Spontaneous activity of rat dorsal horn cells in spinal segments of sciatic projection following transection of sciatic nerve or of corresponding dorsal roots.

Natural forms of stimulation were used to compare the spontaneous and evoked activity of dorsal horn neurons in three groups of rats: controls with no surgical lesion, rats with transection of the sciatic nerve and rats with transection of the dorsal roots at the same segmental level. In control rats, cells encountered in the dorsal horn were classified according to their peripheral field as tactile specific, convergent tactile and nociceptive, nociceptive, or movement driven. In 20 control animals, only 20% of the 140 cells with a peripheral field were spontaneously active.

Stereotaxic atlas of the pig brain.

A stereotaxic atlas of the pig brain has been established. It consists of 60 frontal and 18 sagittal drawings illustrating Nissl stained sections. A stereotaxic apparatus adapted for the Pig was used to determine the brain coordinates.

A stereotaxic atlas of the grey lesser mouse lemur brain (Microcebus murinus).

In response to the growing interest in the prosimian Microcebus murinus for studies on cerebral aging, the stereotaxic atlas of its brain was carried out in view of further anatomical, biochemical, electrophysiological, and behavioral investigations as well as for therapeutic experiments. This primate, which could be a valuable model for neuroscientific studies in various domains, presents numerous physiological advantages (e.g.

Characteristics of neurons with high-frequency discharge in the central nervous system and their relationship to chronic pain. Experimental and clinical investigations.

High-frequency extracellular unitary activity was recorded mainly in the ventral caudal nucleus of the thalamus in chronic-pain patients. These high-frequency discharge (hyperactive) neurons shows three types of discharge pattern with different interval histograms. Some of these hyperactive neurons were suppressed by the administration of a calcium antagonist (nicardipine).

Stimulation in the rat of a nerve fiber bundle by a short UV pulse from an excimer laser.

A bundle of central nervous fibers was excited in the rat with a short pulse (40 ns) of UV light produced by an excimer laser. Evoked responses were recorded in the thalamic ventralis posterior nucleus after stimulation of the medial lemniscus or the cuneate bundle in the spinal cord. The effects of electrical and optical fiber applied UV stimulation were compared in both cases.