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Li, A. A.

Publications and source records attributed to Li, A. A..

2 recordsLinked to original sources

Emergence of Probabilistic Representation in the Neural Network of Primary Visual Cortex

During the early development of mammalian visual system, the distribution of neuronal preferred orientations in the primary visual cortex (V1) gradually shifts to match the major orientation features of an environment, achieving optimal representation of the environment. By combining the computational modeling and experimental electrophysiological recording, we provide a circuitry plasticity mechanism that underlies the developmental emergence of such matched representation in the visual cortical network. Specifically, in a canonical circuit of densely interconnected pyramidal cells and inhibitory parvalbumin-expressing (PV+) fast-spiking interneurons in the V1 layer 2/3, our model successfully simulates the experimental observations and further reveals that the non-uniform inhibition, mediated by local interneurons, exerts a key role in shaping the network representation through spike timing-dependent synaptic modifications. The experimental results confirm that PV+ interneurons in the V1 are capable of providing such non-uniform inhibition during a short period after the vision onset. Thus, our study elucidates a circuitry mechanism for acquisition of the prior knowledge of environment for optimal inference in sensory neural system.

neuroscience↗

Neural control of steering in walking Drosophila

Orienting behaviors provide a continuous stream of information about an organisms sensory experiences and plans. Thus, to study the links between sensation and action, it is useful to identify the neurons in the brain that control orienting behaviors. Here we describe descending neurons in the Drosophila brain that predict and influence orientation (heading) during walking. We show that these cells have specialized functions: whereas one cell type predicts sustained low-gain steering, the other predicts transient high-gain steering. These latter cells integrate internally-directed steering signals from the head direction system with stimulus-directed steering signals from multimodal sensory pathways. The inputs to these cells are organized to produce "see-saw" steering commands, so that increasing output from one brain hemisphere is accompanied by decreasing output from the other hemisphere. Together, our results show that internal and external drives are integrated to produce descending motor commands with different timescales, for flexible and precise control of an organisms orientation in space.

neuroscience↗