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To investigated the activity ofSA-beta-GAL in rat hippocampus at different ages. Method: Hippocampus of 6, 18 and 24 month-age rats were observed by histochemical staining for SA-beta-GAL and cytochemical staining for SA-beta-GAL on prolong cultured hippocampal neurons. Results: SA-beta-GAL activity elevated in hippocampal pyramidal cells of CA3 region with advanced age. The upregulated SA-beta-GAL...
This paper reports a novel method for fully automated segmentation of rodent brain volume by extending the robust active shape models to incorporate an automatic prior shape selection process. This automatic prior shape selection process using support vector machines provides an automatic shape initialization method for further segmentation of rodent brain structures such as Cerebellum, Neocortex,...
The hippocampus is among the first structures affected in Alzheimer's disease (AD); hippocampal MRI volumetry is a potential biomarker for AD but is hindered by the limitations of manual segmentation. We propose a fully automatic method using probabilistic and anatomical priors for hippocampus segmentation. Probabilistic information is derived from 16 young controls and anatomical knowledge is modeled...
By analyzing interpoint comparisons, we obtain significant results describing the relationship in "hippocampus shape-space" of clinically depressed, high risk, and control populations. In particular, our analysis demonstrates that the high risk population is closer in shape-space to the control population than to the clinically depressed population.
This paper describes the application of a novel segmentation method in high resolution MRI subvolumes containing hippocampus in five subjects and occipital lobe in five subjects. The alternating kernel mixture (AKM) algorithm is used to segment the MRI subvolumes into cerebrospinal fluid, gray matter, and white matter. The segmentation is validated by comparison with manual segmentation. The misclassification...
This study introduced a localized approach for magnetic resonance microscopy (MRM) of the rat brain. A single-loop radiofrequency (RF) receiver coil designed for micro-imaging was developed by using electromagnetic simulation software widely used in communication fields. With transmit-only and receive-only (TORO) configuration, receive-only surface coil can achieve higher signal-to-noise ratio (SNR)...
The role of the hippocampus in associative memory is the establishment of long-term, declarative memories. For example, memories for facts, name and life experiences. Damage to the hippocampus leads to loss of ability to convert short-term memory to new long-term memories. This can happen due to epilepsy, stroke, dementia or head injuries. One of the possibilities of providing a solution to this problem...
We present a novel method of statistical surface-based morphometry based on the use of non-parametric permutation tests and a spherical wavelet (SWC) shape representation. As an application, we analyze two brain structures, the caudate nucleus and the hippocampus, and compare the results obtained to shape analysis using a sampled point representation. Our results show that the SWC representation indicates...
Dynamic causal modeling was used to quantify effective connectivity among limbic regions within each brain hemisphere. fMRI data obtained from seven healthy, normal subjects belonging to the low trait anxiety group during passive viewing of emotionally-valent facial stimuli was used for connectivity analyses. A fully connected and reciprocal model consisting of the amygdala, hippocampus and prefrontal...
We are developing a CMOS device with integrated imaging array, electrical stimulus electrodes and chemical delivery for neural imaging and interfacing. Our aim is to perform functional imaging deep inside the mouse hippocampus at the molecular level. The device has an irregular front shape to minimize injury during insertion into the brain. Four electrodes are embedded strategically on the image array...
Learning and memory rely on the strict regulation of communication between neurons in the hippocampus. The mossy fiber (MF) pathway connects the dentate gyrus to the auto-associative CA3 network, and the information it carries is controlled by a feedforward circuit combining disynaptic inhibition with monosynaptic excitation. Analysis of the MF associated circuit using a mapped clock oscillator (MCO)...
We have developed and demonstrated the use of a dedicated CMOS device for in vivo functional imaging of the mouse brain. In order to achieve this, a 176times144 pixel array image sensor is designed, fabricated and specially packaged using a novel process. By using on-chip fluorescence imaging configuration, we have successfully imaged deep inside the hippocampus of the mouse brain. Functional imaging...
Learning and memory rely on the strict regulation of communication between neurons in the hippocampus. The mossy fiber (MF) pathway connects the dentate gyrus to the auto-associative CA3 network, and the information it carries is controlled by a feedforward circuit combining disynaptic inhibition with monosynaptic excitation. Analysis of the MF associated circuit using a mapped clock oscillator (MCO)...
A total of 32 microwire electrodes were implanted bilaterally into the hippocampus of Sprague-Dawley rats, which were then stimulated in the manner prescribed for the chronic limbic epilepsy model. After the initial seizure brought on by the stimulation, the animals were recorded at a high sampling rate (~12 kHz) for the entire duration of the latent period. Coherence was calculated across channels...
We have developed and demonstrated the use of a dedicated CMOS device for in vivo functional imaging of the mouse brain. In order to achieve this, a 176times144 pixel array image sensor is designed, fabricated and specially packaged using a novel process. By using on-chip fluorescence imaging configuration, we have successfully imaged deep inside the hippocampus of the mouse brain. Functional imaging...
A total of 32 microwire electrodes were implanted bilaterally into the hippocampus of Sprague-Dawley rats, which were then stimulated in the manner prescribed for the chronic limbic epilepsy model. After the initial seizure brought on by the stimulation, the animals were recorded at a high sampling rate (~12 kHz) for the entire duration of the latent period. Coherence was calculated across channels...
Recently neurodegenerative diseases such as Alzheimer's disease (AD) and senile dementia have been associated with vascular alterations. We are using modified vascular corrosion casting combined with micro-computed tomography to evaluate the vascular pattern in normal and pathological tissue from APP23 transgenic animals. Our newly developed hierarchical imaging framework allows for non-destructive...
Nowadays, more and more studies have focused on the physiological and pathological effect of nitric oxide (NO). In this study, we directly measured extracellular NO levels in the hippocampus of rats using NO probe. Simultaneously, the artery blood pressure was recorded. It was found that after the administration of Nomega- nitro-L-arginine methyl ester (L-NAME), the NO signal came down and the artery...
Recent physiological evidence has suggested that initiation of partial epileptic seizures may be due to a desynchronization rather than hypersynchronization of neuronal communication at a seizure focus. This hypothesis was tested using a computational model of the hippocampal slice possessing a physiologically-consistent network structure and behavior. When desynchronization was simulated using either...
This paper demonstrates that a novel neural structure can be useful for formation of long-term memory. An essential core of the proposed model is a control signal for learning or memory formation, inspired by a possible biological learning mechanism observed in cerebral cortices and hippocampus. From a biological point of view, the control signal can be generated by the limbic system according to...
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