scholarly journals Discrete attractor dynamics underlying selective persistent activity in frontal cortex

2017 ◽  
Author(s):  
Hidehiko K. Inagaki ◽  
Lorenzo Fontolan ◽  
Sandro Romani ◽  
Karel Svoboda
Keyword(s):  
Short Term Memory ◽  
Network Modeling ◽  
Motor Planning ◽  
Delayed Response ◽  
Persistent Activity ◽  
Short Term ◽  
Population Activity ◽  
Term Memory ◽  
Attractor Dynamics ◽  
Response Task

AbstractShort-term memories link events separated in time, such as past sensation and future actions. Short-term memories are correlated with selective persistent activity, which can be maintained over seconds. In a delayed response task that requires short-term memory, neurons in mouse anterior lateral motor cortex (ALM) show persistent activity that instructs future actions. To elucidate the mechanisms underlying this persistent activity we combined intracellular and extracellular electrophysiology with optogenetic perturbations and network modeling. During the delay epoch, both membrane potential and population activity of ALM neurons funneled towards discrete endpoints related to specific movement directions. These endpoints were robust to transient shifts in ALM activity caused by optogenetic perturbations. Perturbations occasionally switched the population dynamics to the other endpoint, followed by incorrect actions. Our results are consistent with discrete attractor dynamics underlying short-term memory related to motor planning.

scholarly journals Targeted photostimulation uncovers circuit motifs supporting short-term memory

2019 ◽  
Author(s):  
Kayvon Daie ◽  
Karel Svoboda ◽  
Shaul Druckmann
Keyword(s):  
Neural Activity ◽  
Neural Circuit ◽  
Short Term Memory ◽  
Functional Organization ◽  
Neuronal Population ◽  
Delayed Response ◽  
Short Term ◽  
Population Activity ◽  
Term Memory ◽  
Stimulus Offset

AbstractShort-term memory is associated with persistent neural activity without sustained input, arising from the interactions between neurons with short time constants1,2. A variety of neural circuit motifs could account for measured neural activity3–7. A mechanistic understanding of the neural circuits supporting short-term memory requires probing network connectivity between functionally characterized neurons8. We performed targeted photostimulation of small (< 10) groups of neurons, while imaging the response of hundreds of other neurons9,10, in anterior-lateral motor cortex (ALM) of mice performing a delayed response task11. Mice were instructed with brief auditory stimuli to make directional movements (lick left or lick right), but only after a three second delay epoch. ALM contains neurons with delay epoch activity that is selective for left or right choices. Targeted photostimulation of groups of neurons during the delay epoch allowed us to observe the functional organization of population activity and recurrent interactions underlying short-term memory. These experiments revealed strong coupling between neurons sharing similar selectivity. Brief photostimulation of functionally related neurons produced changes in activity in sparse subpopulations of nearby neurons that persisted for several seconds following stimulus offset, far outlasting the duration of the perturbation. Photostimulation produced behavioral biases that were predictable based on the selectivity of the perturbed neuronal population. These results suggest that ALM contains multiple intercalated modules, consisting of recurrently coupled neurons, that can independently maintain persistent activity.

scholarly journals The evolution of primate short-term memory

2021 ◽  
Author(s):  
Many Primates
Keyword(s):  
Social Factors ◽  
Cognitive Abilities ◽  
Short Term Memory ◽  
Memory Performance ◽  
Delayed Response ◽  
Primate Cognition ◽  
Short Term ◽  
Closely Related Species ◽  
Term Memory ◽  
Response Task

Short-term memory is implicated in a range of cognitive abilities and is critical for understanding primate cognitive evolution. To investigate the effects of phylogeny, ecology and sociality on short-term memory ability, we tested 421 non-human primates across 41 species in a pre-registered, experimental delayed-response task. Our results confirm previous findings that longer delays decrease memory performance across species and taxa. Our analyses demonstrate a considerable contribution of phylogeny over ecological and social factors on the distribution of short-term memory performance in primates; closely related species had more similar short-term memory abilities. However, interdependencies between phylogeny and socioecology of a given species present an obstacle to disentangling the effects of each of these factors on the evolution of short-term memory capacity. The dataset corresponding to the study is freely accessible and constitutes an important resource for studying the evolution of primate cognition.

scholarly journals Visual short-term memory for 3D shapes reveals similar properties to simple 2D features

2019 ◽  
Author(s):  
Joel Robitaille ◽  
Stephen Emrich
Keyword(s):  
Short Term Memory ◽  
Memory Load ◽  
Memory Performance ◽  
Delayed Response ◽  
Short Term ◽  
Complex Objects ◽  
Term Memory ◽  
Visual Short Term Memory ◽  
2D And 3D ◽  
3D Shapes

In the past two decades, significant advances have been made to understand the psychophysical properties of visual short-term memory (VSTM). Most studies, however, make inferences based on memory for simple surface features of 2D shapes. Here, we examined the role of object complexity and dimensionality on the psychophysical properties of VSTM by comparing orientation memory for 2D lines and complex 3D objects in a delayed-response continuous report task, where memory load (Experiment 1) or axis of rotation (Experiment 2) was manipulated. In both experiments, our results demonstrate an overall cost of complexity that affected participants raw errors as well as their guess rate and response precision derived from mixture modelling. We also demonstrate that participants’ memory performance is correlated between stimulus types and that memory performance for both 2D and 3D shapes is better fit to the variable precision model of VSTM than to tested competing models. Interestingly, the ability to report complex objects is not consistent across axes of rotation. These results indicate that, despite the fact that VSTM shares similar properties for 2D and 3D shapes, VSTM is far from being a unitary process and is affected by stimulus properties such as complexity and dimensionality.

Neuromodulation of Reactive Sensorimotor Mappings as a Short-Term Memory Mechanism in Delayed Response Tasks

2002 ◽  
Vol 10 (3-4) ◽  
pp. 185-199 ◽  
Author(s):  
Tom Ziemke ◽  
Mikael Thieme
Keyword(s):  
Short Term Memory ◽  
Neural Nets ◽  
Memory Representation ◽  
Delayed Response ◽  
Short Term ◽  
Term Memory ◽  
Memory Mechanism ◽  
Control Networks ◽  
Behavioral Dynamics ◽  
Sensorimotor Mechanisms

This article addresses the relation between memory, representation, and adaptive behavior. More specifically, it demonstrates and discusses the use of synaptic plasticity, realized through neuromodulation of sensorimotor mappings, as a short-term memory mechanism in delayed response tasks. A number of experiments with extended sequential cascaded networks, that is, higher-order recurrent neural nets, controlling simple robotic agents in six different delayed response tasks are presented. The focus of the analysis is on how short-term memory is realized in such control networks through the dynamic modulation of sensorimotor mappings (rather than through feedback of neuronal activation, as in conventional recurrent nets), and how these internal dynamics interact with environmental/behavioral dynamics. In particular, it is demonstrated in the analysis of the last experimental scenario how this type of network can make very selective use of feedback/memory, while as far as possible limiting itself to the use of reactive sensorimotor mechanisms and occasional switches between them.

scholarly journals A Diverse Range of Factors Affect the Nature of Neural Representations Underlying Short-Term Memory

2018 ◽  
Author(s):  
A. Emin Orhan ◽  
Wei Ji Ma
Keyword(s):  
Neural Circuits ◽  
Short Term Memory ◽  
Persistent Activity ◽  
Short Term ◽  
Diverse Range ◽  
Term Memory ◽  
Temporal Complexity ◽  
Wide Range ◽  
Activity Models ◽  
The Brain

AbstractSequential and persistent activity models are two prominent models of short-term memory in neural circuits. In persistent activity models, memories are represented in persistent or nearly persistent activity patterns across a population of neurons, whereas in sequential models, memories are represented dynamically by a sequential pattern of activity across the population. Experimental evidence for both types of model in the brain has been reported previously. However, it has been unclear under what conditions these two qualitatively different types of solutions emerge in neural circuits. Here, we address this question by training recurrent neural networks on several short-term memory tasks under a wide range of circuit and task manipulations. We show that sequential and nearly persistent solutions are both part of a spectrum that emerges naturally in trained networks under different conditions. Fixed delay durations, tasks with higher temporal complexity, strong network coupling, motion-related dynamic inputs and prior training in a different task favor more sequential solutions, whereas variable delay durations, tasks with low temporal complexity, weak network coupling and symmetric Hebbian short-term synaptic plasticity favor more persistent solutions. Our results help clarify some seemingly contradictory experimental results on the existence of sequential vs. persistent activity based memory mechanisms in the brain.

Application of the Method of Second Order Sign Behavior To the Study of Non-Spatial Delayed Response in Rhesus Monkeys

Behaviour ◽  
1969 ◽  
Vol 35 (1-2) ◽  
pp. 128-136 ◽  
Author(s):  
Bruno Cardu
Keyword(s):  
Rhesus Monkeys ◽  
Short Term Memory ◽  
Memory Span ◽  
Second Order ◽  
Delayed Response ◽  
Short Term ◽  
Term Memory ◽  
First Order ◽  
The Moment ◽  
Sign Behavior

AbstractThe behavior of seven rhesus monkeys on a test of non-spatial delayed response based on the method of second order sign behavior is reported. Four stimuli were used: two first order stimuli presented individually (two sounds or two lights) and two second order stimuli presented simultaneously (two objects). Subjects first learned to associate one of the objects to each of the two first order stimuli. An interval between the termination of the first signal and the moment of choice was then introduced; hence the subjects' short-term memory could be estimated. All subjects succeeded in this task; the limits of the memory span ranged from 20 to 45 seconds.

scholarly journals Persistent activity in a recurrent circuit underlies courtship memory in Drosophila

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Xiaoliang Zhao ◽  
Daniela Lenek ◽  
Ugur Dag ◽  
Barry J Dickson ◽  
Krystyna Keleman
Keyword(s):  
Dopaminergic Neurons ◽  
Mushroom Body ◽  
Neural Circuits ◽  
Short Term Memory ◽  
Persistent Activity ◽  
Short Term ◽  
Present Evidence ◽  
Term Memory ◽  
Time Periods ◽  
Over Time

Recurrent connections are thought to be a common feature of the neural circuits that encode memories, but how memories are laid down in such circuits is not fully understood. Here we present evidence that courtship memory in Drosophila relies on the recurrent circuit between mushroom body gamma (MBγ), M6 output, and aSP13 dopaminergic neurons. We demonstrate persistent neuronal activity of aSP13 neurons and show that it transiently potentiates synaptic transmission from MBγ>M6 neurons. M6 neurons in turn provide input to aSP13 neurons, prolonging potentiation of MBγ>M6 synapses over time periods that match short-term memory. These data support a model in which persistent aSP13 activity within a recurrent circuit lays the foundation for a short-term memory.

Sign in / Sign up

Export Citation Format

Share Document