The magnetization-prepared rapid gradient-echo (MP-RAGE) T1-weighted high resolution structural MRI is a mainstay tool used to identify morphometric biomarkers of disease conditions, progression and treatment effects despite a critical limitation: the relaxation signal on which inferences are based is nearly indistinguishable for gray matter vs. blood flow (Lu et al., 2004; Wright et al., 2008). Thus, apparent reported morphometric findings might be at least partially related to transient changes in blood flow or other physiological signals.

Consistent with this technical limitation, using a standard analysis technique, voxel based morphometry (VBM), we recently reported that a single dose of a medication had “apparent” effects on T1-weighted MRIs (Franklin et al., 2013). Specifically, we observed medication-induced decreases in gray matter volume in the anterior cingulate and other regions that overlapped with changes in brain blood flow (perfusion). Similarly, others have shown effects of medication on T1-weighted scans that are likely transient. For example, acute levodopa administration altered gray matter indices on T1-weighted images in the midbrain (Salgado-Pineda et al., 2006). Further, in a well-controlled longitudinal VBM study of patients with attention deficit hyperactivity disorder (ADHD), Hoekzema et al.

In a study published in Science Advances, a research team led by Prof. Liu Chengbo from the Shenzhen Institutes of Advanced Technology (SIAT) of the Chinese Academy of Sciences developed a 1.7-gram head-mounted microscope. This innovative device can simultaneously capture neural activity and cerebral hemodynamics in freely moving mice, providing a novel tool for exploring neurovascular coupling (NVC) in the brain and studying neurological disorders.

NVC represents the close temporal and regional relationship between neural activity and cerebral blood flow and oxygenation. When neural activity is initiated in a specific brain region, the metabolic demand within that region increases, leading to enhanced blood flow to supply greater amounts of oxygen and glucose, thus meeting the elevated metabolic needs of neurons. Conversely, if pathological changes hinder cerebral vessels’ capacity to provide sufficient oxygen and energy, the functional activity of the corresponding brain region will be significantly affected.

Conventional NVC imaging techniques face challenges in achieving simultaneous in vivo high spatiotemporal resolution of neuronal activity and cerebral blood flow. This makes it difficult to accurately capture the dynamic relationship between neural activity and local hemodynamic changes. In addition, most existing studies use head-fixed setups which do not reflect true neurovascular coupling during natural animal behaviors.

Mass General Brigham researchers found that interactions between immune and brain cells drive fear responses, but treatment with psychedelics like MDMA and psilocybin may reverse these effects.

The new study suggests that fear and the immune system are connected in previously unknown ways. The researchers found that the immune system can influence stress and fear behaviors by changing how brain cells communicate.

The investigators further showed that psychedelic treatments could target these neuroimmune interactions and reduce stress-induced fear in preclinical models and found similar results in human tissue samples. Results are published in Nature.