Tractography delineates microstructural changes in the trigeminal nerve after focal radiosurgery for trigeminal neuralgia.

Purpose: Focal radiosurgery is a common treatment modality for trigeminal neuralgia (TN), a neuropathic facial pain condition. Assessment of treatment effectiveness is primarily clinical, given the paucity of investigational tools to assess trigeminal nerve changes. Since diffusion tensor imaging (DTI) provides information on white matter microstructure, we explored the feasibility of trigeminal nerve tractography and assessment of DTI parameters to study microstructural changes after treatment.

Three-dimensional in vivo modeling of vestibular schwannomas and surrounding cranial nerves with diffusion imaging tractography.

Background: Preservation of cranial nerves (CNs) is of paramount concern in the treatment of vestibular schwannomas, particularly in large tumors with thinned and distorted CN fibers. However, imaging of the CN fibers surrounding vestibular schwannomas has been limited with 2-dimensional imaging alone.

Objective: To assess whether tractography of the CN combined with anatomic magnetic resonance imaging of the tumor can provide superior 3-dimensional (3D) visualization of tumor/CN complexes.

In vivo visualization of cranial nerve pathways in humans using diffusion-based tractography.

Objective: Diffusion-based tractography has emerged as a powerful technique for 3-dimensional tract reconstruction and imaging of white matter fibers; however, tractography of the cranial nerves has not been well studied. In particular, the feasibility of tractography of the individual cranial nerves has not been previously assessed.

Methods: 3-Tesla magnetic resonance imaging scans, including anatomic magnetic resonance images and diffusion tensor images, were used for this study.

Noise-induced increase in human auditory evoked neuromagnetic fields.

Noise is usually detrimental to auditory perception. However, recent psychophysical studies have shown that low levels of broadband noise may improve signal detection. Here, we measured auditory evoked fields (AEFs) while participants listened passively to low-pitched and high-pitched tones (Experiment 1) or complex sounds that included a tuned or a mistuned component that yielded the perception of concurrent sound objects (Experiment 2).

Cingulate NMDA NR2B receptors contribute to morphine-induced analgesic tolerance.

Morphine is widely used to treat chronic pain, however its utility is hindered by the development of tolerance to its analgesic effects. While N-methyl-D-aspartate (NMDA) receptors are known to play roles in morphine tolerance and dependence, less is known about the roles of individual NMDA receptor subtypes. In this study, Ro 256981, an antagonist of the NMDA receptor subunit NR2B, was used to reduce the expression of analgesic tolerance to morphine.

Increased anxiety-like behavior and enhanced synaptic efficacy in the amygdala of GluR5 knockout mice.

GABAergic transmission in the amygdala modulates the expression of anxiety. Understanding the interplay between GABAergic transmission and excitatory circuits in the amygdala is, therefore, critical for understanding the neurobiological basis of anxiety. Here, we used a multi-disciplinary approach to demonstrate that GluR5-containing kainate receptors regulate local inhibitory circuits, modulate the excitatory transmission from the basolateral amygdala to the central amygdala, and control behavioral anxiety.

Enhanced presynaptic neurotransmitter release in the anterior cingulate cortex of mice with chronic pain.

The anterior cingulate cortex (ACC) is a forebrain structure known for its roles in learning and memory. Recent studies show that painful stimuli activate the prefrontal cortex and that brain chemistry is altered in this area in patients with chronic pain. Components of the CNS that are involved in pain transmission and modulation, from the spinal cord to the ACC, are very plastic and undergo rapid and long-term changes after injury.