Essentials for Interpreting Intracranial Vessel Wall MRI Results: State of the Art.

Intracranial vessel wall (VW) MRI has become widely available in clinical practice, providing multiple uses for evaluation of neurovascular diseases. The Vessel Wall Imaging Study Group of the American Society of Neuroradiology has recently reported expert consensus recommendations for the clinical implementation of this technique. However, the complexity of the neurovascular system and caveats to the technique may challenge its application in clinical practice.

Fast whole brain MR imaging of dynamic susceptibility contrast changes in the cerebrospinal fluid (cDSC MRI).

Purpose: The circulation of cerebrospinal fluid (CSF) is closely associated with many aspects of brain physiology. When gadolinium(Gd)-based contrast is administered intravenously, pre- and post-contrast MR signal changes can often be observed in the CSF at certain locations within the intra-cranial space, mainly due to the lack of a blood-brain barrier in the dural blood vessels. This study aims to develop and systemically optimize MRI sequences that can detect dynamic signal changes in the CSF after Gd administration with a sub-millimeter spatial resolution, a temporal resolution of <10 s, and whole brain coverage.

Neural mechanisms of economic choices in mice.

Economic choices entail computing and comparing subjective values. Evidence from primates indicates that this behavior relies on the orbitofrontal cortex. Conversely, previous work in rodents provided conflicting results.

Multi-atlas tool for automated segmentation of brain gray matter nuclei and quantification of their magnetic susceptibility.

Quantification of tissue magnetic susceptibility using MRI offers a non-invasive measure of important tissue components in the brain, such as iron and myelin, potentially providing valuable information about normal and pathological conditions during aging. Despite many advances made in recent years on imaging techniques of quantitative susceptibility mapping (QSM), accurate and robust automated segmentation tools for QSM images that can help generate universal and sharable susceptibility measures in a biologically meaningful set of structures are still not widely available. In the present study, we developed an automated process to segment brain nuclei and quantify tissue susceptibility in these regions based on a susceptibility multi-atlas library, consisting of 10 atlases with T1-weighted images, gradient echo (GRE) magnitude images and QSM images of brains with different anatomic patterns.

Added value of contrast echocardiography in characterization of nonischemic cardiomyopathy.

Nonischemic cardiomyopathy (NICM) is a group of noncoronary heterogonous myocardial diseases. The heterogonous nature of NICM has impeded its diagnosis. In the present case series, we demonstrate the added value of using contrast echocardiography in the characterization of NICM.

Different profiles of main and accessory olfactory bulb mitral/tufted cell projections revealed in mice using an anterograde tracer and a whole-mount, flattened cortex preparation.

A whole-mount, flattened cortex preparation was developed to compare profiles of axonal projections from main olfactory bulb (MOB) and accessory olfactory bulb (AOB) mitral and tufted (M/T) cells. After injections of the anterograde tracer, Phaseolus vulgaris leucoagglutinin, mapping of labeled axons using a Neurolucida system showed that M/T cells in the AOB sent axons primarily to the medial and posterior lateral cortical amygdala, with minimal branching into the piriform cortex. By contrast, M/T cells in the MOB displayed a network of collaterals that branched off the primary axon at several levels of the lateral olfactory tract (LOT).

A direct main olfactory bulb projection to the 'vomeronasal' amygdala in female mice selectively responds to volatile pheromones from males.

The main olfactory system, like the accessory olfactory system, responds to pheromones involved in social communication. Whereas pheromones detected by the accessory system are transmitted to the hypothalamus via the medial ('vomeronasal') amygdala, the pathway by which pheromones are detected and transmitted by the main system is not well understood. We examined in female mice whether a direct projection from mitral/tufted (M/T) cells in the main olfactory bulb (MOB) to the medial amygdala exists, and whether medial amygdala-projecting M/T cells are activated by volatile urinary odors from conspecifics or a predator (cat).

Effect of bilateral accessory olfactory bulb lesions on volatile urinary odor discrimination and investigation as well as mating behavior in male mice.

Previous research raises the possibility that urinary volatiles from estrous female mice activate mitral cells in the accessory olfactory bulb (AOB) of male mice following detection via the main olfactory epithelium as opposed to the vomeronasal organ. We asked whether bilateral lesions of the AOB would disrupt the ability of male mice to discriminate between urinary volatiles from mice of different sexes or endocrine states, or affect their interest in investigating these odors when they were presented sequentially in home-cage habituation/dishabituation tests. Males with either partial or complete bilateral lesions of the AOB resembled sham-operated control males in their ability to discriminate between ovariectomized and estrous female urinary volatiles as well as between male and estrous female urinary volatiles.

Differential gene expression between sensory neocortical areas: potential roles for Ten_m3 and Bcl6 in patterning visual and somatosensory pathways.

Adult neocortical areas are characterized by marked differences in cytoarchitecture and connectivity that underlie their functional roles. The molecular determinants of these differences are largely unknown. We performed a microarray analysis to identify molecules that define the somatosensory and visual areas during the time when afferent and efferent projections are forming.

Development of sex differences in the principal nucleus of the bed nucleus of the stria terminalis of mice: role of Bax-dependent cell death.

Neuron number in the principal nucleus of the bed nucleus of the stria terminalis (BNSTp) is greater in adult male mice than in females. Deletion of the proapoptotic gene, Bax, increases the number of BNSTp cells in adulthood and eliminates the sex difference in cell number. Here, we map the ontogeny of sex differences in nuclear volume and cell number in the BNSTp of neonatal mice, and evaluate the role of cell death in the development of these differences.

Sex difference in Fos induced by male urine in medial amygdala-projecting accessory olfactory bulb mitral cells of mice.

We previously reported that exposure to soiled male bedding induced Fos protein immunoreactivity (Fos-IR) in significantly more neurons of the vomeronasal organ (VNO) and medial amygdala of gonadectomized, estradiol-treated female than male mice whereas no such sex difference was seen in the intervening mitral cells of the accessory olfactory bulb (AOB). We asked whether a sexually dimorphic functional response to male urinary pheromones might be revealed in AOB mitral cells that project specifically to the medial amygdala. Gonadectomized mice of both sexes were treated with estradiol and 3 days later received bilateral injections of the retrograde tracer, Cholera toxin-B (CTB) into the medial amygdala.