Faculty Bibliography

Psychophysiologic studies use air puff as an aversive stimulus to document abnormal fear conditioning in children of parents with anxiety disorders. This study used functional magnetic resonance imaging (fMRI) to examine changes in amygdala activity during air-puff conditioning among adults. Blood oxygen level-dependent (BOLD) signal was monitored in seven adults during 16 alternating presentations of two different colored lights (CS+ vs. CS-), one of which was consistently paired with an aversive air puff. A region-of-interest analysis demonstrated differential change in BOLD signal in the right but not left amygdala across CS+ versus CS- viewing. The amygdala is engaged by pairing of a light with an air puff. Given that prior studies relate air-puff conditioning to risk for anxiety in children, these methods may provide an avenue for directly studying the developmental neurobiology of fear conditioning

The cerebral deposition of amyloid beta-peptide, a central event in Alzheimer's disease (AD) pathogenesis, begins several years before the onset of clinical symptoms. Non-invasive detection of AD pathology at this initial stage would facilitate intervention and enhance treatment success. Here, we demonstrate the ability of high field strength MRI to detect regional brain volume reductions and ventricular enlargement in the PS-APP transgenic mouse model of AD more sensitively than histopathologic analysis by unbiased stereology. Moreover, the transverse relaxation time T2, an intrinsic MR parameter thought to reflect impaired cell physiology, was altered substantially in cortical regions containing beta-amyloid but only slightly in cerebellum, which contains little beta-amyloid. MR measures were also minimally altered in mice expressing mutant presenilin-1, which do not deposit beta-amyloid, supporting the view that the MR abnormalities in PS-APP mice are partly related to amyloid beta-peptide deposition. These results set the stage for MRI to aid in the early diagnosis of AD and the evaluation of potential therapies in transgenic animal models and in patients