title: The tipping point: Value differences and parallel dorsal-ventral frontal circuits gating human approach-avoidance behavior.
abstract: Excessive avoidance and diminished approach behavior are both prominent features of anxiety, trauma and stress related disorders. Despite this, little is known about the neuronal mechanisms supporting gating of human approach-avoidance behavior. Here, we used functional magnetic resonance imaging (fMRI) to track dorsal anterior cingulate and medial prefrontal (dACC/dmPFC) activation along an approach-avoidance continuum to assess sensitivity to competing appetitive and aversive contingencies and correspondence with behavior change. Behavioral and fMRI experiments were conducted using a novel approach-avoidance task where a monetary reward appeared in the presence of a conditioned stimulus (CS), or threat, that signaled increasing probability of unconditioned stimulus (US) delivery. Approach produced the reward or probabilistic US, while avoidance prevented US delivery, and across trials, reward remained fixed while the CS threat level varied unpredictably. Increasing the CS threat level (i.e., US probability) produced the desired approach-avoidance transition and inverted U-shaped changes in decision times, electrodermal activity and activation in pregenual ACC, dACC/dmPFC, striatum, anterior insula and inferior frontal regions. Conversely, U-shaped changes in activation were observed in dorsolateral and ventromedial prefrontal cortex and bimodal changes in the orbitofrontal and ventral hippocampus. These new results show parallel dorsal-ventral frontal circuits support gating of human approach-avoidance behavior where dACC/dmPFC signals inversely correlate with value differences between approach and avoidance contingencies while ventral frontal signals correlate with the value of predictable outcomes. Our findings provide an important bridge between basic research on brain mechanisms of value-guided decision-making and value-focused clinical theories of anxiety and related interventions.
authors.affiliation: Department of Behavior Analysis, University of North Texas, 1155 Union Circle, Box 310919, Denton, TX 76203-0919, USA. Electronic address: Michael.Schlund@Unt.Edu.
authors.forename: Michael W
authors.initials: MW
authors.lastname: Schlund
authors.affiliation: Department of Psychology and Liberal Arts, Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL 32901, USA. Electronic address: abrewer@fit.edu.
authors.forename: Adam T
authors.initials: AT
authors.lastname: Brewer
authors.affiliation: Department of Behavior Analysis, University of North Texas, 1155 Union Circle, Box 310919, Denton, TX 76203-0919, USA.
authors.forename: Sandy K
authors.initials: SK
authors.lastname: Magee
authors.affiliation: Department of Educational Psychology and Leadership, Texas Tech University, 3008 18th Street, Lubbock, TX 79409-1071, USA. Electronic address: d.richman@ttu.edu.
authors.forename: David M
authors.initials: DM
authors.lastname: Richman
authors.affiliation: Department of Behavior Analysis, University of North Texas, 1155 Union Circle, Box 310919, Denton, TX 76203-0919, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Solomon
authors.affiliation: Department of Behavior Analysis, University of North Texas, 1155 Union Circle, Box 310919, Denton, TX 76203-0919, USA.
authors.forename: MaDonna
authors.initials: M
authors.lastname: Ludlum
authors.affiliation: Department of Psychology, Swansea University, Singleton Park Campus, Swansea SA2 8PP, United Kingdom; Department of Psychology, Reykjavík University, Menntavegur 1, Nauthólsvík, 101 Reykjavík, Iceland. Electronic address: s.o.dymond@swansea.ac.uk.
authors.forename: Simon
authors.initials: S
authors.lastname: Dymond
mesh_terms: D001288:Attention / Q000502:physiology*; D001362:Avoidance Learning / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D002755:Choice Behavior / Q000502:physiology*; D003214:Conditioning, Classical; D005260:Female; D005625:Frontal Lobe / Q000502:physiology*; D006179:Gyrus Cinguli / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009415:Nerve Net / Q000502:physiology*; D012201:Reward; D055815:Young Adult
keywords: Anterior cingulate; Anxiety; Approach–avoidance; Conflict; Decision making; Threat