Topic: receptive field

Feedforward convolutional neural networks are currently the state-of-the-art approach for characterizing the transfer function of early visual cortical neurons. It is well known that the visual cortex has massive recurrent connections. Would models using recurrent circuits provide better neural response prediction than feedforward models? Here, we show that recurrent models consistently outperform feedforward ones when their parameters and hyperparameters are carefully matched. These benefits are robust against variation in the type of activation functions, loss function, number of channels, a

The size of a neuron’s receptive field increases along the visual hierarchy. Neurons in higher-order visual areas integrate information through a canonical mechanism called normalization, where neurons respond sublinearly to multiple stimuli in the receptive field (Carandini & Heeger, 2012). Neurons in visual cortex exhibit highly heterogeneous degrees of normalization, which can be measured by normalization index, defined as the sum of a neuron’s firing rate to each one of two stimuli divided by its firing rate when both stimuli are presented. Interestingly, it has been demonstrated that

Neurons in primary Visual Cortex (V1) have a receptive field (RF) or "center", the region in visual space in which appropriate stimuli drive the neuron to fire. Stimuli surrounding the RF modulate these responses, a phenomenon known as contextual modulation. Here we consider 3 types of contextual modulation: i) classical surround suppression: the response of cells in V1 decreases when the stimulus size is increased beyond the RF size; ii) inverse surround suppression: neurons in layer L2/3 –but not layer L4– of mouse V1 respond to a lack of contrast in their RF when the surround is filled with

Pyramidal neurons have prominent apical dendrites that are hypothesised to modulatesomatic output. In the visual cortex, apical dendrites may receive contextual signals via top-down inputs and local inhibition. It is not known, however, what causal effects they play indriving or suppressing somatic activity, and how they shape a neuron’s visual tuning.We recorded activity of pyramidal neurons sparsely expressing GCaMP7s in layer 5 of visualcortex in awake mice before and after pruning their apical dendrites with two-photondendrotomy. Together with the neuron’s receptive field and orientation/d