We, like many other mammals, are essentially visual animals. Thus the visual system of our brains must achieve a daunting task: it creates, in real time, an internal representation of the external world that it is used by other parts of the brain to guide our behavior. But, how do we actually see? how does this neural system accomplish the job? A parsimonious explanation proposes that visual information is analyzed in a series of sequential steps starting in the retina and continuing along the multiple visual cortical areas. As a result, the information captured by the approximately 105 millions of photoreceptors in the back of each eye is continuously rearranged in a complex combination of points and lines of different orientations and curvatures that are defined by differences in local contrast, color, relative timing, depth, movement, etc. Ultimately, by mechanisms that remain largely unknown, these elementary features of the image are integrated into the perception (our “vision”) of each individual object in the visual scene.
In our lab, we want to understand the synaptic mechanisms and neural circuits that underlie the earliest stages of visual processing and perception. Our main goal is to determine the synaptic structure of the thalamocortial microcircuit at a functional level, which currently represent one of the most fascinating challenges of systems neuroscience. In addition, since vision is the most accessible and best understood of our senses, our results directly inform theoretical models (both conceptual and computational) that are proposed to explain the functional organization of the cerebral cortex and thalamus in general. Finally, a better understanding of the visual system is essential to develop prosthesis that will eventually restore vision to the blind and, on a shorter time scale, to design more efficient tools for the rapidly growing field of object recognition


Representative Publications

Martinez LM. , " The generation of visual cortical receptive fields. " Progress in Brain Res. . 154 , 73 - 92 ( 2006 )

Hirsch JA. , Martinez LM. " Circuits that build visual cortical receptive fields. " Trends in Neurosciences . 29 , 30 - 39 ( 2006 )

Martinez LM. , Wang Q.,Reid RC.,Pillai C., Alonso JM.,Sommer FT. and Hirsch JA. " Receptive field structure varies with layer in the primary visual cortex. " Nature Neuroscience . 8 , 372 - 379 ( 2005 )

Hirsch JA. , Martinez LM.,Pillai C., Alonso JM., Wang Q. and Sommer FT " Functionally distinct inhibitory neurons at the first stage of visual cortical processing. " Nature Neuroscience . 6 , 1300 - 1308 ( 2003 )

Martinez LM.* , Alonso JM.* " Construction of complex receptive fields in primary visual cortex. " Neuron . 32 , 515 - 525 ( 2001 ) * Co-author