www.elsevier.com/locate/brainres Available online at www.sciencedirect.com Research Report Evidence for rostro-caudal functional organization in multiple brain areas related to goal-directed behavior Matthew L. Dixon a,n , Kieran C.R. Fox a , Kalina Christoff a,b a Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, BC, Canada V6T 1Z4 b Brain Research Centre, University of British Columbia, Vancouver, BC, Canada V6T 1Z4 article info Article history: Accepted 10 May 2014 Available online 16 May 2014 Keywords: Lateral prefrontal cortex Medial prefrontal cortex Cingulate Insula Rules Action Goals Motivation Rostro-caudal organization abstract The functional organization of brain areas supporting goal-directed behavior is debated. Some accounts suggest a rostro-caudal organization, while others suggest a broad recruitment as part of a multiple demand network. We used fMRI and an anatomical region of interest (ROI) approach to test which account better characterizes the organiza- tion of key brain areas related to goal-directed behavior: the lateral prefrontal cortex (LPFC), medial prefrontal cortex (MPFC), cingulate cortex, and insula. Subjects performed a cognitive control task with distinct trial events corresponding to rule representation, rule maintenance, action execution, and monitoring progress towards an overarching motiva- tional goal. The use of ROIs allowed us to look for evidence of rostro-caudal gradients during each event separately. Our results provide strong evidence for rostro-caudal gradients in all regions. During the action execution period, activation was robust in caudal ROIs and decreased linearly moving to rostral ROIs in the LPFC, cingulate cortex, and MPFC. Conversely, during the goal monitoring period, activation was weak in caudal ROIs and increased linearly moving to the rostral ROIs in the aforementioned regions. The insula exhibited the reverse pattern. These findings provide evidence for rostro-caudal organization in multiple regions within the same study. More importantly, they demon- strate that rostro-caudal gradients can be observed during individual trial events, ruling out confounding factors such as task difficulty. & 2014 Elsevier B.V. All rights reserved. 1. Introduction Goal-directed behavior involves the representation of a motiva- tional goal (i.e., a desired outcome), forming rules for guiding actions, physical execution of those actions, and monitoring feedback indicating progress towards the motivational goal. The neural network underlying these processes includes the lateral prefrontal cortex (LPFC), insula, cingulate cortex, and medial prefrontal cortex (MPFC), among other regions (Badre and D’ Esposito, 2007; Bunge et al., 2003; Cole and Schneider, 2007; Dixon and Christoff, 2012, 2014; Dosenbach et al., 2006; Duncan, 2010; Koechlin et al., 2003; Kouneiher et al., 2009; Rushworth et al., 2007). A fundamental goal for cognitive neuroscience is understanding the precise functional organization of these http://dx.doi.org/10.1016/j.brainres.2014.05.012 0006-8993/& 2014 Elsevier B.V. All rights reserved. n Corresponding author. Fax: þ1 604 822 6923. E-mail addresses: mattdixon@psych.ubc.ca (M.L. Dixon), kfox@psych.ubc.ca (K.C.R. Fox), kchristoff@psych.ubc.ca (K. Christoff). brain research 1572 (2014) 26–39