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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Aging Neurosci. | doi: 10.3389/fnagi.2019.00028

Age Affects How Task Difficulty and Complexity Modulate Perceptual Decision-Making

 Claudine Habak1*, Mohamed L. Seghier1, Julie Brûlé2,  Mohamed A. Fahim1 and  Oury Monchi3
  • 1Cognitive Neuroimaging Unit, Emirates College for Advanced Education, United Arab Emirates
  • 2École d'optométrie, Université de Montréal, Canada
  • 3Department of Clinical Neurosciences and Department of Radiology, Hotchkiss Brain Institute, University of Calgary, Canada

Decisions differ in difficulty and rely on perceptual information that varies in richness (complexity); aging affects cognitive function including decision-making, and yet, the interaction between difficulty and perceptual complexity have rarely been addressed in aging. Using a parametric fMRI modulation analysis and psychophysics, we address how task difficulty affects decision-making when controlling for the complexity of the perceptual context in which decisions are made. Perceptual complexity was varied in a factorial design while participants made perceptual judgements on the spatial frequency of two patches that either shared the same orientation (simple condition) or were orthogonal in orientation (complex condition). Psychophysical thresholds were measured for each participant in each condition and served to set individualized levels of difficulty during scanning. Findings indicate that discriminability interacts with complexity, to influence decisional difficulty. Modulation as a function of difficulty is maintained with age, as indicated by coupling between increased activation in fronto-parietal regions and suppression in the lateral hubs, however, age has a specific effect in the ventral anterior cingulate cortex (ACC), driven by performance at near-threshold (difficult) levels for the simpler stimulus combination condition, but not the more complex one. Taken together, our findings suggest that the context of difficulty, or what is perceived as important, changes with age, and that decisions that would seem neutral to younger participants, may carry more emphasis with age.

Keywords: Aging, Decision - making, Perceptual Discriminability, task difficulty, task complexity, fMRI signal modulation, fMRI — functional magnetic resonance imaging, Psychophysics

Received: 15 Aug 2018; Accepted: 31 Jan 2019.

Edited by:

Rubem C. Guedes, Federal University of Pernambuco, Brazil

Reviewed by:

Harriet A. Allen, University of Nottingham, United Kingdom
Keith J. Gamble, Middle Tennessee State University, United States  

Copyright: © 2019 Habak, Seghier, Brûlé, Fahim and Monchi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Claudine Habak, Emirates College for Advanced Education, Cognitive Neuroimaging Unit, Abu Dhabi, United Arab Emirates, Claudine.Habak@gmail.com