Granule cells location

The actual strength of the convergence of individual mossy fibers to Purkinje cells depends on the distribution of their mossy fiber rosettes. Electrophysiological studies of Bower and Woolston (1983) in the rat demonstrated that Purkinje cells are most responsive to mossy fiber input that reaches the granule cells located immediately below them. Llinas (1982) explained this strong radial connectivity by the greater number of... 

The radial or laminar organization of the non-pE AON system may relate to a proposed plan of radial or laminar organization between mitral and tufted cells and granule cells. As reviewed earlier, the lateral dendrites of different mitral cells preferentially arborize at a particular depth of the EPL. The dendrites of some mitral cells arborize in the deeper parts of the EPL just above the mitral cell layer while the lateral dendrites of other mitral cells preferentially arborize more superficially in the EPL. The apical dendrites of granule cells located in the superficial part of the GCL arborize in... 

The majority of the inputs to the granule cells are excitatory, each of which provides a small depolarizing current to the membrane of the cell body. The point of contact between the axonal projection from the neuron and an adjacent cell is termed the s)mapse which under the electron microscope appears as a swelling at the end of the axon. Most synapses are excitatory and are usually located along the dendritic branches of the neuron. The contributions of the individual excitatory s)mapses are additive and, as a result, when an excitatory stimulus occurs a wave of depolarizing current travels down the axon to stimulate the adjacent cell body. However, some synapses are inhibitory, usually fewer in number and strategically located near the cell body. These synapses, when activated, inhibit the effects of any excitatory currents which may travel down the dendritic processes and thereby block their actions on the neuron (Figure 2.1). 

In the islands of Calleja, D3 binding sites and mRNA are located on the entire population of granule cells, which establish sparse contacts with dopaminergic axons (Diaz et ah, 1995). An extensive coexpression of D3 and D3 mRNAs was found in the granule cells of the island of Calleja major, which express substance P mRNA (Ridray et ah, 1998). 

The basic circuitry of the MOB. Axons of ORNs travel in the ONL and synapse in the GL on the dendrites of mitrai ceiis (MC), tufted ceiis (externai tufted ceii, ET middie tufted ceii, MT), and generic juxtagiomeruiar (JG) neurons, which include perigiomeruiar ceiis (PG), ET ceiis, and short axon ceiis (SA). SA ceiis interconnect different giomeruii. There are serial and reciprocal synapses between the apicai dendrites of mitral/tufted cells and the processes of JG neurons. Superficial tufted cells (ST) are located in the superficial EPL or at the GL-EPL border. The lateral dendrites of mitral/tufted cells form serial and reciprocal synapses with the apical dendrites of granule cells (GC) in the EPL. GCs are located in the GCL and the MCL. The axons of mitral/tufted cells project locally to GCs (not shown) and also to primary olfactory cortex via the lateral olfactory tract (LOT). The bulb also contains other populations of interneurons neurons, including the van Gehuchten cells (VG) within the EPL... 

Cerebellar nuclei that contain the target cells of the Purkinje cell axons have been described in species of all vertebrate classes. In some species of fish target cells of the Purkinje cell axons are also located within the cortex among the Purkinje cells (the eurodendroid cells of Nieuwenhuys et al., 1974). The cells of the fourth cortical layer in some aquatic mammals, that are located below the granule cells in the white matter, can be considered as displaced cerebellar nuclear cells (Ogawa, 1934). 

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