White matter microstructural differences underlying beta oscillations during speech in adults who stutter.

The basal ganglia-thalamocortical (BGTC) loop may underlie speech deficits in developmental stuttering. In this study, we investigated the relationship between abnormal cortical neural oscillations and structural integrity alterations in adults who stutter (AWS) using a novel magnetoencephalography (MEG) guided tractography approach. Beta oscillations were analyzed using sensorimotor speech MEG, and white matter pathways were examined using tract-based spatial statistics (TBSS) and probabilistic tractography in 11 AWS and 11 fluent speakers.

Effect of word phonetic properties on stuttering anticipation and speech production in adults who stutter.

Purpose: Stuttering anticipation is a significant factor in an individual's stuttering experience. People who stutter have reported words and sounds that they anticipate stuttering on. Attempts at understanding the association between stuttering anticipation and stuttering outcomes and the impact of phonetic properties on stuttering anticipation and overt stuttering have been insufficiently examined.

Amygdala-prefrontal connectivity during appraisal of symptom-related stimuli in obsessive-compulsive disorder.

Background: Cognitive models of obsessive-compulsive disorder (OCD) posit dysfunctional appraisal of disorder-relevant stimuli in patients, suggesting disturbances in the processes relying on amygdala-prefrontal connectivity. Recent neuroanatomical models add to the traditional view of dysfunction in corticostriatal circuits by proposing alterations in an affective circuit including amygdala-prefrontal connections. However, abnormalities in amygdala-prefrontal coupling during symptom provocation, and particularly during conditions that require stimulus appraisal, remain to be demonstrated directly.

A preliminary study on the neural oscillatory characteristics of motor preparation prior to dysfluent and fluent utterances in adults who stutter.

Purpose: Recent literature on speech production in adults who stutter (AWS) has begun to investigate the neural mechanisms characterizing speech-motor preparation prior to speech onset. Compelling evidence has suggested that stuttering is associated with atypical processing within cortical and sub-cortical motor networks, particularly in the beta frequency range, that is effective before speech production even begins. Due to low stuttering frequency in experimental settings, however, the literature has so far predominantly reported on fluent speech production in AWS.

Estimating the sample size required to detect an arterial spin labelling magnetic resonance imaging perfusion abnormality in voxel-wise group analyses.

Background: Voxel-based analyses are pervasive across the range of neuroimaging techniques. In the case of perfusion imaging using arterial spin labelling (ASL), a low signal-to-noise technique, there is a tradeoff between the contrast-to-noise required to detect a perfusion abnormality and its spatial localisation. In exploratory studies, the use of an a priori region of interest (ROI), which has the benefit of averaging multiple voxels, may not be justified.

Effect of 5-hydroxytryptamine (serotonin) receptor inhibitors on the radiation-induced bystander effect.

Purpose: To test the importance of serotonin as a signaling molecule involved in the production and response of radiation-induced bystander effects.

Materials And Methods: HPV-G human keratinocyte cultures were spiked with various concentrations of Granisetron or Ketanserin and subject to either 0 Gy or 0.5 Gy X-irradiation to observe the inhibitor's effects on bystander signal production.

A role for p53 in the response of bystander cells to receipt of medium borne signals from irradiated cells.

Purpose: A number of contradictory studies have reported a role or not for p53 (protein 53) in the production of radiation-induced bystander effects. Most of these studies looked at a range of cell lines with normal or compromised p53 function.

Methods: In this study, Human Colon Tumour line 116 (HCT 116) cells with confirmed wild type p53 function and a corresponding p53 null HCT 116 line were used to test for bystander signal production and response to bystander signals in a mix/match protocol using the medium transfer technique.