Changes of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) in the model of experimental acute hydrocephalus in rabbits.

Background: To study the integrity of white matter, we investigated the correlation between the changes in neuroradiological and morphological parameters in an animal model of acute obstructive hydrocephalus.

Methods: Hydrocephalus was induced in New Zealand rabbits (n = 10) by stereotactic injection of kaolin into the lateral ventricles. Control animals received saline in place of kaolin (n = 10).

Brain processing of tonic muscle pain induced by infusion of hypertonic saline.

Most of the previous studies on the effects of pain on Regional Cerebral Blood Flow (rCBF) had been done with brief cutaneous or intramuscular painful stimuli. The aim of the present study was to investigate the effect on rCBF of long lasting tonic experimental muscle pain. To this end we performed PET investigations of rCBF following tonic experimental low back pain induced by continuous intramuscular infusion of hypertonic (5%) saline (HS) with computer controlled infusion pump into the right erector spinae on L(3) level in 19 healthy volunteers.

Comparison of brain activation after sustained non-fatiguing and fatiguing muscle contraction: a positron emission tomography study.

The concept of fatigue refers to a class of acute effects that can impair motor performance, and not to a single mechanism. A great deal is known about the peripheral mechanisms underlying the process of fatigue, but our knowledge of the roles of the central structures in that process is still very limited. During fatigue, it has been shown that peripheral apparatus is capable of generating adequate force while central structures become insufficient/sub-optimal in driving them.

Changes in human regional cerebral blood flow following hypertonic saline induced experimental muscle pain: a positron emission tomography study.

A positron emission tomography imaging study was performed on 16 healthy volunteers to reveal changes in cortical activation during acute muscle pain induced by intra-muscular injection of hypertonic saline into the left triceps brachii muscle. Changes in regional cerebral blood flow (rCBF) were measured with the use of [(15)O] labelled water during 'Rest1', 'Needle' (insertion of a needle without injection), 'Rest2' and 'Pain' conditions. Differences in rCBF were found in the comparison of Pain and Needle, and Pain and Rest2 conditions, revealing activation of the contralateral insula and putamen.

Comparison of brain activity during different types of proprioceptive inputs: a positron emission tomography study.

It has been shown that the primary and secondary somatosensory cortex, as well as the supplementary motor area (SMA), are involved in central processing of proprioceptive signals during passive and active arm movements. However, it is not clear whether different cortical areas are involved in processing of different proprioceptive inputs (skin, joint, muscle receptors), what their relative contributions might be, where kinesthetic sensations are formed within the CNS, and how they interact when the full peripheral proprioceptive machinery acts. In this study we investigated the representation of the brain structures involved in the perception of passive limb movement and illusory movement generated by muscle tendon vibration.