Coherent noise source identification in multi channel analysis

The evaluation of coherent noise can provide useful information in the study of detectors. The identification of coherent noise sources is also relevant for uncertainty calculations in analyse where several channels are combined. The study of the covariance matrix give information about coherent noises. Since covariance matrix of high dimension data could be difficult to analyse, the development of analysis tools is needed. Principal Component Analysis (PCA) is a powerful tool for such analysis. It has been shown that we can use PCA to find coherent noises in ATLAS calorimeter or the CALICE Si-W electromagnetic calorimeter physics prototype. However, if several coherent noise sources are combined, the interpretation of the PCA may become complicated. In this paper, we present another method based on the study of the covariance matrix to identify noise sources. This method has been developed for the study of front end ASICs dedicated to CALICE calorimeters. These calorimeters are designed and studied for experiments at the ILC. We also study the reliability of the method with simulations. Although this method has been developped for a specific application, it can be used for any multi channel analysis.Comment: Public version of the CALICE Internal Note CIN-02

Neural evidence for lexical parafoveal processing

In spite of the reduced visual acuity, parafoveal information plays an important role in natural reading. However, competing models on reading disagree on whether words are previewed parafoveally at the lexical level. We find neural evidence for lexical parafoveal processing by combining a rapid invisible frequency tagging (RIFT) approach with magnetoencephalography (MEG) and eye-tracking. In a silent reading task, target words are tagged (flickered) subliminally at 60 Hz. The tagging responses measured when fixating on the pre-target word reflect parafoveal processing of the target word. We observe stronger tagging responses during pre-target fixations when followed by low compared with high lexical frequency targets. Moreover, this lexical parafoveal processing is associated with individual reading speed. Our findings suggest that reading unfolds in the fovea and parafovea simultaneously to support fluent reading

Markers of cognitive function in individuals with metabolic disease: Morquio Syndrome and Tyrosinemia Type III

We characterized cognitive function in two metabolic diseases. MPS–IVa (mucopolysaccharidosis IVa, Morquio) and tyrosinemia type III individuals were assessed using tasks of attention, language and oculomotor function. MPS–IVa individuals were slower in visual search, but the display size effects were normal, and slowing was not due to long reaction times (ruling out slow item processing or distraction). Maintaining gaze in an oculomotor task was difficult. Results implicated sustained attention and task initiation or response processing. Shifting attention, accumulating evidence and selecting targets were unaffected. Visual search was also slowed in tyrosinemia type III, and patterns in visual search and fixation tasks pointed to sustained attention impairments, although there were differences from MPS–IVa. Language was impaired in tyrosinemia type III but not MPS–IVa. Metabolic diseases produced selective cognitive effects. Our results, incorporating new methods for developmental data and model selection, illustrate how cognitive data can contribute to understanding function in biochemical brain systems

Designing Vibrotactile Widgets with Printed Actuators and Sensors

Physical controls are fabricated through complicated assembly of parts requiring expensive machinery and are prone to mechanical wear. One solution is to embed controls directly in interactive surfaces, but the proprioceptive part of gestural interaction that makes physical controls discoverable and usable solely by hand gestures is lost and has to be compensated, by vibrotactile feedback for instance. Vibrotactile actuators face the same aforementioned issues as for physical controls. We propose printed vibrotactile actuators and sensors. They are printed on plastic sheets, with piezoelectric ink for actuation, and with silver ink for conductive elements, such as wires and capacitive sensors. These printed actuators and sensors make it possible to design vibrotactile widgets on curved surfaces, without complicated mechanical assembly

Saccades are locked to the phase of alpha oscillations during natural reading

We saccade 3 to 5 times per second when reading. However, little is known about the neuronal mechanisms coordinating the oculomotor and visual systems during such rapid processing. Here, we ask if brain oscillations play a role in the temporal coordination of the visuomotor integration. We simultaneously acquired MEG and eye-tracking data while participants read sentences silently. Every sentence was embedded with a target word of either high or low lexical frequency. Our key finding demonstrated that saccade onsets were locked to the phase of alpha oscillations (8 to 13 Hz), and in particular, for saccades towards low frequency words. Source modelling demonstrated that the alpha oscillations to which the saccades were locked, were generated in the right-visual motor cortex (BA 7). Our findings suggest that the alpha oscillations serve to time the processing between the oculomotor and visual systems during natural reading, and that this coordination becomes more pronounced for demanding words