INTRODUCTION Several studies have indicated that the shape of the brain can be influenced by experience and environment. Whether these shape changes occur rapidly and consistently in a learning paradigm is, however, still unknown. METHODS In this study ...

The brain is a highly complex, interconnected structure with parallel and hierarchical networks distributed within and between neural systems. Functional connectivity mapping using resting-state functional MRI (rsfMRI) enables non-invasive visualization...

Transgenic mouse models of Alzheimer’s disease are produced to understand the role of particular genes and to have available animal models, which mimic the clinical condition in order to test therapeutic interventions. Thus, there is a growing need for non-invasive tracking of pathology in mice at high spatial resolutions, afforded by high-resolution MRI (microMRI). - In this study we used microMRI to follow structural changes over 2 years in brains of transgenic mice overexpressing V717F APP (PDAPP mice). Homozygous (n=11), heterozygous (n=8) PDAPP female mice and wildtype controls (n=7) initially 3-6 months of age were used for the study. The mice were imaged every three months for 22 months. All imaging was performed on a 7.1 T magnet using a 3D diffusion-weighted sequence and a spatial resolution of 58 µm x 58 µm x 469 µm. Quantitative analysis of was performed using NIH image. The most striking structural difference between homozygous PDAPP mice and wildtype mice was the magnitude of lateral and 3rd v...

Chemogenetic manipulation of neuronal activities has been enabled by a designer receptor (designer receptor exclusively activated by designer drugs, DREADD) that is activated exclusively by clozapine- N -oxide (CNO). Here, we applied CNO as a functional reporter probe to positron emission tomography (PET) of DREADD in living brains. Mutant human M4 DREADD (hM4Di) expressed in transgenic (Tg) mouse neurons was visualized by PET with microdose [11C]CNO. Deactivation of DREADD-expressing neurons in these mice by nonradioactive CNO at a pharmacological dose could also be captured by arterial spin labeling MRI (ASL-MRI). Neural progenitors derived from hM4Di Tg-induced pluripotent stem cells were then implanted into WT mouse brains and neuronal differentiation of the grafts could be imaged by [11C]CNO-PET. Finally, ASL-MRI captured chemogenetic functional manipulation of the graft neurons. Our data provide the first demonstration of multimodal molecular/functional imaging of cells expressing a functional gene r...

In this functional magnetic resonance imaging study we tested whether the predictability of stimuli affects responses in primary visual cortex (V1). The results of this study indicate that visual stimuli evoke smaller responses in V1 when their onset or motion direction can be predicted from the dynamics of surrounding illusory motion. We conclude from this finding that the human brain anticipates forthcoming sensory input that allows predictable visual stimuli to be processed with less neural activation at early stages of cortical processing.

Spontaneous recovery after spinal cord injury is limited. After an incomplete spinal cord injury, however, significant functional recovery occurs, probably due to synaptic plasticity and formation of new circuits. Compared to the motor systems, little is known about regeneration and/or plasticity in the sensory system after spinal cord injury. Therefore we designed methods to explore functional and structural plasticity of sensory pathways following contusion injury of the spinal cord by means of functional MRI and behavioral tests. Rats received a weight drop injury (12.5 or 6.25 mm) and were tested after 1, 4 or 16 weeks. Functional MRI using the BOLD technique in response to electric stimulation of the hindlimbs, gave rise to signals in sensorimotor cortex. The monitored BOLD signals were compared to different behavioral tests, such as BBB, gridway and hotplate. The results suggest a discrepancy between motor and sensory recovery. Thus animals with complete loss of sensation could show a high degree of ...

Background: Numerous studies in human and non-human primates have shown that merely observing other's actions can modulate activity in the observer's motor cortices. Similar automatic responses have also been suggested in human somatosensory cortices wh...

Girls with Rett syndrome (RTT) show an early and marked decrease in brain and cerebral size, but relatively little is known about the regional and tissue-type specificity of this reduction. In the present study, we examined regional brain volume changes...

White-matter tractography using diffusion-weighted MRI imaging (DWI) is widely used to study anatomical connections in the primate brain. Recent interest in corticothalamocortical circuits suggests that communication across cortex depends significantly ...

The pathologic hallmark of spinal cord (SC) injury is a progressive tissue decay at the damage site. Understanding the stages of the progression of pathology would be very helpful in developing strategies for SC injury repair. The evolution of pathology in the transection injury has been described. Longitudinal studies, ex vivo by histology [PNAS(1996)93:111791] and in vivo by MRI, of the transection site in rat SC suggest that an intrinsic reparative repertoire is activated after injury. However, by the end of the 3rd wk postinjury (PI) the repair is aborted and chronic inflammation/decay take over yielding a widening cavity. These data point to the existence of a window of opportunity for developing strategies for preventing the onset of tissue decay, eg, radiation therapy at this critical period can facilitate natural repair in sectioned SC1. The focus now is on contusion which is more similar to the human SC injury. Here we obtained by MRI a dynamic in vivo view of the events' progression at the lesion...