Anatomical substrate

Stimulation of the subthalamic nucleus or globus pallidus by an implanted electrode and stimulator has yielded good results for the management of the clinical fluctuations occurring in advanced parkinsonism. The anatomic substrate for such therapy is indicated in Figure 28-1. Such procedures are contraindicated in patients with secondary or atypical parkinsonism, dementia, or failure to respond to dopaminergic medication. 

Sesack SR, Carr DB, Omelchenko N, Pinto A. 2003. Anatomical substrates for glutamate-dopamine interactions, evidence for specificity of connections and extrasynaptic actions. Ann. N.Y. Acad. Sci. 1003 36-52. 

Schmahmann ID (2001a) The cerebrocerebellar system anatomic substrates of the cerebellar contribution to cognition and emotion. Int Rev Psychiatry 13 247-260. 

Sitges M, Teijeira VA, Scalise A, et al. Is there an anatomical substrate for idiopathic paroxysmal atrial fibrillation A case-control echocardiographic study. Europace 2007 9 294—8. 

Kimura et al. 1987) although its action on male sexual responses is not known. Nevertheless, this pathway could provide the neuroendocrine and anatomical substrates to regulate copulatory behavior in male rats. 

The anatomic substrate of potential collateral pathways (particularly involving the circle of Willis) must also be assessed, which requires angiographic study of the intracranial circulation from selective carotid and vertebral injections. Prospective identification of major breaks within the circle of Willis that result in partial or complete isolation of the cerebral circulation [e.g. ipsilateral absent Al segment and posterior communicating artery (PCoA)], is often enough to dissuade one from performing a balloon test... 

If the relations between toxemia of pr nancy and atherosclerosis are really as close as is suggested by the above findings, a more extensive study of the biochemistry, anatomical pathology, and incidence of toxemia should provide valuable information for atherosclerosis. Toxemia of pregnancy is a disease of limited duration and provides a very valuable pathologic-anatomical substrate in the placenta. Furthermore, studies of the incidence of atherosclerotic disease in these subjects, at a more advanced age, in comparison with that in normal controls, should prove very informative. Oliver and Boyd (1955a) have made one such study. 

The multicentric nature of tremor implies that the neurochemistry of several brain areas is important, but while tremor is by far the most studied aspect of the Parkinsonian triad it is the least understood on the neurochemical level. Much of the confusion in the literature lies in the failure to identify the type of tremor under study, since a variety of tremors can arise from a variety of anatomical substrates [8]. Thus, although a number of cholinergic drugs do produce tremor it is doubtful if the fine characteristics of such tremors are truly those seen in Parkinsonism [8,241]. Nevertheless, it is clear that if the striatum exerts an influence upon thalamic neurons to produce Parkinsonian tremor then the neurochemistry of the striatum plays... 

There are many clinical observations (e.g. neglect syndrome) supporting a right frontal dominance in attention capacity. An enlarged right frontal lobe may provide the underlying anatomical substrate for this attention asymmetry in humans. 

All empirical findings have been correlated to the histological structure of the human cortex. The correspondence between the results and the neuro-anatomical substrate gives strong evidence for the reality of these processes. Nevertheless all these findings have to be replicated by independent researchers. 

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