Information processing in a midbrain visual pathway

Visual information is processed in brain via the intricate interactions between neurons. We investigated a midbrain visual pathway: optic tectum and its isthmic nucleus) that is motion sensitive and is thought as part of attentional system. We determined the physiological properties of individual neurons as well as their synaptic connections with intracellular recordings. We reproduced the center-surround receptive field structure of tectal neurons in a dynamical recurrent feedback loop. We reveal in a computational model that the anti-topographic inhibitory feedback could mediate competitive stimulus selection in a complex visual scene. We also investigated the dynamics of the competitive selection in a rate model. The isthmotectal feedback loop gates the information transfer from tectum to thalamic rotundus. We discussed the role of a localized feedback projection in contributing to the gating mechanisms with both experimental and numerical approaches. We further discussed the dynamics of the isthmotectal system by considering the propagation delays between different components. We conclude that the isthmotectal system is involved in attention-like competitive stimulus selection and control the information coding in the motion sensitive SGC-I neurons by modulating the retino-tectal synaptic transmission

Interiors and furnishings designed by Miguel Fisac for the CSIC

[ES] Conocida y fotografiada parte de la producción de Miguel Fisac relacionada con el mobiliario para el CSIC, no había sido estudiada hasta ahora en su conjunto. Se recogen cronológicamente los diferentes estilos utilizados para los distintos espacios, las motivaciones expresadas por el propio arquitecto, su estado actual y las consideraciones que puedan permitir su inclusión en el Patrimonio Artístico del CSIC y la declaración de alguna de ellas, como la “librería científica” como Bien de Interés Cultural.[EN] Although Miguel Fisac’s designs for the furnishings in the Spanish Council for Scientific Research are well known and widely photographed, they had not, to date, been studied as a whole. This chronological review of the styles used to create different spatial effects describes both the author’s motivations as explained by the architect himself and the present condition of the furnishings. Considerations in support of their inclusion in the Council’s Artistic Estate are discussed, advocating —in the case of the “Scientific Library”— the award of Asset of Cultural Interest status.Peer reviewe

Recurrent antitopographic inhibition mediates competitive stimulus selection in an attention network

Topographically organized neurons represent multiple stimuli within complex visual scenes and compete for subsequent processing in higher visual centers. The underlying neural mechanisms of this process have long been elusive. We investigate an experimentally constrained model of a midbrain structure: the optic tectum and the reciprocally connected nucleus isthmi. We show that a recurrent antitopographic inhibition mediates the competitive stimulus selection between distant sensory inputs in this visual pathway. This recurrent antitopographic inhibition is fundamentally different from surround inhibition in that it projects on all locations of its input layer, except to the locus from which it receives input. At a larger scale, the model shows how a focal top-down input from a forebrain region, the arcopallial gaze field, biases the competitive stimulus selection via the combined activation of a local excitation and the recurrent antitopographic inhibition. Our findings reveal circuit mechanisms of competitive stimulus selection and should motivate a search for anatomical implementations of these mechanisms in a range of vertebrate attentional systems