Electro-physiological changes in the brain induced by caffeine or glucose nasal spray

Area of Science:

• Neuroscience
• Cognitive Science
• Pharmacology

Background:

• A direct link between oral glucose (GLUC) and caffeine (CAF) intake and brain function is established.
• The existence of a similar direct pathway from the nasal cavity to the brain for these substrates remains to be investigated.

Purpose of the Study:

• To determine if a direct link exists for glucose and caffeine delivered via nasal spray (NAS) to the brain.
• To investigate the effects of nasal glucose and caffeine on cognitive performance and brain activity.

Main Methods:

• Ten healthy males received placebo (PLAC), glucose (GLUC), or caffeine (CAF) nasal sprays in a double-blind, randomized order.
• Cognitive function was assessed using the Stroop task, measuring reaction times and accuracy.
• Brain activity was monitored using electroencephalography (EEG), with source localization performed using sLORETA.

Main Results:

• Nasal spray administration activated the anterior cingulate cortex (ACC).
• Glucose nasal spray (GLUC-NAS) increased beta activity in the insula and enhanced P300 amplitude/reduced latency in specific EEG channels during cognitive tasks.
• Caffeine nasal spray (CAF-NAS) increased theta and beta activity in frontal cortices and activated cingulate, insular, and sensorymotor cortices.

Conclusions:

• Nasal delivery of glucose and caffeine directly influences brain activity, potentially via nasal taste receptors.
• Glucose nasal spray demonstrated improved cognitive efficiency, while both substrates activated distinct brain regions.
• No significant effect on the Stroop task performance was observed despite observed brain activity changes.