Dissecting amygdala cell types in fear and extinction

The mammalian brain consists of billions of neurons; Individual neurons serve as building blocks (Cajal 1911, translation Swanson and Swanson 1995). However, studying individual neurons is simply insufficient to understand how the brain works. A promising approach is the cell-type-specific approach, an effort to classify neurons that perform the same function as a single cell type (functional definition, see (Luo et al., 2008)) and to understand their roles in information processing and behavioral outputs. Nevertheless, the limitation of this definition is that we barely know the precise functions or roles of neurons, and even in very well-characterized neurons such as retinal ganglion cells, there would likely be remaining unknown functions. Thus, as an operational definition to drive neuroscience forward, defining cell types using genetic tools that allow us to access specific subsets of neurons was suggested and widely accepted in an almost implicit manner. This consensus is based on an optimistic view that, at some point, the operational genetic definition and the ultimate functional definition would converge. In this thesis, having this philosophy in mind, I try to match several operationally defined amygdala cell types with their distinct functions/roles in the context of fear and extinction learning. In Project 1, I demonstrate that a cell-type in the amygdala complex defined by molecular marker expression exerts essential functions in fear and extinction by composing a unique mutual inhibition circuit motif. In Project 2, I find that a cell-type in the basolateral amygdala defined by di-synaptic downstream target show unprecedented functional specificity in fear learning. Finally, in Project 3, I aim to characterize functions and roles of cell types in the basolateral amygdala defined by dynamic, neuronal activity-dependent gene expression upon learning. Collectively, this thesis serves as an important stepping stone to achieving the convergence between definitions of a cell type

Symmetry, bifurcation and stacking of the central configurations of the planar 1+4 body problem

In this work we are interested in the central configurations of the planar 1+4 body problem where the satellites have different infinitesimal masses and two of them are diametrically opposite in a circle. We can think this problem as a stacked central configuration too. We show that the configuration are necessarily symmetric and the other sattelites has the same mass. Moreover we proved that the number of central configuration in this case is in general one, two or three and in the special case where the satellites diametrically opposite have the same mass we proved that the number of central configuration is one or two saying the exact value of the ratio of the masses that provides this bifurcation.Comment: 9 pages, 2 figures. arXiv admin note: text overlap with arXiv:1103.627

Characterizing Planetary Orbits and the Trajectories of Light

Exact analytic expressions for planetary orbits and light trajectories in the Schwarzschild geometry are presented. A new parameter space is used to characterize all possible planetary orbits. Different regions in this parameter space can be associated with different characteristics of the orbits. The boundaries for these regions are clearly defined. Observational data can be directly associated with points in the regions. A possible extension of these considerations with an additional parameter for the case of Kerr geometry is briefly discussed.Comment: 49 pages total with 11 tables and 10 figure

The complete set of solutions of the geodesic equations in the space-time of a Schwarzschild black hole pierced by a cosmic string

We study the geodesic equations in the space-time of a Schwarzschild black hole pierced by an infinitely thin cosmic string and give the complete set of analytical solutions of these equations for massive and massless particles, respectively. The solutions of the geodesic equations can be classified according to the particle's energy and angular momentum, the ratio between the component of the angular momentum aligned with the axis of the string and the total angular momentum, the deficit angle of the space-time and as well the horizon radius (or mass) of the black hole. For bound orbits of massive test particles we calculate the perihelion shift, we discuss light deflection and comment on the Newtonian limit.Comment: 21 pages; section 3 shortened, references added; accepted for publication in Phys. Rev.

Orbits in the Field of a Gravitating Magnetic Monopole

Orbits of test particles and light rays are an important tool to study the properties of space-time metrics. Here we systematically study the properties of the gravitational field of a globally regular magnetic monopole in terms of the geodesics of test particles and light. The gravitational field depends on two dimensionless parameters, defined as ratios of the characteristic mass scales present. For critical values of these parameters the resulting metric coefficients develop a singular behavior, which has profound influence on the properties of the resulting space-time and which is clearly reflected in the orbits of the test particles and light rays.Comment: 24 pages, 15 figures. Accepted for publication in GR

Physicians' explanatory behaviours and legal liability in decided medical malpractice litigation cases in Japan

<p>Abstract</p> <p>Background</p> <p>A physician's duty to provide an adequate explanation to the patient is derived from the doctrine of informed consent and the physician's duty of disclosure. However, findings are extremely limited with respect to physicians' specific explanatory behaviours and what might be regarded as a breach of the physicians' duty to explain in an actual medical setting. This study sought to identify physicians' explanatory behaviours that may be related to the physicians' legal liability.</p> <p>Methods</p> <p>We analysed legal decisions of medical malpractice cases between 1990 and 2009 in which the pivotal issue was the physician's duty to explain (366 cases). To identify factors related to the breach of the physician's duty to explain, an analysis was undertaken based on acknowledged breaches with regard to the physician's duty to explain to the patient according to court decisions. Additionally, to identify predictors of physicians' behaviours in breach of the duty to explain, logistic regression analysis was performed.</p> <p>Results</p> <p>When the physician's explanation was given before treatment or surgery (<it>p </it>= 0.006), when it was relevant or specific (<it>p </it>= 0.000), and when the patient's consent was obtained (<it>p </it>= 0.002), the explanation was less likely to be deemed inadequate or a breach of the physician's duty to explain. Patient factors related to physicians' legally problematic explanations were patient age and gender. One physician factor was related to legally problematic physician explanations, namely the number of physicians involved in the patient's treatment.</p> <p>Conclusion</p> <p>These findings may be useful in improving physician-patient communication in the medical setting.</p

Geodesics of electrically and magnetically charged test particles in the Reissner-Nordstr\"om space-time: analytical solutions

We present the full set of analytical solutions of the geodesic equations of charged test particles in the Reissner-Nordstr\"om space-time in terms of the Weierstra{\ss} $\wp$, $\sigma$ and $\zeta$ elliptic functions. Based on the study of the polynomials in the $\vartheta$ and $r$ equations we characterize the motion of test particles and discuss their properties. The motion of charged test particles in the Reissner-Nordstr\"om space-time is compared with the motion of neutral test particles in the field of a gravitomagnetic monopole. Electrically or magnetically charged particles in the Reissner-Nordstr\"om space-time with magnetic or electric charges, respectively, move on cones similar to neutral test particles in the Taub-NUT space-times

Characterization of metal-insulator-semicomductor capacitors with insulating nitride films grown on 4H-SiC

ArticleJAPANESE JOURNAL OF APPLIED PHYSICS. 47(1):676-678(2008)journal articl