Current research has demonstrated that many species, including our beloved canines, share brain circuitry very similar to the human part of the brain that controls emotion - the amygdala and the periaqueductal
Neonatal injury alters adult pain sensitivity by increasing opioid tone in the periaqueductal
Key structures include the periaqueductal
grey (PAG) region of the midbrain and the rostral ventromedial medulla (Figure 1).
These structures are connected with the amygdala, hippocampus, hypothalamus, periaqueductal
gray matter, and the limbic regions of the frontal and temporal lobes.
* Intractable hiccough, nausea, or vomiting is present for more than 2 days with evidence of a periaqueductal
medullary lesion on MRI.
Leigh syndrome is diagnosed on the basis of progressive neurologic regression, often provoked by an infection, along with characteristic MRI findings (T2 prolongation in bilateral basal ganglia, in particular the putamen, brainstem nuclei, periaqueductal
gray matter, and central white matter).
A Papadopoulou et al (Basel, Switzerland) reported that the use of 30 double invention recovery (DIR) sequence was of particular value as it allows identification of periaqueductal
lesions in MS patients.
They abut each other at the midline immediately anterior (ventral) to the periaqueductal
grey (PAG) surrounding the cerebral aqueduct and posterior (dorsal) to the medial longitudinal fasciculus (MLF) carrying connections between various brainstem nuclei involved in ocular motor control (Figure 3).
The NTS projects into the periaqueductal
grey and the locus coeruleus; both of which are involved in the modulation of nocioceptive pathways (6, 30) Thus, stimulation of the NTS produces an antinocicetpive effect (1).
Abnormal histiogenesis and proliferation of periaqueductal
grey matter in the midbrain can result in primary stenosis or formation of numerous minute channels through the aqueduct.