Judging Time-to-Passage of looming sounds: evidence for the use of distance-based information

Perceptual judgments are an essential mechanism for our everyday interaction with other moving agents or events. For instance, estimation of the time remaining before an object contacts or passes us is essential to act upon or to avoid that object. Previous studies have demonstrated that participants use different cues to estimate the time to contact or the time to passage of approaching visual stimuli. Despite the considerable number of studies on the judgment of approaching auditory stimuli, not much is known about the cues that guide listeners’ performance in an auditory Time-to-Passage (TTP) task. The present study evaluates how accurately participants judge approaching white-noise stimuli in a TTP task that included variable occlusion periods (portion of the presentation time where the stimulus is not audible). Results showed that participants were able to accurately estimate TTP and their performance, in general, was weakly affected by occlusion periods. Moreover, we looked into the psychoacoustic variables provided by the stimuli and analysed how binaural cues related with the performance obtained in the psychophysical task. The binaural temporal difference seems to be the psychoacoustic cue guiding participants’ performance for lower amounts of occlusion, while the binaural loudness difference seems to be the cue guiding performance for higher amounts of occlusion. These results allowed us to explain the perceptual strategies used by participants in a TTP task (maintaining accuracy by shifting the informative cue for TTP estimation), and to demonstrate that the psychoacoustic cue guiding listeners’ performance changes according to the occlusion period.This study was supported by: Bial FoundationGrant 143/14 (https://www.bial.com/en/bial_foundation.11/11th_symposium.219/ fellows_preliminary_results.235/fellows_ preliminary_results.a569.html); FCT PTDC/EEAELC/112137/2009 (https://www.fct.pt/apoios/projectos/consulta/vglobal_projecto?idProjecto=112137&idElemConcurso=3628); and COMPETE: POCI-01-0145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio

Circulation and Oxygen Distribution in the Tropical Atlantic Cruise No. 80, Leg 1; October 26 to November 23, 2009 Mindelo (Cape Verde) to Mindelo (Cape Verde)

METEOR cruise 80/1 was a contribution to the SFB 754 “Climate-Biogeochemistry Interactions in the Tropical Ocean”. Shipboard, glider and moored observations are used to study the temporal and spatial variability of physical and biogeochemical parameters within the oxygen minimum zone (OMZ) of the tropical North Atlantic. As part of the BMBF “Nordatlantik” project, it further focuses on the equatorial current system including the Equatorial Undercurrent (EUC) and intermediate currents below. During the cruise, hydrographic station observations were performed using a CTD/O2 rosette, including water sampling for salinity, oxygen, nutrients and other biogeochemical tracers. Underway current measurements were successfully carried out with the 75 kHz ADCP borrowed from R/V POSEIDON during the first part of the cruise, and R/V METEOR’s 38 kHz ADCP during the second part. During M80/1, an intensive mooring program was carried out with 8 mooring recoveries and 8 mooring deployments. Right at the beginning of the cruise, a multidisciplinary mooring near the Cape Verde Islands was recovered and redeployed. Within the framework of SFB 754, two moorings with CTD/O2 profilers were recovered and redeployed with other instrumentation in the center and at the southern rim of the OMZ of the tropical North Atlantic. The equatorial mooring array as part of BMBF “North Atlantic” project consists of 5 current meter moorings along 23°W between 2°S and 2°N. It is aimed at quantifying the variability of the thermocline water supply toward the equatorial cold tongue which develops east of 10°W during boreal summer. Several glider missions were performed during the cruise. One glider was recovered that was deployed two months earlier. Another glider was deployed for two short term missions, near the equator for about 8 days and near 8°N for one day. This glider was equipped with a new microstructure probe in addition to standard sensors, i.e. CTD/O2, chlorophyll and turbidity

Human Umbilical Cord Blood Cells Restore Brain Damage Induced Changes in Rat Somatosensory Cortex

Intraperitoneal transplantation of human umbilical cord blood (hUCB) cells has been shown to reduce sensorimotor deficits after hypoxic ischemic brain injury in neonatal rats. However, the neuronal correlate of the functional recovery and how such a treatment enforces plastic remodelling at the level of neural processing remains elusive. Here we show by in-vivo recordings that hUCB cells have the capability of ameliorating the injury-related impairment of neural processing in primary somatosensory cortex. Intact cortical processing depends on a delicate balance of inhibitory and excitatory transmission, which is disturbed after injury. We found that the dimensions of cortical maps and receptive fields, which are significantly altered after injury, were largely restored. Additionally, the lesion induced hyperexcitability was no longer observed in hUCB treated animals as indicated by a paired-pulse behaviour resembling that observed in control animals. The beneficial effects on cortical processing were reflected in an almost complete recovery of sensorimotor behaviour. Our results demonstrate that hUCB cells reinstall the way central neurons process information by normalizing inhibitory and excitatory processes. We propose that the intermediate level of cortical processing will become relevant as a new stage to investigate efficacy and mechanisms of cell therapy in the treatment of brain injury

Comparative proteomics using 2-D gel electrophoresis and mass spectrometry as tools to dissect stimulons and regulons in bacteria with sequenced or partially sequenced genomes

We propose two-dimensional gel electrophoresis (2-DE) and mass spectrometry to define the protein components of regulons and stimulons in bacteria, including those organisms where genome sequencing is still in progress. The basic 2-DE protocol allows high resolution and reproducibility and enables the direct comparison of hundreds or even thousands of proteins simultaneously. To identify proteins that comprise stimulons and regulons, peptide mass fingerprint (PMF) with matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI-TOF-MS) analysis is the first option and, if results from this tool are insufficient, complementary data obtained with electrospray ionization tandem-MS (ESI-MS/MS) may permit successful protein identification. ESI-MS/MS and MALDI-TOF-MS provide complementary data sets, and so a more comprehensive coverage of a proteome can be obtained using both techniques with the same sample, especially when few sequenced proteins of a particular organism exist or genome sequencing is still in progress

Effects of hypoxic ischemic brain injury and hUCB treatment on receptive field (RF) and cortical map size.

<p>a) In lesioned rats the size of the left cortical hindpaw (HP) representation was significantly reduced after hypoxic ischemic brain injury (HI) (p = 0.005 vs. controls, p = 0.004 vs. contralateral hemisphere). Treatment with hUCB cells prevented map changes in the left cortical HP representation. b)–d) images of the cortical surface of the left hemisphere of a control (b), lesioned (c) and hUCB treated rat (d). Numbers indicate penetration sites, x indicate non-cutaneous responses, hl hindlimb. Borders of the maps are outlined. Scale bar 1 mm. e) In lesioned rats RF size of the right HP was increased (p = 0.007 vs. controls, p = 0.03 vs. HP ipsilateral to the lesion). hUCB treatment lead to moderate RF increase, not significantly different from controls (p = 0.558). Bars represent s.e.m. f–h) examples of RFs on the right and left HP for a control (f), lesioned (g) and hUCB treated rat (h). Number of rats used: control group n =  10, lesion group n =  17, hUCB group n =  6. A total of 975 RFs were recorded (left hemisphere: control 127: lesioned 97, treated 85; right hemisphere: control 192, lesioned 327, treated 147).</p

Histological and immunohistological analysis of brains.

<p>In Klüver-Barrera stained sections animals of the lesion group (a) and the transplantation group (b) showed clear cystic infarction within the left hemispheres, accompanied by an enlargement of the lateral ventricle and partial destruction of the hippocampus. Immunohistochemical detection of CD68 (green) and cleaved-caspase-3 expression (red) point to the occurrence of inflammation and apoptotic cell death in left hemispheres of animals of the lesion group (c) and transplantation group (d). In contrast, left hemispheres of control animals and right hemispheres of all animals were devoid of CD68 and cleaved-caspase-3 immunosignals (not shown). Immunohistochemical detection of HLA-DR demonstrated the presence of hUCB cells in the vicinity of the lesion in the transplantation group only (f), which are absent in the lesioned brain (e). No HLA-DR positive cells could be detected contralateral to the lesion in both the groups of lesioned (g) and transplanted rats (h). Scale bar left: 5 mm, scale bar right: 50 µm.</p

Length profiles of RFs.

<p>Percent activity evoked at three locations along the distal-proximal axis of the paw normalized to the activity recorded at the RF center. Data for RFs located on the heel are shown in a) and c), data for RFs with centers on the toe are depicted in b) and d). Top: recordings from the right, intact hemisphere, bottom: recordings from the left hemisphere. Stimulation locations on the paw are shown in the figurines in e). The distance from the RF centre at which 50% of neuronal activity (dashed line) was reached is indicated by arrows. Error bars represent s.e.m. For stimulation of the left paw in all groups comparable length profiles were obtained. In contrast, following stimulation of the right paw, significant differences (asterisks indicate significant differences p<0.05) were found for the length profiles obtained for control vs. lesioned animals, and for lesioned vs. treated animals, but not between control and treated rats. PSTHs recorded from neurons in the left hemisphere, whose RFswere located on the toes in control (f), lesioned (g) and transplanted rats (h) following tactile stimulation at the toe, pad, and heel. Whereas the activity evoked by stimulation on the pad and heel is low in controls (f), we found substantially enhanced activity after pad and heel stimulation in lesioned rats (g). In hUCB treated animals the activity pattern was comparable to control animals lacking the activation observed after pad and heel stimulation found in lesioned rats (h). Number of rats used: control group n =  7, lesion group n =  10, hUCB group n =  5. A total of 153 length profiles were recorded (left hemisphere: control 23: lesioned 24, treated 30; right hemisphere: control 24, lesioned 24, treated 28.</p

Time line of the experiments.

<p>Time line of the experiments, indicating the time points of the surgery, the treatment and the electrophysiological and behavioural experiments.</p