Annals of the New York Academy of Sciences
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Ann. N. Y. Acad. Sci. · May 2003
ReviewNeuroprotection trek--the next generation: neuromodulation I. Techniques--deep brain stimulation, vagus nerve stimulation, and transcranial magnetic stimulation.
Neuromodulation denotes controlled electrical stimulation of the central or peripheral nervous system. The three forms of neuromodulation described in this paper-deep brain stimulation, vagus nerve stimulation, and transcranial magnetic stimulation-were chosen primarily for their demonstrated or potential clinical usefulness. Deep brain stimulation is a completely implanted technique for improving movement disorders, such as Parkinson's disease, by very focal electrical stimulation of the brain-a technique that employs well-established hardware (electrode and pulse generator/battery). ⋯ Vagus nerve stimulation differs from deep brain stimulation, however, in that afferent stimulation of the vagus nerve results in diffuse effects on many regions throughout the brain. Although use of deep brain stimulation for applications beyond movement disorders will no doubt involve placing the stimulating electrode(s) in regions other than the thalamus, subthalamus, or globus pallidus, the use of vagus nerve stimulation for applications beyond epilepsy-for example, depression and eating disorders-is unlikely to require altering the hardware significantly (although stimulation protocols may differ). Transcranial magnetic stimulation is an example of an external or non-implanted, intermittent (at least given the current state of the hardware) stimulation technique, the clinical value of which for neuromodulation and neuroprotection remains to be determined.
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Chemists talk about causes and make frequent use of the verb "to cause." They use the verb "to cause" for its generality in identifying causal chains, whether all the details of those chains are established or some remain unclear. Most of these causal chains bottom out in attractions and repulsions. Attractions and repulsions are causal relations that are chemically basic; chemistry has no further story to tell about why attraction and repulsion are causal. If there is some further story to tell about the causal status of attraction and repulsion, it is left to physics to tell it, but it is not obvious that the absence of such a story would prevent chemists from using attractions and repulsions in their causal explanations.
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Ann. N. Y. Acad. Sci. · May 2003
ReviewNeuroprotection trek--the next generation: neuromodulation II. Applications--epilepsy, nerve regeneration, neurotrophins.
Three examples of neuroprotective applications of electrical stimulation-neuromodulation-are considered: (1) the diagnosis and treatment of epilepsy, (2) the augmentation of peripheral nerve regeneration after transection, and (3) the interaction between electrical stimulation and neurotrophins (notably brain derived neurotrophic factor [BDNF]) in various neuroprotective situations. The research cited demonstrates clear benefit from appropriate electrical stimulation in the treatment of (1) certain patients with medication-refractory epilepsy, and (2) the functional regeneration of peripheral nerves after transection and surgical repair. ⋯ The roles of BDNF and other neurotrophins in several disorders of the nervous system are discussed in the context of neuromodulation and its augmentation of neurotrophins. Neuromodulation-at least in part through its effect on BDNF and other neurotrophins-will likely play a major role in the treatment (and possibly prevention) of disorders of the nervous system for which neuroproteive pharmacologic agents have traditionally been sought.
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Ann. N. Y. Acad. Sci. · Apr 2003
ReviewConsideration of a unified model of amygdalar associative functions.
This paper considers issues arising from presentations by Barry Everitt and Gorica Petrovich concerning amygdalar involvement in appetitive conditioning. Studies reported by these researchers are beginning to unravel the distribution of associative functions among amygdalar nuclei and their efferent targets. ⋯ Most students of this issue will agree that no prima facie integration is readily apparent in current scholarship. Although we do not here provide the definitive integration, we do attempt to take some preliminary, broad-brush steps towards that goal.