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...

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 ...

Amyloid-Related Imaging Abnormalities (ARIA) are MRI-defined adverse events frequently observed in the context of anti-Aβ immunotherapy trials in patients with Alzheimer’s disease (AD). ARIA-H include cerebral microbleeds (CMBs) and cortical superficial...

Accuracy of targeting is critical for the success of cell transplantation and recombinant viral vector mediated gene therapy. We compared the accuracy of conventional atlas guided stereotaxis to MRI guided stereotactic targeting into various basal ganglia nuclei in hemiparkinsonian (HP) monkeys. High resolution 3-D T1 weighted MR images of the brain were obtained in 27 HP monkeys fitted with a MRI compatible stereotactic frame. This was immediately followed by cranial surgery with the frame in situ. Thirteen additional HP monkeys underwent stereotactic atlas guided cranial surgery for placement of cell transplants. Following extensive behavioral testing, microelectrode recording (MER) and PET imaging all animals were euthanized and perfused with 4% paraformaldehyde. The brains were cut in coronal sections and stained to determine the accuracy of stereotactic placements. Preliminary data analysis indicate that MRI guided stereotaxis was accurate (2 caudate and 3 putamen targets) in 16 out of 16 animals anal...

Although there has been recent interest in the study of childhood and adolescent brain development, very little is known about normal brain development in the first few months of life. In older children, there are regional differences in cortical gray matter development, whereas cortical gray and white matter growth after birth has not been studied to a great extent. The adult human brain is also characterized by cerebral asymmetries and sexual dimorphisms, although very little is known about how these asymmetries and dimorphisms develop. We used magnetic resonance imaging and an automatic segmentation methodology to study brain structure in 74 neonates in the first few weeks after birth. We found robust cortical gray matter growth compared with white matter growth, with occipital regions growing much faster than prefrontal regions. Sexual dimorphism is present at birth, with males having larger total brain cortical gray and white matter volumes than females. In contrast to adults and older children, the l...

The relationship between limbic activity and emotional reactions to and enhanced memory for emotional material has been established for nonverbal stimuli. However, it is unknown whether this relationship holds for other stimuli such as words and whether it is modulated by individual differences in personality variables (e.g., Canli et al., 1999). We examined emotional memory and emotional reactions to verbal and nonverbal (photograph) stimuli using functional magnetic resonance imaging. The goals were to examine the neural correlates of emotional reactions to pleasant, unpleasant, and neutral verbal material, compare these correlates to the correlates of reactions to nonverbal material, and identify brain areas whose activity is correlated with memory for each type of emotional material. In addition, personality trait data were assessed to examine the possible modulatory role of personality characteristics. Functional imaging was conducted with a Philips 1.5 T ACS/NT scanner using gradient-recalled echo-pl...

An artificial thrombosis generation is well-established method of preclinical animal models to study mechanisms of thrombosis-caused diseases, for instance, a cerebral stroke and a cardiac infarction. In addition, it is used to investigate diagnostic an...

Introduction: Each whisker corresponds to a single functional column in the Barrel field. In vivo observation of activation induced by whisker stimulation is important for the analysis of the functional linkage. Activity-Induced Manganese-enhanced (AIM) MRI is reported as a hemodynamics independent method in functional MRI study (Lin, et al.). Mn2+ enters neurons through voltage-gated Ca2+ channels during nerve action potential and leads to signal enhancement in active brain areas. The purpose of this study is to detect brain activation during whisker stimulation with high spatial resolution using hemodynamics independent AIM MRI. Materials and Methods: Male SD rats were divided into 3 groups: normal control (n = 5), multi whiskers stimulation (n = 5), and single whisker stimulation (n = 5). Animals were prepared using previously described methods (Aoki I, NMR in Biomed. 2004, 17:1-12). The blood brain barrier was disrupted by 25% D-mannitol. Whisker E1 was stimulated with 2Hz frequency during the MnCl2 in...

Destruction or changes associated with myelin membranes in the CNS play a key role in the pathogenesis of multiple sclerosis and other related neurodegenerative disorders. A long-standing goal has been to detect and quantify myelin content in vivo . For this reason, we have developed a myelin-imaging technique based on positron emission tomography (PET). PET is a quantitative imaging modality that has been widely used in clinical settings for direct assessment of biological processes at the molecular level. However, lack of myelin-imaging probes has hampered the use of PET for imaging of myelination in the CNS. Here, we report a myelin-imaging agent, termed Case Imaging Compound (CIC) that readily penetrates the blood–brain barrier and preferentially localizes to myelinated regions of the brain. After radiolabeling with positron-emitting carbon-11, [11C]CIC–PET was conducted in longitudinal studies using a lysolethicin-induced rat model of focal demyelination and subsequent remyelination. Quantitative anal...

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...