A computational model-based analysis of basal ganglia pathway changes in Parkinson's disease inferred from resting-state fMRI.

Previous computational model-based approaches for understanding the dynamic changes related to Parkinson's disease made particular assumptions about Parkinson's disease-related activity changes or specified dopamine-dependent activation or learning rules. Inspired by recent model-based analysis of resting-state fMRI, we have taken a data-driven approach. We fit the free parameters of a spiking neuro-computational model to match correlations of blood oxygen level-dependent signals between different basal ganglia nuclei and obtain subject-specific neuro-computational models of two subject groups: Parkinson patients and matched controls. When comparing mean firing rates at rest and connectivity strengths between the control and Parkinsonian model groups, several significant differences were found that are consistent with previous experimental observations. We discuss the implications of our approach and compare its results also with the popular "rate model" of the basal ganglia. Our study suggests that a model-based analysis of imaging data from healthy and Parkinsonian subjects is a promising approach for the future to better understand Parkinson-related changes in the basal ganglia and corresponding treatments.

Determining Position Inside Non-industrial Buildings Using Ultrasound Transducers.

The position determination inside a building where no GPS signal is beingreceived can be ascertained using laser transmitters in industrial situations where there areno people or using triangulation of the signal strength, normally electro-magnetic signals,if the required accuracy is more than a metre. Our solution is aimed at situations wherepeople are present and where the required accuracy is less than 30 cm, such as in shoppingprecincts or supermarkets. To achieve this, a network of ultrasonic transmitters is fittedinto the ceiling which receives a synchronised time signal. Each transmitter has a uniqueidentifier code and emits its code with a delay with respect to the common time signalwhich is proportional to its code number with an ASK modulation over the ultrasonic bandcentred on 40 KHz. The receivers circulating beneath the transmitters receive the codes ofthose within their detection range, translate the time delays into distances and then obtaintheir position by triangulation since the receivers know the position of every transmitter.Since the receivers are not synchronised with the common time signal or the actual speedof the sound, whose value varies appreciably with temperature, relative humidity andatmospheric pressure, a consecutive approximation algorithm has been introduced. This isbased on the fact that the Z coordinator of the receiver is known and constant and thus it is possible, with only three different identifiers received, to deduce the phase of the common time signal and estimate the speed of the sound with a fourth identifier.

Tactile Fabric Panel in an Eight Zones Structure.

By introducing a percentage of conductive material during the manufacture ofsewing thread, it is possible to obtain a fabric which is able to detect variations in pressurein certain areas. In previous experiments the existence of resistance variations has beendemonstrated, although some constrains of cause and effect were found in the fabric. Theresearch has been concentrated in obtaining a fabric that allows electronic detection of itsshape changes. Additionally, and because a causal behavior is needed, it is necessary thatthe fabric recovers its original shape when the external forces cease. The structure of thefabric varies with the type of deformation applied. Two kinds of deformation aredescribed: those caused by stretching and those caused by pressure. This last type ofdeformation gives different responses depending on the conductivity of the object used tocause the pressure. This effect is related to the type of thread used to manufacture thefabric. So, if the pressure is caused by a finger the response is different compared to theresponse caused by a conductive object. Another fact that has to be mentioned is that apressure in a specific point of the fabric can affect other detection points depending on theforce applied. This effect is related to the fabric structure. The goals of this article arevalidating the structure of the fabric used, as well as the study of the two types ofdeformation mentioned before.