Diffusion tensor imaging in Huntington's disease reveals distinct patterns of white matter degeneration associated with motor and cognitive deficits.

White matter (WM) degeneration is an important feature of Huntington's disease (HD) neuropathology. To investigate WM degeneration we used Diffusion Tensor Imaging and Tract-Based Spatial Statistics to compare Fractional Anisotropy, Mean Diffusivity (MD), parallel diffusivity and perpendicular diffusivity (λ⊥) in WM throughout the whole brain in 17 clinically diagnosed HD patients and 16 matched controls. Significant WM diffusivity abnormalities were identified primarily in the corpus callosum (CC) and external/extreme capsules in HD patients compared to controls.

A longitudinal diffusion tensor imaging study in symptomatic Huntington's disease.

Objective: The striatum and its projections are thought to be the earliest sites of Huntington's disease (HD) pathology. This study aimed to investigate progression of striatal pathology in symptomatic HD using diffusion tensor imaging.

Method: Diffusion weighted images were acquired in 18 HD patients and in 17 healthy controls twice, 1 year apart.

A functional magnetic resonance imaging study of the effects of low frequency right prefrontal transcranial magnetic stimulation in depression.

The study aimed to explore the biological effects of low-frequency repetitive transcranial magnetic stimulation (LFR-TMS) treatment applied to the right prefrontal cortex, comparing this with the effects of high-frequency left-sided (HFL-TMS) in patients with treatment-resistant depression. Twenty-six patients with treatment-resistant depression were randomized to receive either daily LFR-TMS or HFL-TMS treatment for 3 weeks and underwent functional magnetic resonance imaging during a planning task before and after treatment. Patients responded clinically to both forms of treatment with no difference in the degree of response (F1,24 = 0.

A preliminary fMRI study of the effects on cortical activation of the treatment of refractory auditory hallucinations with rTMS.

Three patients underwent fMRI during a word generation task before and after successful treatment of auditory hallucinations with rTMS and were compared to four control subjects. There was a significant increase and more normal task related brain activation in brain areas involved in language processing including left temporoparietal cortex after rTMS treatment.

Increased cortical recruitment in Huntington's disease using a Simon task.

Cognitive deficits in Huntington's disease (HD) have been attributed to neuronal degeneration within the striatum; however, postmortem and structural imaging studies have revealed more widespread morphological changes. To examine the impact of HD-related changes in regions outside the striatum, we used functional magnetic resonance imaging (fMRI) in HD to examine brain activation patterns using a Simon task that required a button press response to either congruent or incongruent arrow stimuli. Twenty mild to moderate stage HD patients and 17 healthy controls were scanned using a 3T GE scanner.

EEG coherence measures during auditory hallucinations in schizophrenia.

We studied the change in EEG alpha-band average coherence between auditory hallucination (AH) and non-auditory hallucination (non-AH) states in seven auditory hallucinating schizophrenia patients. Four cortical regions were considered based on the existing dominant models for auditory hallucinations, the inner speech model and the central auditory processing deficit (CAPD) model. Coherences between electrodes located over Broca's area (BA 44/45) and Wernicke's area (BA 22/42) and between electrodes located over left-right temporal cortices were examined.