Space and time in the parietal cortex: fMRI Evidence for a meural asymmetry

How are space and time related in the brain? This study contrasts two proposals that make different predictions about the interaction between spatial and temporal magnitudes. Whereas ATOM implies that space and time are symmetrically related, Metaphor Theory claims they are asymmetrically related. Here we investigated whether space and time activate the same neural structures in the inferior parietal cortex (IPC) and whether the activation is symmetric or asymmetric across domains. We measured participants’ neural activity while they made temporal and spatial judgments on the same visual stimuli. The behavioral results replicated earlier observations of a space-time asymmetry: Temporal judgments were more strongly influenced by irrelevant spatial information than vice versa. The BOLD fMRI data indicated that space and time activated overlapping clusters in the IPC and that, consistent with Metaphor Theory, this activation was asymmetric: The shared region of IPC was activated more strongly during temporal judgments than during spatial judgments. We consider three possible interpretations of this neural asymmetry, based on 3 possible functions of IPC

The nature of semantic priming by subliminal spatial words: Embodied or disembodied?

Theories of embodied semantics (ES) suggest that a critical part of understanding what a word means consists of simulating the sensorimotor experience related to the word's referent. Some proponents of ES have suggested that sensorimotor activations are mandatory and highly automatic during semantic processing. Evidence supporting this claim comes from masked priming studies showing that unconsciously perceived spatial words (e.g., up, down) can directly modulate action performance on the basis of their meaning. However, a closer look reveals that such priming effects can be explained also in terms of symbolic (disembodied) semantic priming or nonsemantic mechanisms. In this study we sought to understand whether sensorimotor processing takes place during language understanding outside awareness. We used spatial words as a test bed and across 6 experiments we teased apart the possibility that action priming could be explained by: (a) nonsemantic mechanisms, (b) symbolic semantic priming, or (c) embodied semantic priming. The critical finding is that when symbolic and nonsemantic mechanisms were prevented, allowing only for a genuinely embodied semantic priming, no effect was found. Conversely, facilitation emerged in the same experimental paradigm when embodied priming was prevented and symbolic priming was allowed. Despite extensive testing, we found no evidence that unconsciously perceived words can activate sensorimotor processes, although these words are processed up to the semantic level. We thus conclude that sensorimotor activations might need conscious access to emerge during language understanding. (PsycINFO Database Recor

Exploring the interaction between handedness and body parts ownership by means of the Implicit Association Test

The experience of owning a body is built upon the integration of exteroceptive, interoceptive, and proprioceptive signals. Recently, it has been suggested that motor signals could be particularly important in producing the feeling of body part ownership. One thus may hypothesize that the strength of this feeling may not be spatially uniform; rather, it could vary as a function of the degree by which different body parts are involved in motor behavior. Given that our dominant hand plays a leading role in our motor behavior, we hypothesized that it could be more strongly associated with one’s self compared to its non-dominant counterpart. To explore whether this possible asymmetry manifests as a stronger implicit association of the right hand (vs left hand) with the self, we administered the Implicit Association Test to a group of 70 healthy individuals. To control whether this asymmetric association is human-body specific, we further tested whether a similar asymmetry characterizes the association between a right (vs left) animal body part with the concept of self, in an independent sample of subjects (N = 70, 140 subjects total). Our results revealed a linear relationship between the magnitude of the implicit association between the right hand with the self and the subject’s handedness. In detail, the strength of this association increased as a function of hand preference. Critically, the handedness score did not predict the association of the right-animal body part with the self. These findings suggest that, in healthy individuals, the dominant and non-dominant hands are differently perceived at an implicit level as belonging to the self. We argue that such asymmetry may stem from the different roles that the two hands play in our adaptive motor behavior

Urised As An Alternative To Phase-contrast Microscopy In The Differentiation Between Glomerular And Non-glomerular Hematuria

Background: Differentiation between glomerular and non-glomerular hematuria by observation of the erythrocyte morphology using phase-contrast is a time-consuming and labor-intensive procedure that requires skilled personnel. This paper has the purpose to evaluate the performance of UriSed (also called sediMAX (R) in some countries) as an alternative to the phase-contrast microscopic analysis of erythrocyte morphology. Methods: 312 urine samples with hematuria were analyzed by UriSed and by phase-contrast microscopy. Based on the presence of codocytes and/or acanthocytes, samples were classified as non-glomerular and glomerular. Kappa correlation was used to assess the agreement between both methods. Results: Our data showed excellent agreement between erythrocyte morphology analyzed by both methods (r = 0.974, kappa = 0.9484, p <0.001) with only 8 samples presenting discordant results. Conclusions: UriSed proved to be a precise and accurate alternative to the gold standard phase-contrast microscopy.615/Jun64364

Frequency-based neural discrimination in fast periodic visual stimulation

Humans capitalize on statistical cues to discriminate fundamental units of information within complex streams of sensory input. We sought neural evidence for this phenomenon by combining fast periodic visual stimulation (FPVS) and EEG recordings. Skilled readers were exposed to sequences of linguistic items with decreasing familiarity, presented at a fast rate and periodically interleaved with oddballs. Crucially, each sequence comprised stimuli of the same category, and the only distinction between base and oddball items was the frequency of occurrence of individual tokens within a stream. Frequency-domain analyses revealed robust neural responses at the oddball presentation rate in all conditions, reflecting the discrimination between two locally-emerged groups of items purely informed by token frequency. Results provide evidence for a fundamental frequency-tuned mechanism that operates under high temporal constraints and could underpin category bootstrapping. Concurrently, they showcase the potential of FPVS for providing a direct neural measure of implicit statistical learning

Field reliability of GaAs emitters for fiber optic telecommunication systems

GaAs based emitters are widely used in telecommunication systems, and will be probably the core of short haul communications, even if a lot of doubts still exist on their reliability and the few available field results are not too optimistic. For these reasons we decided to follow with a particular attention all the problems related to these devices, investigating reliability by means of accelerated tests and of an accurate survey of field troubles. In this paper, we first of all report our field data, coming from more than five years experience, which show that "reasonable" results (in the range of 2000 FITs for LDs), can be obtained with commercially available devices; as a second step, failure analysis allows to localize failures,thus understanding the appropriate corrective actions to be taken. highlighting the specific process report also same For chip related failures, detailed examples are reported, different failure mechanisms, that, when not related to defects, are the same found during accelerated tests; we examples of failures due to interconnections and packaging

A redshift survey towards the CMB Cold Spot

We have carried out a redshift survey using the VIMOS spectrograph on the VLT towards the Cosmic Microwave Background cold spot. A possible cause of the cold spot is the Integrated Sachs-Wolfe effect imprinted by an extremely large void (hundreds of Mpc in linear dimension) at intermediate or low redshifts. The redshift distribution of over seven hundred z<1 emission-line galaxies drawn from an I-band flux limited sample of galaxies in the direction of the cold spot shows no evidence of a gap on scales of Delta-z> 0.05 as would be expected if such a void existed at 0.35<z<1. There are troughs in the redshift distribution on smaller scales (Delta-z ~0.01) indicating that smaller scale voids may connect regions separated by several degrees towards the cold spot. A comparison of this distribution with that generated from similarly-sized subsamples drawn from widely-spaced pointings of the VVDS survey does not indicate that the redshift distribution towards the cold spot is anomalous or that these small gaps can be uniquely attributed to real voids.Comment: MNRAS in press, 6 page