Magnetic resonance imaging (MRI) has greatly extended the exploration of neuroplasticity in behaving animals and humans. Imaging studies recently uncovered structural changes that occur in gray and white matter, mainly after long-term training. A recent diffusion tensor imaging (DTI) study showed that training in a car racing game for 2 h induces changes in the hippocampus and parahippocampal gyri. However, the effect of short-term training on the white matter microstructure is unknown. Here we investigated the influence of short learning tasks on structural plasticity in the white matter, and specifically in the fornix, in humans and rats. Human subjects performed a 2 h spatial learning task, and rats underwent training for 1 d in a Morris water maze. Between tasks, subjects were scanned with DTI, a diffusion MRI framework sensitive to tissue microstructure. Using tract-based spatial statistics, we found changes in diffusivity indices in both humans and rats. In both species, changes in diffusion in the f...

Multiple sclerosis (MS) is a demyelinating and inflammatory disease of the central nervous system. Its diagnosis is clinical, and confirmed by magnetic resonance imaging that is not ideal for discrimination of white or grey demyelination from inflammato...

We demonstrated recently that nucleus Robustus Archistriatalis (RA) can be visualized in living canaries by Magnetic Resonance Imaging (MRI) following injection of manganese (Mn2+) in the High Vocal Center (HVc). Within a few hours Mn2+, a Ca2+ analogue, is taken up by HVc neurons. It is then transported to- and allows the visualization of RA. We investigated whether hearing conspecific songs, which affects electrical activity in HVc, can modulate the rate of RA labeling by Mn2+. Male canaries were chronically implanted with a cannula in HVc and serial MRI images were collected within the first 8 hours following Mn2+ injection on two occasions about 2-3 weeks apart in the same birds that were either exposed to conspecific songs or no songs throughout the MRI procedure. The Mn2+ uptake in RA as a function of time was fitted to a sigmoidal function providing estimates of the maximal intensity, shape of the curve and time to reach half of maximal intensity. Hearing songs induced a significant shift in the Mn2...

MRI is increasingly being used to delineate morphological and organizational changes underlying neurological disorders. Successfully detecting these changes depends on the MRI data quality. Image artifacts frequently compromise the utility of MRI and ca...

Acetylcholine is a neurotransmitter that plays a key role in motivation, arousal, attention, learning, and memory in the brain. Since its discovery, numerous efforts have been poured into understanding the regulatory mechanism of acetylcholine towards b...

Although extensive evidence exists for the reinforcing properties of drugs of abuse such as cocaine, relatively less research has addressed the functional neuroanatomical correlates of the cognitive sequelae of these drugs. We present a functional magnetic resonance imaging study of a GO-NOGO task in which successful performance required prepotent behaviors to be inhibited. Significant cingulate, pre-supplementary motor and insula hypoactivity was observed for both successful NOGOs and errors of commission in chronic cocaine users relative to cocaine-naive controls. This attenuated response, in the presence of comparable activation levels in other task-related cortical areas, suggests cortical and psychological specificity in the locus of drug abuse-related cognitive dysfunction. The results suggest that addiction may be accompanied by a disruption of brain structures critical for the higher-order, cognitive control of behavior.

The medial temporal lobe (MTL) is the first brain area to succumb to neurofibrillary tau pathology in Alzheimer's disease (AD). Postmortem human tissue evaluation suggests that this pathology propagates in an ordered manner, with the entorhinal cortex (ERC) and then CA1 stratum radiatum and stratum lacunosum-moleculare (CA1–SRLM)—two monosynaptically connected structures—exhibiting selective damage. Here, we hypothesized that, if ERC and CA1–SRLM share an early vulnerability to AD pathology, then atrophy should occur in a proportional manner between the two structures. We tested this hypothesis in living humans, using ultra-high field 7.0 T MRI to make fine measurements of MTL microstructure. Among a pool of age-matched healthy controls and patients with amnestic mild cognitive impairment and mild AD, we found a significant correlation between ERC and CA1–SRLM size that could not be explained by global atrophy affecting the MTL. Of the various structures that contribute axons or dendrites into the CA1–SRLM...

In older adults hyperintense signal is often found in the cerebral white matter on T2-weighted magnetic resonance imaging. These white matter lesions are found to be clinically associated with a cognitive, mood, and functional disturbances. These lesion...

Introduction In functional magnetic resonance imaging (fMRI) research, considerable efforts are targeted at understanding how functional connectivity (FC) regulates brain function. While FC is typically computed using temporal correlation in blood oxyge...

Background: Functional connectivity is the integrated representation of functional dynamics within the structural network of the brain. Non-invasive methods such as electroencephalography and functional magnetic resonance imaging (fMRI) are commonly use...