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Carmin, C. N., Wiegartz, P. S., Hoff, J. A., & Kondos, G. T. (2003). Cardiac anxiety in patients self-referred for electron beam tomography. Journal of Behavioral Medicine, 26(1), 67-80.
Studies have repeatedly shown that as many as 43% of patients undergoing coronary angiograms have no evidence of coronary heart disease (CHD). Fear of cardiac-related sensations has been posited as one explanation for complaints of chest pain in patients without CHD. The purpose of this study is to examine variables associated with cardiac anxiety in a sample of individuals self-referred for noninvasive coronary calcium screening. Nearly one quarter of the subjects screened experienced chest pain in the absence of coronary artery calcium (CAC). Individuals without evidence of CAC were more likely to report higher levels of heart-focused attention, even when subjects with any risk factors for CHD were excluded from the analyses. Men were more likely to have evidence of coronary calcium, although a greater proportion of women reported chest pain. Women generally endorsed higher levels of cardioprotective behavior, heart- focused attention, and fear of heart-related sensations. Findings are discussed in relation to treatment of cardiac anxiety and the prevention of unnecessary medical procedures.
[top of page 16 of handout]Morris, J. S., & Dolan, R. J. (2004). Dissociable amygdala and orbitofrontal responses during reversal fear conditioning. Neuroimage, 22(1), 372-380.
The neural mechanisms underlying the persistence and plasticity of human emotional learning are unknown. Here we describe dissociable neural responses in amygdala and orbitofrontal cortex during acquisition and reversal of discriminatory fear conditioning. During acquisition, increased responses in bilateral amygdala were elicited by a face stimulus (A = CS+) predictive of an aversive noise compared to another nonpredictive face (B = CS-). With subsequent reversal of the conditioning contingency, face B (new CS+) elicited enhanced responses in right orbitofrontal cortex, while face A (old CS+) continued to evoke increased responses in right ventral amygdala. Thus, while orbitofrontal cortex exhibited rapid reversal of acquired fear responses, ventral amygdala showed a persistent, nonreversing "memory" for previous fear-related stimulus associations.
Mineka, S., & Ohman, A. (2002). Phobias and preparedness: The selective, automatic, and encapsulated nature of fear. Biological Psychiatry, 52(10), 927-937.
We describe evidence for an evolved module for fear elicitation and fear learning with four primary characteristics. First, it is preferentially activated by stimuli related to survival threats in evolutionary history. Thus, fear-relevant stimuli lead to superior conditioning of aversive associations compared with fear-irrelevant stimuli. Second, the module is automatically activated by fear- relevant stimuli, meaning that fear activation occurs before conscious cognitive analysis of the stimulus can occur. Third, the fear module is relatively impenetrable to conscious cognitive control, and fear conditioning with fear-relevant stimuli can occur even with subliminal conditioned stimuli. Fourth, the amygdala seems to be the central brain area dedicated to the fear module. Finally, we propose that there are two levels of fear conditioning, with an emotional level that is relatively independent of the cognitive contingency level, each mediated by different brain areas. (C) 2002 Society of Biological Psychiatry.
Hermans, D., Dirikx, T., Vansteenwegenin, D., Baeyens, F., Van den Bergh, O., & Eelen, P. (2005). Reinstatement of fear responses in human aversive conditioning. Behaviour Research and Therapy, 43(4), 533-551.
The treatment of choice for a number of anxiety disorders is exposure therapy. However, successful reduction of fear through exposure is sometimes followed by a (partial) return of symptoms of fear (return of fear, ROF; Clin. Psychol. Rev. 9 (1989) 147). Several possible learning mechanisms have been suggested to explain ROF The present study focuses on reinstatement, which refers to the observation that mere US-only presentations can 'reinstate' previously extinguished fear responses. Although animal research has repeatedly demonstrated this phenomenon, little is known about fear reinstatement in humans. The present study employed a differential aversive conditioning procedure: after acquisition and a subsequent extinction procedure, a series of four unpredicted US-only trials was scheduled in the reinstatement group. A significant reinstatement effect was observed for US-expectancy ratings and fear ratings in the reinstatement group.. These findings constitute a first demonstration of reinstatement of conditioned fear responses in humans.