Human hip–ankle coordination emerging from multisensory feedback control

Human sensorimotor control involves inter-segmental coordination to cope with the complexity of a multi-segment system. The combined activation of hip and ankle muscles during upright stance represents the hip–ankle coordination. This study postulates that the coordination emerges from interactions on the sensory levels in the feedback control. The hypothesis was tested in a model-based approach that compared human experimental data with model simulations. Seven subjects were standing with eyes closed on an anterior–posterior tilting motion platform. Postural responses in terms of angular excursions of trunk and legs with respect to vertical were measured and characterized using spectral analysis. The presented control model consists of separate feedback modules for the hip and ankle joints, which exchange sensory information with each other. The feedback modules utilize sensor-derived disturbance estimates rather than ‘raw’ sensory signals. The comparison of the human data with the simulation data revealed close correspondence, suggesting that the model captures important aspects of the human sensory feedback control. For verification, the model was re-embodied in a humanoid robot that was tested in the human laboratory. The findings show that the hip–ankle coordination can be explained by interactions between the feedback control modules of the hip and ankle joints.     

Working memory improvement with non-invasive brain stimulation of the dorsolateral prefrontal cortex: A systematic review and meta-analysis

Recent studies have used non-invasive brain stimulation (NIBS) techniques, such as repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), to increase dorsolateral prefrontal cortex (DLPFC) activity and, consequently, working memory (WM) performance. However, such experiments have yielded mixed results, possibly due to small sample sizes and heterogeneity of outcomes. Therefore, our aim was to perform a systematic review and meta-analyses on NIBS studies assessing the n-back task, which is a reliable index for WM. From the first data available to February 2013, we looked for sham-controlled, randomized studies that used NIBS over the DLPFC using the n-back task in PubMed/MEDLINE and other databases. Twelve studies (describing 33 experiments) matched our eligibility criteria. Active vs. sham NIBS was significantly associated with faster response times (RTs), higher percentage of correct responses and lower percentage of error responses. However, meta-regressions showed that tDCS (vs. rTMS) presented only an improvement in RT, and not in accuracy. This could have occurred in part because almost all tDCS studies employed a crossover design, possibly due to the reliable tDCS blinding. Study design was also associated with no improvement in correct responses in the active vs. sham groups. To conclude, rTMS of the DLPFC significantly improved all measures of WM performance whereas tDCS significantly improved RT, but not the percentage of correct and error responses. Mechanistic insights on the role of DLPFC in WM are further discussed, as well as how NIBS techniques could be used in neuropsychiatric samples presenting WM deficits, such as major depression, dementia and schizophrenia.     

Stimulating performance: A scoping review on transcranial electrical stimulation effects on olympic sports

Transcranial electrical stimulation (tES) is widely used to explore the role of various cortical regions involved in a multitude of motor and cognitive processes. Recently, tES has been discussed as being able to potentially enhance performance in sports and even been suggested as a potential way of boosting performance in competitions. In this scoping review, we systematically investigate the literature on tES-induced performance modulations on Olympic sports. The aim is to create a critical overview of the emerging field of tES-enhanced sports performance. Further, methodological approaches, research desiderata, and potential directions for future research will be identified. The final dataset shows a large variation in methodology and a lack of research into the area. Further, partially sub-optimal choices in study design, methodology, and lacking consistency in reporting procedures may impede valid conclusions and obscured the effects of tES on Olympic sports. Consequently, we outline future directions and areas to improve research.     

Muting,filtering and transforming space: Autistic children's sensory ‘tactics’ for navigating mainstream school space following transition to secondary school

Mainstream school spaces provide significant sensory challenges to children with Autism Spectrum Disorder (ASD). In this paper, we provide in-depth qualitative insight of the ‘sensory tactics’ developed by children to navigate neurotypical spaces following transition to secondary school. Informed by work in sensory geography, and de Certeau's ‘strategies’ and ‘tactics’ concepts, we demonstrate that through muting, filtering and transforming space, children find ways to navigate the sensorially demanding environments of mainstream secondary school, e.g. finding quiet, orderly spaces - albeit in ways that do not entirely negate the sensory challenges the school environment presents. The paper concludes with several recommendations regarding ways that mainstream school spaces can be designed and/or existing spaces altered so as to be more sensitive to the sensory diversity of children with ASD.     

Abatement of intractable vocal stereotypy using an overcorrection procedure

We conducted a series of reversals to compare the effects of four different treatments on vocal stereotypy emitted by a 7‐year‐old boy with autism. The results showed that (1) the level of vocal stereotypy decreased during exposure to matched stimulation but returned to high levels immediately upon its removal; (2) stereotypy did not significantly decrease during differential reinforcement of other behavior; and (3) contingent withdrawal of movies and music (i.e., response cost) was only moderately effective. However, positive practice overcorrection decreased vocal stereotypy by clinically significant levels. Further, when differential reinforcement of engagement in a Lego^® building task was implemented, the level of engagement was significantly higher when positive practice overcorrection was in place than when overcorrection was withdrawn. Copyright © 2011 John Wiley & Sons, Ltd.     

A novel approach to mechanical foot stimulation during human locomotion under body weight support

Input from the foot plays an essential part in perceiving support surfaces and determining kinematic events in human walking. To simulate adequate tactile pressure inputs under body weight support (BWS) conditions that represent an effective form of locomotion training, we here developed a new method of phasic mechanical foot stimulation using light-weight pneumatic insoles placed inside the shoes (under the heel and metatarsus). To test the system, we asked healthy participants to walk on a treadmill with different levels of BWS. The pressure under the stimulated areas of the feet and subjective sensations were higher at high levels of BWS and when applied to the ball and toes rather than heels. Foot stimulation did not disturb significantly the normal motor pattern, and in all participants we evoked a reliable step-synchronized triggering of stimuli for each leg separately. This approach has been performed in a general framework looking for “afferent templates” of human locomotion that could be used for functional sensory stimulation. The proposed technique can be used to imitate or partially restore surrogate contact forces under body weight support conditions.     

Postural configuration affects the perception of earth-based space during pitch tilt

This study investigates the relative contribution of body parts in the elaboration of a whole-body egocentric attraction phenomenon previously observed during earth-based judgments. This was addressed through a particular earth-based task requiring estimating the possibility of passing under a projected line, imagining a forward horizontal displacement. Different postural configurations were tested, involving whole-body tilt, trunk tilt alone or head tilt alone. Two legs positions relative to the trunk were manipulated. Results showed systematic deviations of the subjective “passability” toward the tilt, linearly related to the tilt magnitude. For each postural configuration, the egocentric influence appeared to be highly dependent on the position of trunk and head axes, whereas the legs position appeared not relevant. When compared to the whole-body tilt condition, tilting the trunk alone consistently reduced the amount of the deviation toward the tilt, whereas tilting the head alone consistently increased it. Our results suggest that several specific effects from multiple body parts can account for the global deviation of the estimates observed during whole-body tilt. Most importantly, we support that the relative contribution of the body segments could mainly depend on a reweighting process, probably based on the reliability of sensory information available for a particular postural set.     

Effective connectivity hierarchically links temporoparietal and frontal areas of the auditory dorsal stream with the motor cortex lip area during speech perception

A left-hemispheric cortico-cortical network involving areas of the temporoparietal junction (Tpj) and the posterior inferior frontal gyrus (pIFG) is thought to support sensorimotor integration of speech perception into articulatory motor activation, but how this network links with the lip area of the primary motor cortex (M1) during speech perception is unclear. Using paired-coil focal transcranial magnetic stimulation (TMS) in healthy subjects, we demonstrate that Tpj → M1 and pIFG → M1 effective connectivity increased when listening to speech compared to white noise. A virtual lesion induced by continuous theta-burst TMS (cTBS) of the pIFG abolished the task-dependent increase in pIFG → M1 but not Tpj → M1 effective connectivity during speech perception, whereas cTBS of Tpj abolished the task-dependent increase of both effective connectivities. We conclude that speech perception enhances effective connectivity between areas of the auditory dorsal stream and M1. Tpj is situated at a hierarchically high level, integrating speech perception into motor activation through the pIFG.     

Transient beneficial effects of excitatory theta burst stimulation in a patient with phonological agraphia after left supramarginal gyrus infarction

We report a patient showing isolated phonological agraphia after an ischemic stroke involving the left supramarginal gyrus (SMG). In this patient, we investigated the effects of focal repetitive transcranial magnetic stimulation (rTMS) given as theta burst stimulation (TBS) over the left SMG, corresponding to the Brodmann area (BA) 40. The patient and ten control subjects performed a dictational words and nonwords writing task before, and 5 and 30 min after they received excitatory intermittent TBS (iTBS) over the left BA 40, the right hemisphere homologous to BA 40, the Wernicke’s area, or the primary visual cortex.ITBS over the left SMG lead to a brief facilitation of phonological non-words writing to dictation. This case study report illustrates that rTMS is able to influence, among other language functions, the phonological loading processes during the written language production in stroke patients.     

An integrative review of sensory marketing: Engaging the senses to affect perception,judgment and behavior

I define “sensory marketing” as “marketing that engages the consumers' senses and affects their perception, judgment and behavior.” From a managerial perspective, sensory marketing can be used to create subconscious triggers that characterize consumer perceptions of abstract notions of the product (e.g., its sophistication or quality). Given the gamut of explicit marketing appeals made to consumers every day, subconscious triggers which appeal to the basic senses may be a more efficient way to engage consumers. Also, these sensory triggers may result in consumers' self-generation of (desirable) brand attributes, rather than those verbally provided by the advertiser. The understanding of these sensory triggers implies an understanding of sensation and perception as it applies to consumer behavior—this is the research perspective of sensory marketing. This review article presents an overview of research on sensory perception. The review also points out areas where little research has been done, so that each additional paper has a greater chance of making a bigger difference and sparking further research. It is quite apparent from the review that there still remains tremendous need for research within the domain of sensory marketing—research that can be very impactful.