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Temporal sequencing of brain activations in menopausal hot flashes
Author(s) -
Freedman Robert R,
Murphy Eric,
Diwadkar Vaibhav A
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.956.10
Subject(s) - insula , interoception , neuroscience , psychology , brain activity and meditation , context (archaeology) , audiology , medicine , electroencephalography , biology , paleontology , perception
The insula, associated with interoception and representation of internal physiological states is a terminus in the thermoreceptive spinothalamocortical pathway within which the dorsal raphe (DR), is an early signaling region. Menopausal hot flashes (HF) are internal thermal events that activate the insula but the precedents of this activity are unknown. We assessed the time course of activity in the DR and insula in the context of HFs using fMRI conducted on 20 postmenopausal women with HFs (mean age 52 yrs). Subjects were heated with ventral and dorsal heating pads (42°C) throughout. HF onset was signaled with an increase of 2μmho/30 s in sternally recorded SCL's acquired synchronously with fMRI. Data were analyzed using SPM2 in a 30 image (1 minute) tri‐partitioned (Baseline, Pre‐Flash, post‐Flash: 10 images/partition) window around HF onset. Extracted time series from the raphe and insula were normalized to the mean activation value in Baseline. A significant interaction between partition and region, F (2,2388)=3.39, p <.034, indicated a rise in DR but not insula activity in the pre‐Flash partition. These results document a temporally ordered pattern of detectable physiological events associated with endogenously generated thermal events, and suggest that activity in the human medulla, central to homeostatis, precedes the detectable onset of menopausal flashes and the response of regions such as the insula.