High trait anxiety and hyporeactivity to stress of the dorsomedial prefrontal cortex: a combined phMRI and Fos study in rats

Acupoint-specific fMRI patterns in human brain

Specific central nervous system (CNS) responses to acupuncture have recently attracted attention. It is important to understand the differences in fMRI images of the brain evoked by acupuncture at an acupoint and at a nearby "sham" point. Here, we report analyses of fMRI images of the brains of 37 healthy volunteers in response to acupuncture at Liv3 (Taichong) and LI4 (Hegu) versus their sham points. We found common activation areas in response to Liv3 or LI4 acupuncture in the middle temporal gyrus and cerebellum, along with deactivation areas in the middle frontal gyrus and inferior parietal lobule, compared with the effects of acupuncture at sham points. Acupuncture at Liv3 evoked specific activation at the postcentral gyrus, posterior cingulate, parahippocampal gyrus, BA 7, 19 and 41, but deactivation at the inferior frontal gyrus, anterior cingulate, BA 17 and 18, compared with acupuncture at its sham point. Acupuncture at LI4 evoked specific activation at the temporal pole, but deactivation at the precentral gyrus, superior temporal gyrus, pulvinar and BA 8, 9 and 45, compared with acupuncture at its sham point. These observations reveal that acupuncture at acupoints induces specific patterns of brain activity, and these patterns may relate to the therapeutic effects of acupuncture.

Methodological considerations in rat brain BOLD contrast pharmacological MRI

RATIONALE AND OBJECTIVES

Blood oxygen level dependent (BOLD) contrast pharmacological magnetic resonance imaging (phMRI) is an increasingly popular technique that allows the non-invasive investigation of spatial and temporal changes in rat brain function in response to pharmacological stimulation in vivo. Rat brain BOLD contrast phMRI is, at present, established in few neuropharmacological laboratories, and various issues associated with the technique require attention. The present review is primarily aimed at psychopharmacologists with no previous experience of phMRI, who are interested in the practical aspects that phMRI studies entail.

RESULTS AND DISCUSSION

Experimental and analytical considerations, including anaesthesia, physiological monitoring, drug dose and delivery, scanning protocols, statistical approaches and the interpretation of phMRI data, are discussed.