scholarly journals Reward modulates cortical representations of action

2020 ◽  
Author(s):  
Tyler J. Adkins ◽  
Taraz G. Lee
Keyword(s):  
Performance Enhancement ◽  
Motor Planning ◽  
Neural Mechanism ◽  
List Type ◽  
Behavioral Performance ◽  
Sequence Production ◽  
On Line ◽  
Elevated Activity ◽  
Improved Performance ◽  
Human Participants

AbstractPeople are capable of rapid on-line improvements in performance when they are offered a reward. The neural mechanism by which this performance enhancement occurs remains unclear. We investigated this phenomenon by offering monetary reward to human participants, contingent on successful performance in a sequence production task. We found that people performed actions more quickly and accurately when they were offered large rewards. Increasing reward magnitude was associated with elevated activity throughout the brain prior to movement. Multivariate patterns of activity in these reward-responsive regions encoded information about the upcoming action. Follow-up analyses provided evidence that action decoding in pre-SMA and other motor planning areas was improved for large reward trials and successful action decoding was associated with improved performance. These results suggest that reward may enhance performance by enhancing neural representations of action used in motor planning.HighlightsReward enhances behavioral performance.Reward enhances action decoding in motor planning areas prior to movement.Enhanced action decoding coincides with improved behavioral performance.

scholarly journals A Password Meter without Password Exposure

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 345
Author(s):  
Pyung Kim ◽  
Younho Lee ◽  
Youn-Sik Hong ◽  
Taekyoung Kwon
Keyword(s):  
Performance Enhancement ◽  
Homomorphic Encryption ◽  
Optimization Techniques ◽  
Third Party ◽  
Fully Homomorphic Encryption ◽  
Performance Achievement ◽  
Server Side ◽  
On Line ◽  
Internal Mechanism ◽  
High Chance

To meet password selection criteria of a server, a user occasionally needs to provide multiple choices of password candidates to an on-line password meter, but such user-chosen candidates tend to be derived from the user’s previous passwords—the meter may have a high chance to acquire information about a user’s passwords employed for various purposes. A third party password metering service may worsen this threat. In this paper, we first explore a new on-line password meter concept that does not necessitate the exposure of user’s passwords for evaluating user-chosen password candidates in the server side. Our basic idea is straightforward; to adapt fully homomorphic encryption (FHE) schemes to build such a system but its performance achievement is greatly challenging. Optimization techniques are necessary for performance achievement in practice. We employ various performance enhancement techniques and implement the NIST (National Institute of Standards and Technology) metering method as seminal work in this field. Our experiment results demonstrate that the running time of the proposed meter is around 60 s in a conventional desktop server, expecting better performance in high-end hardware, with an FHE scheme in HElib library where parameters support at least 80-bit security. We believe the proposed method can be further explored and used for a password metering in case that password secrecy is very important—the user’s password candidates should not be exposed to the meter and also an internal mechanism of password metering should not be disclosed to users and any other third parties.

rTMS of Medial Parieto-occipital Cortex Interferes with Attentional Reorienting during Attention and Reaching Tasks

2013 ◽  
Vol 25 (9) ◽  
pp. 1453-1462 ◽  
Author(s):  
Marco Ciavarro ◽  
Ettore Ambrosini ◽  
Annalisa Tosoni ◽  
Giorgia Committeri ◽  
Patrizia Fattori ◽  
...  
Keyword(s):  
Posterior Parietal Cortex ◽  
Motor Planning ◽  
Occipital Cortex ◽  
Reaching Movements ◽  
Dorsal Part ◽  
Visual Stream ◽  
Reaching Task ◽  
On Line ◽  
Posterior Parietal

Unexpected changes in the location of a target for an upcoming action require both attentional reorienting and motor planning update. In both macaque and human brain, the medial posterior parietal cortex is involved in both phenomena but its causal role is still unclear. Here we used on-line rTMS over the putative human V6A (pV6A), a reach-related region in the dorsal part of the anterior bank of the parieto-occipital sulcus, during an attention and a reaching task requiring covert shifts of attention and planning of reaching movements toward cued targets in space. We found that rTMS increased RTs to invalidly cued but not to validly cued targets during both the attention and reaching task. Furthermore, we found that rTMS induced a deviation of reaching endpoints toward visual fixation and that this deviation was larger for invalidly cued targets. The results suggest that reorienting signals are used by human pV6A area to rapidly update the current motor plan or the ongoing action when a behaviorally relevant object unexpectedly occurs in an unattended location. The current findings suggest a direct involvement of the action-related dorso-medial visual stream in attentional reorienting and a more specific role of pV6A area in the dynamic, on-line control of reaching actions.

scholarly journals Rewards interact with explicit knowledge to enhance skilled motor performance

2019 ◽  
Author(s):  
Sean P. Anderson ◽  
Tyler J. Adkins ◽  
Bradley S. Gary ◽  
Taraz G. Lee
Keyword(s):  
Motor Skills ◽  
Motor Performance ◽  
Explicit Knowledge ◽  
Motor Planning ◽  
Action Selection ◽  
The Other ◽  
Monetary Incentives ◽  
Sequential Movements ◽  
Human Participants ◽  
Sequencing Task

AbstractFrom typing on a keyboard to playing the piano, many everyday skills require the ability to quickly and accurately perform sequential movements. It is well-known that the availability of rewards leads to increases in motivational vigor whereby people enhance both the speed and force of their movements. However, in the context of motor skills, it is unclear whether rewards also lead to more effective motor planning and action selection. Here, we trained human participants to perform four separate sequences in a skilled motor sequencing task. Two of these sequences were trained explicitly and performed with pre-cues that allow for the planning of movements, while the other two were trained implicitly. Immediately following the introduction of performance-contingent monetary incentives, participants improved their performance on all sequences consistent with enhancements in motivational vigor. However, there was a much larger performance boost for explicitly trained sequences. We replicated these results in a second, pre-registered experiment with an independent sample. We conclude from these experiments that rewards enhance both the planning of movements as well as motivational vigor.

scholarly journals A distributed circuit for associating environmental context with motor choice in retrosplenial cortex

2021 ◽  
Vol 7 (35) ◽  
pp. eabf9815
Author(s):  
Luis M. Franco ◽  
Michael J. Goard
Keyword(s):  
Motor Planning ◽  
Retrosplenial Cortex ◽  
Behavioral Performance ◽  
Motor Action ◽  
Motor Outputs ◽  
Cortical Circuit ◽  
Task Variables ◽  
Subcortical Regions ◽  
Motor Actions ◽  
Temporal Profiles

During navigation, animals often use recognition of familiar environmental contexts to guide motor action selection. The retrosplenial cortex (RSC) receives inputs from both visual cortex and subcortical regions required for spatial memory and projects to motor planning regions. However, it is not known whether RSC is important for associating familiar environmental contexts with specific motor actions. We test this possibility by developing a task in which motor trajectories are chosen based on the context. We find that mice exhibit differential predecision activity in RSC and that optogenetic suppression of RSC activity impairs task performance. Individual RSC neurons encode a range of task variables, often multiplexed with distinct temporal profiles. However, the responses are spatiotemporally organized, with task variables represented along a posterior-to-anterior gradient along RSC during the behavioral performance, consistent with histological characterization. These results reveal an anatomically organized retrosplenial cortical circuit for associating environmental contexts with appropriate motor outputs.

scholarly journals Belief in Control: Voluntary Choice Enhances Subsequent Task Performance under Undefeated Choice-Outcome Causation

2021 ◽  
Author(s):  
Xiaoxiao Luo ◽  
Lihui Wang ◽  
xiaolin zhou
Keyword(s):  
Search Task ◽  
Behavioral Performance ◽  
Search Performance ◽  
Blank Screen ◽  
Subsequent Behavior ◽  
Series Of Experiments ◽  
Improved Performance ◽  
Voluntary Choice ◽  
Task Irrelevant ◽  
Subsequent Task

Humans are believed to have volition through which they act upon and change the external environment. As an exercise of volition, making a voluntary choice facilitates the subsequent behavioral performance relative to a forced choice. However, it is unclear how this facilitation is constrained by the perceived relationship between a choice and its outcome. In a series of experiments, participants were free or forced to choose one of two presented pictures. The outcome of the choice was then revealed, which could be always the chosen picture or always the unchosen picture (i.e., a confirmed choice-outcome causation), a blank screen with no picture at all (i.e., an unrevealed choice-outcome relation), the chosen or unchosen picture with equal probability (i.e., a defeated choice-outcome causation), or a third picture different from the two preceding options (again, a defeated choice-outcome causation). Participants then complete a visual search task with the task-irrelevant picture (or the blank screen) serving as a background. Results showed that the search performance was improved after a voluntary choice under both the confirmed causation and the unrevealed relation, but not under the defeated causation. Over individuals, the improved performance due to voluntary choice under confirmed causation positively correlated with the improved performance under the unrevealed relation, and with the reported belief in controlling the outcome of the choice. Our findings suggest that the exercise of volition motivates subsequent behavior, and this motivation is restricted to an “undefeated” choice-outcome causation which affords a belief in controlling the outcome by exerting volition.

scholarly journals A Distributed Circuit for Associating Environmental Context to Motor Choice in Retrosplenial Cortex

2020 ◽  
Author(s):  
Luis M. Franco ◽  
Michael J. Goard
Keyword(s):  
Motor Planning ◽  
Retrosplenial Cortex ◽  
Behavioral Performance ◽  
Motor Action ◽  
Motor Outputs ◽  
Cortical Circuit ◽  
Task Variables ◽  
Subcortical Regions ◽  
Motor Actions ◽  
Temporal Profiles

ABSTRACTDuring navigation, animals often use recognition of familiar environmental contexts to guide motor action selection. The retrosplenial cortex (RSC) receives inputs from both visual cortex and subcortical regions required for spatial memory, and projects to motor planning regions. However, it is not known whether RSC is important for associating familiar environmental contexts with specific motor actions. Here, we test this possibility by developing a task in which trajectories are chosen based on the context. We find that mice exhibit differential pre-decision activity in RSC, and that optogenetic suppression of RSC activity impairs task performance. Individual RSC neurons encode a range of task variables, often multiplexed with distinct temporal profiles. However, the responses are spatiotemporally organized, with task variables represented along a posterior-to-anterior gradient along RSC during the behavioral performance, consistent with histological characterization. These results reveal an anatomically-organized retrosplenial cortical circuit for associating environmental contexts to appropriate motor outputs.

scholarly journals Relationships between measures of boat acceleration and performance in rowing, with and without controlling for stroke rate and power output

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0249122
Author(s):  
Ana C. Holt ◽  
Kevin Ball ◽  
Rodney Siegel ◽  
William G. Hopkins ◽  
Robert J. Aughey
Keyword(s):  
Power Output ◽  
Performance Enhancement ◽  
Rate Of Change ◽  
Stroke Rate ◽  
Negative Acceleration ◽  
Improved Performance ◽  
And Performance ◽  
Late Recovery ◽  
Mixed Modelling ◽  
Substantial Change

Purpose Boat acceleration profiles provide a valuable feedback tool by reflecting both rower technique and force application. Relationships between measures of boat acceleration and velocity to inform interpretation of boat acceleration profiles in rowing were investigated here. Methods Thirteen male singles, nine female singles, eight male pairs, and seven female pairs participated (national and international level, age 18–27 y). Data from each stroke for 74 2000-m races were collected using Peach PowerLine and OptimEye S5 GPS units. General linear mixed modelling established modifying effects on velocity of two within-crew SD of boat acceleration variables for each boat class, without and with adjustment for stroke rate and power, to identify potential performance-enhancement strategies for a given stroke rate and power. Measures of acceleration magnitude at six peaks or dips, and six measures of the rate of change (jerk) between these peaks and dips were analyzed. Results were interpreted using rejection of non-substantial and substantial hypotheses with a smallest substantial change in velocity of 0.3%. Results Several boat acceleration measures had decisively substantial effects (-2.4–2.5%) before adjustment for stroke rate and power. Most effect magnitudes reduced after adjustment for stroke rate and power, although maximum negative drive acceleration, peak drive acceleration, jerk during the mid-drive phase, and jerk in the late recovery remained decisively substantial (-1.8–1.9%) in some boat classes. Conclusion Greater absolute values of maximum negative drive acceleration and jerk in the late recovery are related to improved performance, likely reflecting delayed rower centre-of-mass negative acceleration in preparation for the catch. Greater absolute values of peak drive acceleration, first peak acceleration, and jerk in the early and mid-drive are also associated with improved performance, likely reflecting propulsive force during the drive. These proposed mechanisms provide potential strategies for performance enhancement additional to increases in stroke rate and power output.

scholarly journals Design and Investigation of Gate Stacked Vertical TFET with N+ SiGe Pocket Doped Heterojunction for Performance Enhancement

2021 ◽  
Author(s):  
Shilpi Gupta ◽  
Subodh Wariya ◽  
shailendra singh
Keyword(s):  
Silicon Germanium ◽  
Performance Enhancement ◽  
Electron Tunneling ◽  
Metal Gate ◽  
Ultra Low Power ◽  
Drive Current ◽  
High Drive ◽  
Electric Field Direction ◽  
Vertical Electric Field ◽  
Improved Performance

Abstract In this paper, a novel delta-doped N + Silicon-Germanium Gate Stacked Triple Metal Gate Vertical TFET (Delta doped N + GS TMG VTFET) is proposed and investigated using the Silvaco TCAD simulation tool. Four different combinations were presented and compared with and without the gate stacking method and Si0.2Ge0.8 N + pocket delta-doped layer to render the optimized results. Among all, Delta doped N + GS TMG VTFET structure comes out with a very steep sub-threshold slope (9.75 mV/dec), 40 % lower than the first configuration of TMG VTFET. The inclusion of the N + delta-doped layer between the source and channel and gate will enhance the ON-state drive current performance by reducing the OFF-state leakage current. This happens due to the lower bandgap of the N + delta-doped layer cause narrow BTBT, which results in a high drive current. The Triple metal gate is designed to mitigate the ambipolar conduction by modulating the optimized wok function at 4.15, 4.3, and 4.15 eV. The distribution of the source channel in the vertical structure will enhance the device's scalability due to the electron tunneling moves in the vertical electric field direction. The optimally constructed structure demonstrates improved performance, such as a high ION/IOFF current ratio (~ 1013) and sub-threshold voltage (0.33 V). The results obtained from the proposed device make it suitable for the ultra-low-power device application.

scholarly journals QUANTILE PROBABILITY PREDICTIONS: A DEMONSTRATIVE PERFORMANCE ANALYSIS OF FORECASTS OF US COVID-19 DEATHS

2021 ◽  
Vol 9 (2) ◽  
pp. 139-163
Author(s):  
Mary E. Thomson ◽  
◽  
Andrew C. Pollock ◽  
Jennifer Murray ◽  
◽  
...  
Keyword(s):  
Performance Enhancement ◽  
Analytical Framework ◽  
Future Research ◽  
Emergency Situations ◽  
Forecasting Performance ◽  
Data Points ◽  
The Mean ◽  
Probability Forecasts ◽  
Improved Performance ◽  
Different Sources

An analytical framework is presented for the evaluation of quantile probability forecasts. It is demonstrated using weekly quantile forecasts of changes in the number of US COVID-19 deaths. Empirical quantiles are derived using the assumption that daily changes in a variable follow a normal distribution with time varying means and standard deviations, which can be assumed constant over short horizons such as one week. These empirical quantiles are used to evaluate quantile forecasts using the Mean Squared Quantile Score (MSQS), which, in turn, is decomposed into sub-components involving bias, resolution and error variation to identify specific aspects of performance, which highlight the strengths and weaknesses of forecasts. The framework is then extended to test if performance enhancement can be achieved by combining diverse forecasts from different sources. The demonstration illustrates that the technique can effectively evaluate quantile forecasting performance based on a limited number of data points, which is crucial in emergency situations such as forecasting pandemic behavior. It also shows that combining the predictions with quantile probability forecasts generated from an Autoregressive Order One, AR(1) model provided substantially improved performance. The implications of these findings are discussed, suggestions are offered for future research and potential limitations are considered.

scholarly journals Transient beta activity and connectivity during sustained motor behaviour

2021 ◽  
Author(s):  
Irene Echeverria-Altuna ◽  
Andrew J. Quinn ◽  
Nahid Zokaei ◽  
Mark W. Woolrich ◽  
Anna C. Nobre ◽  
...  
Keyword(s):  
Long Range ◽  
Isometric Contraction ◽  
Task Demands ◽  
Beta Activity ◽  
List Type ◽  
Motor Behaviour ◽  
Event Duration ◽  
The Status ◽  
Human Participants ◽  
The Brain

AbstractNeural oscillations are thought to play a central role in orchestrating activity states between distant neural populations. In humans, long-range neural connectivity has been particularly well characterised for 13-30 Hz beta activity which becomes phase coupled between the motor cortex and the contralateral muscle during isometric contraction. Based on this and related observations, beta activity and connectivity have been linked to sustaining stable cognitive and motor states – or the ‘status quo’ – in the brain. Recently, however, beta activity has been shown to be short-lived, as opposed to sustained – though so far this has been reported for regional beta activity in tasks without sustained motor demands. Here, we measured magnetoencephalography (MEG) and electromyography (EMG) in 18 human participants performing an isometric-contraction (gripping) task designed to yield sustained behavioural output. If cortico-muscular beta connectivity is directly responsible for sustaining a stable motor state, then beta activity should be (or become) sustained in this context. In contrast, we found that beta activity and connectivity with the downstream muscle were transient, even when participants engaged in sustained gripping. Moreover, we found that sustained motor requirements did not prolong beta-event duration in comparison to rest. These findings suggest that long-range neural synchronisation may entail short ‘bursts’ of frequency-specific connectivity, even when task demands – and behaviour – are sustained.HighlightsTrial-average 13-30 Hz beta activity and connectivity with the muscle appear sustained during stable motor behaviourSingle-trial beta activity and connectivity are short-lived, even when motor behaviour is sustainedSustained task demands do not prolong beta-event duration in comparison to resting state

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