Attentional modulation in human primary olfactory cortex.
Central to the concept of attention is the fact that identical stimuli can be processed in different ways. In olfaction, attention may designate the identical flow of air through the nose as either respiration or olfactory exploration. Here we have used functional magnetic resonance imaging (fMRI) to probe this attentional mechanism in primary olfactory cortex (POC). We report a dissociation in POC that revealed attention-dependent and attention-independent subregions. Whereas a temporal subregion comprising temporal piriform cortex (PirT) responded equally across conditions, a frontal subregion comprising frontal piriform cortex (PirF) and the olfactory tubercle responded preferentially to attended sniffs as opposed to unattended sniffs. In addition, a task-specific anticipatory response occurred in the attention-dependent region only. This dissociation was consistent across two experimental designs: one focusing on sniffs of clean air, the other focusing on odor-laden sniffs. Our findings highlight the role of attention at the earliest cortical levels of olfactory processing.
Zelano
Christina
C
Program in Biophysics, University of California at Berkeley, Berkeley, California 94720, USA.
Bensafi
Moustafa
M
Porter
Jess
J
Mainland
Joel
J
Johnson
Brad
B
Bremner
Elizabeth
E
Telles
Christina
C
Khan
Rehan
R
Sobel
Noam
N
D000328:Adult; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D018728:Entorhinal Cortex / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009812:Odorants; D009833:Olfactory Pathways / Q000502:physiology*; D012123:Pulmonary Ventilation / Q000502:physiology; D012903:Smell / Q000502:physiology