109 research outputs found
Effects of reinforcement learning on gaze following of gaze and head direction in early infancy: An interactive eyeâtracking study
The current four experiments investigated gaze following behavior in response to gaze and head turns in 4âmonthâolds and how reinforcement learning influences this behavior (N = 99). Using interactive eye tracking, infantsâ gaze elicited an animation whenever infants followed a personâs head or gaze orientation (Experiment 1.1, 2.1 and 2.2) or looked at the opposite side (Experiment 1.2). Infants spontaneously followed the direction of a turning head with and without simultaneously shifted gaze direction (Cohenâs d: 0.93â1.05) but not the direction of isolated gaze shifts. We only found a weak effect of reinforcement on gaze following in one of the four experiments. Results will be discussed with regard to the impact of reinforcement on the maintenance of already existing gaze following behavior
Interpersonal neural synchrony when predicting othersâ actions during a game of rock-paper-scissors
As members of a social species, we spend most of our time interacting with others. In interactions, we tend to mutually align our behavior and brain responses to communicate more effectively. In a semi-computerized version of the Rock-Paper-Scissors game, we investigated whether people show enhanced interpersonal neural synchronization when making explicit predictions about othersâ actions. Across four experimental conditions, we measured the dynamic brain activity using the functional near-infrared spectroscopy (fNIRS) hyperscanning method. Results showed that interpersonal neural synchrony was enhanced when participants played the game together as they would do in real life in comparison to when they played the game on their own. We found no evidence of increased neural synchrony when participants made explicit predictions about othersâ actions. Hence, neural synchrony may depend on mutual natural interaction rather than an explicit prediction strategy. This study is important, as it examines one of the presumed functions of neural synchronization namely facilitating predictions
DEEP: A dual EEG pipeline for developmental hyperscanning studies
Cutting-edge hyperscanning methods led to a paradigm shift in social neuroscience. It allowed researchers to measure dynamic mutual alignment of neural processes between two or more individuals in naturalistic contexts. The ever-growing interest in hyperscanning research calls for the development of transparent and validated data analysis methods to further advance the field. We have developed and tested a dual electroencephalography (EEG) analysis pipeline, namely DEEP. Following the preprocessing of the data, DEEP allows users to calculate Phase Locking Values (PLVs) and cross-frequency PLVs as indices of inter-brain phase alignment of dyads as well as time-frequency responses and EEG power for each participant. The pipeline also includes scripts to control for spurious correlations. Our goal is to contribute to open and reproducible science practices by making DEEP publicly available together with an example mother-infant EEG hyperscanning dataset
Visual category representations in the infant brain
Visual categorization is a human core cognitive capacity1,2 that depends on the development of visual category representations in the infant brain.3,4,5,6,7 However, the exact nature of infant visual category representations and their relationship to the corresponding adult form remains unknown.8 Our results clarify the nature of visual category representations from electroencephalography (EEG) data in 6- to 8-month-old infants and their developmental trajectory toward adult maturity in the key characteristics of temporal dynamics,2,9 representational format,10,11,12 and spectral properties.13,14 Temporal dynamics change from slowly emerging, developing representations in infants to quickly emerging, complex representations in adults. Despite those differences, infants and adults already partly share visual category representations. The format of infants' representations is visual features of low to intermediate complexity, whereas adults' representations also encode high-complexity features. Theta band activity contributes to visual category representations in infants, and these representations are shifted to the alpha/beta band in adults. Together, we reveal the developmental neural basis of visual categorization in humans, show how information transmission channels change in development, and demonstrate the power of advanced multivariate analysis techniques in infant EEG research for theory building in developmental cognitive science
DEEP: A dual EEG pipeline for developmental hyperscanning studies
Cutting-edge hyperscanning methods led to a paradigm shift in social neuroscience. It allowed researchers to measure dynamic mutual alignment of neural processes between two or more individuals in naturalistic contexts. The ever-growing interest in hyperscanning research calls for the development of transparent and validated data analysis methods to further advance the field. We have developed and tested a dual electroencephalography (EEG) analysis pipeline, namely DEEP. Following the preprocessing of the data, DEEP allows users to calculate Phase Locking Values (PLVs) and cross-frequency PLVs as indices of inter-brain phase alignment of dyads as well as time-frequency responses and EEG power for each participant. The pipeline also includes scripts to control for spurious correlations. Our goal is to contribute to open and reproducible science practices by making DEEP publicly available together with an example mother-infant EEG hyperscanning dataset
Nanoscale plasmonic phenomena in CVD-grown MoS2 monolayer revealed by ultra- broadband synchrotron radiation based nano-FTIR spectroscopy and near-field microscopy
Nanoscale plasmonic phenomena observed in single and bi-layers of molybdenum
disulfide (MoS2) on silicon dioxide (SiO2) are reported. A scattering type
scanning near-field optical microscope (s-SNOM) with a broadband synchrotron
radiation (SR) infrared source was used. We also present complementary optical
mapping using tunable CO2-laser radiation. Specifically, there is a
correlation of the topography of well-defined MoS2 islands grown by chemical
vapor deposition, as determined by atomic force microscopy, with the infrared
(IR) signature of MoS2. The influence of MoS2 islands on the SiO2 phonon
resonance is discussed. The results reveal the plasmonic character of the MoS2
structures and their interaction with the SiO2 phonons leading to an
enhancement of the hybridized surface plasmon-phonon mode. A theoretical
analysis shows that, in the case of monolayer islands, the coupling of the
MoS2 optical plasmon mode to the SiO2 surface phonons does not affect the
infrared spectrum significantly. For two-layer MoS2, the coupling of the extra
inter-plane acoustic plasmon mode with the SiO2 surface transverse phonon
leads to a remarkable increase of the surface phonon peak at 794 cmâ1. This is
in agreement with the experimental data. These results show the capability of
the s-SNOM technique to study local multiple excitations in complex non-
homogeneous structures
Lrp1 is essential for lethal Rift Valley fever hepatic disease in mice
Rift Valley fever virus (RVFV) is an emerging arbovirus found in Africa. While RVFV is pantropic and infects many cells and tissues, viral replication and necrosis within the liver play a critical role in mediating severe disease. The low-density lipoprotein receptor-related protein 1 (Lrp1) is a recently identified host factor for cellular entry and infection by RVFV. The biological significance of Lrp1, including its role in hepatic disease in vivo, however, remains to be determined. Because Lrp1 has a high expression level in hepatocytes, we developed a mouse model in which Lrp1 is specifically deleted in hepatocytes to test how the absence of liver Lrp1 expression affects RVF pathogenesis. Mice lacking Lrp1 expression in hepatocytes showed minimal RVFV replication in the liver, longer time to death, and altered clinical signs toward neurological disease. In contrast, RVFV infection levels in other tissues showed no difference between the two genotypes. Therefore, Lrp1 is essential for RVF hepatic disease in mice
Near-field magneto-caloritronic nanoscopy on ferromagnetic nanostructures
Near-field optical microscopy by means of infrared photocurrent mapping has rapidly developed in recent years. In this letter we introduce a near-field
induced contrast mechanism arising when a conducting surface, exhibiting a
magnetic moment, is exposed to a nanoscale heat source. The
magneto-caloritronic response of the sample to near-field excitation of a
localized thermal gradient leads to a contrast determined by the local state of magnetization. By comparing the measured electric response of a magnetic reference sample with numerical simulations we derive an estimate of the field enhancement and the corresponding temperature profile induced on the sample surface.This work was supported by the Deutsche Forschungsgemeinschaft through grant HE 2063/5-1 to JH. The work also received funding from the ERC synergy grant No. 61011
Magneto-Seebeck microscopy of domain switching in collinear antiferromagnet CuMnAs
Antiferromagnets offer spintronic device characteristics unparalleled in ferromagnets owing to their lack of stray fields, THz spin dynamics, and rich materials landscape. Microscopic imaging of antiferromagnetic domains is one of the key prerequisites for understanding physical principles of the device operation. However, adapting common magnetometry techniques to the dipolar-field-free antiferromagnets has been a major challenge. Here we demonstrate in a collinear antiferromagnet a thermoelectric detection method by combining the magneto-Seebeck effect with local heat gradients generated by scanning far-field or near-field techniques. In a 20-nm epilayer of uniaxial CuMnAs we observe reversible 180â switching of the NĂ©el vector via domain wall displacement, controlled by the polarity of the current pulses. We also image polarity-dependent 90â switching of the NĂ©el vector in a thicker biaxial film, and domain shattering induced at higher pulse amplitudes. The antiferromagnetic domain maps obtained by our laboratory technique are compared to measurements by the established synchrotron-based technique of x-ray photoemission electron microscopy using x-ray magnetic linear dichroism
Multilab Direct Replication of Flavell, Beach, and Chinsky (1966): Spontaneous Verbal Rehearsal in a Memory Task as a Function of Age
Work by Flavell, Beach, and Chinsky indicated a change in the spontaneous production of overt verbalization behaviors when comparing young children (age 5) with older children (age 10). Despite the critical role that this evidence of a change in verbalization behaviors plays in modern theories of cognitive development and working memory, there has been only one other published near replication of this work. In this Registered Replication Report, we relied on researchers from 17 labs who contributed their results to a larger and more comprehensive sample of children. We assessed memory performance and the presence or absence of verbalization behaviors of young children at different ages and determined that the original pattern of findings was largely upheld: Older children were more likely to verbalize, and their memory spans improved. We confirmed that 5- and 6-year-old children who verbalized recalled more than children who did not verbalize. However, unlike Flavell et al., substantial proportions of our 5- and 6-year-old samples overtly verbalized at least sometimes during the picture memory task. In addition, continuous increase in overt verbalization from 7 to 10 years old was not consistently evident in our samples. These robust findings should be weighed when considering theories of cognitive development, particularly theories concerning when verbal rehearsal emerges and relations between speech and memory
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