Integration of Direction Cues Is Invariant to the Temporal Gap between Them

Kiani, R., Churchland, A. K., Shadlen, M. N. (October 2013) Integration of Direction Cues Is Invariant to the Temporal Gap between Them. Journal of Neuroscience, 33 (42). pp. 16483-9. ISSN 1529-2401 (Electronic)0270-6474 (Linking)

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Abstract

Many decisions involve integration of evidence conferred by discrete cues over time. However, the neural mechanism of this integration is poorly understood. Several decision-making models suggest that integration of evidence is implemented by a dynamic system whose state evolves toward a stable point representing the decision outcome. The internal dynamics of such point attractor models render them sensitive to the temporal gaps between cues because their internal forces push the state forward once it is dislodged from the initial stable point. We asked whether human subjects are as sensitive to such temporal gaps. Subjects reported the net direction of stochastic random dot motion, which was presented in one or two brief observation windows (pulses). Pulse strength and interpulse interval varied randomly from trial to trial. We found that subjects' performance was largely invariant to the interpulse intervals up to at least 1 s. The findings question the implementation of the integration process via mechanisms that rely on autonomous changes of network state. The mechanism should be capable of freezing the state of the network at a variety of firing rate levels during temporal gaps between the cues, compatible with a line of stable attractor states.

Item Type: Paper
Subjects: organism description > animal behavior
organism description > animal behavior > decision making
CSHL Authors:
Communities: CSHL labs > Churchland lab
Depositing User: Matt Covey
Date: 16 October 2013
Date Deposited: 05 Nov 2013 22:01
Last Modified: 03 Dec 2014 15:22
PMCID: PMC3797371
Related URLs:
URI: https://repository.cshl.edu/id/eprint/28829

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