Neurofeedback relying on functional magnetic resonance imaging (fMRI-nf) heralds new prospects for self-regulating brain and behavior. Here we provide the first comprehensive review of the fMRI-nf literature and the first systematic database of fMRI-nf findings. We synthesize information from 99 fMRI-nf experiments-the bulk of currently available data. The vast majority of fMRI-nf findings suggest that self-regulation of specific brain signatures seems viable; however, replication of concomitant behavioral outcomes remains sparse. To disentangle placebo influences and establish the specific effects of neurofeedback, we highlight the need for double-blind placebo-controlled studies alongside rigorous and standardized statistical analyses. Before fMRI-nf can join the clinical armamentarium, research must first confirm the sustainability, transferability, and feasibility of fMRI-nf in patients as well as in healthy individuals. Whereas modulating specific brain activity promises to mold cognition, emotion, thought, and action, reducing complex mental health issues to circumscribed brain regions may represent a tenuous goal. We can certainly change brain activity with fMRI-nf. However, it remains unclear whether such changes translate into meaningful behavioral improvements in the clinical domain.
Mesial temporal lobe epilepsy (MTLE) is a focal epileptic disorder that is frequently associated with hippocampal sclerosis. This study investigated whether blocking angiogenesis prevents the development of seizures and hippocampal atrophy in the pilocarpine rat model of MTLE. To block angiogenesis, a subset of animals were given sunitinib orally. Continuous video recordings were performed to identify seizures. Brains were then extracted and sectioned, and hippocampal surfaces and angiogenesis were assessed. After a latent period of 6.6 ± 2.6 days, the sham-treated pilocarpine rats presented convulsive seizures, while the pilocarpine rats treated with sunitinib did not develop seizures. Sham-treated pilocarpine rats but not sunitinib-treated pilocarpine rats had significantly smaller hippocampi. Endothelial cell counts in sham-treated pilocarpine rats were significantly greater than in controls and sunitinib-treated pilocarpine rats. Blocking angiogenesis immediately following the initial insult in this animal model prevented thus angiogenesis and hippocampal atrophy and averted the development of clinical seizures.
Cognitive neuroscientists rarely consider the influence that body position exerts on brain activity; yet, postural variation holds important implications for the acquisition and interpretation of neuroimaging data. Whereas participants in most behavioral and EEG experiments sit upright, many prominent brain imaging techniques (e.g., fMRI) require participants to lie supine. Here we demonstrate that physical comportment profoundly alters baseline brain activity as measured by magnetoencephalography (MEG)—an imaging modality that permits multipostural acquisition. We collected resting-state MEG data from 12 healthy participants in three postures (lying supine, reclining at 45°, and sitting upright). Source-modeling analysis revealed a broadly distributed influence of posture on resting brain function. Sitting upright versus lying supine was associated with greater high-frequency (i.e., beta and gamma) activity in widespread parieto-occipital cortex. Moreover, sitting upright and reclining postures correlated with dampened activity in prefrontal regions across a range of bandwidths (i.e., from alpha to low gamma). The observed effects were large, with a mean Cohen's d of 0.95 ( SD = 0.23). In addition to neural activity, physiological parameters such as muscle tension and eye blinks may have contributed to these posture-dependent changes in brain signal. Regardless of the underlying mechanisms, however, the present results have important implications for the acquisition and interpretation of multimodal imaging data (e.g., studies combining fMRI or PET with EEG or MEG). More broadly, our findings indicate that generalizing results—from supine neuroimaging measurements to erect positions typical of ecological human behavior—would call for considering the influence that posture wields on brain dynamics.
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