Spinal cord intrinsic neurons

P2X6 CNS, motor neurons in spinal cord - (does not function as homomulti-mer) Intrinsic ion channel... 

Figure 1.8 Some basic neuronal systems. The three different brain areas shown (I, II and III) are hypothetical but could correspond to cortex, brainstem and cord while the neurons and pathways are intended to represent broad generalisations rather than recognisable tracts. A represents large neurons which have long axons that pass directly from one brain region to another, as in the cortico spinal or cortico striatal tracts. Such axons have a restricted influence often only synapsing on one or a few distal neurons. B are smaller inter or intrinsic neurons that have their cell bodies, axons and terminals in the same brain area. They can occur in any region and control (depress or sensitise) adjacent neurons. C are neurons that cluster in specific nuclei and although their axons can form distinct pathways their influence is a modulating one, often on numerous neurons rather than directly controlling activity, as with A . Each type of neuron and system uses neurotransmitters with properties that facilitate their role...

The arrival of action potentials in the dorsal horn of the spinal cord, carrying the sensory information either from nociceptors in inflammation or generated both from nociceptors and intrinsically after nerve damage, produces a complex response to pain. Densely packed neurons, containing most of the channels, transmitters and receptors found anywhere in the CNS, are present in the zones where the C-fibres terminate... 

Fig. 7. Schematic drawing of a transverse section through the forebrain depicting pathways likely to use glutamate as a neurotransmitter. I = principal subcortical afferents to the thalamus from. somatosensory relay nuclei and the spinal cord (a), cerebellar nuclei (h). and retina (c) 2 = intrinsic neurons and retinal inputs to the hypothalamus 3 = thalamocortical inputs 4 = corticothalamic inputs 5 = cortical inputs to the basal ganglia and other areas in the brainstem and spinal cord 6 = associational and commi.ssural connections in the cerebral cortex. For further details, see Sections 3.5-3.9.

During the last 150 years the morphology of the cerebellum attracted numerous histologists. Its relatively simple structure, with its three-layered cortex and clearly defined afferent and efferent connections made it one of the favourite sites in the brain to test out new hypotheses on the connectivity, the development and chemical interaction in nervous tissue. We have attempted to review present knowledge about the external and internal morphology of the cerebellum and to relate the classical topography of the cerebellum to the more recently discovered chemical specificity of its neurons and afferent and efferent pathways. Not all what is new in the histochemistry of the cerebellum is relevant to a better understanding of its chemoarchitecture. This review, therefore, does not pretend to be complete. It is focussed on afferent and intrinsic connections of the cerebellum. The efferent connections of the cerebellum to the brain stem and the spinal cord have not been systematically covered. 

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