Short-term memory

…and how ring models can explain the short-term memory involved.

Persistent neural activity underlies key cognitive functions like short-term memory. To support persistent neural activity, circuits must learn to balance recurrent amplification (prolonging network time constants) with sufficient robustness to gate out perturbations in local parts of the network. It remains unclear how such persistent and robust representations emerge in neural circuits. Neurons in the mouse anterior lateral motor cortex (ALM) exhibit preparatory activity during motor planning, a robust persistent activity maintained by both hemispheres. We used longitudinal two-photon calciu

Short-term plasticity (STP) dynamically regulates synaptic strength on the timescale of milliseconds to seconds, playing a critical role in moment-to-moment information processing within neural circuits. Deficits in STP have been implicated in neurological and psychiatric disorders, but its precise contribution to higher cognitive functions and behavioral flexibility remains poorly understood. Here, we address this gap by focusing on synaptotagmin-7 (SYT7), a calcium sensor essential for facilitation---a form of STP in which high-frequency stimulation briefly enhances neurotransmitter release.

Real-world decisions often require combining different cognitive computations. Recent findings suggest that, on the one hand, these computations are distributed across the cortex. On the other hand, cortical microcircuits seem to implement them via (near) orthogonal population-activity patterns. But how are these local geometries combined at the level of cortex-wide dynamics? To answer this, we developed a new task for mice navigating in virtual reality (VR) to temporally disentangle different cognitive computations. Mice first accumulate evidence to determine the predominant color of a random

The brain encodes information in the spiking dynamics of recurrently connected inhibitory (I) and excitatory (E) neurons. Recurrent Spiking Neural Networks (RSNNs) have the potential to illuminate mechanisms of neurobiological computation. While inhibition and excitation underlie cortical dynamics, the roles of individual E and I neurons, as well as distinct I neuron subclasses, remain unclear. To elucidate these roles, we created biologically plausible RSNNs with leaky integrate and fire neurons and trained the networks on variations of a temporal task. We find that distinct interneuron subcl

Endurance training can improve cognitive function in aging people. It seems related to the expression of neurotrophic factors stimulating neurogenesis in the hippocampus and synaptic plasticity in the cortex and/or hippocampus. However, the benefits are highly dependent on the duration, intensity and frequency of exercise, which remains to determine. The aim of the current study is to compare 4 weeks of either high-intensity interval (HIIT) or moderate-intensity continuous (MICT) training on cognition, endurance and sensorimotor performance, and neuroplasticity markers. For that, 24 aged rats

It is challenging to create chemical-induced models of Alzheimer’s disease without using genetically bred animals. Intracerebroventricular (ICV) streptozocin (STZ) administration at a sub-diabetogenic dose can serve as a viable model for cognitive impairment associated with Alzheimer's disease via a disruption of glucose and energy metabolism in the brain, accompanied by oxidative stress and a concurrent impact on cognitive function. The aim of this study is to evaluate the behavioral results of once or twice injections of the ICV STZ administration methods. ICV guide cannulas were placed unil

…summing these to form a single memory-stored home vector. While path integration is a primary navigation mechanism for many invertebrates, little is known about the temporal degradation of this vector memory. To investigate how long the home v

The process of memory consolidation involves the transfer of information from short-term memory (STM) to long-term memory (LTM). Memory consolidation requires activation of the dorsal hippocampus (dHP), especially under conditions of high memory load. In this study, we asked whether there is a limit to the memory capacity, that is, the amount of information that can be stored during unique experiences. Using male and female outbred CD1 mice subjected to a modified version of the object recognition test, we found that females, despite having the same 6- object STM capacity as males, appear to t

…evidence and maintain the choice in short-term memory until the motor response. Previous modelling work has proposed that recurrent circuit dynamics underlie these two processes and that N-methyl-D-aspartate receptors (NMDARs) are necessary for proper network function. Electrophysiological evidence indicates that circuits in the frontal cortex may carry out these computations but the role of NMDAR has not been systematically tested. We developed an auditory two-alternative delayed-choice (2ADC) task for head-fixed mice

…to have retrieved information via short-term memory. However, how this was achieved remains unclear.In this work, we extended the nonlinear mean-field model of Wong and Wang (2006) by incorporating a

Perceptual memories store our experiences; they are the basis for our understanding the external world and guiding our decisions. Despite fast-paced research in this field, behavioral and cognitive constructs are often custom built around the investigators’ preferred task, and general principles across tasks are still missing. To address these issues, we performed psychophysical experiments aiming to build a computational model comprised of interconnected functional units, each performing a specific task-independent operation. The interaction between units and the readout of the system can be

…However, short-term memory maintenance in these networks has mostly been implemented through static attractors. Thus, it remains unclear if and how RNNs can encode memories in the relative phase of oscillations. Here we show that such phase-dependent coding can arise through the training of RNNs on memory tasks. We characterize how the emerg

…neural network activity underpinning short-term memory in mice. Relevant techniques covered include: simultaneous multi-regional recordings using multiple 64-channel H probes during head-fixed behavior in mice. simultaneous optogenetics and population recording. analysis of population recordings to infer interactions between brain regions. Reference: Chen G, Kang B, Lindsey J, Druckmann S, Li N, (2021). Modularity and robustness of frontal cortex networks. Cell, 184(14):3717-3730.

Planning, a prospective form of short-term memory, is a cognitive function that has been predominantly attributed to the cortex. Recent experiments, however, have concluded that the thalamus and other subcortical structures participate in this function. A comprehensive computational framework to link neural dynamics and cognition in the context of large-scale subcortical-cortical circuits is lacking. In this computational study, we elucidated the dynamical mechanisms by which the cortex, thalamus and other subcortical structures jointly contribute to planning. Recurrent circuitry in the cort

…the serial order of items within short-term memory [4]. Based on recordings of spiking activity and local field potentials (LFPs) of epilepsy patients performing a multi-item sequential memory task, we show phase-dependent spiking during the delay, with preferred phases that were related to stimulus position within the s