Reticular formation cerebellum

The extrapyramidal motor system controls muscle movement through a system of pathways and nerve tracts that connect the cerebral cortex, basal ganglia, thalamus, cerebellum, reticular formation, and spinal neurons. Patients with PD lose dopamine neurons in the substantia nigra, which is located in the midbrain within the brain stem. The substantia... 

A global view of consciousness is that it is generated throughout the entire brain, as a result of synchronisation of relevant neural networks. Specific systems or regions—for example the cerebral cortex, brainstem reticular formation and thalamic nuclei—may be key anatomical integrators. Areas with the most widespread interconnections are pivotal, and on this basis the cortex and thalamus are more relevant than cerebellum and striatum for example. Frontal cortex for example connects with every other brain region, both in terms of input and output, with 80% of such connections accounted for by cortico-cortical connections. Thalamic intralaminar nuclei are, in conjunction with the reticular nucleus, reciprocally connected to all cortical areas. By contrast the cerebellum has very few output pathways and striatal-cortical input is (via the thalamus) confined to frontal lobe. 

Benzodiazepines act throughout the CNS. Proposed relationships between site of action and effect include the following spinal cord (muscle relaxation), brain stem (anticonvulsant effects), brain stem reticular formation (sedative effects), cerebellum (ataxia), and limbic and cortical areas (anxiolytic effects). Action outside the CNS is limited to coronary vasodilation with intravenous (IV) administration and neuromuscular blockade with very high doses of BZs. 

The basal pontine nuclei, the nucleus reticularis tegmenti pontis and the adjacent paramedian pontine reticular formation are connected with the cerebellum through the middle cerebellar peduncle. Both the nucleus reticularis tegmenti pontis and the paramedian pontine reticular formation send their fibers through the midline raphe into the pes pontis (fibrae rectae), where they deflect laterally to occupy the deep stratum of the middle cerebellar peduncle. 

The paramedian pontine reticular formation of the cat projects bilaterally to lobule VII and the caudal part of lobule VI and to the ansiform lobule, i.e. to the visual areas of the cerebellum involved in control of saccades (Gerrits and Voogd, 1986 Yamada and Noda, 1987). Fibers of the reticular nucleus of the pons distribute bilaterally, with ipsilateral predominance, to all lobules of the cerebellum, with the exception of the lobules I and X and the dorsal paraflocculus (Kawamura and Hashikawa, 1981 Gerrits and Voogd, 1986). This projection includes the flocculus and the adjacent part of the ventral paraflocculus (Fig. 203) (Gerrits and Voogd, 1989) and collateral projections to the cerebellar nuclei (see Section 5.6.). 

Gerrits NM, Voogd J (1986) The nucleus reticularis tegmenti pontis and the adjacent rostral paramedian reticular formation differential projections to the cerebellum and the caudal brain stem. Exp. Brain Res., 62, 29 5. 

Fig. 1.4 Diagram of a dorsal view of the brainstem the cerebellum has been removed. The extent of the reticular formation within the brainstem is illustrated. The reticular formation is a polysynaptic network that consists of three regions a series of midUne raphe nuclei (the median reticular formation, which is the site of origin of the major serotonergic pathways in the nervous system) this is flanked bUateraUy by the paramedian reticular formation (an efferent system of magnoceUular neurons with ascending and descending projections) and farthest from the midhne, the lateral reticular formation, consisting of parvoceUular neurons that project transversely See also Color Insert)...

Endogenous TAs act as agonists of a TA-associated receptor 1 (TAARl) [12-14]. Thyronamines like 3-iodothyronamine, which are thyroid hormone derivatives, also show potent agonistic activity for TAARl [12]. TAARl mRNA is expressed in trace (in cerebellum, dorsal root ganglia, hippocampus, hypothalamus, liver, medulla, pancreas, pituitary, pontine reticular formation, prostate, skeletal muscle, and spleen), low (amygdala, kidney, lung, and small intestine), and moderate (stomach) amounts in human tissues [13]. 

Thus, the neuropathological studies confirm that serious, but nonspecific damage to the nervous system occurs in poisoning with organic lead compounds. The nerve cells in the hippocampus, reticular formation, and cerebellum may be particularly sensitive to Et4Pb. This is in agreement with cHnical effects upon memory, attention level, psychomotor, and EEG changes. 

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