Olfactory system mitral/tufted cells

Major connections of the main olfactory system. Axons of MOB mitral/tufted cells (circles in the EPL and MCL, respectively) project as the LOT to synapse in a number of structures collectively referred to as primary olfactory cortex (POC). Centrifugal inputs to MOB include feedback projections from POC as well as inputs from subcortical forebrain and brainstem neuromodulatory cell groups. Abbreviations AON, anterior olfactory nucleus DP, dorsal peduncular cortex Ent, entorhinal cortex IG-AHC, indusium griseum-anterior hippocampal continuation LC, locus coeruleus NDB, nucleus of the diagonal band PeCo, periamygdaloid cortex PC, piriform cortex RN, raphe nuclei (dorsal and median raphe) TT, taenia tecta Tu, olfactory tubercle... 

Olfactory nerve stimulation activates both glomerular (JG and mitral/tufted cells which are reciprocally connected) and infraglomerular (Mitral/granule/mitral) inhibitory systems. Therefore, it is difficult to separate the relative contribution of these two inhibitory systems to mitral cell inhibition. However, stimulation of the olfactory nerve (orthodromic stimulation) results in a longer lasting inhibition of mitral cells than stimulation... 

Meisami, E. and Safari, L. (1981) A quantitative study of the effects of early unilateral olfactory deprivation of the number and distribution of mitral and tufted cells and of the glomeruli in the rat olfactory system. Brain Res, 221. 81-107. 

Scott, J.W. (1981) Electrophysiological identification of mitral and tufted cells and distribution of their axons in the olfactory system of the rat. J. Neurophysiol., 46, 918-931. 

Farther upstream in the olfactory system, the projection neurons from the olfactory bulb (mitral and tufted cells) distribute themselves to myriad destinations [19], whieh in turn project elsewhere and, in most cases, send a return link to the originating location [19]. These distributed projection pathways allow for numerous influences on behavior e.g., the odorant can be spoken about, presumably because of connections to cortex [19] odors may influence mood and emotion, even at subconscious levels [20], because of diverse eonneetions to limbic structures [19] physiological, e.g., autonomic and neuroendocrine, responses may be modulated by odors, because olfaction communicates rather directly with the hypothalamopitui-tary gonadal axis [21]. 

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