In placebo hypoalgesia research, the strength of treatment expectations and experiences are key components. However, the reliability or precision of expectations had been mostly ignored although being a likely source for interindividual differences. In the present study, we adopted a Bayesian framework, naturally combining expectation magnitudes and precisions. This postulates that expectations...

Cannabinoids play an important role in activity-dependent changes in synaptic activity and can interfere in several brain functions, including responses to aversive stimuli. The regions responsible for their effects, however, are still unclear. Cannabinoid type 1 (CB1) receptors are widely distributed in the central nervous system and are present in the periaqueductal gray (PAG), a midbrain str...

The periaqueductal gray (PAG) plays an important role in analgesia as well as in motor activities, such as vocalization, cardiovascular changes and movements of the neck, back and hind limbs. Although the anatomical pathways for vocalization and cardiovascular control are rather well understood, this is not the case for the pathways controlling the neck, back and hind limb movements. This led u...

In a 27-year-old patient with Gilles de la Tourette's syndrome a pineal tumor had been found 10 years previously and was apparently a coincidental finding. Minute calcifications were later detected around the third ventricle and the mesencephalic periaqueductal gray matter by high resolution computed tomography. It is argued that this observation may support Devinsky's speculations that midbrai...

Abbreviations: ECBS, Endocannabinoids; AEA, An amide hydrolase; CB1, Cannabinoid type 1 receptor; CB2 TRPV1, Transient potential vanilloid type 1 receptor; CBD, tex; MPFC, Medial prefrontal córtex; PL, Prelimbic; HI Hippocampus; PAG, Periaqueductal gray matter; THC, Δ9 Elevated plusmaze; VCT, Vogel conflict test; AP, Anteropos ⁎ Corresponding author at: Pharmacology Departme Preto, University o...

BACKGROUND AND PURPOSE Subclinical cerebral edema occurs in many, if not most, children with diabetic ketoacidosis (DKA) and may be an indicator of subtle brain injury. Brain ratios of N-acetylaspartate (NAA) to creatine (Cr), measured by proton MR spectroscopy, decrease with neuronal injury or dysfunction. We hypothesized that brain NAA/Cr ratios may be decreased in children in DKA, indicating...

EXPERIMENTS IN BIOLOGICAL SCIENCE are often envisioned as ultimately providing rational approaches to problems confronting human health. Additionally, pragmatic solutions evoked by clinical problems often provoke new questions in basic science. Deep brain stimulation therapy in human patients with implanted electrodes (2, 4, 5) has provided an opportunity for evaluation of basic science predict...

In this Neuro Forum we discuss the significance of a recent study by Yu et al. (Neuroimage Clin 6: 100-108, 2014). The authors examined functional connectivity of a key node of the descending pain modulation pathway, the periaqueductal gray (PAG), in chronic back pain patients. Altered PAG connectivity to pain-related regions was found; we place results within the context of recent literature a...

This report describes the postcontrast MR findings of Wernicke encephalopathy seen in a malnourished 11-year-old boy. The examination showed increased signal on T2-weighted images in the periaqueductal gray matter and medial thalami. On T1-weighted acquisition, these areas showed decreased signal intensity, but on postcontrast T1-weighted examination, they showed moderately intense enhancement....

The midbrain periaqueductal gray (PAG) region is organized into distinct subregions that coordinate survival-related responses during threat and stress [Bandler R, Keay KA, Floyd N, Price J (2000) Brain Res 53 (1):95-104]. To examine PAG function in humans, researchers have relied primarily on functional MRI (fMRI), but technological and methodological limitations have prevented researchers fro...