Co-activation of the amygdala, hippocampus and inferior frontal gyrus during autobiographical memory retrieval.

Functional MRI was used to investigate the role of medial temporal lobe and inferior frontal lobe regions in autobiographical recall. Prior to scanning, participants generated cue words for 50 autobiographical memories and rated their phenomenological properties using our autobiographical memory questionnaire (AMQ). During scanning, the cue words were presented and participants pressed a button when they retrieved the associated memory. The autobiographical retrieval task was interleaved in an event-related design with a semantic retrieval task (category generation). Region-of-interest analyses showed greater activation of the amygdala, hippocampus, and right inferior frontal gyrus during autobiographical retrieval relative to semantic retrieval. In addition, the left inferior frontal gyrus showed a more prolonged duration of activation in the semantic retrieval condition. A targeted correlational analysis revealed pronounced functional connectivity among the amygdala, hippocampus, and right inferior frontal gyrus during autobiographical retrieval but not during semantic retrieval. These results support theories of autobiographical memory that hypothesize co-activation of frontotemporal areas during recollection of episodes from the personal past.

Insight into CO Activation over Cu(100) under Electrochemical Conditions

The reduction of CO₂ on copper electrodes has attracted great attentions in the last decades, since it provides a sustainable approach for energy restore. During the CO₂ reduction process, the electron transfer to CO_ads is experimentally suggested to be the crucial step. In this work, we examine two possible pathways in CO activation, i.e. to generate COH_ads and CHO_ads, respectively, by performing the state-of-the-art constrained ab initio molecular dynamics simulations on the charged Cu(100) electrode under aqueous conditions, which is close to the realistic electrochemical condition. The free energy profile in the formation of COH_ads via the coupled proton and electron transfer is plotted. Furthermore, by Bader charge analyses, a linear relationship between C-O bond distance and the negative charge in CO fragment is unveiled. The formation of CHO_ads is identified to be a surface catalytic reaction, which requires the adsorption of H atom on the surface first. By comparing these two pathways, we demonstrate that kinetically the formation of COH_ads is more favored than that of CHO_ads, while CHO_ads is thermodynamically more stable. This work reveals that CO activation via COH_ads intermediate is an important pathway in electrocatalysis, which could provide some insights into CO₂ electroreduction over Cu electrodes.

Co-activation of JAK/STAT and p38 MAPK pathways by type I interferon enhances apoptosis in human basophils

It has previously been published that interferon-α (type I IFN) improves clinical symptoms of asthma patients. Since human basophils are major inflammatory cells in maintaining chronic allergic asthma we investigate whether type I IFN affect human blood basophils. Furthermore, previous studies have shown that spontaneous apoptosis of human basophils is slow due to constitutive expression of anti-apoptotic BCL-2 family members. In addition, IL-3 exceptionally promotes survival of basophils by enhancing constitutive expression of BCL-2 family members and by inducing de-novo expression of Pim-1 kinase. Thus, we also assessed whether type I IFN might overcome IL-3-induced survival of human basophils. Our data show that type I IFN enhances apoptosis in purified human blood basophils compared to spontaneous apoptosis of controls or type II IFN treated cells. Furthermore, we demonstrate that both type I IFN and FasL enhance apoptosis in human basophils with similar efficiency in a rather additive than synergistic way. Analyses of signaling pathways reveal that type I IFN promote prolonged phosphorylation of STAT1/STAT2. By using a pan-JAK inhibitor the phosphorylation of STAT1/STAT2 is inhibited and most importantly the pro-apoptotic effect of type I IFN is abolished. On the other hand, type I IFN do not reduce IL-3-induced de novo expression of Pim-1 and BCL-2. This is in line with our observation that IL-3-induced survival is dominant over type I IFN-enhanced apoptosis. In addition, phosphorylation of p38 MAPK in type I IFN treated cells is comparable to non-treated cells. Particularly however, inhibition of this p-p38 activity abrogates apoptosis as well. We conclude that type I IFN-enhanced apoptosis is tightly regulated by the cooperation of JAK/STAT and p38 MAPK pathways. Our study identifies a so far unknown effect of type I IFN and may explain the improved clinical symptoms of asthma patients treated with type I IFN.

The effects of foam rolling on muscular co-activation around the knee joint

The major objectives of this thesis were to determine if foam rolling had any effect on antagonist muscle activation and whether those changes would alter muscular co-activation patterns. The results from this thesis along with current literature will help clinicians to develop adequate exercise prescription for rehabilitative and pre-activity purposes. The existing literature has shown that foam rolling or roller massagers can increase range of motion (ROM), improve performance, and alter pain perception, however little research exists regarding changes in muscle activation following foam rolling. This study developed a reliable method for measuring muscle activation around the knee joint and using that method found that foam rolling the quadriceps can impair hamstrings muscle activation likely due to greater levels of perceived pain when rolling the quadriceps.

Medial and lateral hamstrings and quadriceps co-activation affects knee joint kinematics and ACL elongation : a pilot study

Low-temperature oxidation of CO over Pd/CeO2-TiO2 catalysts with different pretreatments

A comprehensive study of the low-temperature oxidation of CO was conducted over Pd/TiO2, Pd/CeO2, and Pd/CeO2-TiO2 pretreated by a series of calcination and reduction processes. The catalysts were characterized by N-2 adsorption, XRD, H-2 chemisorption, and diffuse-reflectance infrared Fourier transform spectroscopy. The results indicated that Pd/CeO2-TiO2 has the highest activity among these catalysts, whether in the calcined state or in the reduced state. The activity of all of the catalysts can be improved significantly by the pre-reduction, and it seems that the reduction at low temperature (LTR. 150 degrees C) is more effective than that at high temperature (HTR, 500 degrees C), especially for Pd/CeO2 and Pd/TiO2. The catalysts with various supports and pretreatments are also different in the reaction mechanisms for CO oxidation at low temperature. Over Pd/TiO2, the reaction may proceed through a surface reaction between the weakly adsorbed CO and oxygen (Langmuir-Hinshelwood). For Ce-containing catalysts, however, an alteration of reaction mechanism with temperature and the involvement of the oxygen activation at different sites were observed, and the light-off profiles of the calcined Pd/CeO2 and Pd/CeOi-TiO2 show a distortion before CO conversion achieves 100%. At low temperature, CO oxidation proceeds mainly via the reaction between the adsorbed CO on Pd-0 sites and the lattice oxygen of surface CeO2 at the Pd-Ce interface, whereas at high temperature it proceeds via the reaction between the adsorbed CO and oxygen. The high activity of Pd/CeO2-TiO2 for the low-temperature CO oxidation was probably due to the enhancements of both CO activation, caused by the facilitated reduction of Pd2+ to Pd-0, and oxygen activation, through the improvement of the surface oxygen supply and the oxygen vacancies formation. The reduction pretreatment enhances metal-support interactions and oxygen vacancy formation and hence improves the activity of CO oxidation. (c) 2005 Elsevier Inc. All rights reserved.

Padrão de co-ativação dos músculos do tronco durante exercícios com haste oscilatória

This study aimed to compare trunk muscle co-activation pattern during exercises using an oscillatory pole. Twelve volunteers participated in this study, in which they performed three different exercises. EMG activity of internal oblique (IO), external oblique (EO), rectus abdominis (RA), multifidus (MU) and iliocostalis lumborum (IL) was collected. The EMG signals were analyzed in time domain (RMS) and muscles activation ratios were computed as follow: anterior-posterior (A/P=RA+EO+IO/MU+IL), MU/IL and OE/OI. The bilateral oscillation of the pole in frontal plane (exercise II) promoted a higher value of MU/IL ratio than unilateral oscillation of the pole in sagital plane (exercise III). Also, the bilateral oscillation of the pole in frontal plane (exercise II) and the unilateral oscillation of the pole in sagital plane (exercise III) caused higher values of the IO/EO than bilateral oscillation of the pole in transversal plane (exercise I). Thus, the exercises II and III required higher activation of trunk stabilizer muscles, being more indicate for training, which aims higher recruitment of these muscles in daily activities.

Análise da rotação ombro-quadril e co-contração muscular do tronco durante um movimento de rotação axial com manuseio de carga

Pós-graduação em Engenharia Mecânica - FEG

Spatio-temporal evaluation of neck muscle activation during postural perturbations in healthy subjects

The purpose of this study was to examine the spatio-temporal activation of the sternocleidomastoid (SCM) and cervical extensor (CE) muscles with respect to the deltoid muscle onset during rapid voluntary upper limb movement in healthy volunteers. The repeatability and reliability of the spatio-temporal aspects of the myoelectric signals were also examined. Ten subjects performed bilateral and unilateral rapid upper limb flexion, abduction and extension in response to a visual stimulus. EMG onsets and normalised root mean square (nRMS) values were calculated for the SCM and CE muscles. Subjects attended three testing sessions over non-consecutive days allowing the repeatability and reliability of these measures to be assessed. The SCM and CE muscles demonstrated feed-forward activation (activation within 50 ms of deltoid onset) during rapid arm movements in all directions. The sequence and magnitude of neck muscle activation displayed directional specificity, however, the neck flexor and extensor muscles displayed co-activation during all perturbations. EMG onsets demonstrated high repeatability in terms of repeated measure precision (nSEM in the range 1.9-5.7%). This was less evident for the repeatability of nRMS values. The results of this study provide a greater understanding of cervical neuromotor control strategies. During bilateral and unilateral upper limb perturbations, the SCM and CE muscles demonstrate feed-forward co-activation. It seems apparent that feed-forward activation of neck muscles is a mechanism necessary to achieve stability for the visual and vestibular systems, whilst ensuring stabilisation and protection of the cervical spine. (C) 2004 Elsevier Ltd. All rights reserved.

Androgen-regulated genes differentially modulated by the androgen receptor coactivator L-dopa decarboxylase in human prostate cancer cells

Background The androgen receptor is a ligand-induced transcriptional factor, which plays an important role in normal development of the prostate as well as in the progression of prostate cancer to a hormone refractory state. We previously reported the identification of a novel AR coactivator protein, L-dopa decarboxylase (DDC), which can act at the cytoplasmic level to enhance AR activity. We have also shown that DDC is a neuroendocrine (NE) marker of prostate cancer and that its expression is increased after hormone-ablation therapy and progression to androgen independence. In the present study, we generated tetracycline-inducible LNCaP-DDC prostate cancer stable cells to identify DDC downstream target genes by oligonucleotide microarray analysis. Results Comparison of induced DDC overexpressing cells versus non-induced control cell lines revealed a number of changes in the expression of androgen-regulated transcripts encoding proteins with a variety of molecular functions, including signal transduction, binding and catalytic activities. There were a total of 35 differentially expressed genes, 25 up-regulated and 10 down-regulated, in the DDC overexpressing cell line. In particular, we found a well-known androgen induced gene, TMEPAI, which wasup-regulated in DDC overexpressing cells, supporting its known co-activation function. In addition, DDC also further augmented the transcriptional repression function of AR for a subset of androgen-repressed genes. Changes in cellular gene transcription detected by microarray analysis were confirmed for selected genes by quantitative real-time RT-PCR. Conclusion Taken together, our results provide evidence for linking DDC action with AR signaling, which may be important for orchestrating molecular changes responsible for prostate cancer progression.

Functional adaptation and rehabilitation following total knee replacement

This research project evaluated the biomechanical and functional outcomes of patients following total knee replacement measured at 6 and 12 months following surgery. Using more objective measures, patients were examined to determine changes in biomechanical and neuromuscular function during performance of activities of daily living such as walking, stair climbing and turning. Adaptations in joint positioning and performance were identified and progressive improvements were made in some areas of locomotor function. The findings of the study provided important objective information to contribute to the design and evaluation of prostheses, new surgical and rehabilitation procedures and improved recovery of patients.

GABAA and NMDA receptors contribute to synaptic integration in lateral amygdala neurons

In classical fear conditioning a neutral conditioned stimulus (CS), is paired with an aversive unconditioned stimulus (US). The CS thereby acquires the capacity to elicit a fear response. This type of associative learning is thought to require co-activation of principal neurons in the lateral nucleus of the amygdala (LA) by two sets of synaptic inputs...

GABAa receptors contribute to synaptic integration in lateral amygdala neurons

In classical fear conditioning a neutral conditioned stimulus (CS) such as a tone, is paired with an aversive unconditioned stimulus (US) such as a shock. The CS thereby acquires the capacity to elicit a fear response. This type of associative learning is thought to require co-activation of principle neurons in the lateral nucleus of the amygdala (LA) by two sets of synaptic inputs, a weak CS and a strong US...

Tactile processing in human somatosensory and auditory cortices

Tactile sensation plays an important role in everyday life. While the somatosensory system has been studied extensively, the majority of information has come from studies using animal models. Recent development of high-resolution anatomical and functional imaging techniques has enabled the non-invasive study of human somatosensory cortex and thalamus. This thesis provides new insights into the functional organization of the human brain areas involved in tactile processing using magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI). The thesis also demonstrates certain optimizations of MEG and fMRI methods. Tactile digit stimulation elicited stimulus-specific responses in a number of brain areas. Contralateral activation was observed in somatosensory thalamus (Study II), primary somatosensory cortex (SI; I, III, IV), and post-auditory belt area (III). Bilateral activation was observed in secondary somatosensory cortex (SII; II, III, IV). Ipsilateral activation was found in the post-central gyrus (area 2 of SI cortex; IV). In addition, phasic deactivation was observed within ipsilateral SI cortex and bilateral primary motor cortex (IV). Detailed investigation of the tactile responses demonstrated that the arrangement of distal-proximal finger representations in area 3b of SI in humans is similar to that found in monkeys (I). An optimized MEG approach was sufficient to resolve such fine detail in functional organization. The SII region appeared to contain double representations for fingers and toes (II). The detection of activations in the SII region and thalamus improved at the individual and group levels when cardiac-gated fMRI was used (II). Better detection of body part representations at the individual level is an important improvement, because identification of individual representations is crucial for studying brain plasticity in somatosensory areas. The posterior auditory belt area demonstrated responses to both auditory and tactile stimuli (III), implicating this area as a physiological substrate for the auditory-tactile interaction observed in earlier psychophysical studies. Comparison of different smoothing parameters (III) demonstrated that proper evaluation of co-activation should be based on individual subject analysis with minimal or no smoothing. Tactile input consistently influenced area 3b of the human ipsilateral SI cortex (IV). The observed phasic negative fMRI response is proposed to result from interhemispheric inhibition via trans-callosal connections. This thesis contributes to a growing body of human data suggesting that processing of tactile stimuli involves multiple brain areas, with different spatial patterns of cortical activation for different stimuli.