Serotonin (5-HT) modulates pain and anxiety from within the midbrain periaqueductal gray (PAG). In the present study, the effects of 5-HT- and 5-HT(1/2) subtype-selective ligands on rat PAG neurons were examined using whole cell patch-clamp recordings in brain slices. In voltage clamp, 5-HT produced outward and inward currents in distinct subpopulations of neurons that varied throughout differe...

To the Editor: Typical clinical features of Wernicke’s encephalopathy are caused by vitamin B1 deficiency and include confusion, ataxia, and ophthalmoplegia. Although it can occur in all malnourished patients, it is far more frequent in alcoholics. Brain MRI is a central diagnostic tool that usually discloses high signal lesions in T2-weighted imaging symmetrically affecting mammillary bodies, ...

Following intraocular injection of cholera toxin subunit B (CTB), optic afferents to the dorsal pontine region were observed in Mongolian gerbils, Chilean degus, and laboratory rats. CTB-positive optic axons emerge at the caudal pole of the superior colliculus, descend through the periaqueductal gray, and innervate the lateral parabrachial nucleus. This projection appears to be a continuation o...

This review and meta-analysis aims at summarizing and integrating the human neuroimaging studies that report periaqueductal gray (PAG) involvement; 250 original manuscripts on human neuroimaging of the PAG were identified. A narrative review and meta-analysis using activation likelihood estimates is included. Behaviors covered include pain and pain modulation, anxiety, bladder and bowel functio...

Central pathways transmit pain from peripheral regions to one of the most important area of the descending pain modulatory system, the Periaqueductal gray (PAG). Independent discoveries in the past suggest that the PAG contains afferent input, output neurons and intrinsic interneurons. An attempt was made in the present study to find out the effects of more than one kind of noxious stimulus on ...

Anatomical and physiological experiments were conducted to characterize the interactions between the lateral hypothalamus (LH) and the periaqueductal gray (PAG) and to determine the role of neurotensin in their interaction. Anatomical studies using injection of Phaseolus vulgaris leucoagglutinin into the LH showed an extensive projection to the ventromedial and the ventrolateral PAG and a less ...

Single unit activity was recorded extracellularly from the periaqueductal gray matter (PAG) and the superior colliculus of three monkeys during spontaneous saccades and fixation. Most saccade-related cells were found in the dorsal and lateral regions of the PAG and they paused with saccades. The pause preceded the onset of saccades by 34.5 +/- 6.8 msec (n = 31). In 90% of the 31 PAG cells, the ...