A multi-region recurrent circuit for evidence accumulation in rats.

Decision-making based on noisy evidence requires accumulating evidence and categorizing it to form a choice. Here we evaluate a proposed feedforward and modular mapping of this process in rats: evidence accumulated in anterodorsal striatum (ADS) is categorized in prefrontal cortex (frontal orienting fields, FOF). Contrary to this, we show that both regions appear to be indistinguishable in their encoding/decoding of accumulator value and communicate this information bidirectionally.

Transitions in dynamical regime and neural mode underlie perceptual decision-making.

Perceptual decision-making is the process by which an animal uses sensory stimuli to choose an action or mental proposition. This process is thought to be mediated by neurons organized as attractor networks . However, whether attractor dynamics underlie decision behavior and the complex neuronal responses remains unclear.

A neural mechanism for learning from delayed postingestive feedback.

Animals learn the value of foods based on their postingestive effects and thereby develop aversions to foods that are toxic and preferences to those that are nutritious. However, it remains unclear how the brain is able to assign credit to flavors experienced during a meal with postingestive feedback signals that can arise after a substantial delay. Here, we reveal an unexpected role for postingestive reactivation of neural flavor representations in this temporal credit assignment process.

Feedback determines the structure of correlated variability in primary visual cortex.

The variable responses of sensory neurons tend to be weakly correlated (spike-count correlation, r). This is widely thought to reflect noise in shared afferents, in which case r can limit the reliability of sensory coding. However, it could also be due to feedback from higher-order brain regions.

Saccadic modulation of stimulus processing in primary visual cortex.

Saccadic eye movements play a central role in primate vision. Yet, relatively little is known about their effects on the neural processing of visual inputs. Here we examine this question in primary visual cortex (V1) using receptive-field-based models, combined with an experimental design that leaves the retinal stimulus unaffected by saccades.

Synchronous Spikes Are More Effective (but Not for Long).

The efficacy of spiking synchrony in corticocortical communication is poorly understood. A new study (Zandvakili and Kohn, 2015) in this issue provides compelling evidence that synchrony in a source population is not efficacious beyond the input layers of the target population.

Population interactions between parietal and primary motor cortices during reach.

Neural interactions between parietal area 2/5 and primary motor cortex (M1) were examined to determine the timing and behavioral correlates of cortico-cortical interactions. Neural activity in areas 2/5 and M1 was simultaneously recorded with 96-channel microelectrode arrays in three rhesus monkeys performing a center-out reach task. We introduce a new method to reveal parietal-motor interactions at a population level using partial spike-field coherence (PSFC) between ensembles of neurons in one area and a local field potential (LFP) in another.

High-resolution eye tracking using V1 neuron activity.

Studies of high-acuity visual cortical processing have been limited by the inability to track eye position with sufficient accuracy to precisely reconstruct the visual stimulus on the retina. As a result, studies of primary visual cortex (V1) have been performed almost entirely on neurons outside the high-resolution central portion of the visual field (the fovea). Here we describe a procedure for inferring eye position using multi-electrode array recordings from V1 coupled with nonlinear stimulus processing models.