title: In favor of general probability distributions: lateral prefrontal and insular cortices respond to stimulus inherent, but irrelevant differences.
abstract: A key aspect of optimal behavior is the ability to predict what will come next. To achieve this, we must have a fairly good idea of the probability of occurrence of possible outcomes. This is based both on prior knowledge about a particular or similar situation and on immediately relevant new information. One question that arises is: when considering converging prior probability and external evidence, is the most probable outcome selected or does the brain represent degrees of uncertainty, even highly improbable ones? Using functional magnetic resonance imaging, the current study explored these possibilities by contrasting words that differ in their probability of occurrence, namely, unbalanced ambiguous words and unambiguous words. Unbalanced ambiguous words have a strong frequency-based bias towards one meaning, while unambiguous words have only one meaning. The current results reveal larger activation in lateral prefrontal and insular cortices in response to dominant ambiguous compared to unambiguous words even when prior and contextual information biases one interpretation only. These results suggest a probability distribution, whereby all outcomes and their associated probabilities of occurrence--even if very low--are represented and maintained.
authors.affiliation: School of Psychological Sciences, The University of Manchester, Zochonis Building, Brunswick Street, Manchester, M13 9PL, UK. anna.mestres-misse@manchester.ac.uk.|Max Planck Institute for Human Cognitive and Brain Sciences, 04103, Leipzig, Germany. anna.mestres-misse@manchester.ac.uk.
authors.forename: Anna
authors.initials: A
authors.lastname: Mestres-Missé
authors.affiliation: Max Planck Institute for Human Cognitive and Brain Sciences, 04103, Leipzig, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Trampel
authors.affiliation: Max Planck Institute for Human Cognitive and Brain Sciences, 04103, Leipzig, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Turner
authors.affiliation: School of Psychological Sciences, The University of Manchester, Zochonis Building, Brunswick Street, Manchester, M13 9PL, UK.|Max Planck Institute for Human Cognitive and Brain Sciences, 04103, Leipzig, Germany.
authors.forename: Sonja A
authors.initials: SA
authors.lastname: Kotz
mesh_terms: D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D002755:Choice Behavior / Q000502:physiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D017397:Prefrontal Cortex / Q000502:physiology*; D011336:Probability; D011930:Reaction Time; D011932:Reading; D012660:Semantics; D016008:Statistical Distributions; D055815:Young Adult
keywords: Ambiguity; Anterior insula; Prefrontal cortex; Probability distributions; Uncertainty; fMRI