scholarly journals The Neurodynamic Decision Variable in Human Multi-alternative Perceptual Choice

2019 ◽  
Vol 31 (2) ◽  
pp. 262-277 ◽  
Author(s):  
Carmen Kohl ◽  
Laure Spieser ◽  
Bettina Forster ◽  
Sven Bestmann ◽  
Kielan Yarrow
Keyword(s):  
Sequential Sampling ◽  
Human Action ◽  
Corticospinal Excitability ◽  
Decision Variable ◽  
Dynamic Changes ◽  
Baseline Activity ◽  
Decision Alternative ◽  
Response Alternatives ◽  
Action Representations ◽  
Accumulator Models

The neural dynamics underpinning binary perceptual decisions and their transformation into actions are well studied, but real-world decisions typically offer more than two response alternatives. How does decision-related evidence accumulation dynamically influence multiple action representations in humans? The heightened conservatism required in multiple compared with binary choice scenarios suggests a mechanism that compensates for increased uncertainty when multiple choices are present by suppressing baseline activity. Here, we tracked action representations using corticospinal excitability during four- and two-choice perceptual decisions and modeled them using a sequential sampling framework. We found that the predictions made by leaky competing accumulator models to accommodate multiple choices (i.e., reduced baseline activity to compensate increased uncertainty) were borne out by dynamic changes in human action representations. This suggests a direct and continuous influence of interacting evidence accumulators, each favoring a different decision alternative, on downstream corticospinal excitability during complex choice.

scholarly journals Perspective on Variability in the Development of Human Action

2010 ◽  
Vol 90 (12) ◽  
pp. 1860-1867 ◽  
Author(s):  
Linda Fetters
Keyword(s):  
Life Span ◽  
Physical Therapist ◽  
Therapeutic Process ◽  
Human Action ◽  
Environmental Constraints ◽  
Dynamic Changes ◽  
Inherent Error ◽  
Neurological Insult ◽  
Functional Actions

Humans are designed not only with variability but for variability. This article explores the important contribution of variability to successful human action. Human systems for action have abundant variability of tissues and processes. This plasticity provides for the necessary flexibility when humans encounter the metric and dynamic changes of growth, development, and adaptation of action across the life span. However, variability must have definable limits. The reduction of possible solutions to probable solutions and the reduction of variability appear to be common assumptions of most theories of human action. The lack of variability of action is a hindrance to the development of skilled, functional action, and excessive variability interferes with the production of automatic, dependable, and typical functional action. The lack of variability and excessive variability are hallmarks of the movement patterns produced by people across the life span following neurological insult. Active problem solving as therapy, with its inherent error as a part of the therapeutic process, is critical to the successful learning of functional actions. The role of the physical therapist is to create movement environments and provide personal and environmental constraints that elicit and support self-produced functional actions.

scholarly journals A data-driven investigation of human action representations

2021 ◽  
Vol 21 (9) ◽  
pp. 2552
Author(s):  
Diana C Dima ◽  
Tyler Tomita ◽  
Christopher Honey ◽  
Martin N Hebart ◽  
Leyla Isik
Keyword(s):  
Human Action ◽  
Data Driven ◽  
Action Representations

scholarly journals The geometry of the representation of decision variable and stimulus difficulty in the parietal cortex

2021 ◽  
Author(s):  
Gouki Okazawa ◽  
Christina E. Hatch ◽  
Allan Mancoo ◽  
Christian K. Machens ◽  
Roozbeh Kiani
Keyword(s):  
Decision Variable ◽  
Supporting Evidence ◽  
Response Patterns ◽  
Task Context ◽  
Firing Rates ◽  
Neural Ensembles ◽  
Decision Variables ◽  
Action Representations ◽  
Opposite Response ◽  
And Task

SummaryLateral intraparietal (LIP) neurons represent formation of perceptual decisions involving eye movements. In circuit models for these decisions, neural ensembles that encode actions compete to form decisions. Consequently, decision variables (DVs) are represented as partially potentiated action plans, where ensembles increase their average responses for stronger evidence supporting their preferred actions. As another consequence, DV representation and readout are implemented similarly for decisions with identical competing actions, irrespective of input and task context differences. Here, we challenge those core principles using a novel face-discrimination task, where LIP firing rates decrease with supporting evidence, contrary to conventional motion-discrimination tasks. These opposite response patterns arise from similar mechanisms in which decisions form along curved population-response manifolds misaligned with action representations. These manifolds rotate in state space based on task context, necessitating distinct readouts. We show similar manifolds in lateral and medial prefrontal cortices, suggesting a ubiquitous representational geometry across decision-making circuits.

scholarly journals Comparative investigations of manual action representations: evidence that chimpanzees represent the costs of potential future actions involving tools

2012 ◽  
Vol 367 (1585) ◽  
pp. 48-58 ◽  
Author(s):  
Scott H. Frey ◽  
Daniel J. Povinelli
Keyword(s):  
Tool Use ◽  
Cerebral Hemisphere ◽  
Food Reward ◽  
Task Demands ◽  
Limited Attention ◽  
Present Moment ◽  
Internal Action ◽  
Human Cerebellum ◽  
Response Alternatives ◽  
Action Representations

The ability to adjust one's ongoing actions in the anticipation of forthcoming task demands is considered as strong evidence for the existence of internal action representations. Studies of action selection in tool use reveal that the behaviours that we choose in the present moment differ depending on what we intend to do next . Further, they point to a specialized role for mechanisms within the human cerebellum and dominant left cerebral hemisphere in representing the likely sensory costs of intended future actions. Recently, the question of whether similar mechanisms exist in other primates has received growing, but still limited, attention. Here, we present data that bear on this issue from a species that is a natural user of tools, our nearest living relative, the chimpanzee. In experiment 1, a subset of chimpanzees showed a non-significant tendency for their grip preferences to be affected by anticipation of the demands associated with bringing a tool's baited end to their mouths. In experiment 2, chimpanzees' initial grip preferences were consistently affected by anticipation of the forthcoming movements in a task that involves using a tool to extract a food reward. The partial discrepancy between the results of these two studies is attributed to the ability to accurately represent differences between the motor costs associated with executing the two response alternatives available within each task. These findings suggest that chimpanzees are capable of accurately representing the costs of intended future actions, and using those predictions to select movements in the present even in the context of externally directed tool use.

scholarly journals A neural turning point - the EEG P3 component tracks unfolding changes of mind

2020 ◽  
Author(s):  
Elisabeth Parés-Pujolràs ◽  
Jeremy Hatchuel ◽  
Patrick Haggard
Keyword(s):  
Turning Point ◽  
Sequential Sampling ◽  
Neural Correlates ◽  
Neural Mechanisms ◽  
Human Cognition ◽  
Decision Variable ◽  
Visual Stream ◽  
Evidence Accumulation ◽  
Early Decision ◽  
P3 Component

AbstractThe ability to change one’s mind is a key feature of human cognition. Yet, the neural mechanisms underpinning our capacity to change our minds remain poorly understood. Here, we investigated the neural correlates of evidence accumulation and changes of mind in a two-step sequential sampling task. Participants provided a first, quick guess regarding the relative frequencies of target letters in a visual stream, followed by a slower, more deliberate decision. We found that the P3 amplitude evoked by successive target letters tracks an internal signed decision variable and predicts choices on a single-trial level. Moreover, this neural decision variable offers new insights into the dynamics of changes of mind. In particular, we show that the start of evidence accumulation after the early decision constitutes a neural turning point: the P3 evoked by the first letter contrary to the initial decision can be used to predict subsequent changes of mind. Our results highlight a critical interaction between the processing of external evidence and endogenous modulations of decisional parameters that facilitate reversing an original decision.

scholarly journals Dynamic changes in Anterior Cingulate Cortex ensembles mark the transition from exploration to exploitation

2019 ◽  
Author(s):  
Eldon Emberly ◽  
K Seamans Jeremy
Keyword(s):  
Anterior Cingulate Cortex ◽  
Cingulate Cortex ◽  
Anterior Cingulate ◽  
Trial And Error ◽  
Dynamic Changes ◽  
Neural Representations ◽  
Complex Forms ◽  
Value Learning ◽  
Action Representations ◽  
Incremental Process

AbstractThe ability to acquire knowledge about the value of stimuli or actions factors into simple foraging behaviors as well as complex forms of decision making. The anterior cingulate cortex (ACC) is thought to be involved in these processes, although the manner in which neural representations acquire value is unclear. Here we recorded from ensembles of ACC neurons as rats learned which of 3 levers was rewarded each day through a trial and error process. Action representations remained largely stable during exploration, but there was an abrupt, coordinated and differential change in the representation of rewarded and nonrewarded levers by ACC neurons at the point where the rat realized which lever was rewarded and began to exploit it. Thus, rather than a gradual, incremental process, value learning in ACC can occur in an all-or-none manner and help to initiate strategic shifts in forging behavior.

scholarly journals Decisions reduce sensitivity to subsequent information

2015 ◽  
Vol 282 (1810) ◽  
pp. 20150228 ◽  
Author(s):  
Zohar Z. Bronfman ◽  
Noam Brezis ◽  
Rani Moran ◽  
Konstantinos Tsetsos ◽  
Tobias Donner ◽  
...  
Keyword(s):  
Sequential Sampling ◽  
Computational Modelling ◽  
Mean Value ◽  
Decision Makers ◽  
Numerical Sequence ◽  
Decision Variable ◽  
New Information ◽  
Sequential Sampling Models ◽  
Accumulation Mechanism ◽  
The Mean

Behavioural studies over half a century indicate that making categorical choices alters beliefs about the state of the world. People seem biased to confirm previous choices, and to suppress contradicting information. These choice-dependent biases imply a fundamental bound of human rationality. However, it remains unclear whether these effects extend to lower level decisions, and only little is known about the computational mechanisms underlying them. Building on the framework of sequential-sampling models of decision-making, we developed novel psychophysical protocols that enable us to dissect quantitatively how choices affect the way decision-makers accumulate additional noisy evidence. We find robust choice-induced biases in the accumulation of abstract numerical (experiment 1) and low-level perceptual (experiment 2) evidence. These biases deteriorate estimations of the mean value of the numerical sequence (experiment 1) and reduce the likelihood to revise decisions (experiment 2). Computational modelling reveals that choices trigger a reduction of sensitivity to subsequent evidence via multiplicative gain modulation, rather than shifting the decision variable towards the chosen alternative in an additive fashion. Our results thus show that categorical choices alter the evidence accumulation mechanism itself, rather than just its outcome, rendering the decision-maker less sensitive to new information.

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