Changes in Intermuscular Coherence as a Function of Age and Phase of Speech Production During an Overt Reading Task.

PURPOSE: The authors evaluated changes in intermuscular coherence (IMC) of orofacial and speech breathing muscles across phase of speech production in healthy younger and older adults. METHOD: Sixty adults (30 younger = M: 26.97 year; 30 older = M: 66.37 year) read aloud a list of 40 words. IMC was evaluated across phase: preparation (300 ms before speech onset), initiation (300 ms after onset), and total execution (entire word). RESULTS: Orofacial IMC was lowest in the initiation, higher in preparation, and highest for the total execution phase. Chest wall IMC was lowest for the preparation and initiation and highest for the total execution phase. Despite age-related differences in accuracy, neuromuscular modulation for phase was similar between groups. CONCLUSION: These results expand our knowledge of speech motor control by demonstrating that IMC is sensitive to phase of speech planning and production.

Integration of spatio-temporal dynamics in emotion-cognition interactions: A simultaneous fMRI-ERP investigation using the emotional oddball task.

Although a large corpus of evidence has identified brain regions and networks involved in emotion-cognition interactions, it remains unclear how spatial and temporal dynamics of the mechanisms by which emotion interfaces with cognition are integrated. Capitalizing on multi-modal brain imaging approaches, we used simultaneous functional magnetic resonance imaging (fMRI) and event-related potential (ERP) recordings, to investigate the link between spatial and temporal aspects of processing in an emotional oddball task, and in relation to personality measures reflecting basic affective responses and emotion control. First, fMRI captured expected dorso-ventral dissociations, with greater response to targets in regions of dorsal brain networks (e.g., dorsolateral prefrontal cortex) and to emotional distracters in regions of ventral networks (e.g., ventrolateral prefrontal cortex, vlPFC). Also, ERP responses to targets were associated with a prominent P300, and responses to distracters with the late positive potential (LPP). Second, providing evidence for spatio-temporal integration of brain signals, ERP-informed fMRI analyses showed a link between LPP amplitude at parietal electrodes and the fMRI signal in the vlPFC, to emotional distraction. Third, regarding the link to personality measures, increased emotional arousability and attentional impulsiveness was associated with greater LPP differences between negative distracters and targets and enhanced response to negative distracters in the amygdala, respectively. Furthermore, we identified opposing relations between responses to emotional distraction and individual scores for cognitive reappraisal and self-control impulsiveness in posterior vlPFC. This suggests a greater engagement of this region in participants with reduced tendencies to employ reappraisal as a coping strategy and those with reduced ability to control impulsive responses during emotional distraction. Together, supporting the feasibility of integrating multi-dimensional approaches to clarify neural mechanisms of emotion-cognition interactions, these results point to convergence and complementarity between measures that differentially capture spatio-temporal dynamics of brain activity, and their associations with measures of individual differences in affective responses and control.

Differential Cortical Control of Chest Wall Muscles During Pressure- and Volume-Related Expiratory Tasks and the Effects of Acute Expiratory Threshold Loading.

We examined whether or not coherence between chest wall intercostal and oblique muscles changed as a function of lung volume excursion, alveolar pressure, and muscular demand. We also assessed the effects of acute expiratory threshold loading (ETL) on chest wall muscular control. A total of 15 healthy adults (7 males; average age = 28 years) completed maximum performance and ETL tasks. Chest wall surface electromyographic and kinematic recordings were made. Participants also performed a session of acute ETL. We showed that corticomuscular control of the chest wall varied as a function of lung volume excursion and muscular effort. Acute ETL had some effect on respiratory kinematics but not coherence.

Two-Layered and Stretchable e-Textile Patches for Wearable Healthcare Electronics.

Wearable healthcare systems require skin-adhering electrodes that allow maximal comfort for patients as well as an electronics system to enable signal processing and transmittance. Textile-based electronics, known as "e-textiles," is a platform technology that allows comfort for patients. Here, two-layered e-textile patches are designed by controlled permeation of Ag-particle/fluoropolymer composite ink into a porous textile. The permeated ink forms a cladding onto the nanofibers in the textile substrate, which is beneficial for mechanical and electrical properties of the e-textile. The printed e-textile features conductivity of ≈3200 S cm-1 , whereas 1000 cycles of 30% uniaxial stretching causes the resistance to increase only by a factor of ≈5, which is acceptable in many applications. Controlling over the penetration depth enables a two-layer design of the e-textile, where the sensing electrodes and the conducting traces are printed in the opposite sides of the substrate. The formation of vertical interconnected access is remarkably simple as an injection from a syringe. With the custom-developed electronic circuits, a surface electromyography system with wireless data transmission is demonstrated. Furthermore, the dry e-textile patch collects electroencephalography with comparable signal quality to commercial gel electrodes. It is anticipated that the two-layered e-textiles will be effective in healthcare and sports applications.

Changes in White Matter Integrity following Intensive Voice Treatment (LSVT LOUD®) in Children with Cerebral Palsy and Motor Speech Disorders.

Preliminary evidence suggests that intensive voice and speech treatment based on activity-dependent neuroplasticity principles holds promise for affecting positive change in children with cerebral palsy (CP) and motor speech disorders. Diffusion tensor imaging (DTI) allows researchers to make inferences about the integrity of white matter tracks and provides a sensitive measure of neuroplasticity. Previous treatment studies looking at the effects of training on white matter integrity have shown positive results, but these studies have been limited to gross motor function. Eight children with motor speech disorders and CP (3 females; age 8-16 years) and an age- and sex-matched group of typically developing (TD) children participated. Each child with CP completed a full dose of LSVT LOUD® and a 12-week maintenance program. Participants attended 3 recording sessions: before and after treatment, and after the maintenance period. TD children were tested at the same 3 time points. Recording sessions for both groups of children included measures of white matter integrity using DTI and acoustic measures of voice and speech. Fractional anisotropy (FA) was measured for 2 motor tracts and 5 association tracts. In children with CP, we observed an increase in FA in several motor and association tracts immediately following treatment and 12 weeks after treatment. Acoustic data on untrained tasks were correlated with changes in FA detected immediately following treatment and after the 12-week maintenance program. These findings suggest that long-term practice of skills attained during the treatment phase enhances white matter tract integrity in speech production networks.

Changes in brain activity following intensive voice treatment in children with cerebral palsy.

Eight children (3 females; 8-16 years) with motor speech disorders secondary to cerebral palsy underwent 4 weeks of an intensive neuroplasticity-principled voice treatment protocol, LSVT LOUD® , followed by a structured 12-week maintenance program. Children were asked to overtly produce phonation (ah) at conversational loudness, cued-phonation at perceived twice-conversational loudness, a series of single words, and a prosodic imitation task while being scanned using fMRI, immediately pre- and post-treatment and 12 weeks following a maintenance program. Eight age- and sex-matched controls were scanned at each of the same three time points. Based on the speech and language literature, 16 bilateral regions of interest were selected a priori to detect potential neural changes following treatment. Reduced neural activity in the motor areas (decreased motor system effort) before and immediately after treatment, and increased activity in the anterior cingulate gyrus after treatment (increased contribution of decision making processes) were observed in the group with cerebral palsy compared to the control group. Using graphical models, post-treatment changes in connectivity were observed between the left supramarginal gyrus and the right supramarginal gyrus and the left precentral gyrus for the children with cerebral palsy, suggesting LSVT LOUD enhanced contributions of the feedback system in the speech production network instead of high reliance on feedforward control system and the somatosensory target map for regulating vocal effort. Network pruning indicates greater processing efficiency and the recruitment of the auditory and somatosensory feedback control systems following intensive treatment. Hum Brain Mapp 38:4413-4429, 2017. © 2017 Wiley Periodicals, Inc.

Investigating the contribution of ventral-lexical and dorsal-sublexical pathways during reading in bilinguals.

Several studies suggest the existence of ventral-lexical and dorsal-sublexical systems for reading. The relative contribution of these pathways can be manipulated by stimulus type and task demands. However, little is known about how bilinguals use these systems to read in their second language. In this study diffusion tensor imaging (DTI) was used to investigate the relationship between white matter (WM) integrity and reaction time in a group of 12 Chinese-English bilingual and 11 age-matched English monolingual adults. Considering a dual-route model of reading, the following four tracts were isolated in both the left and right hemispheres using a tractography measurement approach. Ventral tracts included the uncinate fasciculus (UF) and the inferior longitudinal fasciculus (ILF). The dorsal tracts of interest were the arcuate fasciculus (AF) and the superior longitudinal fasciculus (SLF). A significant correlation between the reaction time in a reading task and the mean diffusivity (MD) value was observed in the right UF in both bilingual and monolingual groups. Moreover, in the bilingual group we observed significantly more positive relationships between reaction time and MD in the right AF, and bilaterally in the SLF. We concluded that the relative contribution of the dorsal system for reading is greater in bilinguals than monolinguals. Further, these findings implicate a role of the right hemisphere in reading.

Computational model of excitatory/inhibitory ratio imbalance role in attention deficit disorders.

Impairments in attentional behaviors, including over-selectivity, under-selectivity, distractibility and difficulty in shift of attention, are widely reported in several developmental disorders, including autism. Uncharacteristic inhibitory to excitatory neuronal number ratio (IER) and abnormal synaptic strength levels in the brain are two broadly accepted neurobiological disorders observed in autistic individuals. These neurobiological findings are contrasting and their relation to the atypical attentional behaviors is not clear yet. In this paper, we take a computational approach to investigate the relation of imbalanced IER and abnormal synaptic strength to some well-documented spectrum of attentional impairments. The computational model is based on a modified version of a biologically plausible neural model of two competing minicolumns in IT cortex augmented with a simple model of top-down attention. Top-down attention is assumed to amplify (attenuates) attended (unattended) stimulus. The inhibitory synaptic strength parameter in the model is set such that typical attentional behavior is emerged. Then, according to related findings, the parameter is changed and the model's attentional behavior is considered. The simulation results show that, without any change in top-down attention, the abnormal inhibitory synaptic strength values--and IER imbalance- result in over-selectivity, under-selectivity, distractibility and difficulty in shift of attention in the model. It suggests that the modeled neurobiological abnormalities can be accounted for the attentional deficits. In addition, the atypical attentional behaviors do not necessarily point to impairments in top-down attention. Our simulations suggest that limited changes in the inhibitory synaptic strength and variations in top-down attention signal affect the model's attentional behaviors in the same way. So, limited deficits in the inhibitory strength may be alleviated by appropriate change in top-down attention biasing. Nevertheless, our model proposes that this compensation is not possible for very high and very low values of the inhibitory strength.

Differences in white matter reflect atypical developmental trajectory in autism: A Tract-based Spatial Statistics study.

Autism is a neurodevelopmental disorder in which white matter (WM) maturation is affected. We assessed WM integrity in 16 adolescents and 14 adults with high-functioning autism spectrum disorder (ASD) and in matched neurotypical controls (NT) using diffusion weighted imaging and Tract-based Spatial Statistics. Decreased fractional anisotropy (FA) was observed in adolescents with ASD in tracts involved in emotional face processing, language, and executive functioning, including the inferior fronto-occipital fasciculus and the inferior and superior longitudinal fasciculi. Remarkably, no differences in FA were observed between ASD and NT adults. We evaluated the effect of age on WM development across the entire age range. Positive correlations between FA values and age were observed in the right inferior fronto-occipital fasciculus, the left superior longitudinal fasciculus, the corpus callosum, and the cortical spinal tract of ASD participants, but not in NT participants. Our data underscore the dynamic nature of brain development in ASD, showing the presence of an atypical process of WM maturation, that appears to normalize over time and could be at the basis of behavioral improvements often observed in high-functioning autism.