consistent implementation of decisions in the brain一致的实现决策在大脑中.pdf

Consistent Implementation of Decisions in the Brain 1 2 3 James A. R. Marshall *, Rafal Bogacz , Iain D. Gilchrist 1 Department of Computer Science/Kroto Research Institute, University of Sheffield, Sheffield, United Kingdom, 2 Department of Computer Science, University of Bristol, Bristol, United Kingdom, 3 School of Experimental Psychology, University of Bristol, Bristol, United Kingdom Abstract Despite the complexity and variability of decision processes, motor responses are generally stereotypical and independent of decision difficulty. How is this consistency achieved? Through an engineering analogy we consider how and why a system should be designed to realise not only flexible decision-making, but also consistent decision implementation. We specifically consider neurobiologically-plausible accumulator models of decision-making, in which decisions are made when a decision threshold is reached. To trade-off between the speed and accuracy of the decision in these models, one can either adjust the thresholds themselves or, equivalently, fix the thresholds and adjust baseline activation. Here we review how this equivalence can be implemented in such models. We then argue that manipulating baseline activation is preferable as it realises consistent decision implementation by ensuring consistency of motor inputs, summarise empirical evidence in support of this hypothesis, and suggest that it could be a general principle of decision making and implementation. Our goal is therefore to review how neurobiologically-plausible models of decision-making can manipulate speed-accuracy trade-offs using different mechanisms, to consider which of these mechanisms has more desirable decision- implementation