Just as a conductor coordinates different instruments in an orchestra to produce a symphony, breathing coordinates hippocampal brain waves to strengthen memory while we sleep, reports a new Northwestern Medicine study.

This is the first time breathing rhythms during sleep have been linked to these hippocampal brain waves—called slow waves, spindles and ripples—in humans. Scientists knew these waves were linked to memory but their underlying driver was unknown. The study is published in the Proceedings of the National Academy of Sciences.

“To strengthen memories, three special neural oscillations emerge and synchronize in the hippocampus during sleep, but they were thought to come and go at random times,” said senior study author Christina Zelano, professor of neurology at Northwestern University Feinberg School of Medicine. “We discovered that they are coordinated by breathing rhythms.”

Glyphosate use in the United States (US) has increased each year since the introduction of glyphosate-tolerant crops in 1996, yet little is known about its effects on the brain. We recently found that C57BL/6J mice dosed with glyphosate for 14 days showed glyphosate and its major metabolite aminomethylphosphonic acid present in brain tissue, with corresponding increases in pro-inflammatory cytokine tumor necrosis factor-⍺ (TNF-⍺) in the brain and peripheral blood plasma. Since TNF-⍺ is elevated in neurodegenerative disorders such as Alzheimer’s Disease (AD), in this study, we asked whether glyphosate exposure serves as an accelerant of AD pathogenesis. Additionally, whether glyphosate and aminomethylphosphonic acid remain in the brain after a recovery period has yet to be examined.

We hypothesized that glyphosate exposure would induce neuroinflammation in control mice, while exacerbating neuroinflammation in AD mice, causing elevated Amyloid-β and tau pathology and worsening spatial cognition after recovery. We dosed 4.5-month-old 3xTg-AD and non-transgenic (NonTg) control mice with either 0, 50 or 500 mg/kg of glyphosate daily for 13 weeks followed by a 6-month recovery period.

We found that aminomethylphosphonic acid was detectable in the brains of 3xTg-AD and NonTg glyphosate-dosed mice despite the 6-month recovery. Glyphosate-dosed 3xTg-AD mice showed reduced survival, increased thigmotaxia in the Morris water maze, significant increases in the beta secretase enzyme (BACE-1) of amyloidogenic processing, amyloid-β (Aβ) 42 insoluble fractions, Aβ 42 plaque load and plaque size, and phosphorylated tau (pTau) at epitopes Threonine 181, Serine 396, and AT8 (Serine 202, Threonine 205). Notably, we found increased pro-and anti-inflammatory cytokines and chemokines persisting in both 3xTg-AD and NonTg brain tissue and in 3xTg-AD peripheral blood plasma.

Objective: Intermittent energy restriction (IER) is an effective weight loss strategy. However, little is known about the dynamic effects of IER on the brain-gut-microbiome axis.

Methods: In this study, a total of 25 obese individuals successfully lost weight after a 2-month IER intervention. FMRI was used to determine the activity of brain regions. Metagenomic sequencing was performed to identify differentially abundant gut microbes and pathways in from fecal samples.

Results: Our results showed that IER longitudinally reduced the activity of obese-related brain regions at different timepoints, including the inferior frontal orbital gyrus in the cognitive control circuit, the putamen in the emotion and learning circuit, and the anterior cingulate cortex in the sensory circuit. IER longitudinally reduced E. coli abundance across multiple timepoints while elevating the abundance of obesity-related Faecalibacterium prausnitzii, Parabacteroides distasonis, and Bacterokles uniformis. Correlation analysis revealed longitudinally correlations between gut bacteria abundance alterations and brain activity changes.