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Neuronal connections

Each sensory afferent neuron connects with an interneuron or accessory neuron. These interneurons are located entirely within the CNS, with the majority occurring in the cerebral cortex. They form numerous interconnections and are the means by which all cognitive information, thoughts and feelings, are processed. It should be emphasised that the main role of this processing of information is inhibitory. The sensory receptors provide the CNS with a massive amount of data. The interneurons process and filter this into a limited amount of useful and important informa tion. Conscious information processing forms just one part of this activity. A great deal of brain activity is concerned with routine processes, which continue without conscious awareness. [Pg.10]

A variety of different types of tissue preparation are used to study neurosecretion and synaptic transmission. A classical preparation is the frog NMJ (discussed below). The brain slice has been used for many years for biochemical studies of CNS metabolism and is a useful preparation for electrophysiological studies of synaptic transmission in the CNS. Slices can be oriented to maintain the local neuronal circuitry and can be thin, 0.3 mm, to minimize anoxia. The transverse hippocampal slice is widely used as an electrophysiological preparation to study synaptic plasticity (see Ch. 53). Primary cultures of neurons from selected CNS areas and sympathetic ganglia are also frequently used. They permit excellent visual identification of individual neurons and control of the extracellular milieu, but the normal neuronal connections are disrupted. [Pg.169]

Braitenberg, V. and Schiiz, A. Cortex Statistics and Geometry of Neuronal Connectivity, 2nd edn. Berlin, Springer, 1998. [Pg.289]

The abdominal vagus and sympathetic nerves are the most important afferent inputs involved in vomiting induced by chemotherapy and radiation [31]. The input from vestibular nerves and the cerebellum plays an important role in the motion disease [52]. The afferent inputs from vagal, trigeminal and glossopharyngeal nerves terminate eventually in the nucleus solitarius tract located in the medulla oblongata which has neuronal connections with other medullary areas involved in emesis, for example, area postrema [53]. [Pg.307]

INBORN GENETIC PROGRAMS CONTROL FORMATION OF NEURONAL CONNECTIONS, WHEREAS AaiVITY REGULATES THEIR REMODELING... [Pg.12]

Again, keep in mind that the control attributed to each lobe mentioned above is not exclusive of the other lobes because of the integrated network of neurons connecting various portions of the brain. In addition there are other distinct bodies or diffuse neuronal systems which lie within the lobes just described. [Pg.140]

Most but not all neuron connections rely on the passage of neurotransmitters across a synaptic deft. The neurons that connect to musdes controlling eye movement, however, are different in that they have what are called electrical synapses, which are direct connections between the neurons and the musdes (there s no gap). The high speeds of these direct connections provide for eye motion that is quick and jerky—a useful trait. Some fish have electrical synapses in their tails, an arrangement that provides for rapid escape from predators. [Pg.517]

The olfactory region located in the poorly accessible recessed roof of the nasal passages offers the potential for certain compounds to circumvent the blood-brain barrier and enter into the brain [48]. The olfactory sensory cells are in contact with both the nasal cavity and the CNS and this neuronal connection constitutes a direct pathway to the brain. By utilizing this pathway drugs would not only circumvent the blood-brain barrier, but also avoid any hepatic first-pass effect and degradation in the blood compartment, a particularly important issue in the case of peptide drugs. [Pg.368]

Aston-Jones and Card, 2000 Husak et al., 2000 Kelly and Strick, 2000) as virus particles. The foreign genes they express can, therefore, be used as markers for neuronal connections. This property is not shared by rAAV particles, which are completely defective for viral replication. [Pg.198]

Jhaveri D., Sen A. and Rodrigues V. (2000b) Mechanisms underlying olfactory neuronal connectivity in Drosophila - the atonal lineage organizes the periphery while sensory neurons and glia pattern the olfactory lobe. Dev. Biol. 226, 73-87. [Pg.692]

Figure 7.7 Diagram of an artificial neuron connected to three input neurons and a bias unit. (From Manallack, D.T. and Livingstone, D.J., Med. Chem. Res., 2, 181-190, 1992. With permission.)... Figure 7.7 Diagram of an artificial neuron connected to three input neurons and a bias unit. (From Manallack, D.T. and Livingstone, D.J., Med. Chem. Res., 2, 181-190, 1992. With permission.)...
A variety of chemically-identified neurons within the ARC receive both indirect (extrinsic) and direct (intrinsic) enkephalinergic neuronal input (Magoul et al., 1993) suggesting a role for enkephalin in the neuroendocrine regulation of pituitary hormone secretion. Enkephalin-IR perikarya in the bed nucleus of the stria terminalis, medial preoptic nucleus, periventricular nucleus and dorsomedial nucleus all provide extrinsic input to the rostral ARC, whereas intrinsic enkephalin neurons connect the rostral and caudal portions of the ARC (Magoul et al., 1993). Enkephalin-IR neurons innervate TH-IR neurons (perikarya and dendrites) in the DM-ARC (but not in the VL-ARC), (5-endorphin neurons in the VL-ARC, and NPY neurons in the ventromedial ARC (Magoul et al., 1994). There are symmetrical synaptic connections between enkephalin axon terminals and POMC perikarya in the ARC (Zhang et al., 1987), and reciprocal synaptic associations with NPY neurons in the ventromedial ARC (Li et al., 1993). [Pg.485]

Schenck A, Bardoni B, Langmann C, Harden N, Mandel JL, Giangrande A (2003) CYFIP/Sra-1 controls neuronal connectivity in Drosophila and links the Racl GTPase pathway to the fragile X protein. Neuron 38 887-898... [Pg.239]


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See also in sourсe #XX -- [ Pg.68 ]




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