project

Visual three-dimensional space (3D) perception relies on binocular correspondence of image features. In most mammals, this correspondence takes place in the cortex, sub-cortical structures preserving monocular information. Numerous studies have indeed shown the existence of cortical neurons sensitive to binocular disparities. How 3D objects are inferred from these binocular disparities? Is there an influence of the inferred object on the binocular sensitivity of each neuron (Qiu et coll., 2007)? To address these questions, it is proposed to record the dynamics of neuronal responses in the primary visual areas of ferrets. The animal will be beforehand trained to stabilize its gaze on a fixation point and this stabilization will be controlled with an eye-tracker. Extra-cellular recordings of neurons in areas 17 and 18 will help define the receptive fields and the characteristics of these neurons in terms of preferred orientation (Wilson et coll., 2016) and binocular sensitivity. Elementary features (lines) or connected objects (lines connected together to form a 3D object) will then be presented to each of these neurones, and temporal dynamics of neuronal response will be analysed. The project requires basic knowledge in electrophysiology and programming, as well as an interest in visual perception.

References

Qiu, F.T., Sugihara, T., von der Heydt, R. (2007). Figure-ground mechanisms provide structure for selective attention. Nature Neuroscience, 10, 1492-1499. 

Wilson, D.E., Whitney, D.E., Scholl, B., and Fitzpatrick, D. (2016). Orientation selectivity and the functional clustering of synaptic inputs in primary visual cortex. Nature Neuroscience, 19, 1003–1009

Contact

Ecole Normale Supérieure - Laboratoire des Systèmes Perceptifs - 29 rue d’Ulm 75005 Paris - pascal.mamassian@ens.fr