6 research outputs found
The Human Brain Encodes Event Frequencies While Forming Subjective Beliefs
To make adaptive choices, humans need to estimate the probability of future events. Based on a Bayesian approach, it is assumed that probabilities are inferred by combining a priori, potentially subjective, knowledge with factual observations, but the precise neurobiological mechanism remains unknown. Here, we study whether neural encoding centers on subjective posterior probabilities, and data merely lead to updates of posteriors, or whether objective data are encoded separately alongside subjective knowledge. During fMRI, young adults acquired prior knowledge regarding uncertain events, repeatedly observed evidence in the form of stimuli, and estimated event probabilities. Participants combined prior knowledge with factual evidence using Bayesian principles. Expected reward inferred from prior knowledge was encoded in striatum. BOLD response in specific nodes of the default mode network (angular gyri, posterior cingulate, and medial prefrontal cortex) encoded the actual frequency of stimuli, unaffected by prior knowledge. In this network, activity increased with frequencies and thus reflected the accumulation of evidence. In contrast, Bayesian posterior probabilities, computed from prior knowledge and stimulus frequencies, were encoded in bilateral inferior frontal gyrus. Here activity increased for improbable events and thus signaled the violation of Bayesian predictions. Thus, subjective beliefs and stimulus frequencies were encoded in separate cortical regions. The advantage of such a separation is that objective evidence can be recombined with newly acquired knowledge when a reinterpretation of the evidence is called for. Overall this study reveals the coexistence in the brain of an experience-based system of inference and a knowledge-based system of inference
Correspondence: Are Cognitive Functions Localizable? Colin Camerer et al. versus Marieke van Rooij and John G. Holden
The Fall 2011 issue of this journal published a
two-paper section on âNeuroeconomics.â One
paper, by Ernst Fehr and Antonio Rangel, clearly
and concisely summarized a small part of the fast-growing
literature. The second paper, âItâs about
Space, Itâs about Time, Neuroeconomics, and the
Brain Sublime,â by Marieke van Rooij and Guy Van
Orden, is beautifully written and enjoyable to read,
but misleading in many critical ways. A number
of economists and neuroscientists working at the
intersection of the two fields shared our reaction
and have signed this letter, as shown below. Some of
the paperâs descriptions of empirical findings and
methods in neuroeconomics are incomplete, badly
out of date, or flatly wrong. In studies the authors
describe in detail, their skeptical interpretations
have often been refuted by published data, old and
new, that they overlook
Artesunate-amodiaquine versus artemether-lumefantrine for the treatment of acute uncomplicated malaria in Congolese children under 10Â years old living in a suburban area: a randomized study
Decision Making: How the Brain Weighs the Evidence
The brain has to weigh incoming sensory evidence against prior beliefs, the relative weight given to each depending on the relative uncertainties. Neuroscience now shows how the human brain accomplishes this