Non-invasive recording from the human olfactory bulb

Abstract

Current methods can, in a non-invasive manner, assess neural activity in all areas of the human brain but the olfactory bulb (OB). The OB is intimately involved in a long list of olfactory tasks, has been suggested to fulfill a role comparable to that of V1 and the thalamus in the visual system, and have been closely linked to a wide range of neuropathologies. Here we present a method for non-invasive recording of signals from the human OB with millisecond precision. We demonstrate that signals obtained via recordings from EEG electrodes at the nasal bridge represent responses from the olfactory bulb - recordings we term Electrobulbogram (EBG). The EBG is localized to the OB, is reliable, and follows response patterns demonstrated in non-human animal models. The EBG will aid future olfactory-related translational work but can also easily be implemented as an everyday clinical tool to detect pathology-related changes in human central olfactory processing in neurodegenerative diseases.