On the atomic structure of an asymmetrical near Σ = 27 grain boundary in copper

The atomic structure of an asymmetrical near Σ = 27 {525} tilt grain boundary (GB) in copper is determined by coupling high-resolution transmission electron microscopy and molecular dynamics simulation. The average GB plane is parallel to {414} in crystal (1) and {343} in crystal (2). The detailed GB structure shows that it is composed of facets always parallel to {101} and {111} in crystals (1) and (2), respectively. The atomic structure of one facet is described using the structural units model. Each facet is displaced with respect to its neighbours by a pure step, giving rise to the asymmetry of the GB plane orientation. The energy of this asymmetrical GB is significantly lower than that of both the {525} symmetrical and the {11,1,11}/{111} asymmetrical Σ = 27 GBs. One GB region displays another atomic structure with a dislocation that accounts for the misfit between interatomic distances in the {414} and {343} GB planes.     

How much does the human medial gastrocnemius muscle contribute to ankle torques outside the sagittal plane?

Ankle movements in the frontal plane are less prominent though not less relevant than movements in the plantar or dorsal flexion direction. Walking on uneven terrains and standing on narrow stances are examples of circumstances likely imposing marked demands on the ankle medio-lateral stabilization. Following our previous evidence associating lateral bodily sways in quiet standing to activation of the medial gastrocnemius (MG) muscle, in this study we ask: how large is the MG contribution to ankle torque in the frontal plane? By arranging stimulation electrodes in a selective configuration, current pulses were applied primarily to the MG nerve branch of ten subjects. The contribution of populations of MG motor units of progressively smaller recruitment threshold to ankle torque was evaluated by increasing the stimulation amplitude by fixed amounts. From smallest intensities (12–32 mA) leading to the firstly observable MG twitches in force-plate recordings, current pulses reached intensities (56–90 mA) below which twitches in other muscles could not be observed from the skin. Key results showed a substantial MG torque contribution tending to rotate upward the foot medial aspect (ankle inversion). Nerve stimulation further revealed a linear relationship between the peak torque of ankle plantar flexion and inversion, across participants (Pearson R > .81, p < .01). Specifically, regardless of the current intensity applied, the peak torque of ankle inversion amounted to about 13% of plantar flexion peak torque. Physiologically, these results provide experimental evidence that MG activation may contribute to stabilize the body in the frontal plane, especially under situations of challenged stability.     

Increased activation in superior temporal gyri as a function of increment in phonetic features

A common assumption is that phonetic sounds initiate unique processing in the superior temporal gyri and sulci (STG/STS). The anatomical areas subserving these processes are also implicated in the processing of non-phonetic stimuli such as music instrument sounds. The differential processing of phonetic and non-phonetic sounds was investigated in this study by applying a “sound-morphing” paradigm, where the presence of phonetic features were parametrically varied, creating a step-wise transition from a non-phonetic sound into a phonetic sound. The stimuli were presented in an event-related fMRI design. The fMRI-BOLD data were analysed using parametric contrasts. The results showed a higher sensitivity for sounds containing phonetic features compared to non-phonetic sounds in the middle part of STG, and in the anterior part of the planum temporale (PT) bilaterally. Although the same areas were involved in the processing of non-phonetic sounds, a difference in activation was evident in the STG, with an increase in activation related to increment of phonetic features in the sounds. The results indicate a stimulus-driven, bottom-up process that utilizes general auditory resources in the secondary auditory cortex, depending on specific phonetic features in the sounds.     

TMS suppression of right pars triangularis, but not pars opercularis, improves naming in aphasia

This study sought to discover if an optimum 1 cm² area in the non-damaged right hemisphere (RH) was present, which could temporarily improve naming in chronic, nonfluent aphasia patients when suppressed with repetitive transcranial magnetic stimulation (rTMS). Ten minutes of slow, 1 Hz rTMS was applied to suppress different RH ROIs in eight aphasia cases. Picture naming and response time (RT) were examined before, and immediately after rTMS. In aphasia patients, suppression of right pars triangularis (PTr) led to significant increase in pictures named, and significant decrease in RT. Suppression of right pars opercularis (POp), however, led to significant increase in RT, but no change in number of pictures named. Eight normals named all pictures correctly; similar to aphasia patients, RT significantly decreased following rTMS to suppress right PTr, versus right POp. Differential effects following suppression of right PTr versus right POp suggest different functional roles for these regions.     

Using transcranial magnetic stimulation methods to probe connectivity between motor areas of the brain

Transcranial magnetic stimulation is increasingly used as a tool to explore cortical motor function in healthy subjects and in patients with neurological disease or injury. This review describes a “twin coil” TMS approach that allows investigation of time related changes in functional connectivity between primary motor cortex and other areas in preparation for a forthcoming movement. Investigations into premotor–motor interactions show that these are specific to the type of task that is performed as well as the muscles used to control the movement, allowing us to monitor information flow within motor networks with millisecond time resolution.     

"Binaural rivalry": dichotic listening as a tool for the investigation of the neural correlate of consciousness

Since about two decades neuroscientists have systematically faced the problem of consciousness: the aim is to discover the neural activity specifically related to conscious perceptions, i.e. the biological properties of what philosophers call qualia. In this view, a neural correlate of consciousness (NCC) is a precise pattern of brain activity that specifically accompanies a particular conscious experience. Almost all studies aimed at investigating the NCC have been carried out in the visual system. One of the most promising paradigms is based on sensory stimuli which elicit bistable percepts, as they allow to decouple subjective perception from the characteristics of the physical stimulation. Such kind of perception can be produced in the visual modality by using particular images (e.g. Rubin's vase/face figure) or by presenting two dissimilar stimuli separately to the two eyes (binocular rivalry). The stimuli compete for perceptual dominance and each image is visible in turn for a few seconds, while the other is suppressed. The use of this methodology has led to important findings concerning visual consciousness, which are briefly discussed. For the investigation of auditory consciousness, a similar stimulation paradigm can be achieved by using dichotic listening, consisting in two different stimuli presented each to one ear, which compete for perception (binaural rivalry). The principal aim of the present mini-review is to discuss the few contributes facing the issue of auditory consciousness and to advance the use of dichotic listening and binaural rivalry as valid tools for its investigation.     

Close Associations and Memory in Brainwriting Groups

The present experiment examined whether or not the type of associations (close (e.g. apple‐pear) and distant (e.g. apple‐fish) word associations) and memory instruction (paying attention to the ideas of others) had effects on the idea generation performances in the brainwriting paradigm in which all participants shared their ideas by using paper slips (Paulus & Yang, 2000). All participants were randomly subjected to exercising on either close or distant word associations ten minutes before the brainstorming session started. The findings showed that exercising on the close associations prior to the brainstorming session led to the generation of more unique ideas, category scanning, and depth of ideas than exercising on the distant ones in a subsequent brainstorming task. Memory instruction led to the generation of fewer ideas than no memory instruction. These findings were discussed from the aspect of the associative memory approach and cognitive stimulation approaches.     

Developmental stimulation in child care centers contributes to young infants’ cognitive development

This study examined whether the quality of caregiver behavior in child care centers contributes to infant cognitive development at 9 months of age. Sixty-four infants (34 boys) were observed with their primary caregivers in child care centers at 3, 6, and 9 months of age. Caregiver behavior was rated for sensitivity and for stimulation of infant development during one-to-one caregiving interactions. Infant cognitive development was assessed using the Bayley Scales of Infant Development-II (Mental Development Index). Higher levels of developmental stimulation in the centers predicted higher levels of infant cognitive development at 9 months, beyond infant cognitive development at 3 months (just before entering child care), parental education, and maternal sensitivity. The results suggest that even small increases in developmental stimulation provided in child care centers in the first year of life may foster infants’ cognitive development.     

经颅直流电刺激在注意缺陷多动障碍治疗中的应用

经颅直流电刺激(tDCS)治疗注意缺陷多动障碍(ADHD)主要是选取患者的背外侧前额叶(DLPFC)作为刺激区域, 通过调节其皮层兴奋性, 从而缓解其ADHD的症状和改善其受损的认知功能。针对tDCS在ADHD治疗研究中的问题, 未来可从有效性、确定最佳刺激参数、个体差异、不同亚型及与其他疗法联合使用等五个方面来进一步研究。