The hypnotic zolpidem increases the synchrony of BOLD signal fluctuations in widespread brain networks during a resting paradigm

Abstract

Networks of brain regions having synchronized fluctuations of the blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) time-series at rest, or “resting state networks” (RSNs), are emerging as a basis for understanding intrinsic brain activity. RSNs are topographically consistent with activity-related networks subserving sensory, motor, and cognitive processes, and studying their spontaneous fluctuations following acute drug challenge may provide a way to understand better the neuroanatomical substrates of drug action. The present within-subject double-blind study used BOLD fMRI at 3T to investigate the functional networks influenced by the non-benzodiazepine hypnotic zolpidem (Ambien®). Zolpidem is a positive modulator of γ-aminobutyric acidA (GABAA) receptors, and engenders sedative effects that may be explained in part by how it modulates intrinsic brain activity. Healthy participants (n= 12) underwent fMRI scanning 45 min after acute oral administration of zolpidem (0, 5, 10, or 20 mg), and changes in BOLD signal were measured while participants gazed at a static fixation point (i.e., at rest). Data were analyzed using group independent component analysis (ICA) with dual regression and results indicated that compared to placebo, the highest dose of zolpidem increased functional connectivity within a number of sensory, motor, and limbic networks. These results are consistent with previous studies showing an increase in functional connectivity at rest following administration of the positive GABAA receptor modulators midazolam and alcohol, and suggest that investigating how zolpidem modulates intrinsic brain activity may have implications for understanding the etiology of its powerful sedative effects.

An eight month randomized controlled exercise intervention alters resting state synchrony in overweight children

“…The concatenated dataset was decomposed using ICA to identify large-scale patterns of functional synchrony in the sample. The inclusion of all participants at both timepoints in the ICA analysis is in accordance with previously published rsfMRI studies using similar analyses (Licata et al, 2013; Martínez et al, In press). Thirty spatially-independent components were identified using automatic dimensionality estimation.…”

Arousal transitions in sleep, wakefulness, and anesthesia are characterized by an orderly sequence of cortical events

“…Fluctuation amplitude and correlations of fMRI signals increased globally not only from wakefulness to light sleep (Fukunaga et al, 2006; Horovitz et al, 2008; Larson-Prior et al, 2009; Olbrich et al, 2009), but also from EO to EC conditions (Bianciardi et al, 2009; Jao et al, 2013; Wong et al, 2013). Most interestingly, the increases in vigilance induced by ingestion of caffeine effectively reduced the amplitude of global signal (Wong et al, 2013), whereas the opposite effects were evident for administration of midazolam (Greicius et al, 2008; Kiviniemi et al, 2005) and zolpidem (Licata et al, 2013), the hypnotic drugs that are known to induce light sedation and drowsiness. Such a relationship is possibly mediated by the appearance of SSTs in states of low vigilance.…”

Brain Regions Responsible for Tinnitus Distress and Loudness: A Resting-State fMRI Study

“…These drugs can affect the cerebral FC. Indeed, BZD have been reported to affect the cerebral FC [62], [63]. We compared the distribution of clinical parameter -rGC or -rGCa plots between subjects with and without medications as shown in Figures 2–7.…”