Stimulation of the rat subthalamic nucleus is neuroprotective following significant nigral dopamine neuron loss.

Deep brain stimulation of the subthalamic nucleus (STN-DBS) is efficacious in treating the motor symptoms of Parkinson's disease (PD). However, the impact of STN-DBS on the progression of PD is unknown. Previous preclinical studies have demonstrated that STN-DBS can attenuate the degeneration of a relatively intact nigrostriatal system from dopamine (DA)-depleting neurotoxins. The present study examined whether STN-DBS can provide neuroprotection in the face of prior significant nigral DA neuron loss similar to PD patients at the time of diagnosis. STN-DBS between 2 and 4 weeks after intrastriatal 6-hydroxydopamine (6-OHDA) provided significant sparing of DA neurons in the SN of rats. This effect was not due to inadvertent lesioning of the STN and was dependent upon proper electrode placement. Since STN-DBS appears to have significant neuroprotective properties, initiation of STN-DBS earlier in the course of PD may provide added neuroprotective benefits in addition to its ability to provide symptomatic relief.

Language representation in the human brain: evidence from cortical mapping.

The manner in which the human brain processes grammatical-syntactic and lexical-semantic functions has been extensively debated in neurolinguistics. The discreteness and selectivity of the representation of syntactic-morphological properties in the dominant frontal cortex and the representation of the lexical-semantics in the temporo-parietal cortex have been questioned. Three right-handed adult male neurosurgical patients undergoing left craniotomy for intractable seizures were evaluated using various grammatical and semantic tasks during cortical mapping. The sampling of language tasks consisted of trials with stimulation (experimental) and without stimulation (control) from sites in the dominant fronto-temporo-parietal cortex The sampling of language implicated a larger cortical area devoted to language (syntactic-morphological and lexical-semantic) tasks. Further, a large part of the fronto-parieto-temporal cortex was involved with syntactic-morphological functions. However, only the parieto-temporal sites were implicated with the ordering of lexicon in sentence construction. These observations suggest that the representation of language in the human brain may be columnar or multilayered.

Endoscopic procedures for resection of arteriovenous malformations.

BACKGROUND: Resection of arteriovenous malformations (AVMs), particularly those located in functional areas, requires precision. To enhance that precision, endoscope-assisted microsurgery has been employed at Loma Linda University. METHODS: Twenty-five consecutive cases of AVM were treated microsurgically with endoscopic assistance. Patients were divided into two groups: (1) those having AVMs in functional areas, and (2) those whose AVMs extended into the ventricle, either in the trigonal area or the capsulocaudatothalamic area. The endoscope was inserted into the subarachnoid space to interrupt communicating venules around the major draining vein and into the cleavage developed between the AVM venous loops and surrounding brain tissue as shunting arterioles and communicating venules were interrupted. For surgery of intraventricular AVMs, the curved endoscope was inserted into the ventricle, providing visualization of the AVM core, which was dissected from the ventricular side. RESULTS: AVMs were totally resected in all cases except for two patients with capsulocaudatothalamic AVMs, which were decreased in size sufficiently to receive radiosurgery. CONCLUSION: Endoscope-assisted microsurgery enhances magnification, illumination, and technical precision while the surgeon is dissecting the AVM core vessels and while operating on AVMs extending into the ventricle.

Dorsal midline proboscis associated with diastematomyelia and tethered cord syndrome. Case report.

There have been sporadic reports on tail proboscis, a vestigial appendage, as part of sacrococcygeal dysraphism. The case the authors present, different from the tail proboscis, is the first report linking a proboscis containing a hemilipomyelomeningocele with tethered cord syndrome, associated with diastematomyelia. Tethering was caused by the diastematomyelia that anchored the split spinal cord. The authors emphasize the importance of prompt diagnostic and therapeutic measures for treatment of this condition.