Parallel mitral and tufted cell pathways route distinct odor information to different targets in the olfactory cortex.
Odor signals are conveyed from the olfactory bulb to the olfactory cortex (OC) by mitral cells (MCs) and tufted cells (TCs). However, whether and how the two types of projection neuron differ in function and axonal connectivity is still poorly understood. Odor responses and axonal projection patterns were compared between MCs and TCs in mice by visualizing axons of electrophysiologically identified single neurons. TCs demonstrated shorter onset latency for reliable responses than MCs. The shorter latency response of TCs was maintained in a wide range of odor concentrations, whereas MCs responded only to strong signals. Furthermore, individual TCs projected densely to focal targets only in anterior areas of the OC, whereas individual MCs dispersedly projected to all OC areas. Surprisingly, in anterior OC areas, the two cell types projected to segregated subareas. These results suggest that MCs and TCs transmit temporally distinct odor information to different OC targets.
Department of Physiology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan. kei.igarashi@ntnu.no
Kei M
KM
Igarashi
Nao
N
Ieki
Myungho
M
An
Yukie
Y
Yamaguchi
Shin
S
Nagayama
Ko
K
Kobayakawa
Reiko
R
Kobayakawa
Manabu
M
Tanifuji
Hitoshi
H
Sakano
Wei R
WR
Chen
Kensaku
K
Mori
D000818:Animals; D001369:Axons / Q000502:physiology; D002087:Butyrates; D016000:Cluster Analysis; D003627:Data Interpretation, Statistical; D003712:Dendrites / Q000502:physiology / Q000648:ultrastructure; D055724:Electrophysiological Phenomena; D007091:Image Processing, Computer-Assisted; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D059906:Neuroimaging; D009474:Neurons / Q000502:physiology*; D009812:Odorants; D009830:Olfactory Bulb / Q000502:physiology; D009833:Olfactory Pathways / Q000166:cytology* / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D017729:Presynaptic Terminals / Q000502:physiology; D012372:ROC Curve; D059010:Single-Cell Analysis; D012903:Smell / Q000502:physiology*; D013844:Thiazoles
C451263:2,4,5 trimethylthiazoline; D002087:Butyrates; D013844:Thiazoles; C019475:2-methylbutanoic acid