Blunted left cingulate activation in mood disorder subjects during a response interference task (the Stroop).

Functional neuroimaging studies have found abnormal anterior cingulate activity in depressed subjects, and other studies have shown that the cingulate gyrus becomes active in healthy subjects during interference tasks. The authors hypothesized that subjects with mood disorder might show blunted cingulate activation during the standard Stroop interference task or during a modified version involving sadness-laden words. In contrast to 11 age- and sex-matched healthy control subjects who activated the left cingulate during the standard Stroop, 11 mood-disordered subjects activated the right anterior cingulate gyrus only slightly and instead showed increased activity in the left dorsolateral prefrontal and visual cortex. This study supports theories of blunted limbic and paralimbic activation and abnormal cingulate activity in depression and adds to the growing knowledge of the functional neuroanatomy of depression.

Understanding emotional prosody activates right hemisphere regions.

BACKGROUND: Defects in expressing or understanding the affective or emotional tone of speech (aprosodias) have been associated with right hemisphere dysfunction, while defects of propositional language have been linked to left hemisphere disease. The brain regions involved in recognition of emotional prosody in healthy subjects is less clear. OBJECTIVES: To investigate the brain regions involved in understanding emotional prosody and to determine whether these differ from those involved in understanding emotion based on propositional content. METHODS: We studied 13 healthy subjects using water labeled with radioactive oxygen 15 and positron emission tomography while they listened to 3 similar sets of spoken English sentences. In different tasks, their responses were based on the emotional propositional content, on the emotional intonation of the sentence (prosody), or on their ability to repeat the second word in the sentence (control). RESULTS: Understanding propositional content activated the prefrontal cortex bilaterally, on the left more than on the right. In contrast, responding to the emotional prosody activated the right prefrontal cortex. CONCLUSION: Neurologically healthy subjects activate right hemisphere regions during emotional prosody recognition.

Regional brain activity when selecting a response despite interference: An H2 (15) O PET study of the stroop and an emotional stroop.

The Stroop interference test requires a person to respond to specific elements of a stimulus while suppressing a competing response. Previous positron emission tomography (PET) work has shown increased activity in the right anterior cingulate gyrus during the Stroop test. It is unclear, however, whether the anterior cingulate participates more in the attentional rather than the response selection aspects of the task or whether different interference stimuli might activate different brain regions. We sought to determine (1) whether the Stroop interference task causes increased activation in the right anterior cingulate as previously reported, (2) whether this activation varied as a function of response time, (3) what brain regions were functionally linked to the cingulate during performance of the Stroop, and (4) whether a modified Stroop task involving emotionally distracting words would activate the cingulate and other limbic and paralimbic regions. Twenty-one healthy volunteers were scanned with H2 (15) O PET while they performed the Stroop interference test (standard Stroop), a modified Stroop task using distracting words with sad emotional content (sad Stroop), and a control task of naming colors. These were presented in a manner designed to maximize the response selection aspects of the task. Images were stereotactically normalized and analyzed using statistical parametric mapping (SPM). Predictably, subjects were significantly slower during the standard Stroop than the sad Stroop or the control task. The left mideingulate region robustly activated during the standard Stroop compared to the control task. The sad Stroop activated this same region, but to a less significant degree. Correlational regional network analysis revealed an inverse relationship between activation in the left mideingulate and the left insula and temporal lobe. Additionally, activity in different regions of the cingulate gyrus correlated with performance speed during the standard Stroop. These results suggest that the left midcingulate is likely to be part of a neural network activated when one attempts to override a competing verbal response. Finally, the left midcingulate region appears to be functionally coupled to the left insula, temporal, and frontal cortex during cognitive interference tasks involving language. These results underscore the important role of the cingulate gyrus in selecting appropriate and suppressing inappropriate verbal responses. © 1994 Wiley-Liss, Inc.