The spider genus Diguetia Simon, 1895 (Araneae: Diguetidae) in North America: a new species, redescriptions, and comments on the distribution of the genus.

A new species of the genus Diguetia Simon, 1895, D. balandra sp. nov. is described, the male of D. signata Gertsch, 1958 is described for the first time and D. dialectica Chamberlin, 1924 stat. reval. is raised to the species level and redescribed based on specimens from Baja California Sur, Mexico. Diguetia imperiosa Gertsch & Mulaik, 1940 is recorded from Baja California Sur. Furthermore, we emend the diagnosis of the genus, biogeographic comments for all North American species. In the United States, California (five species) and Arizona (four species) have more species of Diguetia while the Mexican states of Sonora (five species), Chihuahua, Baja California, Baja California Sur (four species each) and Coahuila (three species) harbor the highest diversity of diguetids. Diguetia canities (McCook, 1890) has the highest number of records (133) in North America. Mexico has a striking diversity of Diguetia with eight out of ten species currently known.

Description of Califorctenus (Cteninae, Ctenidae, Araneae), a new spider genus from Mexico.

Califorctenus gen. nov. (Araneae: Ctenidae) a new genus and a new species (Califorctenus cacachilensis sp. nov.) from the Baja California Peninsula in Mexico are described and illustrated. Califorctenus gen. nov. can be diagnosed by the morphology of the male palp, with embolus cylindrical and elongated, locking lobes of embolus positioned retrolaterally and the cup-shaped and elongated median apophysis.

Neuronal activity of the red nucleus in Parkinson's disease.

Precise placement of the electrodes for stimulation of the subthalamic nucleus (STN) in Parkinson's disease (PD) is crucial for the therapeutic benefit. As a result of the mistargeting and misplacement of the electrodes during surgery in 2 patients with PD, we have characterized the neuronal firing in the red nucleus (RN) and observed the effects of stimulation of this nucleus. Although the neuronal firing (mean +/- SD) of the RN (34 +/- 4.4 Hz) resembles that described for the STN (33.1 +/- 16.6 Hz), a higher proportion of cells responded to the movement of the contralateral limbs (70-80%). Stimulation in the area of the RN-induced intolerable side effects without motor improvement. We conclude that the STN and RN have some similar neurophysiological features but can be distinguished intraoperatively. This initial description of the physiological characteristics of the RN in humans will draw attention to the possibility of confusing the RN and STN during intraoperative recording.