Rhythmic air-puff into nasal cavity modulates activity across multiple brain areas: A non-invasive brain stimulation method to reduce ventilator-induced memory impairment

Reply to Salimi et al.: Stimulating Neural Pathways to Reduce Mechanical Ventilation–associated Neurocognitive Dysfunction

“…Our group greatly appreciated the comments from Salimi and colleagues in a recent letter on our article ( 1 ), proposing that the stimulation of neuropathways in conjunction with mechanical ventilation (MV) could result in better cognitive function after MV ( 1 ). Salimi and colleagues demonstrated that mice undergoing volume-control MV for 2 hours along with nasal puff synchronized to the breathing cycle had better working memory compared with mice undergoing volume-control MV alone ( 1 ). The authors reported that nasal puffs coupled with the respiratory cycle improved neural activity in many areas of the brain, especially the prefrontal cortex and ventral hippocampus ( 1 ).…”

“…Salimi and colleagues demonstrated that mice undergoing volume-control MV for 2 hours along with nasal puff synchronized to the breathing cycle had better working memory compared with mice undergoing volume-control MV alone ( 1 ). The authors reported that nasal puffs coupled with the respiratory cycle improved neural activity in many areas of the brain, especially the prefrontal cortex and ventral hippocampus ( 1 ). Furthermore, the authors stated that the resultant stimulation of the mechanoreceptors in the nasal cavity in synchrony with MV could promote neurogenesis and reduce neuroinflammation, and conversely, the inhibition of olfactory bulb activity has been associated with impaired neurogenesis and greater neuroinflammation ( 1 ).…”

“…The authors reported that nasal puffs coupled with the respiratory cycle improved neural activity in many areas of the brain, especially the prefrontal cortex and ventral hippocampus ( 1 ). Furthermore, the authors stated that the resultant stimulation of the mechanoreceptors in the nasal cavity in synchrony with MV could promote neurogenesis and reduce neuroinflammation, and conversely, the inhibition of olfactory bulb activity has been associated with impaired neurogenesis and greater neuroinflammation ( 1 ). Although they concluded that the elimination of olfactory bulb activity might be associated with cognitive impairment after prolonged MV, the authors have not found statistical significance for the effect of nasal puffing on the protective theta and delta oscillations in the olfactory bulb and postulated that this was probably due to the inhibitory GABAergic circuits presented in this area ( 1 ).…”

Stimulating Neural Pathways to Reduce Mechanical Ventilation–associated Neurocognitive Dysfunction

“…Altogether, we presumed that eliminated OB activity and respiratory-coupled oscillations might provoke cognitive dysfunctions observed in patients under prolonged MV. We recently applied rhythmic air-puffs into nasal cavities, synchronized with ventilator-delivered breaths, in endotracheal intubated animals under MV ( 9 ). This neurostimulation approach could restore respiration-coupled oscillations in the brain and, importantly, prevent memory impairments that are typically seen after recovery from MV ( 9 ).…”

“…We recently applied rhythmic air-puffs into nasal cavities, synchronized with ventilator-delivered breaths, in endotracheal intubated animals under MV ( 9 ). This neurostimulation approach could restore respiration-coupled oscillations in the brain and, importantly, prevent memory impairments that are typically seen after recovery from MV ( 9 ). We proposed the rhythmic nasal air-puffs as a noninvasive stimulation approach to reduce or prevent MV-associated adverse neurological events.…”