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The Influence of Uncertainty on Functional Connectivity during tThe Influence of Uncertainty on Functional Connectivity during the Perception of Aversive Pictureshe Perception of Aversive PicturesJohn D. Herrington, Issidoros Sarinopoulos, Mai Youa Lor, Eric E. Steege, Kristen L. Mackiewicz and Jack B. Nitschke

Waisman Laboratory for Brain Imaging and Behavior, Departments of Psychology and Psychiatry, University of Wisconsin, Madison, WI USA

IntroductionMany anxiety disorders are associated with increased uncertainty about aversive events. However, few studies to date have examined whether this uncertainty is associated with unique patterns of brain activity.

We have previously shown that anterior Insula and amygdala respond to aversion and its anticipation insula (Nitschke et al., 2006a Nitschke et al., 2006a; Mackiewicz et al., 2006). We have also shown that insula activation can be modulated by expectancy (Nitschke et al., 2006b). Anterior insula has been linked with categorization uncertainty (Grinband et al, 2006) and, the role of the amygdala in coding uncertainty, as has been suggested previously in relation to classical conditioning (Rosen & Donley, 2006).

Medial prefrontal cortex (PFC) and anterior cingulate cortex (ACC) areas may modulate activity in other brain regions involved in emotion, including amygdala (Bechara, et al., 1999; Etkin et al., 2006).

The present project examines regional activation and functional connectivity during the presentation of aversive stimuli preceded by ambiguous versus unambiguous cues.

Hypotheses1) The experience of uncertainty regarding exposure to aversive

stimuli is associated with increased activity in amygdala and insula

2) Amygdala and insula will show increased connectivity with medial PFC and ACC during the experience of uncertainty.

fMRI Data Analysis:1) Uncertainty Effect: Multiple regression analyses (carried out separately for each intracerebral voxel) predicted activity from explanatory variables representing the uncertain and certain aversive picture trials. Parameter estimates ( s) for these two conditions were compared to one another via a paired t-test. When isolating significant clusters, family-wise error was controlled via the application of per-voxel (p < .05) and a size criterion determed by a Monte Carlo simulation. Significant clusters of activation for uncertain trials found in left and right amygdala and insula were used as seed regions for subsequent connectivity analyses.

2) Connectivity Analysis: Connectivity between amygdala/insula and all other intracerebral areas was tested via per-voxel multiple regression predicting activity across the time series from the interaction of condition (certain or uncertain negative pictures) and the average time series within four separate ROIs (i.e., left and right amygdala and insula). Interaction s for certain or uncertain were compared to one another via four paired t-tests. A conjunction map was constructed using a joint probability threshold of a p value of 0.0001. This procedure (Nitschke et al., 2006a) yielded a mask containing only those voxels that were significantly activated above t=1.69 (p=0.099) in each of the four contrasts, such that the probability of finding a voxel that is independently significant in each and both contrasts (i.e., the joint probability) can be estimated by multiplying the probabilities for each contrast: 0.099 x 0.099 x 0.099 x 0.099 = p<0.0001.

Method (Continued)

DiscussionThe experience of uncertainty regarding exposure to aversive stimuli is associated with increased activation in amygdala and insula.

Medial PFC and ACC regions showed increased connectivity with bilateral amygdala and insula for uncertain aversive stimuli.

Present data suggest that activation in emotion regions during uncertainty may be modulated by distinct sectors in medial PFC and ACC.

MethodParticipants: 36 undergraduates (16 female) free of neurological or medical problems.

Design and Stimuli: Trials followed an event related design.

Trial Design:

Greater activation for uncertain versus certain aversive picture trials in bilateral amygdala (panel A) and insula (panel B).

2) Connectivity Analysis: Bilateral amygdala and insula in the figure above showed increased connectivity with ventromedial PFC, dorsomedial PFC and ACC for uncertain versus certain aversive picture trials.

1) Uncertainty Effect: As predicted, amygdala and insula showed greater activation for aversive pictures preceded by uncertain cues.

ReferencesCox, R. W. (1996). AFNI: software for analysis and visualization of functional magnetic resonance neuroimages. Computations in

Biomedical Research, 29, 162-173.

Bechara A, Damasio H, Damasio AR and Lee GP. (1999).Different contributions of the human amygdala and ventromedial prefrontal cortex to decisionmaking. J Neurosci 19, 5473–5481.

Etkin, A., Egner, T., Peraza, D., Kandel, E. R., & Hirsh, J. (2006). Resolving emotional conflict: A role for the rostral anterior cingulate cortex in modulating activity in the amygdala. Neuron, 51, 871–882.

Grinband J, Hirsch J, Ferrera VP. (2006). A neural representation of categorization uncertainty in the human brain. Neuron, 49, 757-63.

Lang, P. J., Bradley, M. M., & Cuthbert, B. N. (1999). International affective picture system: Technical manual and affective ratings. Gainsville, FL: University of Florida Press.

Mackiewicz, K. L., Sarinopoulos, I., Cleven, K. L., & Nitschke J. B. (2006). The effect of anticipation and the specificity of sex differences for amygdala and hippocampus function in emotional memory. Proc Natl Acad Sci, 103, 38, 14200-14205.

Nitschke, J. B., Sarinopoulos, I., Mackiewicz, K. L., Schaefer, H. S., & Davidson, R. J. (2006a). Functional neuroanatomy of aversion and its anticipation. Neuroimage, 106-116.

Nitschke, J. B., Dixon , G.E., Sarinopoulos, I., Short, S.J., Cohen, J.D., Smith, E.E., Kosslyn, S.M., Rose, R.M., & Davidson, R.J. (2006). Altering expectancy dampens neural response to aversive taste in primary taste cortex. Nature Neuroscience, 9, 435-442.

Rosen JB, Donley MP. (2006). Animal studies of amygdala function in fear and uncertainty: relevance to human research. BiolPsychol., 73, 49-60.

Acknowledgements: Support for this study was provided by the NIMH grant K08-MH63984 and ROI-MH74847 (JBN). We would like to thank Andy Alexander, Michael Anderle, Ron Fisher, Hillary Schaefer, and Allison Schaus for their contributions to this study.

For further information please contact John Herrington at jdherrin@uiuc.edu and Jack Nitschke at jnitschke@wisc.edu.

Presented at Society for Neuroscience 2006, Atlanta, GA

Warning stimuli consisted of an X indicating that the next stimulus would be aversive, an O indicating that the next stimulus would be neutral, and a question mark indicating that the next stimulus was equally likely to be aversive or neutral. Each picture (International Affective Picture System; Lang et al., 1999), was presented only once during the experiment. The experiment consisted of three 9-minute functional runs with 8 aversive, neutral, and ambiguous trials per run.

fMRI Data Acquisition: Data were collected using a G.E. 3 Tesla scanner (TR/TE/Flip Angle = 2000 ms/30 ms/90º). fMRI processing was carried out via AFNI (Cox, 1996). Functional images were motion corrected, temporally filtered (highpass cutoff = .017Hz), and intensity normalized.

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Results