Olfaction

This study investigates the causal effects of low-intensity transcranial focused ultrasound (tFUS) on odor valence perception and odor-elicited avoidance behaviors in healthy adults. Participants undergo sham and active tFUS targeting the amygdala (AMYG) and ventral striatal olfactory tubercle (VSOT) in a within-subject, randomized, sham-controlled crossover design. Outcomes include subjective odor ratings and objective neurophysiological and behavioral indices of odor valence processing. This research is exploratory and mechanistic in nature and is not intended to evaluate clinical safety or therapeutic efficacy.

Olfaction is a prominent entity that determines a person's quality of life. During human evolution, olfaction has played an essential role in determining safe food, assessing threats, and developing social relationships. Endoscopic endonasal surgeries are widely used today for the removal of brain tumors involving the pituitary and skull base. The minimal invasiveness, rapid recovery, better visualization, and lower occurrence of complication make endonasal endoscopic surgery an ideal approach for tumors involving the pituitary and midline skull base. However, the olfactory epithelium is at risk of injury during endoscopic skull base surgeries due to the orientation of the olfactory epithelium fibers.It has been found that the olfactory neuroepithelium extends from the cribriform plate superiorly to the septum for the superior-most 1 to 2 cm medially and onto the upper half of the superior turbinates laterally.It also extends from the face of the sphenoid posteriorly to the attachment of the middle turbinate anteriorly.This makes the olfactory fibers susceptible to injury during endonasal surgery that requires superior or upper limb septal incisions, such as the pedicled nasoseptal flap (the Hadad-Bassagasteguy flap) and modified nasoseptal rescue flap.It has been debated whether using a scalpel instead of cautery could have a differential effect on the olfaction of an individual, as some surgeons believe that the heat generated by a cautery injures the nearby olfactory mucosa.This study aims at determining the method which is better at preserving the olfactory capacity of an individual undergoing endoscopic endonasal skull base surgery.