Glomerular layer

TABLE 1. Neuron types in the main olfactory bulb 

Layer Neuron type Sizes Cell density 

Abbreviations GL, glomerular layer EPL, external plexiform layer MCL, mitral cell layer IPL, internal plexiform layer GCL, granule cell layer EZ, ependymal zone. 

The majority of the juxtaglomerular neurons can be classified as one of three types  

10-15 m in long axis, lie in the periglomerular region and usually have a single apical 

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Fig. 2.18 Chemosensory pathways, Bony Fish, (a) Peripheral ON = Olfactory nv. (input axons) GL = glomerular layer ICL = internal cell layer MCI = mitral cell layer RC = ruffed cell and CF = centrifugal fibre (from Sorensen, 1998). (b) CNS interconnections (from Bardach and Villars, 1968).

Wilson K.C. and Raisman G. (1981). Estimation of numbers of vomeronasal synapses in the glomerular layer of the accessory olfactory bulb of the mouse at different ages. Brain Res 205, 245-254. 

The glomerular layer of the olfactory bulb contains a substantial population of dopaminergic neurons. Dopamine acting at D2-like heteroreceptors inhibits glutamate release from terminals of the olfactory sensory neurons and hence may modulate the olfactory nerve synapse (Table 1). 

The highest density of D2 receptor, as measured by selective radiolabeled drugs or antibodies, was found in the NAc, olfactory tubercle, olfactory bulb (glomerular layer) and CPu. In the pituitary gland, D2 receptors were found to be present at a high level in the intermediate lobe. 

Johnson BA, Leon M. Modular representations of odorants in the glomerular layer of the rat olfactory bulb and the effects of stimulus concentration. J. Comp. Neurol. 2000 422 496-509. Laing DG, Legha PK, Jinks AL, Hutchinson 1. Relationship between molecular structure, concentration and odor qualities of oxygenated aliphatic molecules. Chem. Senses 2003 28 57-69. Rossiter K. Quantitative relationships between structure and the fruity odor of esters. Perfumer Flavorist 1996 21 33-36, 38-40, 42-44, 46. 

Johnson BA, Leon M. 2000a. Modular representations of odorants in the glomerular layer of the rat olfactory bulb and the effects of stimulus concentration. J Comp Neurol... 

Kosaka K, Toida K, Margolis FL, Kosaka T. 1997. Chemically defined neuron groups and their subpopulations in the glomerular layer of the rat main olfactory bulb-II. Prominent differences in the intraglomerular dendritic arborization and their relationship to olfactory nerve terminals. Neuroscience 76 775-786. 

Chemically defined neuron groups and their subpopulations in the glomerular layer of the rat main olfactory bulb. Neurosci Res 23 73-88. 

Pinching AJ, Powell TP. 1971a. The neuron types of the glomerular layer of the olfactory bulb. J Cell Sci 9 305-345. 

Abbreviations Al = primary auditory area ac = anterior commissure Acc = accumbens nucleus AON = anterior olfactory nucleus BF = barrel field BLA = basolateral nucleus of the amygdala CAl = cornu ammonis 1 CA3 = cornu ammonis 3 cc = corpus callosum Cg = cingulate area CPu = caudate-putamen DCb = deep cerebellar nuclei DCo = dorsal cochlear nucleus DG = dentate gyrus DMV = dorsal motor nucleus of the vagus nerve ECu = external cuneate nucleus EP = external plexiform layer ER = entorhinal cortex f = fornix Fa = facial nucleus fa = facial nerve fr = fasciculus retroflexus G1 = glomerular layer GPe = (external segment of the)... 

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