A Comparison of Macaque Behavior and Superior Colliculus Neuronal Activity to Predictions From Models of Two-Choice Decisions

2003 ◽  
Vol 90 (3) ◽  
pp. 1392-1407 ◽  
Author(s):  
Roger Ratcliff ◽  
Anil Cherian ◽  
Mark Segraves
Keyword(s):  
Superior Colliculus ◽  
Diffusion Model ◽  
Decision Process ◽  
Full Range ◽  
Reaction Times ◽  
Behavioral Data ◽  
Neural Systems ◽  
Neural Recordings ◽  
Counter Model ◽  
Psychological Models

Recently, models in psychology have been shown capable of accounting for the full range of behavioral data from simple two-choice decision tasks: mean reaction times for correct and error responses, accuracy, and the reaction time distributions for correct and error responses. At the same time, recent data from neural recordings have allowed investigation of the neural systems that implement such decisions. In the experiment presented here, neural recordings were obtained from superior colliculus prelude/buildup cells in two monkeys while they performed a two-choice task that has been used in humans for testing psychological models of the decision process. The best-developed psychological model, the diffusion model, and a competing model, the Poisson counter model, were explicitly fit to the behavioral data. The pattern of activity shown in the prelude/buildup cells, including the point at which response choices were discriminated, was matched by the evidence accumulation process predicted from the diffusion model using the parameters from the fits to the behavioral data but not by the Poisson counter model. These results suggest that prelude/buildup cells in the superior colliculus, or cells in circuits in which the superior colliculus cells participate, implement a diffusion decision process or a variant of the diffusion process.

Effects of Local Nicotinic Activation of the Superior Colliculus on Saccades in Monkeys

2005 ◽  
Vol 93 (1) ◽  
pp. 519-534 ◽  
Author(s):  
Masayuki Watanabe ◽  
Yasushi Kobayashi ◽  
Yuka Inoue ◽  
Tadashi Isa
Keyword(s):  
Superior Colliculus ◽  
Reaction Times ◽  
Low Frequency ◽  
Visually Guided ◽  
Population Activity ◽  
Affected Area ◽  
Movement Field ◽  
Neural Interactions ◽  
Restricted Region

To examine the role of competitive and cooperative neural interactions within the intermediate layer of superior colliculus (SC), we elevated the basal SC neuronal activity by locally injecting a cholinergic agonist nicotine and analyzed its effects on saccade performance. After microinjection, spontaneous saccades were directed toward the movement field of neurons at the injection site (affected area). For visually guided saccades, reaction times were decreased when targets were presented close to the affected area. However, when visual targets were presented remote from the affected area, reaction times were not increased regardless of the rostrocaudal level of the injection sites. The endpoints of visually guided saccades were biased toward the affected area when targets were presented close to the affected area. After this endpoint effect diminished, the trajectories of visually guided saccades remained modestly curved toward the affected area. Compared with the effects on endpoints, the effects on reaction times were more localized to the targets close to the affected area. These results are consistent with a model that saccades are triggered by the activities of neurons within a restricted region, and the endpoints and trajectories of the saccades are determined by the widespread population activity in the SC. However, because increased reaction times were not observed for saccades toward targets remote from the affected area, inhibitory interactions in the SC may not be strong enough to shape the spatial distribution of the low-frequency preparatory activities in the SC.

scholarly journals Spatial models of imagery for remembered scenes are more likely to advance (neuro)science than symbolic ones

2002 ◽  
Vol 25 (2) ◽  
pp. 185-186
Author(s):  
Neil Burgess
Keyword(s):  
Spatial Models ◽  
Reaction Times ◽  
Behavioral Data ◽  
Mammalian Brain ◽  
Hemispatial Neglect ◽  
Spatial Mechanism ◽  
Bodily Movement

Hemispatial neglect in imagery implies a spatially organised representation. Reaction times in memory for arrays of locations from shifted viewpoints indicate processes analogous to actual bodily movement through space. Behavioral data indicate a privileged role for this process in memory. A proposed spatial mechanism makes contact with direct recordings of the representations of location and orientation in the mammalian brain.

scholarly journals Neurophysiological Manifestations of Phonological Processing: Latency Variation of a Negative ERP Component Timelocked to Phonological Mismatch

1994 ◽  
Vol 6 (3) ◽  
pp. 204-219 ◽  
Author(s):  
Peter Praamstra ◽  
Antje S. Meyer ◽  
Willem J. M. Levelt
Keyword(s):  
Reaction Times ◽  
Event Related Potentials ◽  
Error Rates ◽  
Behavioral Data ◽  
Decision Task ◽  
Delayed Response ◽  
Target Onset ◽  
Brain Potentials ◽  
Related Potentials ◽  
Response Task

Two experiments examined phonological priming effects on reaction times, error rates, and event-related brain potential (ERP) measures in an auditory lexical decision task. In Experiment 1 related prime-target pairs rhymed, and in Experiment 2 they alliterated (i.e., shared the consonantal onset and vowel). Event-related potentials were recorded in a delayed response task. Reaction times and error rates were obtained both for the delayed and an immediate response task. The behavioral data of Experiment 1 provided evidence for phonological facilitation of word, but not of nonword decisions. The brain potentials were more negative to unrelated than to rhyming word-word pairs between 450 and 700 rnsec after target onset. This negative enhancement was not present for word-nonword pairs. Thus, the ERP results match the behavioral data. The behavioral data of Experiment 2 provided no evidence for phonological Facilitation. However, between 250 and 450 msec after target onset, i.e., considerably earlier than in Experiment 1, brain potentials were more negative for unrelated than for alliterating Word-word and word-nonword pairs. It is argued that the ERP effects in the two experiments could be modulations of the same underlying component, possibly the N400. The difference in the timing of the effects is likely to be due to the fact that the shared segments in related stimulus pairs appeared in different word positions in the two experiments.

Saccade Reaction Times Are Influenced by Caudate Microstimulation Following and Prior to Visual Stimulus Appearance

2011 ◽  
Vol 23 (7) ◽  
pp. 1794-1807 ◽  
Author(s):  
Masayuki Watanabe ◽  
Douglas P. Munoz
Keyword(s):  
Superior Colliculus ◽  
Visual Stimulus ◽  
Reaction Times ◽  
Electrical Microstimulation ◽  
Task Instructions ◽  
Linear Approach ◽  
Model Predictions ◽  
Saccade Control ◽  
Sensory Evidence ◽  
Task Conditions

Several cognitive models suggest that saccade RTs are controlled flexibly not only by mechanisms that accumulate sensory evidence after the appearance of a sensory stimulus (poststimulus mechanisms) but also by mechanisms that preset the saccade control system before the sensory event (prestimulus mechanisms). Consistent with model predictions, neurons in structures tightly related to saccade initiation, such as the superior colliculus and FEF, have poststimulus and prestimulus activities correlated with RTs. It has been hypothesized that the BG influence the saccade initiation process by controlling both poststimulus and prestimulus activities of superior colliculus and FEF neurons. To examine this hypothesis directly, we delivered electrical microstimulation to the caudate nucleus, the input stage of the oculomotor BG, while monkeys performed a prosaccade (look toward a visual stimulus) and antisaccade (look away from the stimulus) paradigm. Microstimulation applied after stimulus appearance (poststimulus microstimulation) prolonged RTs regardless of saccade directions (contra/ipsi) or task instructions (pro/anti). In contrast, microstimulation applied before stimulus appearance (prestimulus microstimulation) shortened RTs, although the effects were limited to several task conditions. The analysis of RT distributions using the linear approach to threshold with ergodic rate model revealed that poststimulus microstimulation prolonged RTs by reducing the rate of rise to the threshold for saccade initiation, whereas fitting results for prestimulus microstimulation were inconsistent across different task conditions. We conclude that both poststimulus and prestimulus activities of caudate neurons are sufficient to control saccade RTs.

scholarly journals Survivor interaction contrasts for errored response times: Non-parametric contrasts for serial and parallel systems

2020 ◽  
Author(s):  
Haiyuan Yang ◽  
Daniel R. Little ◽  
Ami Eidels ◽  
James T. Townsend
Keyword(s):  
Diffusion Model ◽  
Response Times ◽  
Parallel Systems ◽  
P Systems ◽  
Formal Proofs ◽  
Free Response ◽  
Systems Factorial Technology ◽  
Counter Model ◽  
Survivor Interaction Contrast ◽  
Processing Architecture

Systems Factorial Technology (SFT) is a theoretically-derived methodology that allows for strong inferences to be made about the underlying processing architecture (e.g., whether processing occurs in a pooled, coactive fashion or independently, in serial or in parallel). Measures of mental architecture using SFT have been restricted to the use of error-free response times. In this paper, through formal proofs and demonstrations, we extended the measure of architecture, the survivor interaction contrast (SIC), to response times conditioned on whether they are correct or incorrect. We show that so long as an ordering relation (between stimulus conditions of different difficulty) is preserved, unique conditional SIC predictions are found for several classes of processing models. We further prove that this ordering relation holds for the popular Wiener diffusion model for both correct and error RTs but fails under some instantiations of a Poisson counter model.

scholarly journals Validating marker-less pose estimation with 3D x-ray radiography

2021 ◽  
Author(s):  
Dalton D Moore ◽  
Jeffrey D Walker ◽  
Jason N MacLean ◽  
Nicholas G Hatsopoulos
Keyword(s):  
Pose Estimation ◽  
High Speed ◽  
Full Range ◽  
Three Dimensional ◽  
Small Degree ◽  
X Ray ◽  
Neural Recordings ◽  
Radiography System ◽  
Median Error ◽  
Natural Movement

To reveal the neurophysiological underpinnings of natural movement, neural recordings must be paired with accurate tracking of limbs and postures. Here we validate the accuracy of DeepLabCut (DLC) by comparing it to a 3D x-ray video radiography system that tracks markers placed under the skin (XROMM). We record behavioral data simultaneously with XROMM and high-speed video for DLC as marmosets engage in naturalistic foraging and reconstruct three-dimensional kinematics in a shared coordinate system. We find that DLC tracks position and velocity of 12 markers on the forelimb and torso with low median error (0.272 cm and 1.76 cm/s, respectively) corresponding to 2.9% of the full range of marker positions and 5.9% of the range of speeds. For studies that can accept this relatively small degree of error, DLC and similar marker-less pose estimation tools enable the study of more naturalistic, unconstrained behaviors in many fields including non-human primate motor control.

scholarly journals Inferring the function performed by a recurrent neural network

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0248940
Author(s):  
Matthew Chalk ◽  
Gasper Tkacik ◽  
Olivier Marre
Keyword(s):  
Neural Network ◽  
Neural Systems ◽  
Inverse Reinforcement Learning ◽  
Neural Recordings ◽  
Reward Function ◽  
Structure Changes ◽  
The Neural Network ◽  
Theoretical Predictions ◽  
Neural Network Dynamics ◽  
Model Circuit

A central goal in systems neuroscience is to understand the functions performed by neural circuits. Previous top-down models addressed this question by comparing the behaviour of an ideal model circuit, optimised to perform a given function, with neural recordings. However, this requires guessing in advance what function is being performed, which may not be possible for many neural systems. To address this, we propose an inverse reinforcement learning (RL) framework for inferring the function performed by a neural network from data. We assume that the responses of each neuron in a network are optimised so as to drive the network towards ‘rewarded’ states, that are desirable for performing a given function. We then show how one can use inverse RL to infer the reward function optimised by the network from observing its responses. This inferred reward function can be used to predict how the neural network should adapt its dynamics to perform the same function when the external environment or network structure changes. This could lead to theoretical predictions about how neural network dynamics adapt to deal with cell death and/or varying sensory stimulus statistics.

scholarly journals The diffusion model of reaction time for recent negative probes

2020 ◽  
Vol 13 (1) ◽  
pp. 35-50
Author(s):  
B.B. Velichkovsky ◽  
F.R. Sultanova ◽  
D.V. Tatarinov ◽  
A.A. Kachina
Keyword(s):  
Diffusion Model ◽  
Drift Rate ◽  
Short Term Memory ◽  
Reaction Times ◽  
Long Term Memory ◽  
Memory Scanning ◽  
Short Term ◽  
Cognitive Representations ◽  
Term Memory ◽  
Scanning Task

The study investigates the problem of information displacement from short-term memory. In two experiments, reaction times for recent negative probes were analyzed in the Sternberg’s memory scanning task. The diffusion model of reaction times was used with parameters estimated with the fast-dm software. It was found (experiment 1) that recent negative probes are characterized by a reduction in the speed of information accumulation (drift rate). This suggests residual activation of irrelevant cognitive representation in memory after they have been displaced from short-term memory. It was also found (experiment 2) that negative probes semantically related to items in a preceding target set (semantic recent negative probes) are characterized by a similar decrease in the drift rate. This suggests activation spreading from irrelevant cognitive representations displaced from short-term memory along semantic connections and identifies activated long-term memory as the target of information displacement from short-term memory. Additional mechanisms of short-term memory scanning (negative priming and dynamic decision thresholds) are discussed.

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