Pupillometry as a reliable metric of auditory detection and discrimination across diverse stimulus paradigms in animal models

Estimates of detection and discrimination thresholds are often used to explore broad perceptual similarities between human subjects and animal models. Pupillometry shows great promise as a non-invasive, easily-deployable method of comparing human and animal thresholds. Using pupillometry, previous studies in animal models have obtained threshold estimates to simple stimuli such as pure tones, but have not explored whether similar pupil responses can be evoked by complex stimuli, what other stimulus contingencies might affect stimulus-evoked pupil responses, and if pupil responses can be modulated by experience or short-term training. In this study, we used an auditory oddball paradigm to estimate detection and discrimination thresholds across a wide range of stimuli in guinea pigs. We demonstrate that pupillometry yields reliable detection and discrimination thresholds across a range of simple (tones) and complex (conspecific vocalizations) stimuli; that pupil responses can be robustly evoked using different stimulus contingencies (low-level acoustic changes, or higher level categorical changes); and that pupil responses are modulated by short-term training. These results lay the foundation for using pupillometry as a reliable method of estimating thresholds in large experimental cohorts, and unveil the full potential of using pupillometry to explore broad similarities between humans and animal models.publishersversionpublishe

Compact Multiband Planar Fractal Cantor Antenna for Wireless Applications: An Approach

A compact multiband fractal antenna which is a new criterion in communication is proposed. The optimized prototype measures 35 mm × 31 mm × 1.6 mm. The proposed antenna covers WLAN IEEE 802.11b, 802.15, PCS, GSM lower and higher bands, DCS, IMT, UMTS, Wi-Fi, and WLAN wireless applications. The proposed antenna exhibits multiband characteristics with an S11 of −30.69 dB at design frequency and it is found that ~70% of the S11 graph below −10 dB reference is achieved. Experimental S11 has been compared with the one which is obtained using method of moments. The aim of implementing self-affine fractal concept in antenna design makes it flexible in controlling the resonance and bandwidth. This paper investigates self-affine fractal geometry to miniaturize and to resonate multiband frequencies. The prototype model with a good agreement of S11 is reported

CACNB4 Overexpression and Dendritic Spine Loss in Schizophrenia

Reduced density of dendritic spines is an intermediate anatomical phenotype for schizophrenia (Sz). This dissertation is a collection of descriptive studies about dendritic spines and the voltage-gated calcium channel protein β4, a study of a Sz-related β4 manipulation, and the impacts of this manipulation on dendritic spine density and morphology. Chapter 2 is a descriptive study of sex differences in dendritic spines in murine sensory cortex over adolescent neurodevelopment. Chapter 3 is an in-depth assessment of the impacts of CACNB4 overexpression (β4OE) on dendritic spines of male and female adult mice. Chapter 4 is a final descriptive study of sex differences in the β4 interactome of adult mice. Sex differences were deliberately assessed at baseline and in the study of the impacts of β4OE on dendritic spines given the importance of sex as a biological factor and known sex differences in the clinical presentation and expression of Sz. In Chapter 2, we identified sex differences in spine density, and in Chapter 3 evidence for volume- as well as sex-specific β4OE-mediated spine loss; small spines were reduced in female β4OE mice only. These findings provide a model for the intermediate phenotype of small spine loss in primary auditory cortex in Sz and support both our group’s previous suggestion to rethink the Feinberg hypothesis, but also the possibility that small mature spines are eliminated excessively in Sz during adolescence, as Feinberg predicted. In Chapter 4 we found that β1b is significantly enriched in the β4 interactome of male mice only, the presence of which may confer protection for males from the effects of β4OE. Moreover, we detail three pathways through which β4OE could reduce small spine density in female mice. These proposed pathways nominate kinases and MAPs in β4-related spine alterations. Overall, the findings described herein underscore the importance of evaluating the biological sex at baseline, over normal neurodevelopment and following a disease-related manipulation, particularly neurodevelopmental disorders, including Sz

Sobolev spaces on non-Lipschitz subsets of Rn with application to boundary integral equations on fractal screens

We study properties of the classical fractional Sobolev spaces on non-Lipschitz subsets of Rn. We investigate the extent to which the properties of these spaces, and the relations between them, that hold in the well-studied case of a Lipschitz open set, generalise to non-Lipschitz cases. Our motivation is to develop the functional analytic framework in which to formulate and analyse integral equations on non-Lipschitz sets. In particular we consider an application to boundary integral equations for wave scattering by planar screens that are non-Lipschitz, including cases where the screen is fractal or has fractal boundary

Development of Multilayer Partially Reflective Surfaces for Highly Directive Cavity Antennas: A Study

This paper proposes a novel triple-layer partially reflecting surface (PRS) for designing a highly directive antenna. The proposed PRS design has 54% improvement in impedance bandwidth with existing design. The design has multiple cavities, optimized for improved gain and bandwidth performance. The PRS arrays are printed on the dielectric substrate, placed above the ground plane at a height of approximately half wavelength. The reference square microstrip patch antenna operating at a frequency of 5.8 GHz with a gain of 3.77 dBi is enhanced to 13.54 dBi. The measured S11 of the fabricated prototype is −22.12 dB with a VSWR of 1.17 : 1. Measured 3 dB gain bandwidth of the antenna is 390 MHz which is an improvement of 50% compared with the reference antenna. This highly directive antenna is suitable for WiMAX wireless application

Adaptive mechanisms facilitate robust performance in noise and in reverberation in an auditory categorization model

Abstract For robust vocalization perception, the auditory system must generalize over variability in vocalization production as well as variability arising from the listening environment (e.g., noise and reverberation). We previously demonstrated using guinea pig and marmoset vocalizations that a hierarchical model generalized over production variability by detecting sparse intermediate-complexity features that are maximally informative about vocalization category from a dense spectrotemporal input representation. Here, we explore three biologically feasible model extensions to generalize over environmental variability: (1) training in degraded conditions, (2) adaptation to sound statistics in the spectrotemporal stage and (3) sensitivity adjustment at the feature detection stage. All mechanisms improved vocalization categorization performance, but improvement trends varied across degradation type and vocalization type. One or more adaptive mechanisms were required for model performance to approach the behavioral performance of guinea pigs on a vocalization categorization task. These results highlight the contributions of adaptive mechanisms at multiple auditory processing stages to achieve robust auditory categorization