Abstract
We previously identified inspiratory phase locked alpha oscillation during olfactory stimuli in humans. Electroencephalographic dipole tracing identified their source generators in the entorhinal cortex, hippocampus, amygdala, and orbitofrontal cortex. These areas of activations were needed for process of olfactory recognition and emotion. Recent studies reported that olfactory dysfunction is one of the earliest symptoms of Parkinson's disease (PD). In this study, we used the same protocol in PD patients and compared results of PD with those of age matched controls. All PD patients detected odor, but five out of 10 showed impaired odor recognition. Changes in breathing pattern associated with emotional changes during exposure to odor stimuli were not observed in PD patients. Inspiratory phase locked alpha oscillation waveforms were not observed, however, positive waves followed by negative waves were identified approximately 100 ms after inspiration onset. Dipoles of this component were localized in the entorhinal cortex for odor detection in all patients. The entorhinal cortex may play a crucial role in odor detection, however, decreased activation of the entorhinal cortex, and the limbic areas in PD patients may impair odor recognition. [J Physiol Sci. 2008;58 Suppl:S146]
