Sensory evidence integration and action initiation occur in parallel during perceptual decisions

2020 ◽  
Author(s):  
Lluís Hernández-Navarro ◽  
Ainhoa Hermoso-Mendizabal ◽  
Daniel Duque ◽  
Alexandre Hyafil ◽  
Jaime de la Rocha
Keyword(s):  
Time Pressure ◽  
Reaction Times ◽  
Stimulus Presentation ◽  
Perceptual Decision Making ◽  
Evidence Accumulation ◽  
Action Preparation ◽  
Action Model ◽  
The Brain ◽  
Evidence Integration ◽  
Action Initiation

It is commonly assumed that, during perceptual decisions, the brain integrates stimulus evidence until reaching a decision, and then performs the response. There are conditions, however (e.g. time pressure), in which the initiation of the response must be prepared in anticipation of the stimulus presentation. It is therefore not clear when the timing and the choice of perceptual responses depend exclusively on evidence accumulation, or when preparatory motor signals may interfere with this process. Here, we find that, in a free reaction time auditory discrimination task in rats, the timing of fast responses does not depend on the stimulus, although the choices do, suggesting a decoupling of the mechanisms of action initiation and choice selection. This behavior is captured by a novel model, the Parallel Sensory Integration and Action Model (PSIAM), in which response execution is triggered whenever one of two processes, Action Initiation or Evidence Accumulation, reaches a bound, while choice category is always set by the latter. Based on this separation, the model accurately predicts the distribution of reaction times when the stimulus is omitted, advanced or delayed. Furthermore, we show that changes in Action Initiation mediates both post-error slowing and a gradual slowing of the responses within each session. Overall, these results extend the standard models of perceptual decision-making, and shed a new light on the interaction between action preparation and evidence accumulation.

scholarly journals Proactive and reactive accumulation-to-bound processes compete during perceptual decisions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lluís Hernández-Navarro ◽  
Ainhoa Hermoso-Mendizabal ◽  
Daniel Duque ◽  
Jaime de la Rocha ◽  
Alexandre Hyafil
Keyword(s):  
Decision Making ◽  
Reaction Time ◽  
Reaction Times ◽  
Stimulus Presentation ◽  
Auditory Task ◽  
Decision Threshold ◽  
Perceptual Decision Making ◽  
Evidence Accumulation ◽  
Standard Models ◽  
Action Initiation

AbstractStandard models of perceptual decision-making postulate that a response is triggered in reaction to stimulus presentation when the accumulated stimulus evidence reaches a decision threshold. This framework excludes however the possibility that informed responses are generated proactively at a time independent of stimulus. Here, we find that, in a free reaction time auditory task in rats, reactive and proactive responses coexist, suggesting that choice selection and motor initiation, commonly viewed as serial processes, are decoupled in general. We capture this behavior by a novel model in which proactive and reactive responses are triggered whenever either of two competing processes, respectively Action Initiation or Evidence Accumulation, reaches a bound. In both types of response, the choice is ultimately informed by the Evidence Accumulation process. The Action Initiation process readily explains premature responses, contributes to urgency effects at long reaction times and mediates the slowing of the responses as animals get satiated and tired during sessions. Moreover, it successfully predicts reaction time distributions when the stimulus was either delayed, advanced or omitted. Overall, these results fundamentally extend standard models of evidence accumulation in decision making by showing that proactive and reactive processes compete for the generation of responses.

scholarly journals A race between Proactive and Reactive processes during perceptual decisions

2020 ◽  
Author(s):  
Lluís Hernández-Navarro ◽  
Ainhoa Hermoso-Mendizabal ◽  
Daniel Duque ◽  
Jaime de la Rocha ◽  
Alexandre Hyafil
Keyword(s):  
Decision Making ◽  
Reaction Time ◽  
Stimulus Presentation ◽  
Auditory Task ◽  
Decision Threshold ◽  
Perceptual Decision Making ◽  
Evidence Accumulation ◽  
Standard Models ◽  
Reactive Processes ◽  
Action Initiation

Standard models of perceptual decision-making postulate that a response is triggered in reaction to stimulus presentation when the accumulated stimulus evidence reaches a decision threshold. This framework excludes however the possibility that informed responses are generated proactively at a time independent of stimulus. Here, we find that, in a free reaction time auditory task in rats, reactive and proactive responses coexist, suggesting that choice selection and motor initiation, commonly viewed as serial processes, are decoupled in general. We capture this behavior by a novel model in which proactive and reactive responses are triggered whenever either of two competing processes, respectively Action Initiation or Evidence Accumulation, reaches a bound. In both types of response, the choice is ultimately informed by the Evidence Accumulation process. By including the Action Initiation process, the model readily explains premature responses, urgency effects at long reaction times and the slowing of the responses as animals get satiated and tired during sessions. Moreover, it successfully predicts reaction time distributions when the stimulus was either delayed, advanced or omitted. Overall, these results fundamentally extend standard models of evidence accumulation in decision making by showing that proactive and reactive processes compete for the generation of responses.

Novel two-alternative forced choice paradigm for bilateral vibrotactile whisker frequency discrimination in head-fixed mice and rats

2013 ◽  
Vol 109 (1) ◽  
pp. 273-284 ◽  
Author(s):  
Johannes M. Mayrhofer ◽  
Vida Skreb ◽  
Wolfger von der Behrens ◽  
Simon Musall ◽  
Bruno Weber ◽  
...  
Keyword(s):  
Reaction Times ◽  
Stimulus Presentation ◽  
Frequency Discrimination ◽  
Forced Choice ◽  
Peak Performance ◽  
Perceptual Decision Making ◽  
Learning Rates ◽  
Behavioral Paradigm ◽  
Mystacial Vibrissae ◽  
Rats And Mice

Rats and mice receive a constant bilateral stream of tactile information with their large mystacial vibrissae when navigating in their environment. In a two-alternative forced choice paradigm (2-AFC), head-fixed rats and mice learned to discriminate vibrotactile frequencies applied simultaneously to individual whiskers on the left and right sides of the snout. Mice and rats discriminated 90-Hz pulsatile stimuli from pulsatile stimuli with lower repetition frequencies (10–80 Hz) but with identical kinematic properties in each pulse. Psychometric curves displayed an average perceptual threshold of 50.6-Hz and 53.0-Hz frequency difference corresponding to Weber fractions of 0.56 and 0.58 in mice and rats, respectively. Both species performed >400 trials a day (>200 trials per session, 2 sessions/day), with a peak performance of >90% correct responses. In general, rats and mice trained in the identical task showed comparable psychometric curves. Behavioral readouts, such as reaction times, learning rates, trial omissions, and impulsivity, were also very similar in the two species. Furthermore, whisking of the animals before stimulus presentation reduced task performance. This behavioral paradigm, combined with whisker position tracking, allows precise stimulus control in the 2-AFC task for head-fixed rodents. It is compatible with state-of-the-art neurophysiological recording techniques, such as electrophysiology and two-photon imaging, and therefore represents a valuable framework for neurophysiological investigations of perceptual decision-making.

scholarly journals Differentiating between integration and non-integration strategies in perceptual decision making

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Gabriel M Stine ◽  
Ariel Zylberberg ◽  
Jochen Ditterich ◽  
Michael N Shadlen
Keyword(s):  
Decision Making ◽  
Human Subjects ◽  
Perceptual Decision Making ◽  
Integration Model ◽  
Integration Strategy ◽  
Behavioral Observations ◽  
Integration Strategies ◽  
Multiple Samples ◽  
The Brain ◽  
Evidence Integration

Many tasks used to study decision-making encourage subjects to integrate evidence over time. Such tasks are useful to understand how the brain operates on multiple samples of information over prolonged timescales, but only if subjects actually integrate evidence to form their decisions. We explored the behavioral observations that corroborate evidence-integration in a number of task-designs. Several commonly accepted signs of integration were also predicted by non-integration strategies. Furthermore, an integration model could fit data generated by non-integration models. We identified the features of non-integration models that allowed them to mimic integration and used these insights to design a motion discrimination task that disentangled the models. In human subjects performing the task, we falsified a non-integration strategy in each and confirmed prolonged integration in all but one subject. The findings illustrate the difficulty of identifying a decision-maker’s strategy and support solutions to achieve this goal.

scholarly journals Learning optimal decisions with confidence

2018 ◽  
Author(s):  
Jan Drugowitsch ◽  
André G. Mendonça ◽  
Zachary F. Mainen ◽  
Alexandre Pouget
Keyword(s):  
Decision Making ◽  
Time Pressure ◽  
A Priori ◽  
Learning Rule ◽  
Normative Theory ◽  
Perceptual Decision Making ◽  
Sensory Inputs ◽  
Optimal Decisions ◽  
Low Dimensional ◽  
The Brain

AbstractDiffusion decision models (DDMs) are immensely successful models for decision-making under uncertainty and time pressure. In the context of perceptual decision making, these models typically start with two input units, organized in a neuron-antineuron pair. In contrast, in the brain, sensory inputs are encoded through the activity of large neuronal populations. Moreover, while DDMs are wired by hand, the nervous system must learn the weights of the network through trial and error. There is currently no normative theory of learning in DDMs and therefore no theory of how decision makers could learn to make optimal decisions in this context. Here, we derive the first such rule for learning a near-optimal linear combination of DDM inputs based on trial-by-trial feedback. The rule is Bayesian in the sense that it learns not only the mean of the weights but also the uncertainty around this mean in the form of a covariance matrix. In this rule, the rate of learning is proportional (resp. inversely proportional) to confidence for incorrect (resp. correct) decisions. Furthermore, we show that, in volatile environments, the rule predicts a bias towards repeating the same choice after correct decisions, with a bias strength that is modulated by the previous choice’s difficulty. Finally, we extend our learning rule to cases for which one of the choices is more likely a priori, which provides new insights into how such biases modulate the mechanisms leading to optimal decisions in diffusion models.Significance StatementPopular models for the tradeoff between speed and accuracy of everyday decisions usually assume fixed, low-dimensional sensory inputs. In contrast, in the brain, these inputs are distributed across larger populations of neurons, and their interpretation needs to be learned from feedback. We ask how such learning could occur and demonstrate that efficient learning is significantly modulated by decision confidence. This modulation predicts a particular dependency pattern between consecutive choices, and provides new insight into how a priori biases for particular choices modulate the mechanisms leading to efficient decisions in these models.

scholarly journals Differentiating between integration and non-integration strategies in perceptual decision making

2020 ◽  
Author(s):  
Gabriel M Stine ◽  
Ariel Zylberberg ◽  
Jochen Ditterich ◽  
Michael N Shadlen
Keyword(s):  
Decision Making ◽  
Human Subjects ◽  
Perceptual Decision Making ◽  
Integration Model ◽  
Integration Strategy ◽  
Behavioral Observations ◽  
Integration Strategies ◽  
Multiple Samples ◽  
The Brain ◽  
Evidence Integration

ABSTRACTMany tasks used to study decision-making encourage subjects to integrate evidence over time. Such tasks are useful to understand how the brain operates on multiple samples of information over prolonged timescales, but only if subjects actually integrate evidence to form their decisions. We explored the behavioral observations that corroborate evidence-integration in a number of task-designs. Several commonly accepted signs of integration were also predicted by non-integration strategies. Furthermore, an integration model could fit data generated by non-integration models. We identified the features of non-integration models that allowed them to mimic integration and used these insights to design a motion discrimination task that disentangled the models. In human subjects performing the task, we falsified a non-integration strategy in each and confirmed prolonged integration in all but one subject. The findings illustrate the difficulty of identifying a decision-maker’s strategy and support solutions to achieve this goal.

scholarly journals The latency of a visual evoked potential tracks the onset of decision making

2018 ◽  
Author(s):  
Michael D. Nunez ◽  
Aishwarya Gosai ◽  
Joachim Vandekerckhove ◽  
Ramesh Srinivasan
Keyword(s):  
Decision Making ◽  
Response Time ◽  
Response Times ◽  
Stimulus Presentation ◽  
Sensory Stimulus ◽  
Visual Noise ◽  
Perceptual Decision Making ◽  
Perceptual Decision ◽  
Evidence Accumulation ◽  
Visual Encoding

AbstractEncoding of a sensory stimulus is believed to be the first step in perceptual decision making. Previous research has shown that electrical signals recorded from the human brain track evidence accumulation during perceptual decision making (Gold and Shadlen, 2007; O’Connell et al., 2012; Philiastides et al., 2014). In this study we directly tested the hypothesis that the latency of the N200 recorded by EEG (a negative peak occurring between 150 and 275 ms after stimulus presentation in human participants) reflects the visual encoding time (VET) required for completion of figure-ground segregation before evidence accumulation. We show that N200 latencies vary across individuals, are modulated by external visual noise, and increase response time by x milliseconds when they increase by x milliseconds, reflecting a linear regression slope of 1. Simulations of cognitive decision-making theory show that variation in human response times not related to evidence accumulation (including VET) are tracked by the fastest response times. A relationship with a slope of 1 between N200 latencies and VET was found by fitting a linear model between trial-averaged N200 latencies and the 10th percentiles of response times. A slope of 1 was also found between single-trial N200 latencies and response times. Fitting a novel neuro-cognitive model of decision-making also yielded a slope of 1 between N200 latency and non-decision time in multiple visual noise conditions, indicating that N200 latencies track the completion of visual encoding and the onset of evidence accumulation. The N200 waveforms were localized to the cortical surface at distributed temporal and extrastriate locations, consistent with a distributed network engaged in figure-ground segregation of the target stimulus.Significance StatementEncoding of a sensory stimulus is believed to be the first step in perceptual decision making. In this study, we report evidence that visual evoked potentials (EPs) around 200 ms after stimulus presentation track the time of visual figure-ground segregation before the onset of evidence accumulation during decision making. These EP latencies vary across individuals, are modulated by external visual noise, and increase response time by x milliseconds when they increase by x milliseconds. Hierarchical Bayesian model-fitting was also used to relate these EPs to a specific cognitive parameter that tracks time related to visual encoding in a decision-making model of response time. This work adds to the growing literature that suggests that EEG signals can track the component cognitive processes of decision making.

scholarly journals The Effects of Time Pressure on Temporal Overestimation Due to Threat

2021 ◽  
pp. 1-14
Author(s):  
Jason Tipples ◽  
Michael Lupton ◽  
David George
Keyword(s):  
Decision Making ◽  
Logistic Regression ◽  
Time Pressure ◽  
Reaction Times ◽  
Internal Clock ◽  
Multilevel Logistic Regression ◽  
Perceptual Decision Making ◽  
Perceptual Decision ◽  
Do So ◽  
Facial Threat

Abstract How does emotion change the way we perceive time? Studies have shown that we overestimate the duration of faces that express anger of fear–an effect that has been explained as due the speeding of a pacemaker that resides within an internal clock. Here, we test the idea that attending longer to facial threat leads to an overestimation of time. Seventy participants (16 male) estimated the duration of angry, fearful and neutral expressions under conditions designed to either reduce attention to time (by emphasising speedy responses) or lengthen attention to time (by emphasising accuracy). Results were modelled using Bayesian Multilevel Logistic Regression. The results replicate previous findings: speed emphasis reduced temporal sensitivity and led to both a higher overall proportion of long responses and faster reaction times. Facial threat attenuated the drop in temporal sensitivity due to speed instructions supporting the idea that people prolong attention to threat (even when they are not directly instructed to do so). We relate the findings to research into attention bias to threat and more broadly to models of perceptual decision making.

A Neural Index of Inefficient Evidence Accumulation in Dyslexia Underlying Slow Perceptual Decision Making

Cortex ◽  
2021 ◽  
Author(s):  
Nicole R. Stefanac ◽  
Shou-Han Zhou ◽  
Megan M. Spencer-Smith ◽  
Redmond O’Connell ◽  
Mark A. Bellgrove
Keyword(s):  
Decision Making ◽  
Perceptual Decision Making ◽  
Perceptual Decision ◽  
Evidence Accumulation

scholarly journals Confidence in perceptual decision-making is preserved in schizophrenia

2019 ◽  
Author(s):  
Nathan Faivre ◽  
Matthieu Roger ◽  
Michael Pereira ◽  
Vincent de Gardelle ◽  
Jean-Christophe Vergnaud ◽  
...  
Keyword(s):  
Visual Discrimination ◽  
Discrimination Performance ◽  
Perceptual Decision Making ◽  
Task Execution ◽  
Bayesian Analyses ◽  
Functional Deficits ◽  
Evidence Accumulation ◽  
Narrative Assessment ◽  
Mental Operations ◽  
Healthy Participants

AbstractMetacognition is the set of reflexive processes allowing humans to evaluate the accuracy of their mental operations. Deficits in synthetic metacognition have been described in schizophrenia using mostly narrative assessment and linked to several key symptoms. Here, we assessed metacognitive performance by asking individuals with schizophrenia or schizoaffective disorder (N=20) and matched healthy participants (N = 21) to perform a visual discrimination task and subsequently report confidence in their performance. Metacognitive performance was defined as the adequacy between visual discrimination performance and confidence. Bayesian analyses revealed equivalent metacognitive performance in the two groups despite a weaker association between confidence and trajectory tracking during task execution among patients. These results were reproduced using a bounded evidence accumulation model which showed similar decisional processes in the two groups. The inability to accurately attune confidence to perceptual decisions in schizophrenia remains to be experimentally demonstrated, along with the way such impairments may underpin functional deficits.

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