scholarly journals Shared population-level dynamics in monkey premotor cortex during solo action, joint action and action observation

2020 ◽  
Author(s):  
Giovanni Pezzulo ◽  
Francesco Donnarumma ◽  
Simone Ferrari-Toniolo ◽  
Paul Cisek ◽  
Alexandra Battaglia-Mayer
Keyword(s):  
Population Dynamics ◽  
Motor Behavior ◽  
Action Observation ◽  
Premotor Cortex ◽  
Cell Activity ◽  
Population Level ◽  
Neural Dynamics ◽  
Neural Population ◽  
Visuomotor Task ◽  
Task Types

ABSTRACTStudies of neural population dynamics of cell activity from monkey motor areas during reaching show that it mostly represents the generation and timing of motor behavior. We compared neural dynamics in dorsal premotor cortex (PMd) during the performance of a visuomotor task executed under different contexts and during an observation task. In the former, monkeys moved a visual cursor in different directions by applying isometric forces on a joystick, either individually or in cooperation with a conspecific. In the latter, they observed the cursor’s motion guided by the partner. We found that neural dynamics were shared across isometric and observation tasks and they discriminated directions more accurately than task types, suggesting that PMd encodes spatial aspects independently from specific behavioral demands. Therefore, the largest components of population dynamics might reflect higher cognitive processes, such as the representation of action goals or outcomes, rather than mechanisms strictly confined to motor functions.

scholarly journals SHARED POPULATION-LEVEL DYNAMICS IN MONKEY PREMOTOR CORTEX DURING SOLO ACTION, JOINT ACTION AND ACTION OBSERVATION

2021 ◽  
pp. 102214
Author(s):  
Giovanni Pezzulo ◽  
Francesco Donnarumma ◽  
Simone Ferrari-Toniolo ◽  
Paul Cisek ◽  
Alexandra Battaglia-Mayer
Keyword(s):  
Joint Action ◽  
Action Observation ◽  
Premotor Cortex ◽  
Population Level

scholarly journals Movement initiation and grasp representation in premotor and primary motor cortex mirror neurons

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Steven Jack Jerjian ◽  
Maneesh Sahani ◽  
Alexander Kraskov
Keyword(s):  
Mirror Neurons ◽  
Primary Motor Cortex ◽  
Action Observation ◽  
Premotor Cortex ◽  
Movement Control ◽  
Population Level ◽  
Reach To Grasp ◽  
Movement Initiation ◽  
Population Activity ◽  
Spinal Circuitry

Pyramidal tract neurons (PTNs) within macaque rostral ventral premotor cortex (F5) and (M1) provide direct input to spinal circuitry and are critical for skilled movement control. Contrary to initial hypotheses, they can also be active during action observation, in the absence of any movement. A population-level understanding of this phenomenon is currently lacking. We recorded from single neurons, including identified PTNs, in (M1) (n = 187), and F5 (n = 115) as two adult male macaques executed, observed, or withheld (NoGo) reach-to-grasp actions. F5 maintained a similar representation of grasping actions during both execution and observation. In contrast, although many individual M1 neurons were active during observation, M1 population activity was distinct from execution, and more closely aligned to NoGo activity, suggesting this activity contributes to withholding of self-movement. M1 and its outputs may dissociate initiation of movement from representation of grasp in order to flexibly guide behaviour.

scholarly journals Considerations in using recurrent neural networks to probe neural dynamics

2019 ◽  
Vol 122 (6) ◽  
pp. 2504-2521
Author(s):  
Jonathan C. Kao
Keyword(s):  
Neural Networks ◽  
Recurrent Neural Networks ◽  
Single Neuron ◽  
Target Location ◽  
Motor Behavior ◽  
Neural Dynamics ◽  
Neural Population ◽  
Dynamical Mechanism ◽  
Model Complex ◽  
Do So

Recurrent neural networks (RNNs) are increasingly being used to model complex cognitive and motor tasks performed by behaving animals. RNNs are trained to reproduce animal behavior while also capturing key statistics of empirically recorded neural activity. In this manner, the RNN can be viewed as an in silico circuit whose computational elements share similar motifs with the cortical area it is modeling. Furthermore, because the RNN’s governing equations and parameters are fully known, they can be analyzed to propose hypotheses for how neural populations compute. In this context, we present important considerations when using RNNs to model motor behavior in a delayed reach task. First, by varying the network’s nonlinear activation and rate regularization, we show that RNNs reproducing single-neuron firing rate motifs may not adequately capture important population motifs. Second, we find that even when RNNs reproduce key neurophysiological features on both the single neuron and population levels, they can do so through distinctly different dynamical mechanisms. To distinguish between these mechanisms, we show that an RNN consistent with a previously proposed dynamical mechanism is more robust to input noise. Finally, we show that these dynamics are sufficient for the RNN to generalize to tasks it was not trained on. Together, these results emphasize important considerations when using RNN models to probe neural dynamics. NEW & NOTEWORTHY Artificial neurons in a recurrent neural network (RNN) may resemble empirical single-unit activity but not adequately capture important features on the neural population level. Dynamics of RNNs can be visualized in low-dimensional projections to provide insight into the RNN’s dynamical mechanism. RNNs trained in different ways may reproduce neurophysiological motifs but do so with distinctly different mechanisms. RNNs trained to only perform a delayed reach task can generalize to perform tasks where the target is switched or the target location is changed.

scholarly journals Behavioral Triggers of Skin Conductance Responses and Their Neural Correlates in the Primate Amygdala

2009 ◽  
Vol 101 (4) ◽  
pp. 1749-1754 ◽  
Author(s):  
Christopher M. Laine ◽  
Kevin M. Spitler ◽  
Clayton P. Mosher ◽  
Katalin M. Gothard
Keyword(s):  
Skin Conductance ◽  
Single Unit ◽  
Population Level ◽  
Emotional Reaction ◽  
Neural Population ◽  
Experimental Conditions ◽  
Indirect Measure ◽  
Skin Conductance Responses ◽  
The Right ◽  
Sympathetic Arousal

The amygdala plays a crucial role in evaluating the emotional significance of stimuli and in transforming the results of this evaluation into appropriate autonomic responses. Lesion and stimulation studies suggest involvement of the amygdala in the generation of the skin conductance response (SCR), which is an indirect measure of autonomic activity that has been associated with both emotion and attention. It is unclear if this involvement marks an emotional reaction to an external stimulus or sympathetic arousal regardless of its origin. We recorded skin conductance in parallel with single-unit activity from the right amygdala of two rhesus monkeys during a rewarded image viewing task and while the monkeys sat alone in a dimly lit room, drifting in and out of sleep. In both experimental conditions, we found similar SCR-related modulation of activity at the single-unit and neural population level. This suggests that the amygdala contributes to the production or modulation of SCRs regardless of the source of sympathetic arousal.

Modest Gaze-Related Discharge Modulation in Monkey Dorsal Premotor Cortex During a Reaching Task Performed With Free Fixation

2002 ◽  
Vol 88 (2) ◽  
pp. 1064-1072 ◽  
Author(s):  
Paul Cisek ◽  
John F. Kalaska
Keyword(s):  
Premotor Cortex ◽  
Cell Activity ◽  
Delay Period ◽  
Gaze Direction ◽  
Dorsal Premotor Cortex ◽  
Experimental Conditions ◽  
Reaching Task ◽  
Oculomotor Behavior ◽  
Arm Reaching ◽  
Gaze Angle

Recent studies have shown that gaze angle modulates reach-related neural activity in many cortical areas, including the dorsal premotor cortex (PMd), when gaze direction is experimentally controlled by lengthy periods of imposed fixation. We looked for gaze-related modulation in PMd during the brief fixations that occur when a monkey is allowed to look around freely without experimentally imposed gaze control while performing a center-out delayed arm-reaching task. During the course of the instructed-delay period, we found significant effects of gaze angle in 27–51% of PMd cells. However, for 90–95% of cells, these effects accounted for <20% of the observed discharge variance. The effect of gaze was significantly weaker than the effect of reach-related variables. In particular, cell activity during the delay period was more strongly related to the intended movement expressed in arm-related coordinates than in gaze-related coordinates. Under the same experimental conditions, many cells in medial parietal cortex exhibited much stronger gaze-related modulation and expressed intended movement in gaze-related coordinates. In summary, gaze direction-related modulation of cell activity is indeed expressed in PMd during the brief fixations that occur in natural oculomotor behavior, but its overall effect on cell activity is modest.

scholarly journals The epidemiological consequences of immune priming

2012 ◽  
Vol 279 (1746) ◽  
pp. 4505-4512 ◽  
Author(s):  
Hannah J. Tidbury ◽  
Alex Best ◽  
Mike Boots
Keyword(s):  
Immune Response ◽  
Population Dynamics ◽  
Population Level ◽  
Low Doses ◽  
Population Stability ◽  
Invertebrate Immunity ◽  
Invertebrate Host ◽  
Immune Priming ◽  
Pathogen Persistence ◽  
Full Immunity

Exposure to low doses of pathogens that do not result in the host becoming infectious may ‘prime’ the immune response and increase protection to subsequent challenge. There is increasing evidence that such immune priming is a widespread and important feature of invertebrate host–pathogen interactions. Immune priming clearly has implications for individual hosts but will also have population-level implications. We present a susceptible–primed–infectious model—in contrast to the classic susceptible–infectious–recovered framework—to investigate the impacts of immune priming on pathogen persistence and population stability. We describe impacts of immune priming on the epidemiology of the disease in both constant and seasonal environments. A key result is that immune priming may act to destabilize population dynamics. In particular, when the proportion of individuals becoming primed rather than infected is high, but this priming does not confer full immunity, the population may be strongly destabilized through the generation of limit cycles. We discuss the implications of our model both in the context of invertebrate immunity and more widely.

scholarly journals Proteolytic Remodeling of Perineuronal Nets: Effects on Synaptic Plasticity and Neuronal Population Dynamics

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
P. Lorenzo Bozzelli ◽  
Seham Alaiyed ◽  
Eunyoung Kim ◽  
Sonia Villapol ◽  
Katherine Conant
Keyword(s):  
Population Dynamics ◽  
Synaptic Plasticity ◽  
Synaptic Input ◽  
Neuronal Plasticity ◽  
Population Level ◽  
Gamma Oscillations ◽  
Brain Regions ◽  
Neuronal Population ◽  
Perineuronal Nets ◽  
Perineuronal Net

The perineuronal net (PNN) represents a lattice-like structure that is prominently expressed along the soma and proximal dendrites of parvalbumin- (PV-) positive interneurons in varied brain regions including the cortex and hippocampus. It is thus apposed to sites at which PV neurons receive synaptic input. Emerging evidence suggests that changes in PNN integrity may affect glutamatergic input to PV interneurons, a population that is critical for the expression of synchronous neuronal population discharges that occur with gamma oscillations and sharp-wave ripples. The present review is focused on the composition of PNNs, posttranslation modulation of PNN components by sulfation and proteolysis, PNN alterations in disease, and potential effects of PNN remodeling on neuronal plasticity at the single-cell and population level.

scholarly journals Area-specific thalamocortical synchronization underlies the transition from motor planning to execution

2021 ◽  
Vol 118 (6) ◽  
pp. e2012658118
Author(s):  
Abdulraheem Nashef ◽  
Rea Mitelman ◽  
Ran Harel ◽  
Mati Joshua ◽  
Yifat Prut
Keyword(s):  
Primary Motor Cortex ◽  
Premotor Cortex ◽  
Cell Activity ◽  
Motor Planning ◽  
Simultaneous Recording ◽  
Delayed Response ◽  
Neural Responses ◽  
Cortical Cells ◽  
Reaching Task ◽  
Motor Thalamus

We studied correlated firing between motor thalamic and cortical cells in monkeys performing a delayed-response reaching task. Simultaneous recording of thalamocortical activity revealed that around movement onset, thalamic cells were positively correlated with cell activity in the primary motor cortex but negatively correlated with the activity of the premotor cortex. The differences in the correlation contrasted with the average neural responses, which were similar in all three areas. Neuronal correlations reveal functional cooperation and opposition between the motor thalamus and distinct motor cortical areas with specific roles in planning vs. performing movements. Thus, by enhancing and suppressing motor and premotor firing, the motor thalamus can facilitate the transition from a motor plan to execution.

scholarly journals Dynamics of the Auditory Continuity Illusion

2021 ◽  
Vol 15 ◽  
Author(s):  
Qianyi Cao ◽  
Noah Parks ◽  
Joshua H. Goldwyn
Keyword(s):  
Firing Rate ◽  
Noise Burst ◽  
Auditory Scene Analysis ◽  
Quantitative Model ◽  
Neural Dynamics ◽  
Sufficient Evidence ◽  
Neural Population ◽  
Neural Basis ◽  
Continuous Responses ◽  
Conceptual Explanations

Illusions give intriguing insights into perceptual and neural dynamics. In the auditory continuity illusion, two brief tones separated by a silent gap may be heard as one continuous tone if a noise burst with appropriate characteristics fills the gap. This illusion probes the conditions under which listeners link related sounds across time and maintain perceptual continuity in the face of sudden changes in sound mixtures. Conceptual explanations of this illusion have been proposed, but its neural basis is still being investigated. In this work we provide a dynamical systems framework, grounded in principles of neural dynamics, to explain the continuity illusion. We construct an idealized firing rate model of a neural population and analyze the conditions under which firing rate responses persist during the interruption between the two tones. First, we show that sustained inputs and hysteresis dynamics (a mismatch between tone levels needed to activate and inactivate the population) can produce continuous responses. Second, we show that transient inputs and bistable dynamics (coexistence of two stable firing rate levels) can also produce continuous responses. Finally, we combine these input types together to obtain neural dynamics consistent with two requirements for the continuity illusion as articulated in a well-known theory of auditory scene analysis: responses persist through the noise-filled gap if noise provides sufficient evidence that the tone continues and if there is no evidence of discontinuities between the tones and noise. By grounding these notions in a quantitative model that incorporates elements of neural circuits (recurrent excitation, and mutual inhibition, specifically), we identify plausible mechanisms for the continuity illusion. Our findings can help guide future studies of neural correlates of this illusion and inform development of more biophysically-based models of the auditory continuity illusion.

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