NeuroImage
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Many techniques to study early functional brain development lack the whole-brain spatial resolution that is available with fMRI. We utilized a relatively novel method in which fMRI data were collected from children during natural sleep. Stimulus-evoked responses to auditory and visual stimuli as well as stimulus-independent functional networks were examined in typically developing 2-4-year-old children. ⋯ In sum, 2-4 year olds showed a differential fMRI response both between stimulus modalities and between stimuli in the auditory modality. Furthermore, superior temporal regions showed functional connectivity with numerous higher-order regions during sleep. We conclude that the use of sleep fMRI may be a valuable tool for examining functional brain organization in young children.
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Pain requires the integration of sensory, cognitive, and affective information. The use of placebo is a common methodological ploy in many fields, including pain. Neuroimaging studies of pain and placebo analgesia (PA) have yet to identify a mechanism of action. ⋯ Deviations from the B1 model in the PA and PM conditions correspond to our manipulation of expectation for pain. The dynamic changes in inter-regional influence across conditions are interpreted in the context of a self-reinforcing feedback loop involved in the induction and maintenance of PA. Although it is likely that placebo analgesia results partly from afferent inhibition of a nociceptive signal, the mechanisms likely involve the interaction of a cognitive-affective network with input from both hemispheres.