Entity

Time filter

Source Type


Escolano C.,Institute Investigacion En Ingenieria Of Aragon I3A | Navarro-Gil M.,Bit and Brain Technologies S.L. | Garcia-Campayo J.,University of Zaragoza | Minguez J.,Institute Investigacion En Ingenieria Of Aragon I3A
Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS | Year: 2013

Conditioning of the upper-alpha rhythm to improve cognitive performance in healthy users by means of neurofeedback (NF) has been evaluated by several studies, however its effectiveness in people with severe cognitive deficits, such as depressive subjects, remains underexplored. This paper reports on a preliminary uncontrolled study to assess the effects of an upper-alpha NF intervention on patients with major depressive disorder (MDD). The NF effects on the EEG and cognitive performance were assessed. The EEG results showed that patients were able to modulate the upper-alpha rhythm in task-related EEG and during training, in both cases across the executions of the NF sessions, and pre and post within each session. The behavioral results showed the effectiveness of this intervention in a variety of cognitive functions such as working memory, attention, and executive functions. © 2013 IEEE. Source


Sola I.J.,University of Salamanca | Collados M.V.,Institute Investigacion En Ingenieria Of Aragon I3A | Atencia J.,Institute Investigacion En Ingenieria Of Aragon I3A | Varela O.,University of Salamanca | And 4 more authors.
Applied Physics B: Lasers and Optics | Year: 2012

We have designed and developed a pulse compressor with volume transmission holographic gratings to be implemented in post-compression experiments based on filamentation in gases. Pulse compression down to 13 fs has been demonstrated. The gratings have been recorded in commercial PFG-04 dichromated gelatin emulsions with a recording wavelength of 532 nm, attaining sufficient index modulation to achieve high efficiency when they are illuminated by an 800-nm laser. © Springer-Verlag 2011. Source


Lopez-Larraz E.,University of Zaragoza | Lopez-Larraz E.,Institute Investigacion En Ingenieria Of Aragon I3A | Montesano L.,University of Zaragoza | Montesano L.,Institute Investigacion En Ingenieria Of Aragon I3A | And 5 more authors.
PLoS ONE | Year: 2015

Spinal cord injury (SCI) does not only produce a lack of sensory and motor function caudal to the level of injury, but it also leads to a progressive brain reorganization. Chronic SCI patients attempting to move their affected limbs present a significant reduction of brain activation in the motor cortex, which has been linked to the deafferentation. The aim of this work is to study the evolution of the motor-related brain activity during the first months after SCI. Eighteen subacute SCI patients were recruited to participate in bi-weekly experimental sessions during at least two months. Their EEG was recorded to analyze the temporal evolution of the event-related desynchronization (ERD) over the motor cortex, both during motor attempt and motor imagery of their paralyzed hands. The results show that the α and β ERD evolution after SCI is negatively correlated with the clinical progression of the patients during the first months after the injury. This work provides the first longitudinal study of the event-related desynchronization during the subacute phase of spinal cord injury. Furthermore, our findings reveal a strong association between the ERD changes and the clinical evolution of the patients. These results help to better understand the brain transformation after SCI, which is important to characterize the neuroplasticity mechanisms involved after this lesion and may lead to new strategies for rehabilitation and motor restoration of these patients. © 2015 López-Larraz et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Source


Iturrate I.,Institute Investigacion En Ingenieria Of Aragon I3A | Iturrate I.,University of Zaragoza | Montesano L.,Institute Investigacion En Ingenieria Of Aragon I3A | Montesano L.,University of Zaragoza | And 3 more authors.
Journal of Neural Engineering | Year: 2013

Objective. A major difficulty of brain-computer interface (BCI) technology is dealing with the noise of EEG and its signal variations. Previous works studied time-dependent non-stationarities for BCIs in which the user's mental task was independent of the device operation (e.g., the mental task was motor imagery and the operational task was a speller). However, there are some BCIs, such as those based on error-related potentials, where the mental and operational tasks are dependent (e.g., the mental task is to assess the device action and the operational task is the device action itself). The dependence between the mental task and the device operation could introduce a new source of signal variations when the operational task changes, which has not been studied yet. The aim of this study is to analyse task-dependent signal variations and their effect on EEG error-related potentials.Approach. The work analyses the EEG variations on the three design steps of BCIs: an electrophysiology study to characterize the existence of these variations, a feature distribution analysis and a single-trial classification analysis to measure the impact on the final BCI performance.Results and significance. The results demonstrate that a change in the operational task produces variations in the potentials, even when EEG activity exclusively originated in brain areas related to error processing is considered. Consequently, the extracted features from the signals vary, and a classifier trained with one operational task presents a significant loss of performance for other tasks, requiring calibration or adaptation for each new task. In addition, a new calibration for each of the studied tasks rapidly outperforms adaptive techniques designed in the literature to mitigate the EEG time-dependent non-stationarities. © 2013 IOP Publishing Ltd. Source


Aparicio L.C.,University of Zaragoza | Aparicio L.C.,A+ Network | Segarra J.,University of Zaragoza | Segarra J.,Institute Investigacion En Ingenieria Of Aragon I3A | And 6 more authors.
Journal of Systems Architecture | Year: 2011

In multitasking real-time systems it is required to compute the WCET of each task and also the effects of interferences between tasks in the worst case. This is very complex with variable latency hardware, such as instruction cache memories, or, to a lesser extent, the line buffers usually found in the fetch path of commercial processors. Some methods disable cache replacement so that it is easier to model the cache behavior. The difficulty in these cache-locking methods lies in obtaining a good selection of the memory lines to be locked into cache. In this paper, we propose an ILP-based method to select the best lines to be loaded and locked into the instruction cache at each context switch (dynamic locking), taking into account both intra-task and inter-task interferences, and we compare it with static locking. Our results show that, without cache, the spatial locality captured by a line buffer doubles the performance of the processor. When adding a lockable instruction cache, dynamic locking systems are schedulable with a cache size between 12.5% and 50% of the cache size required by static locking. Additionally, the computation time of our analysis method is not dependent on the number of possible paths in the task. This allows us to analyze large codes in a relatively short time (100 KB with 1065 paths in less than 3 min). © 2011 Elsevier B.V. All rights reserved. Source

Discover hidden collaborations