Millisecond-Timescale Local Network Coding in the Rat Primary Somatosensory Cortex

Correlation among neocortical neurons is thought to play an indispensable role in mediating sensory processing of external stimuli. The role of temporal precision in this correlation has been hypothesized to enhance information flow along sensory pathways. Its role in mediating the integration of information at the output of these pathways, however, remains poorly understood. Here, we examined spike timing correlation between simultaneously recorded layer V neurons within and across columns of the primary somatosensory cortex of anesthetized rats during unilateral whisker stimulation. We used Bayesian statistics and information theory to quantify the causal influence between the recorded cells with millisecond precision. For each stimulated whisker, we inferred stable, whisker-specific, dynamic Bayesian networks over many repeated trials, with network similarity of 83.3±6% within whisker, compared to only 50.3±18% across whiskers. These networks further provided information about whisker identity that was approximately 6 times higher than what was provided by the latency to first spike and 13 times higher than what was provided by the spike count of individual neurons examined separately. Furthermore, prediction of individual neurons' precise firing conditioned on knowledge of putative pre-synaptic cell firing was 3 times higher than predictions conditioned on stimulus onset alone. Taken together, these results suggest the presence of a temporally precise network coding mechanism that integrates information across neighboring columns within layer V about vibrissa position and whisking kinetics to mediate whisker movement by motor areas innervated by layer V

Design and evaluation of a low-cost respiratory monitoring device for use with anaesthetized animals

This report describes a simple, non-invasive electronic device that employs a compact accelerometer integrated circuit to transduce movements in the chest wall of an anaesthetized animal into an analogue signal that can be used to calculate the rate and relative depth of respiration. The device requires amplification by signal processing hardware/software which are common to most experimental laboratories. We assessed the sensitivity of the device by its ability to detect changes in respiratory patterns produced by modulating the depth of anaesthesia in isoflurane-anaesthetized Wistar rats. It is widely accepted that many anaesthetic agents affect respiratory patterns, especially respiratory rate (RR), which is often used as an important index of anaesthetic depth. Respiratory parameters obtained with the device were compared with concurrently recorded electroencephalographic and cardiac measures. Different concentrations of anaesthetic agent produced four depths of anaesthesia, identified using established electroencephalographic criteria. The accelerometer was attached easily and securely to the location of maximal chest wall movement and produced a strong respiratory signal that was detectable in all four anaesthetic stages. Deepening the anaesthesia produced a gradual decrease in RR, a decrease in dominant spectral frequency of the electroencephalogram (EEG) but no change in the heart rate. There was a significant correlation between RR and the dominant spectral frequency of the EEG, indicating that one useful application of the monitor could be to identify anaesthetic stages. The results demonstrate that respiratory parameters can be recorded using a simply constructed, low-cost device and suggest an application in the monitoring of anaesthetic depth

Building Information Modelling (BIM) : a summary of some UK experiences as guide to adoption in Nigeria

Building information modelling (BIM) is a term that has been echoed around the world by researchers and practitioners alike. This is a new methodology (essentially electronic capture and focussed, timely distribution of relevant data) of project delivery that improves efficiency and quality of work. Although the word 'building' is used, BIM is equally applicable to civil engineering, utilities and infrastructure projects. Also, the word 'modelling' applies to the broad spectrum of process application not simply models produced by 3d software packages. The most important element in BIM is the 'information' and its beneficial capture and repeat usage. Every sector of the world economy is just looking for ways to produce more with fewer resources or making best use of the resources available. This paradigm shift has brought about the adoption of BIM in the construction industry. This paper will define BIM in simple terms; highlight its benefits and barriers; rationalise its workability, maturity levels and general ideas that it is based upon. The paper will also articulate some actual experiences from the UK at both the government and organisational level and the challenges overcome and some benefits achieved. Just like any other technology or methodology, BIM relies on collaboration for its successful implementation. This collaboration will create an avenue for construction teams to produce and make use of consistent unambiguous information, which will improve the overall efficiency in project delivery. For many people the question still remains. Will this be a solution to the all the problems in the industry? Or will it only solve particular problems? Just like every technology using it correctly will definitely yield benefits. Governments in many countries have recognised the usefulness of BIM and have intervened to make its implementation possible. As a developing country, Nigeria should not be far from making such efforts. There is need for construction industry to take proactive steps to overcome its problems. BIM implementation may not be a panacea to all the problems in the construction industry but it will surely make it better. Construction professionals may look at this idea with scepticism echoed, although it is now being overcome in countries adopting BIM. The earlier they realise that BIM will be the future of the industry the better