The role of the dentate gyrus and adult neurogenesis in hippocampal-basal ganglia associated behaviour

The ability of the brain to continually generate new neurons throughout life is one of the most intensely researched areas of modern neuroscience. While great advancements in understanding the biochemical mechanisms of adult neurogenesis have been made, there remain significant obstacles and gaps in connecting neurogenesis with behavioural and cognitive processes such as learning and memory. The purpose of the thesis was to examine by review and laboratory experimentation the role of the dentate gyrus and of adult neurogenesis within the hippocampus in the performance of cognitive tasks dependent on the hippocampal formation and hippocampal-basal ganglia interactions. Advancement in understanding the role of neurogenesis in these processes may assist in improving treatments for common brain injury and cognitive diseases that affect this region of the brain. Mild chronic stress reduced the acquisition rate of a stimulus-response task (p=0.043), but facilitated the acquisition of a discrimination between a small and a large reward (p=0.027). In locomotor activity assays, chronic stress did not shift the dose-response to methamphetamine. Analysis of 2,5-bromodeoxyuridine incorporation showed that, overall, chronic mild stress did not effect survival of neuronal progenitors . However, learning of the tasks had a positive influence on cell survival in stressed animals (p=0.038). Microinjections of colchicine produced significant lesions of the dentate gyrus and surrounding CA1-CA3 and neocortex. Damage to these regions impaired hippocampal-dependent reference memory (p=0.054) while preserving hippocampal independent simple discrimination learning. In a delay discounting procedure, the lesions did not induce impulsive-like behaviour when delay associated with a large reward was introduced. The experiments uphold a current theory that learning acts as a buffer to mitigate the negative effects of stress on neurogenesis

Exploring the role of instrument design and instrument interaction for eco-innovation: a survey-based analysis of renewable energy innovation in Germany

Empirical research on eco-innovation has produced a substantive body of literature on the relevance of regulation for stimulating such innovation. Much of this work on the role of policy for eco-innovation relies on econometric analyses of company survey data. In this regard, the eco-innovation module introduced in 2008/9 in the Community Innova-tion Survey serves as an important data source that has helped improve our under-standing of the role of environmental and innovation policy for eco-innovation in the Eu-ropean Union (EU). However, so far, this data source has provided only limited oppor-tunities to generate insights into the role of instrument design and instrument interaction for eco-innovation. In this chapter, we present a first attempt to measure such aspects in a company innovation survey based on the example of renewable energy innovation in Germany. In particular, we explore to what extent the design of the German Renewa-ble Energy Sources Act (and the interaction of its feed-in tariffs with the EU emissions trading system) correlates with innovation in renewable power generation technologies. We find instrument design features but not instrument type to be related to eco-innovation. In addition, our exploratory study provides evidence for an interaction effect between climate policy and renewables support policy. Based on these findings, we discuss implications for future research on the role of policy in eco-innovation

Adaptive Kalman Smoothing of AR Signals Disturbed by Impulses and Colored Noise

In this paper, we describe a new and computationally efficient adaptive system for the enhancement of autoregressive (AR) signals which are disturbed by additive white or colored noise and impulsive noise. The system is comprised of an adaptive Kalman filter operating as a fixed lag smoother and a subsystem for AR parameter estimation. A superior performance is achieved by implementing a feedback loop between the Kalman filter output and the parameter estimation. Accordingly, the AR parameters are obtained from the enhanced signal and the influence of the disturbing noise on the parameter estimation is damped down. Impulsive noise is suppressed by an outlier detection scheme and by freezing the Kalman filter update during presence of impulses. The subsystem for AR parameter estimation can operate in a block processing mode or on a sample per sample basis. Another advantage of the adaptive Kalman filter is its tracking capability for short-time stationary signals

Improved Design of Uniform and Nonuniform Modulated Filter Banks

In this paper, we describe an improved design method for multirate modulated filter banks with uniform or nonuniform frequency spacing. Compared to other design techniques, our method converges very rapidly and allows for the design of excellent prototype filters. The optimization procedure avoids nonlinear function minimization and requires linear equation solving only. We demonstrate our method by design examples of filter banks for critical-band analysis/synthesis. 1 INTRODUCTION In the past few years the design of nonuniform filter banks has gained much attention for applications in multiresolution spectral analysis and speech coding systems. The analysis of multirate nonuniform filter banks has been intensively studied and various design theories have been proposed [5, 8, 9, 10, 11]. Although the principal design issues like perfect reconstruction properties and selection of subsampling factors have been investigated in detail, the problem of finding the coefficients of the analy..

Ambient voice control for a personal activity and household assistant

Technologies for ambient assisted living (AAL) are used to increase the quality of life of older or impaired persons. This contribution discusses the utilization of automatic speech recognition (ASR) as a natural interface for control of assistive technologies in everyday life situations. We focus on the use of hands-free systems, the technical challenges for the ASR software caused by this and the benefits for older persons. Moreover, state-of-the-art approaches for improving robustness of ASR systems are presented, discussed and demonstrated by an ASR experiment