It has been argued that the longer lasting effects of low-frequency rTMS trains rely on post-synaptic inhibitory GABAergic synapses, but there remains some uncertainty whether an additional pathophysiological mechanism might support this post-synaptic inhibition. In this study, we investigated whether rTMS at 1 Hz administered for 12 minutes at 90% of motor threshold to the primary motor cortex would lead to any changes in cortical diffusivity of water protons by comparing a series of diffusion weighted MRI (DWI) scans acquired before and after the rTMS train. Impairments of water diffusivity can typically be seen in the acute stage of an ischemic insult or focal status epilepticus, and their reversibility has been shown. Preliminary analysis of the diffusion images shows only a minimally increased signal within the motor region in half of the subjects (3 out of 6). This minimal signal change was no longer present 15 minutes after the end of the rTMS train. The initial signal change in some subjects is not...

The Meet-the-Experts Series will continue with live one-hour webinars after the conclusion of Neuroscience 2022, between December 2022 and September 2023.

Despite a large body of research, extant findings on the functional role of left inferior frontal gyrus (LIFG) in phonological and semantic fluency are still controversial. Based on cross-study comparisons, a recent meta-analysis of neuroimaging results suggests that posterior-dorsal (Brodmann area, BA, 44) and anterior-ventral parts (BA 45) of LIFG contribute differentially to processes of phonologically and semantically cued word retrieval, respectively. In contrast, a subsequent functional magnetic resonance imaging experiment failed to validate the proposed dissociation using a within-subjects design. In particular, no evidence for a specific role of BA 45 in semantic fluency was found. Here, we resolve this apparent controversy by showing that the conflicting findings can be accounted for when considering the influence of task demands and individual ability on resulting functional magnetic resonance imaging activation patterns. By comparing phonological versus semantic fluency, higher activation was r...

Traumatic Brain Injury (TBI) results in diffuse axonal injury (DAI) and diffuse vascular injury (DVI). Both DAI and DVI result from inertial shearing forces, and the two terms are often used interchangeably, the spatial relationships between DAI and DVI...

We used functional MRI to study cerebellar activity during three bimanual coordination tasks: Syncopation at 1.33Hz and synchronization at 1.33Hz and 2.66Hz. Previous research (EEG & MEG) shows that spatiotemporal patterns of brain activation depend on both coordination frequency and the mode of coordination (syncopation or synchronization). Participants coordinated bimanual finger-thumb opposition either on-the-beat (synchronize) or in-between two consecutive beats (syncopate). We used the noise (pings) produced by the scanner (Signa 1.5T, GE Inc.) as auditory stimuli. The repetition time (TR) and number of slices was set in each condition such that the pings took place at the desired frequency, i.e. at 1.33Hz and 2.66Hz. Behavioral performance was monitored as pressure changes in two small air pillows which the subjects were holding between the thumb, and the index and middle finger of each hand. This signal was compared to the time points of pulses produced by the scanner when taking a slice. Results sh...

Increased permeability of the blood-brain barrier (BBB) is important in several neurological disorders. Neuroinflammation is associated with increased BBB breakdown and brain injury. Tumor necrosis factor-alpha (TNF-alpha) is involved in BBB injury and ...

Neurodevelopmental disorders, such as ASD and ADHD, affect males about 3-4 times more often than females. 16p11.2 hemideletion is a copy number variation that is highly associated with neurodevelopmental disorders. Previous work from our lab has shown t...

Background: Therapies based on adeno-associated virus (AAV) technology have demonstrated significant potential to correct CNS pathologies. Although parenchymal delivery has been by far the favored route, the potential advantages of CSF infusion of AAV h...

Athletic performances require quick and accurate perception and cognition of visual information. High-level athletes perform well in three-dimensional multiple object tracking (3D-MOT), which requires dynamic visual information processing, analogous to ...

Introduction: Currently, detecting neurogenesis in the dentate gyrus can only be accomplished in post-mortem tissue. Imaging neurogenesis in living subjects is needed in order to establish its functional significance. Neurogenesis is coupled to angiogenesis, which in turn is coupled to cerebral blood volume (CBV), a variable that can be measured with MRI. In principle, dentate gyrus CBV measured with MRI is expected to be sensitive to neurogenesis. Nevertheless, any manipulation that induces neurogenesis will also cause non-neurogenesis effects, which may also affect CBV. Thus, dentate gyrus CBV is sensitive but not specific to neurogenesis. We hypothesized that we could impose specificity by adjusting dentate gyrus CBV with CBV measured from the CA1 subfield, a neighboring hippocampal subregion that reflects non-neurogenesis factors. Here, we test this hypothesis by determining whether adjusted dentate gyrus CBV, as measured in vivo with MRI, is correlated with neurogenesis. Methods: We used MRI to measur...