Modulating basal ganglia and cerebellar activity to suppress parkinsonian tremor

Despite extensive research, the detailed pathophysiology of the parkinsonian tremor is still unknown. It has been hypothesized that the generation of parkinsonian tremor is related to abnormal activity within the basal ganglia. The cerebello-thalamic-cortical loop has been suggested to indirectly contribute to the expression of parkinsonian tremor. However, the observed tremor-related hyperactivity in the cerebellar loop may have a compensatory rather than a causal role in Parkinson's disease (PD) by preventing tremor from spilling over into voluntary movement. Furthermore, observed overactivation in cerebellar loops has also been associated with a higher ability of PD patients to perform repetitive movements that are cued by auditory or visual stimuli, suggesting that rhythmic synchronization with an auditory timekeeper can be achieved in the absence of intact basal ganglia function. Deep brain stimulation (DBS) in the subthalamic nucleus (STN) is currently an accepted treatment for advanced PD that may significantly improve motor complications and reduce tremor. While DBS directly influences neuronal activity patterns in basal ganglia loops, it may be expected that modulation of the cerebellar loops have an additional effect on parkinsonian tremor if both loops are involved in tremor generation and expression.\ud The aim of this pilot study is to test whether the combination of DBS and auditory cueing has an enhanced effect on tremor reduction. Therefore, in a group of seven PD patients receiving STN-DBS, tremor occurrence in both hands and both feet was sequentially tested while performing repetitive movements cued by an auditory signal. The frequency of the auditory cues ranged from 1.6 Hz, which is within the range of frequencies that can be found during normal movements, and 4.8 Hz, which is near the average PD tremor frequency. Movements and tremor were registered by inertial sensors attached to the hands and feet. The Chi-square test was used to compare the occurrence of tremor in any of the extremities for the different cueing frequencies and DBS “on” and “off”.\ud Compared to the resting condition and the performance of self-paced hand or foot movements, the number of extremities showing tremor was significantly reduced under external cueing conditions when stimulation was “on”. With DBS “off”, only the lower cueing frequencies (1.6 and 3.2 Hz) provided a beneficial effect.\ud From the results it may be hypothesized that modulation of the pathological patterns in basal ganglia (by DBS) and cerebellar activity (by auditory cueing) provides enhanced suppression of action tremor in PD

It support for mass customization

Many authors have written about Mass Customization and its features and categories. Literature on the implementation of Mass Customization, and in particular the supporting information technology, is scant. This paper attempts to fill this gap by focusing on this subject. We determine the key functional requirements and identify possible implementations to show the existence of enabling information technologies for Mass Customization

Cognitive map formation through tactile map navigation in visually impaired and sighted persons

The human brain can form cognitive maps of a spatial environment, which can support wayfinding. In this study, we investigated cognitive map formation of an environment presented in the tactile modality, in visually impaired and sighted persons. In addition, we assessed the acquisition of route and survey knowledge. Ten persons with a visual impairment (PVIs) and ten sighted control participants learned a tactile map of a city-like environment. The map included five marked locations associated with different items. Participants subsequently estimated distances between item pairs, performed a direction pointing task, reproduced routes between items and recalled item locations. In addition, we conducted questionnaires to assess general navigational abilities and the use of route or survey strategies. Overall, participants in both groups performed well on the spatial tasks. Our results did not show differences in performance between PVIs and sighted persons, indicating that both groups formed an equally accurate cognitive map. Furthermore, we found that the groups generally used similar navigational strategies, which correlated with performance on some of the tasks, and acquired similar and accurate route and survey knowledge. We therefore suggest that PVIs are able to employ a route as well as survey strategy if they have the opportunity to access route-like as well as map-like information such as on a tactile map

Cognitive map formation supported by auditory, haptic, and multimodal information in persons with blindness

For efficient navigation, the brain needs to adequately represent the environment in a cognitive map. In this review, we sought to give an overview of literature about cognitive map formation based on non-visual modalities in persons with blindness (PWBs) and sighted persons. The review is focused on the auditory and haptic modalities, including research that combines multiple modalities and real-world navigation. Furthermore, we addressed implications of route and survey representations. Taking together, PWBs as well as sighted persons can build up cognitive maps based on non-visual modalities, although the accuracy sometime somewhat differs between PWBs and sighted persons. We provide some speculations on how to deploy information from different modalities to support cognitive map formation. Furthermore, PWBs and sighted persons seem to be able to construct route as well as survey representations. PWBs can experience difficulties building up a survey representation, but this is not always the case, and research suggests that they can acquire this ability with sufficient spatial information or training. We discuss possible explanations of these inconsistencies

Iso-maleimycin, a Constitutional Isomer of Maleimycin, fromStreptomycessp. QL37

Microbial Biotechnolog

Quantum Critical Dynamics of A Qubit Coupled to An Isotropic Lipkin-Meshkov-Glick Bath

We explore a dynamic signature of quantum phase transition (QPT) in an isotropic Lipkin-Meshkov-Glick (LMG) model by studying the time evolution of a central qubit coupled to it. We evaluate exactly the time-dependent purity, which can be used to measure quantum coherence, of the central qubit. It is found that distinctly different behaviors of the purity as a function of the parameter reveal clearly the QPT point in the system. It is also clarified that the present model is equivalent to an anti Jaynes-Cummings model under certain conditions.Comment: 8 pages, 4 figure