Biomedical subjects

Barnaby D Dunn

Publications and source records attributed to Barnaby D Dunn.

3 recordsLinked to original sources

PubMed2006

Heartbeat perception in depression.

Alterations in bodily awareness have been implicated in depression but there has been little detailed empirical characterisation of the degree and accuracy of body perception in the disorder. The present study examined the objective accuracy of heartbeat perception (using the Schandry mental tracking task) and the subjective degree of bodily focus (using the Bodily Consciousness Questionnaire; BCQ) in healthy control volunteers, a moderately depressed community sample, and a more severely depressed clinic sample (n=18 in each group). The community sample showed less accurate heartbeat perception than the control group as expected. Counter to prediction, however, the more severely depressed clinic sample performed better than the community depressed sample and equivalently to control volunteers on the Schandry task. There were no group differences on subjective bodily awareness. Implications for theories of depression are discussed.

Adult↗

PubMed2005

The somatic marker hypothesis: a critical evaluation.

The somatic marker hypothesis (SMH; [Damasio, A. R., Tranel, D., Damasio, H., 1991. Somatic markers and the guidance of behaviour: theory and preliminary testing. In Levin, H.S., Eisenberg, H.M., Benton, A.L. (Eds.), Frontal Lobe Function and Dysfunction. Oxford University Press, New York, pp. 217-229]) proposes that emotion-based biasing signals arising from the body are integrated in higher brain regions, in particular the ventromedial prefrontal cortex (VMPFC), to regulate decision-making in situations of complexity. Evidence for the SMH is largely based on performance on the Iowa Gambling Task (IGT; [Bechara, A., Tranel, D., Damasio, H., Damasio, A.R., 1996. Failure to respond autonomically to anticipated future outcomes following damage to prefrontal cortex. Cerebral Cortex 6 (2), 215-225]), linking anticipatory skin conductance responses (SCRs) to successful performance on a decision-making paradigm in healthy participants. These 'marker' signals were absent in patients with VMPFC lesions and were associated with poorer IGT performance. The current article reviews the IGT findings, arguing that their interpretation is undermined by the cognitive penetrability of the reward/punishment schedule, ambiguity surrounding interpretation of the psychophysiological data, and a shortage of causal evidence linking peripheral feedback to IGT performance. Further, there are other well-specified and parsimonious explanations that can equally well account for the IGT data. Next, lesion, neuroimaging, and psychopharmacology data evaluating the proposed neural substrate underpinning the SMH are reviewed. Finally, conceptual reservations about the novelty, parsimony and specification of the SMH are raised. It is concluded that while presenting an elegant theory of how emotion influences decision-making, the SMH requires additional empirical support to remain tenable.

Adaptation, Psychological↗

PubMed2004

Categorical and dimensional reports of experienced affect to emotion-inducing pictures in depression.

Self-reported affect to positive and negative emotional pictures was contrasted in people with major depressive disorder (MDD) and never-depressed control participants (n = 25 in each group). The results revealed significant differences in response to positive images (reduced arousal, less pleasant valence, decreased happiness, increased sadness) in MDD but no clear group differences in response to negative stimuli. Extending earlier findings of reduced responsiveness to positive, but not negative, stimuli in MDD (D. M. Sloan, M. E. Strauss, S. W. Quirk, & M. Satajovik, 1997; D. M. Sloan, M. E. Strauss, & K. L. Wisner, 2001), the data indicate that blunted response to positive stimuli is found when both categorical and dimensional ratings are elicited. Further, the data replicate earlier findings of elevated sadness reports to positive stimuli (J. Rottenberg, K. L. Kasch, J. J. Gross, & I. H. Gotlib, 2002), which may reflect broader difficulties in regulating emotions in MDD.

Affect↗