23 documents found, page 1 of 3
Scaling the assessment of emotion regulation effectiveness with a low-cost psyc...
Moreira, Pedro Miguel Silva; Chaves, Pedro; Almeida, Pedro R.; Dias, N. S.In this work, we assessed the reliability of a low-cost psychophysiological system - the James One device - to monitor the electrodermal activity during an emotion induction paradigm. We observed that during emotional expression in response to negative stimuli, participants displayed increased amplitudes of the skin conductance responses, in comparison to the natural observation of neutral pictures and to emoti...
Wireless and wearable EEG acquisition platform for ambulatory monitoring
Pinho, F. T.; Correia, J. H.; Sousa, N. J.; Cerqueira, João José; Dias, N. S.Electroencephalogram (EEG) Ambulatory monitoring has been regarded as a promising tool to improve diagnosis, classification and medication prescription in patients with epilepsy and other paroxysmal diseases. This study presents the development of a wireless and wearable EEG acquisition system for ambulatory monitoring. The platform comprises 32 active dry electrodes, an analog-to-digital conversion unit with 2...
Chronic stress disrupts neural coherence between cortico-limbic structures
Oliveira, João F.; Dias, N. S.; Correia, Mariana; Pereira, Filipa Gama; Sardinha, Vanessa Morais; Lima, Ana Raquel; Oliveira, Ana Filipa MartinsChronic stress impairs cognitive function, namely on tasks that rely on the integrity of cortico-limbic networks. To unravel the functional impact of progressive stress in cortico-limbic networks we measured neural activity and spectral coherences between the ventral hippocampus (vHIP) and the medial prefrontal cortex (mPFC) in rats subjected to short term stress (STS) and chronic unpredictable stress (CUS). CU...
Stress affects theta activity in limbic networks and impairs novelty-induced ex...
Jacinto, L. R.; Reis, Joana Vanessa Santos dos; Dias, N. S.; Cerqueira, João; Correia, José H.; Sousa, NunoExposure to a novel environment triggers the response of several brain areas that regulate emotional behaviors. Here, we studied theta oscillations within the hippocampus (HPC)-amygdala (AMY)-medial prefrontal cortex (mPFC) network in exploration of a novel environment and subsequent familiarization through repeated exposures to that same environment; in addition, we assessed how concomitant stress exposure cou...
3 mm deep microelectrode needle array based on aluminum for neural applications
Peixoto, Alexandre Coumiotis Moreira; Gonçalves, Sandra Beatriz Tomé; Ferreira da Silva, Alexandre; Dias, N. S.; Correia, J. H.This paper presents a simple and cost-effective fabrication method of invasive neural microelectrode arrays based on aluminum, which is a viable alternative to other state-of-the-art technologies that rely primarily on silicon. A 10 x 10 array with 3.0 mm deep reaching pillars were fabricated, each having a pyramidal tip profile. Each aluminum pillar is insulated with a biocompatible layer of aluminum oxide. Th...
Wireless instrumentation system based on dry electrodes for acquiring EEG signals
Dias, N. S.; Carmo, João Paulo Pereira; Mendes, P. M.; Correia, J. H.This paper presents a complete non-invasive Wireless acquisition system based on dry electrodes for electroencephalograms (WiDE-EEG) with emphasis in the electronic system design. The WiDE-EEG is composed by a 2.4GHz radio-frequency (RF) transceiver, biopotential acquisition electronics and dry electrodes. The WiDE-EEG can acquire electroencephalogram (EEG) signals from 5 unipolar channels, with a resolution of...
High-aspect-ratio neural electrode array fabrication using thermomigration process
Peixoto, A. C.; Silva, A. F.; Dias, N. S.; Correia, J. H.A novel fabrication process for a high-aspect-ratio recording and stimulation intracortical neural microelectrode array is described. Using a combination of dicing and KOH wet-etching, microspikes are formed on the surface of a n-type (100), 4 mm thick, silicon wafer. Deep 3 mm cuts are performed in order to produce sharped tip pillars of high-aspect-ratio (0.2x0.2x3 mm). Thermomigration is employed as a select...
Microsystems for wireless sensor networks with biomedical applications
Carmo, João Paulo Pereira; Dias, N. S.; Correia, J. H.This chapter introduces the concept of wireless interface, followed by the discussion of the fundamental items, concerning the fabrication of microsystems comprising low-power devices. Using as example, a design of a RF transceiver the frequency of 2.4 GHz and fabricated using a UMC RF CMOS 0.18 µm process, it will be discussed the main issues in the design of RF transceivers for integration in wireless microsy...
Microneedle array fabrication based on thermomigration
Peixoto, A. C.; Silva, A. F.; Dias, N. S.; Correia, J. H.This paper introduces a method to manufacture microneedle arrays, using a combination of low-cost microfabrication techniques namely, thermomigration, wet-etching KOH solution and thin-film deposition.
Invasive neural electrodes structure fabrication based on aluminum wafers
Peixoto, A. C.; Silva, A. F.; Dias, N. S.; Correia, J. H.Over the last two decades, many researchers have developed a variety of neural electrode types, taking full advantage of silicon microtechnologies. Silicon wafers became the raw structural material for the majority of the developed electrodes, and several techniques had to be studied and established in order to fabricate a feasible silicon-based neural probe. This paper shows an alternative raw material for the...