Prenatal Exposure to Maternal Mood Entropy Is Associated With a Weakened and Inflexible Salience Network in Adolescence

BACKGROUND

Fetal exposure to maternal mood dysregulation influences child cognitive and emotional development, which may have long-lasting implications for mental health. However, the neurobiological alterations associated with this dimension of adversity have yet to be explored. Here, we tested the hypothesis that fetal exposure to entropy, a novel index of dysregulated maternal mood, would predict the integrity of the salience network, which is involved in emotional processing.

METHODS

A sample of 138 child-mother pairs (70 females) participated in this prospective longitudinal study. Maternal negative mood level and entropy (an index of variable and unpredictable mood) were assessed 5 times during pregnancy. Adolescents engaged in a functional magnetic resonance imaging task that was acquired between 2 resting-state scans. Changes in network integrity were analyzed using mixed-effect and latent growth curve models. The amplitude of low frequency fluctuations was analyzed to corroborate findings.

RESULTS

Prenatal maternal mood entropy, but not mood level, was associated with salience network integrity. Both prenatal negative mood level and entropy were associated with the amplitude of low frequency fluctuations of the salience network. Latent class analysis yielded 2 profiles based on changes in network integrity across all functional magnetic resonance imaging sequences. The profile that exhibited little variation in network connectivity (i.e., inflexibility) consisted of adolescents who were exposed to higher negative maternal mood levels and more entropy.

CONCLUSIONS

These findings suggest that fetal exposure to maternal mood dysregulation is associated with a weakened and inflexible salience network. More broadly, they identify maternal mood entropy as a novel marker of early adversity that exhibits long-lasting associations with offspring brain development.

Rapid adaptation of predictive models during language comprehension: Aperiodic EEG slope, individual alpha frequency and idea density modulate individual differences in real-time model updating

Predictive coding provides a compelling, unified theory of neural information processing, including for language. However, there is insufficient understanding of how predictive models adapt to changing contextual and environmental demands and the extent to which such adaptive processes differ between individuals. Here, we used electroencephalography (EEG) to track prediction error responses during a naturalistic language processing paradigm. In Experiment 1, 45 native speakers of English listened to a series of short passages. Via a speaker manipulation, we introduced changing intra-experimental adjective order probabilities for two-adjective noun phrases embedded within the passages and investigated whether prediction error responses adapt to reflect these intra-experimental predictive contingencies. To this end, we calculated a novel measure of speaker-based, intra-experimental surprisal (“speaker-based surprisal”) as defined on a trial-by-trial basis and by clustering together adjectives with a similar meaning. N400 amplitude at the position of the critical second adjective was used as an outcome measure of prediction error. Results showed that N400 responses attuned to speaker-based surprisal over the course of the experiment, thus indicating that listeners rapidly adapt their predictive models to reflect local environmental contingencies (here: the probability of one type of adjective following another when uttered by a particular speaker). Strikingly, this occurs in spite of the wealth of prior linguistic experience that participants bring to the laboratory. Model adaptation effects were strongest for participants with a steep aperiodic (1/f) slope in resting EEG and low individual alpha frequency (IAF), with idea density (ID) showing a more complex pattern. These results were replicated in a separate sample of 40 participants in Experiment 2, which employed a highly similar design to Experiment 1. Overall, our results suggest that individuals with a steep aperiodic slope adapt their predictive models most strongly to context-specific probabilistic information. Steep aperiodic slope is thought to reflect low neural noise, which in turn may be associated with higher neural gain control and better cognitive control. Individuals with a steep aperiodic slope may thus be able to more effectively and dynamically reconfigure their prediction-related neural networks to meet current task demands. We conclude that predictive mechanisms in language are highly malleable and dynamic, reflecting both the affordances of the present environment as well as intrinsic information processing capabilities of the individual.

Separating Stimulus-Induced and Background Components of Dynamic Functional Connectivity in Naturalistic fMRI

We consider the challenges in extracting stimulus-related neural dynamics from other intrinsic processes and noise in naturalistic functional magnetic resonance imaging (fMRI). Most studies rely on inter-subject correlations (ISC) of low-level regional activity and neglect varying responses in individuals. We propose a novel, data-driven approach based on low-rank plus sparse ( [Formula: see text]) decomposition to isolate stimulus-driven dynamic changes in brain functional connectivity (FC) from the background noise, by exploiting shared network structure among subjects receiving the same naturalistic stimuli. The time-resolved multi-subject FC matrices are modeled as a sum of a low-rank component of correlated FC patterns across subjects, and a sparse component of subject-specific, idiosyncratic background activities. To recover the shared low-rank subspace, we introduce a fused version of principal component pursuit (PCP) by adding a fusion-type penalty on the differences between the columns of the low-rank matrix. The method improves the detection of stimulus-induced group-level homogeneity in the FC profile while capturing inter-subject variability. We develop an efficient algorithm via a linearized alternating direction method of multipliers to solve the fused-PCP. Simulations show accurate recovery by the fused-PCP even when a large fraction of FC edges are severely corrupted. When applied to natural fMRI data, our method reveals FC changes that were time-locked to auditory processing during movie watching, with dynamic engagement of sensorimotor systems for speech-in-noise. It also provides a better mapping to auditory content in the movie than ISC.

Parent Language Input Prior to School Forecasts Change in Children's Language-Related Cortical Structures During Mid-Adolescence

Children differ widely in their early language development, and this variability has important implications for later life outcomes. Parent language input is a strong experiential factor predicting the variability in children's early language skills. However, little is known about the brain or cognitive mechanisms that underlie the relationship. In addressing this gap, we used longitudinal data spanning 15 years to examine the role of early parental language input that children receive during preschool years in the development of brain structures that support language processing during school years. Using naturalistic parent-child interactions, we measured parental language input (amount and complexity) to children between the ages of 18 and 42 months (n = 23). We then assessed longitudinal changes in children's cortical thickness measured at five time points between 9 and 16 years of age. We focused on specific regions of interest (ROIs) that have been shown to play a role in language processing. Our results support the view that, even after accounting for important covariates such as parental intelligence quotient (IQ) and education, the amount and complexity of language input to a young child prior to school forecasts the rate of change in cortical thickness during the 7-year period from 5½ to 12½ years later. Examining the proximal correlates of change in brain and cognitive differences has the potential to inform targets for effective prevention and intervention strategies.

Head impact exposure and concussion in women's collegiate club lacrosse

This study sought to describe head impact exposure in women's collegiate club lacrosse. Eleven women's collegiate club lacrosse players wore head impact sensors during eight intercollegiate competitions. Video recordings of competitions were used to verify impact data. Athletes completed questionnaires detailing their concussion history and perceived head impact exposure. During the monitored games, no diagnosed concussions were sustained. Three athletes reported sustaining head impacts (median = 0; range: 0-3 impacts per game). Six impacts registered by the sensors were verified on video across a total of 81 athlete-game exposures. Verified impacts had a median peak linear acceleration of 21.0 g (range: 18.3 g - 48.3 g) and peak rotational acceleration of 1.1 krad/s² (range: 0.7 krad/s² - 5.7 krad/s²). Women competing in collegiate club lacrosse are at a low risk of sustaining head impacts, comparable to previous reports of the high school and collegiate varsity levels of play.

Identifiable Patterns of Trait, State, and Experience in Chronic Stroke Recovery

BACKGROUND

Considerable evidence indicates that the functional connectome of the healthy human brain is highly stable, analogous to a fingerprint.

OBJECTIVE

We investigated the stability of functional connectivity across tasks and sessions in a cohort of individuals with chronic stroke using a supervised machine learning approach.

METHODS

Twelve individuals with chronic stroke underwent functional magnetic resonance imaging (fMRI) seven times over 18 weeks. The middle 6 weeks consisted of intensive aphasia therapy. We collected fMRI data during rest and performance of 2 tasks. We calculated functional connectivity metrics for each imaging run, then applied a support vector machine to classify data on the basis of participant, task, and time point (pre- or posttherapy). Permutation testing established statistical significance.

RESULTS

Whole brain functional connectivity matrices could be classified at levels significantly greater than chance on the basis of participant (87.1% accuracy; P < .0001), task (68.1% accuracy; P = .002), and time point (72.1% accuracy; P = .015). All significant effects were reproduced using only the contralesional right hemisphere; the left hemisphere revealed significant effects for participant and task, but not time point. Resting state data could also be used to classify task-based data according to subject (66.0%; P < .0001). While the strongest posttherapy changes occurred among regions outside putative language networks, connections with traditional language-associated regions were significantly more positively correlated with behavioral outcome measures, and other regions had more negative correlations and intrahemispheric connections.

CONCLUSIONS

Findings suggest the profound importance of considering interindividual variability when interpreting mechanisms of recovery in studies of functional connectivity in stroke.

A Review of Biological Interventions in Chronic Aphasia

Aphasia is a common and debilitating condition following stroke. While the gold standard for aphasia treatment is behavioral speech-language therapy, benefits remain modest in chronic stages of recovery. This limitation motivates the pursuit of novel interventions for chronic aphasia. Here, we review biological approaches that have been used (or proposed for use, in the case of regenerative and genetic therapies) to treat chronic aphasia. These techniques aim to ameliorate the deficits of aphasia by directly manipulating brain function, rather than training lost or compensatory functions, although many have been used to augment effects of behavioral therapy. Specifically, we explore the most robust designs of transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), and pharmacotherapy that have been applied in chronic (≥6 months) post-stroke aphasia. We also consider less investigated approaches including epidural cortical stimulation and photobiomodulation. All methods are currently in nascent phases and restricted to experimental studies and clinical trials. Although the evidence base remains limited, such interventions may ultimately improve language function and quality of life for those living with chronic aphasia. However, it is crucial that application of these methods consider the effects of concomitant speech-language therapy, as biological interventions combined with behaviorally induced experience-dependent plasticity will likely yield the most beneficial and durable outcomes.

One season of head-to-ball impact exposure alters functional connectivity in a central autonomic network

Repetitive head impacts represent a risk factor for neurological impairment in team-sport athletes. In the absence of symptoms, a physiological basis for acute injury has not been elucidated. A basic brain function that is disrupted after mild traumatic brain injury is the regulation of homeostasis, instantiated by activity across a specific set of brain regions that comprise a central autonomic network. We sought to relate head-to-ball impact exposure to changes in functional connectivity in a core set of central autonomic regions and then to determine the relation between changes in brain and changes in behavior, specifically cognitive control. Thirteen collegiate men's soccer players and eleven control athletes (golf, cross-country) underwent resting-state fMRI and behavioral testing before and after the season, and a core group of cortical, subcortical, and brainstem regions was selected to represent the central autonomic network. Head-to-ball impacts were recorded for each soccer player. Cognitive control was assessed using a Dot Probe Expectancy task. We observed that head-to-ball impact exposure was associated with diffuse increases in functional connectivity across a core CAN subnetwork. Increased functional connectivity between the left insula and left medial orbitofrontal cortex was associated with diminished proactive cognitive control after the season in those sustaining the greatest number of head-to-ball impacts. These findings encourage measures of autonomic physiology to monitor brain health in contact and collision sport athletes.

A Dose Relationship Between Brain Functional Connectivity and Cumulative Head Impact Exposure in Collegiate Water Polo Players

A growing body of evidence suggests that chronic, sport-related head impact exposure can impair brain functional integration and brain structure and function. Evidence of a robust inverse relationship between the frequency and magnitude of repeated head impacts and disturbed brain network function is needed to strengthen an argument for causality. In pursuing such a relationship, we used cap-worn inertial sensors to measure the frequency and magnitude of head impacts sustained by eighteen intercollegiate water polo athletes monitored over a single season of play. Participants were evaluated before and after the season using computerized cognitive tests of inhibitory control and resting electroencephalography. Greater head impact exposure was associated with increased phase synchrony [r₍₁₆₎ > 0.626, p < 0.03 corrected], global efficiency [r₍₁₆₎ > 0.601, p < 0.04 corrected], and mean clustering coefficient [r₍₁₆₎ > 0.625, p < 0.03 corrected] in the functional networks formed by slow-wave (delta, theta) oscillations. Head impact exposure was not associated with changes in performance on the inhibitory control tasks. However, those with the greatest impact exposure showed an association between changes in resting-state connectivity and a dissociation between performance on the tasks after the season [r₍₁₆₎ = 0.481, p = 0.043] that could also be attributed to increased slow-wave synchrony [F_{(4, 135)} = 113.546, p < 0.001]. Collectively, our results suggest that athletes sustaining the greatest head impact exposure exhibited changes in whole-brain functional connectivity that were associated with altered information processing and inhibitory control.

Patterns of head impact exposure in men's and women's collegiate club water polo

OBJECTIVES

Recent reports have demonstrated a risk of concussion and subconcussive head impacts in collegiate varsity and international elite water polo. We sought to characterize patterns of head impact exposure at the collegiate club level of water polo.

DESIGN

Prospective cohort study.

METHODS

Head impact sensors (SIM-G, Triax Technologies) were worn by men's (n=16) and women's (n=15) collegiate club water polo players during 11 games. Peak linear acceleration (PLA) and peak rotational acceleration (PRA) of head impacts were recorded by the sensors. Two streams of competition video were used to verify and describe the nature of head impacts.

RESULTS

Men's players sustained 52 verified head impacts of magnitude 39.7±16.3g PLA and 5.2±3.2 krad/s² PRA, and women's players sustained 43 verified head impacts of magnitude 33.7±12.6g PLA and 4.0±2.8krad/s² PRA. Impacts sustained by men had greater PLA than those sustained by women (p=.045). Athletes were impacted most frequently at the offensive center position, to the back of the head, and by an opponent's torso or limb.

CONCLUSIONS

Our cohort of male and female athletes sustained relatively infrequent head impacts during water polo competitions played at the collegiate club level. The amount of head impact exposure in our cohort was dependent on player position, with offensive centers prone to sustaining the most impacts. Head impact sensors are subject to large amounts of false positives and should be used in conjunction with video recordings to verify the validity of impact data.

Language development and brain reorganization in a child born without the left hemisphere

We present a case of a 14-year-old girl born without the left hemisphere due to prenatal left internal carotid occlusion. We combined longitudinal language and cognitive assessments with functional and structural neuroimaging data to situate the case within age-matched, typically developing children. Despite having had a delay in getting language off the ground during the preschool years, our case performed within the normal range on a variety of standardized language tests, and exceptionally well on phonology and word reading, during the elementary and middle school years. Moreover, her spatial, number, and reasoning skills also fell in the average to above-average range based on assessments during these time periods. Functional MRI data revealed activation in right fronto-temporal areas when listening to short stories, resembling the bilateral activation patterns in age-matched typically developing children. Diffusion MRI data showed significantly larger dorsal white matter association tracts (the direct and anterior segments of the arcuate fasciculus) connecting areas active during language processing in her remaining right hemisphere, compared to either hemisphere in control children. We hypothesize that these changes in functional and structural brain organization are the result of compensatory brain plasticity, manifesting in unusually large right dorsal tracts, and exceptional performance in phonology, speech repetition, and decoding. More specifically, we posit that our case's large white matter connections might have played a compensatory role by providing fast and reliable transfer of information between cortical areas for language in the right hemisphere.

Changes in functional connectivity are associated with one season of head-to-ball impact exposure in male collegiate soccer athletes

Objectives

Return-to-play protocols could be improved by a better understanding of the physiologic effects of mild traumatic brain injury (mTBI). Autonomic dysregulation is thought to underlie many of the multi-dimensional symptoms following mTBI and may derive from altered connectivity in the brain central autonomic network (CAN). Understanding the relationship between injury and CAN connectivity could lead to a useful biomarker for mTBI. Toward this end, the present study aimed to establish a formal relationship between non-symptomatic head-to-ball impacts (“headers”) and CAN connectivity in collegiate soccer athletes.

Methods

Eleven male NCAA Division I soccer players were monitored by athletic training staff throughout 1 season for the number of headers. Ten male NCAA Division I athletes (3 cross-country and 7 golfers) served as controls. All participants underwent resting-state fMRI pre- and post-season. Twenty ROIs were selected based on regions previously implicated in control and modulation of autonomic function. Graph theoretical analyses were used to probe changes in network architecture and connectivity. Specific contrasts focused on pre- and post-season changes that were explained by individual differences in exposure to headers (p < 0.05 uncorrected).

Results

Within the 20 node network, increases in headers were associated with reduced degree centrality of the left and right insular cortex and right putamen (p< 0.02), increased degree and betweenness centrality in the left anterior and right posterior Para hippocampal gyri (p< 0.03), and increased betweenness centrality in the anterior cingulate cortex (p = 0.006). Headers were also associated with reduced functional connectivity within the subnetwork including the anterior cingulate cortex (p = 0.0073), right hippocampus, left putamen, and left insular cortex (p< 0.04).

Conclusion

Highly skilled soccer players who sustained the greatest number of head impacts also experienced the greatest altered connectivity among regions associated with autonomic function. Future work to establish autonomic function as an injury biomarker should consider the importance of cumulative impact magnitudes.

Network specialization during adolescence: Hippocampal effective connectivity in boys and girls

Adolescence is a complex period of concurrent mental and physical development that facilitates adult functioning at multiple levels. Despite the growing number of neuroimaging studies of cognitive development in adolescence focusing on regional activation patterns, there remains a paucity of information about the functional interactions across these participating regions that are critical for cognitive functioning, including memory. The current study used structural equation modeling (SEM) to determine how interactions among brain regions critical for memory change over the course of adolescence. We obtained functional MRI in 77 individuals aged 8-16 years old, divided into younger (ages 8-10) and older (ages > 11) cohorts, using an incidental encoding memory task to activate hippocampus formation and associated brain networks, as well as behavioral data on memory function. SEM was performed on the imaging data for four groups (younger girls, younger boys, older girls, and older boys) that were subsequently compared using a stacked model approach. Significant differences were seen between the models for these groups. Younger boys had a predominantly posterior distribution of connections originating in primary visual regions and terminating on multi-modal processing regions. In older boys, there was a relatively greater anterior connection distribution, with increased effective connectivity within association and multi-modal processing regions. Connection patterns in younger girls were similar to those of older boys, with a generally anterior-posterior distributed network among sensory, multi-modal, and limbic regions. In contrast, connections in older girls were widely distributed but relatively weaker. Memory performance increased with age, without a significant difference between the sexes. These findings suggest a progressive reorganization among brain regions, with a commensurate increase in efficiency of cognitive functioning, from younger to older individuals in both girls and boys, providing insight into the age- and gender-specific processes at play during this critical transition period.

Therapy-Induced Plasticity in Chronic Aphasia Is Associated with Behavioral Improvement and Time Since Stroke

Cortical reorganization after stroke is thought to underlie functional improvement. Patterns of reorganization may differ depending on the amount of time since the stroke or the degree of improvement. We investigated these issues in a study of brain connectivity changes with aphasia therapy. Twelve individuals with chronic aphasia participated in a 6-week trial of imitation-based speech therapy. We assessed improvement on a repetition test and analyzed effective connectivity during functional magnetic resonance imaging of a speech observation task before and after therapy. Using structural equation modeling, patient networks were compared with a model derived from healthy controls performing the same task. Independent of the amount of time since the stroke, patients demonstrating behavioral improvement had networks that reorganized to be more similar to controls in two functional pathways in the left hemisphere. Independent of behavioral improvement, patients with remote infarcts (2-7 years poststroke; n = 5) also reorganized to more closely resemble controls in one of these pathways. Patients with far removed injury (>10 years poststroke; n = 3) did not show behavioral improvement and, despite similarities to the normative model and overall network heterogeneity, reorganized to be less similar to controls following therapy in a distinct right-lateralized pathway. Behavioral improvement following aphasia therapy was associated with connectivity more closely approximating that of healthy controls. Individuals who had a stroke more than a decade before testing also showed plasticity, with a few pathways becoming less like controls, possibly representing compensation. Better understanding of these mechanisms may help direct targeted brain stimulation.

Functional neuroanatomy of gesture-speech integration in children varies with individual differences in gesture processing

Gesture is an integral part of children's communicative repertoire. However, little is known about the neurobiology of speech and gesture integration in the developing brain. We investigated how 8- to 10-year-old children processed gesture that was essential to understanding a set of narratives. We asked whether the functional neuroanatomy of gesture-speech integration varies as a function of (1) the content of speech, and/or (2) individual differences in how gesture is processed. When gestures provided missing information not present in the speech (i.e., disambiguating gesture; e.g., "pet" + flapping palms = bird), the presence of gesture led to increased activity in inferior frontal gyri, the right middle temporal gyrus, and the left superior temporal gyrus, compared to when gesture provided redundant information (i.e., reinforcing gesture; e.g., "bird" + flapping palms = bird). This pattern of activation was found only in children who were able to successfully integrate gesture and speech behaviorally, as indicated by their performance on post-test story comprehension questions. Children who did not glean meaning from gesture did not show differential activation across the two conditions. Our results suggest that the brain activation pattern for gesture-speech integration in children overlaps with-but is broader than-the pattern in adults performing the same task. Overall, our results provide a possible neurobiological mechanism that could underlie children's increasing ability to integrate gesture and speech over childhood, and account for individual differences in that integration.

Resistant Hypertension after Hypertensive Intracerebral Hemorrhage Is Associated with More Medical Interventions and Longer Hospital Stays without Affecting Outcome

Background

Hypertension (HTN) is the most common cause of spontaneous intracerebral hemorrhage (ICH). The aim of this study is to investigate the role of resistant HTN in patients with ICH.

Methods and results

We conducted a retrospective study of all consecutive ICH admissions at our medical center from November 2013 to October 2015. The clinical features of patients with resistant HTN (requiring four or more antihypertensive agents to keep systolic blood pressure <140 mm Hg) were compared with those with responsive HTN (requiring three or fewer agents). Of the 152 patients with hypertensive ICH, 48 (31.6%) had resistant HTN. Resistant HTN was independently associated with higher body mass index and proteinuria. Compared to the responsive group, patients with resistant HTN had higher initial blood pressures and greater requirement for ventilator support, hematoma evacuation, hypertonic saline therapy, and nicardipine infusion. Resistant HTN increases length of stay (LOS) in the intensive care unit (ICU) (4.2 vs 2.1 days; p = 0.007) and in the hospital (11.5 vs 7.0 days; p = 0.003). Multivariate regression analysis showed that the rate of systolic blood pressure >140 mm Hg and duration of nicardipine infusion were independently associated with LOS in the ICU. There was no significant difference in hematoma expansion and functional outcome at hospital discharge between the two groups.

Conclusion

Resistant HTN in patients with ICH is associated with more medical interventions and longer LOS without effecting outcome at hospital discharge.

Imitation-based aphasia therapy increases narrative content: a case series

Objective:

To test the generalization of an intensive imitation-based aphasia therapy to an unrelated narrative production task.

Design:

ABA design study (A= no treatment; B= treatment) comparing imitation therapy to a baseline condition (pre-therapy). Participants produced narratives at two pre-therapy and two post-therapy time points. Narratives were analyzed for correct information units to determine the number and percent of communicative words produced.

Setting:

A rehabilitation clinic and participants’ homes.

Participants:

Nineteen people with chronic aphasia following left hemisphere stroke.

Interventions:

Six weeks of intensive imitation therapy (3 x 30 minutes/day; 6 days/week) of words and phrases delivered via dedicated laptop.

Main measures:

We performed t-tests to assess post-therapy changes in narrative production, as well as for intervals during which no intervention was provided. We used stepwise regression to examine the predictive value of demographic, behavioral, and neurological variables in determining treatment outcome.

Results:

Significant gains were made on the narrative production task in both the number (mean = 34.36; p = 0.009) and percent (mean = 3.99; p = 0.023) of correct information units produced. For percent of correct information units, the number of therapy sessions completed was the sole predictor of changes in production following therapy (r= +0.542; p = 0.020). No variables predicted change in number of correct information units produced. There were no significant differences between the two pre-therapy or the two post-therapy time points ( p > 0.294).

Conclusions:

Intensive imitation-based aphasia therapy may promote generalization to an unrelated narrative production task. Further investigation is indicated.

Increased Modularity of Resting State Networks Supports Improved Narrative Production in Aphasia Recovery

The networks that emerge in the analysis of resting state functional magnetic resonance imaging (rsfMRI) data are believed to reflect the intrinsic organization of the brain. One key property of such complex biological networks is modularity, a measure of community structure. This topological characteristic changes in neurological disease and recovery. Nineteen subjects with language disorders after stroke (aphasia) underwent neuroimaging and behavioral assessment at multiple time points before (baseline) and after an imitation-based therapy. Language was assessed with a narrative production task. Group independent component analysis was performed on the rsfMRI data to identify resting state networks (RSNs). For each participant and each rsfMRI acquisition, we constructed a graph comprising all RSNs. We assigned nodal community based on a region's RSN membership, calculated the modularity score, and then correlated changes in modularity and therapeutic gains on the narrative task. We repeated this comparison controlling for pretherapy performance and using a community structure not based on RSN membership. Increased RSN modularity was positively correlated with improvement on the narrative task immediately post-therapy. This finding remained significant when controlling for pretherapy performance. There were no significant findings for network modularity and behavior when nodal community was assigned without consideration of RSN membership. We interpret these findings as support for the adaptive role of network segregation in behavioral improvement in aphasia therapy. This has important clinical implications for the targeting of noninvasive brain stimulation in poststroke remediation and suggests potential for further insight into the processes underlying such changes through computational modeling.

Sentence understanding depends on contextual use of semantic and real world knowledge

Human language allows us to express our thoughts and ideas by combining entities, concepts and actions into multi-event episodes. Yet, the functional neuroanatomy engaged in interpretation of such high-level linguistic input remains poorly understood. Here, we used easy to detect and more subtle "borderline" anomalies to investigate the brain regions and mechanistic principles involved in the use of real-world event knowledge in language comprehension. Overall, the results showed that the processing of sentences in context engages a complex set of bilateral brain regions in the frontal, temporal and inferior parietal lobes. Easy anomalies preferentially engaged lower-order cortical areas adjacent to the primary auditory cortex. In addition, the left supramarginal gyrus and anterior temporal sulcus as well as the right posterior middle temporal gyrus contributed to the processing of easy and borderline anomalies. The observed pattern of results is explained in terms of (i) hierarchical processing along a dorsal-ventral axis and (ii) the assumption of high-order association areas serving as cortical hubs in the convergence of information in a distributed network. Finally, the observed modulation of BOLD signal in prefrontal areas provides support for their role in the implementation of executive control processes.

Review : The Neurobiology of Stroke Rehabilitation

Cerebrovascular disease plays a paramount role in mortality and morbidity, and the clinical and basic sci entific study of acute stroke has blossomed, leading both to increased survival and to increasing numbers of people with disabilities from stroke. Neurobiological study of the chronic form of this prevalent neurological disease has lagged behind investigation of the acute illness. This article reviews how and why this situation will change. Four major points are addressed: 1) The anatomical organizations of functional brain systems are less topographically precise than commonly believed. 2) Cortical plasticity exists in adults and takes a number of forms, including unmasking of existing circuits, growth of new synapses via axonal sprouting or dendritic proliferation, and development of compensatory processes. 3) It is possible to manipulate this plasticity with behavioral and pharmacological interventions, and such manipulations can have a beneficial effect on recovery. 4) Functional neuroimaging, particularly the noninvasive method of fMRI, can be used to study in vivo both cerebral plasticity after stroke and the interventions that might influence recovery by affecting this plasticity. Although there is much to be accomplished, the prognosis is extremely good for a neuroscience of stroke rehabilitation. NEUROSCIENTIST 4:426-434, 1998

The Epidemiology of Sports-Related Head Injury and Concussion in Water Polo

Purpose

Water polo is a sport with a high degree of physicality and aggressive play. Unlike most contact sports, epidemiological data on the incidence or prevalence of head trauma in water polo have not been gathered, reported, or made publicly available. The purpose of this study was to begin a systematic characterization of the risks of head impact and concussion in men and women who play water polo at various levels.

Design

We sent an electronic survey to the 44,000+ members of USA Water Polo, asking questions about concussions, head impacts, and symptoms commonly associated with prior concussion. From over 1500 complete responses, we report summary information on the prevalence of concussions and major head impacts in water polo.

Results

We found that 36% of respondents report sustaining a concussion while playing water polo, with an average of two concussions reported. The prevalence and number of concussions reported varied across positions, levels, and gender. Most strikingly, we found that goalies are at significantly higher risk for concussion, report a significantly more concussions, and appear to experience a qualitatively different type of head impact compared to other positions. Additionally, we found that competition level, gender, and field position are robust predictors of concussion risk.

Conclusion

Our findings demonstrate that concussions are not uncommon in water polo players. We conclude that there is need for systematic concussion reporting in water polo and suggest that understanding the risk factors of concussion in water polo will require fully considering differences in the head impact exposure between different field positions, competition levels, sexes, and differences in exposure between competition and practice.

The pace of vocabulary growth during preschool predicts cortical structure at school age

Children vary greatly in their vocabulary development during preschool years. Importantly, the pace of this early vocabulary growth predicts vocabulary size at school entrance. Despite its importance for later academic success, not much is known about the relation between individual differences in early vocabulary development and later brain structure and function. Here we examined the association between vocabulary growth in children, as estimated from longitudinal measurements from 14 to 58 months, and individual differences in brain structure measured in 3rd and 4th grade (8-10 years old). Our results show that the pace of vocabulary growth uniquely predicts cortical thickness in the left supramarginal gyrus. Probabilistic tractography revealed that this region is directly connected to the inferior frontal gyrus (pars opercularis) and the ventral premotor cortex, via what is most probably the superior longitudinal fasciculus III. Our findings demonstrate, for the first time, the relation between the pace of vocabulary learning in children and a specific change in the structure of the cerebral cortex, specifically, cortical thickness in the left supramarginal gyrus. They also highlight the fact that differences in the pace of vocabulary growth are associated with the dorsal language stream, which is thought to support speech perception and articulation.

Performance Variability as a Predictor of Response to Aphasia Treatment

BACKGROUND

Performance variability in individuals with aphasia is typically regarded as a nuisance factor complicating assessment and treatment.

OBJECTIVE

We present the alternative hypothesis that intraindividual variability represents a fundamental characteristic of an individual's functioning and an important biomarker for therapeutic selection and prognosis.

METHODS

A total of 19 individuals with chronic aphasia participated in a 6-week trial of imitation-based speech therapy. We assessed improvement both on overall language functioning and repetition ability. Furthermore, we determined which pretreatment variables best predicted improvement on the repetition test.

RESULTS

Significant gains were made on the Western Aphasia Battery-Revised (WAB) Aphasia Quotient, Cortical Quotient, and 2 subtests as well as on a separate repetition test. Using stepwise regression, we found that pretreatment intraindividual variability was the only predictor of improvement in performance on the repetition test, with greater pretreatment variability predicting greater improvement. Furthermore, the degree of reduction in this variability over the course of treatment was positively correlated with the degree of improvement.

CONCLUSIONS

Intraindividual variability may be indicative of potential for improvement on a given task, with more uniform performance suggesting functioning at or near peak potential.

Utility of EEG measures of brain function in patients with acute stroke

EEG has been used to study acute stroke for decades; however, because of several limitations EEG-based measures rarely inform clinical decision-making in this setting. Recent advances in EEG hardware, recording electrodes, and EEG software could overcome these limitations. The present study examined how well dense-array (256 electrodes) EEG, acquired with a saline-lead net and analyzed with whole brain partial least squares (PLS) modeling, captured extent of acute stroke behavioral deficits and varied in relation to acute brain injury. In 24 patients admitted for acute ischemic stroke, 3 min of resting-state EEG was acquired at bedside, including in the ER and ICU. Traditional quantitative EEG measures (power in a specific lead, in any frequency band) showed a modest association with behavioral deficits [NIH Stroke Scale (NIHSS) score] in bivariate models. However, PLS models of delta or beta power across whole brain correlated strongly with NIHSS score (R(2) = 0.85-0.90) and remained robust when further analyzed with cross-validation models (R(2) = 0.72-0.73). Larger infarct volume was associated with higher delta power, bilaterally; the contralesional findings were not attributable to mass effect, indicating that EEG captures significant information about acute stroke effects not available from MRI. We conclude that 1) dense-array EEG data are feasible as a bedside measure of brain function in patients with acute stroke; 2) high-dimension EEG data are strongly correlated with acute stroke behavioral deficits and are superior to traditional single-lead metrics in this regard; and 3) EEG captures significant information about acute stroke injury not available from structural brain imaging.

Prevention of post-stroke generalized anxiety disorder, using escitalopram or problem-solving therapy

This study examined the efficacy of antidepressant treatment for preventing the onset of generalized anxiety disorder (GAD) among patients with recent stroke. Of 799 patients assessed, 176 were randomized, and 149 patients without evidence of GAD at the initial visit were included in this double-blind treatment with escitalopram (N=47) or placebo (N=49) or non-blinded problem-solving therapy (PST; 12 total sessions; N=53). Participants given placebo over 12 months were 4.95 times more likely to develop GAD than patients given escitalopram and 4.00 times more likely to develop GAD than patients given PST. Although these results should be considered preliminary, the authors found that both escitalopram and PST were effective in preventing new onset of post-stroke GAD.

Structural correlates of spoken language abilities: A surface-based region-of interest morphometry study

Brain structure can predict many aspects of human behavior, though the extent of this relationship in healthy adults, particularly for language-related skills, remains largely unknown. The objective of the present study was to explore this relation using magnetic resonance imaging (MRI) on a group of 21 healthy young adults who completed two language tasks: (1) semantic fluency and (2) sentence generation. For each region of interest, cortical thickness, surface area, and volume were calculated. The results show that verbal fluency scores correlated mainly with measures of brain morphology in the left inferior frontal cortex and bilateral insula. Sentence generation scores correlated with structure of the left inferior parietal and right inferior frontal regions. These results reveal that the anatomy of several structures in frontal and parietal lobes is associated with spoken language performance. The presence of both negative and positive correlations highlights the complex relation between brain and language.

Neurobiological roots of language in primate audition: common computational properties

Here, we present a new perspective on an old question: how does the neurobiology of human language relate to brain systems in nonhuman primates? We argue that higher-order language combinatorics, including sentence and discourse processing, can be situated in a unified, cross-species dorsal-ventral streams architecture for higher auditory processing, and that the functions of the dorsal and ventral streams in higher-order language processing can be grounded in their respective computational properties in primate audition. This view challenges an assumption, common in the cognitive sciences, that a nonhuman primate model forms an inherently inadequate basis for modeling higher-level language functions.

Abstract W P387: Neurological Correlates Of Brain Function After Acute Stroke--A Dense Array EEG Study

INTRODUCTION: Measures of brain function can complement assessment of injury to inform clinical decision-making after stroke, but the most useful metrics remain uncertain. An acute stroke alters brain function in widespread areas. We therefore reasoned that a whole brain measure of brain function would be better related to behavioral deficits than a regional measure of brain function.

METHODS: In 24 patients hospitalized for acute stroke, resting EEG (256 leads) was recorded for 3 min at the bedside and analyzed offline. Two EEG measures of brain function were extracted: [1] whole brain connectivity, which found the EEG frequency (from 1-30 Hz) and seed point (from among the 256 leads) that best fit whole brain coherence with total NIHSS scores, using a partial least squares regression model; and [2] regional brain activity, which found the EEG frequency and lead where spectral power was most strongly correlated with total NIHSS scores. Analyses were repeated focused on NIHSS motor subscores (Q4-6). All models were validated using a leave-one-out approach.

RESULTS: The 24 patients were age 60.9±13.1yr, 3.5 ± 2.9 d post-onset (range 3hr-12d), and were studied in settings that included ER, ICU, and stroke ward. Whole brain EEG connectivity explained a large fraction of the variance in total NIHSS scores (r^2=0.72); this was achieved in the 2-4 Hz range, with seed over ipsilesional motor cortex, and with model predicting higher NIHSS score when this seed had greater coherence with contralesional frontal/motor regions. Regional brain activity, by comparison, explained a smaller fraction of variance (r^2=0.51), with maximal correlation between total NIHSS and regional EEG power found using a lead over contralesional motor cortex, at 2 Hz. Similar results for whole brain EEG connectivity were obtained when modeling NIHSS motor subscores in the 14 subjects with motor deficits (validated r^2=0.71).

CONCLUSIONS: Dense array EEG recordings could be obtained early after stroke, rapidly and reliably, and at the bedside in widespread hospital settings. Whole brain connectivity measures corresponded to behavioral state better than measures of regional brain activity do. Results support the utility of EEG as a bedside method for evaluating brain functional status after stroke.

New evidence about language and cognitive development based on a longitudinal study: hypotheses for intervention

We review findings from a four-year longitudinal study of language learning conducted on two samples: a sample of typically developing children whose parents vary substantially in socioeconomic status, and a sample of children with pre- or perinatal brain injury. This design enables us to study language development across a wide range of language learning environments and a wide range of language learners. We videotaped samples of children's and parents' speech and gestures during spontaneous interactions at home every four months, and then we transcribed and coded the tapes. We focused on two behaviors known to vary across individuals and environments-child gesture and parent speech-behaviors that have the potential to index, and perhaps even play a role in creating, differences across children in linguistic and other cognitive skills. Our observations have led to four hypotheses that have promise for the development of diagnostic tools and interventions to enhance language and cognitive development and brain plasticity after neonatal injury. One kind of hypothesis involves tools that could identify children who may be at risk for later language deficits. The other involves interventions that have the potential to promote language development. We present our four hypotheses as a summary of the findings from our study because there is scientific evidence behind them and because this evidence has the potential to be put to practical use in improving education.

Cross-linguistic variation in the neurophysiological response to semantic processing: evidence from anomalies at the borderline of awareness

The N400 event-related brain potential (ERP) has played a major role in the examination of how the human brain processes meaning. For current theories of the N400, classes of semantic inconsistencies which do not elicit N400 effects have proven particularly influential. Semantic anomalies that are difficult to detect are a case in point ("borderline anomalies", e.g. "After an air crash, where should the survivors be buried?"), engendering a late positive ERP response but no N400 effect in English (Sanford, Leuthold, Bohan, & Sanford, 2011). In three auditory ERP experiments, we demonstrate that this result is subject to cross-linguistic variation. In a German version of Sanford and colleagues' experiment (Experiment 1), detected borderline anomalies elicited both N400 and late positivity effects compared to control stimuli or to missed borderline anomalies. Classic easy-to-detect semantic (non-borderline) anomalies showed the same pattern as in English (N400 plus late positivity). The cross-linguistic difference in the response to borderline anomalies was replicated in two additional studies with a slightly modified task (Experiment 2a: German; Experiment 2b: English), with a reliable LANGUAGE×ANOMALY interaction for the borderline anomalies confirming that the N400 effect is subject to systematic cross-linguistic variation. We argue that this variation results from differences in the language-specific default weighting of top-down and bottom-up information, concluding that N400 amplitude reflects the interaction between the two information sources in the form-to-meaning mapping.

Brain repair after stroke--a novel neurological model

Following stroke, patients are commonly left with debilitating motor and speech impairments. This article reviews the state of the art in neurological repair for stroke and proposes a new model for the future. We suggest that stroke treatment--from the time of the ictus itself to living with the consequences--must be fundamentally neurological, from limiting the extent of injury at the outset, to repairing the consequent damage. Our model links brain and behaviour by targeting brain circuits, and we illustrate the model though action observation treatment, which aims to enhance brain network connectivity. The model is based on the assumptions that the mechanisms of neural repair inherently involve cellular and circuit plasticity, that brain plasticity is a synaptic phenomenon that is largely stimulus-dependent, and that brain repair required both physical and behavioural interventions that are tailored to reorganize specific brain circuits. We review current approaches to brain repair after stroke and present our new model, and discuss the biological foundations, rationales, and data to support our novel approach to upper-extremity and language rehabilitation. We believe that by enhancing plasticity at the level of brain network interactions, this neurological model for brain repair could ultimately lead to a cure for stroke.

Plastic Changes Following Imitation-Based Speech and Language Therapy for Aphasia

Background. Objective measurement of plastic brain changes induced by a novel rehabilitative approach is a key requirement for validating its biological rationale linking the potential therapeutic gains to the changes in brain physiology. Objective. Based on an emerging notion linking cortical plastic changes to EEG sleep slow-wave activity (SWA) regulation, we aimed to assess the acute plastic changes induced by an imitation-based speech therapy in individuals with aphasia by comparing sleep SWA changes before and after therapy. Methods. A total of 13 left-hemispheric stroke patients underwent language assessment with the Western Aphasia Battery (WAB) before and after 2 consecutive high-density (hd) EEG sleep recordings interleaved by a daytime session of imitation-based speech therapy (Intensive Mouth Imitation and Talking for Aphasia Therapeutic Effects [IMITATE]). This protocol is thought to stimulate bilateral connections between the inferior parietal lobule and the ventral premotor areas. Results. A single exposure to IMITATE resulted in increases in local EEG SWA during subsequent sleep over the same regions predicted by the therapeutic rationale, particularly over the right hemisphere (unaffected by the lesion). Furthermore, changes in SWA over the left-precentral areas predicted changes in WAB repetition scores in our group, supporting the role of perilesional areas in predicting positive functional responses. Conclusions. Our results suggest that SWA changes occurring in brain areas activated during imitation-based aphasia therapy may reflect the acute plastic changes induced by this intervention. Further testing will be needed to evaluate SWA as a non-invasive assessment of changes induced by the therapy and as a predictor of positive long-term clinical outcome.

Consonant accuracy after severe pediatric traumatic brain injury: a prospective cohort study

PURPOSE

The authors sought to describe longitudinal changes in Percentage of Consonants Correct-Revised (PCC-R) after severe pediatric traumatic brain injury (TBI), to compare the odds of normal-range PCC-R in children injured at older and younger ages, and to correlate predictor variables and PCC-R outcomes.

METHOD

In 56 children injured between age 1 month and 11 years, PCC-R was calculated over 12 monthly sessions beginning when the child produced ≥ 10 words. At each session, the authors compared odds of normal-range PCC-R in children injured at younger (≤ 60 months) and older (> 60 months) ages. Correlations were calculated between final PCC-R and age at injury, injury mechanism, gender, maternal education, residence, treatment, Glasgow Coma Score, and intact brain volume.

RESULTS

PCC-Rs varied within and between children. Odds of normal-range PCC-R were significantly higher for the older than for the younger group at all sessions but the first; odds of normal-range PCC-R were 9 to 33 times higher in the older group in sessions 3 to 12. Age at injury was significantly correlated with final PCC-R.

CONCLUSION

Over a 12-month period, severe TBI had more adverse effects for children whose ages placed them in the most intensive phase of PCC-R development than for children injured later.

Brain function overlaps when people observe emblems, speech, and grasping

A hand grasping a cup or gesturing "thumbs-up", while both manual actions, have different purposes and effects. Grasping directly affects the cup, whereas gesturing "thumbs-up" has an effect through an implied verbal (symbolic) meaning. Because grasping and emblematic gestures ("emblems") are both goal-oriented hand actions, we pursued the hypothesis that observing each should evoke similar activity in neural regions implicated in processing goal-oriented hand actions. However, because emblems express symbolic meaning, observing them should also evoke activity in regions implicated in interpreting meaning, which is most commonly expressed in language. Using fMRI to test this hypothesis, we had participants watch videos of an actor performing emblems, speaking utterances matched in meaning to the emblems, and grasping objects. Our results show that lateral temporal and inferior frontal regions respond to symbolic meaning, even when it is expressed by a single hand action. In particular, we found that left inferior frontal and right lateral temporal regions are strongly engaged when people observe either emblems or speech. In contrast, we also replicate and extend previous work that implicates parietal and premotor responses in observing goal-oriented hand actions. For hand actions, we found that bilateral parietal and premotor regions are strongly engaged when people observe either emblems or grasping. These findings thus characterize converging brain responses to shared features (e.g., symbolic or manual), despite their encoding and presentation in different stimulus modalities.

Functional and structural aging of the speech sensorimotor neural system: functional magnetic resonance imaging evidence

The ability to perceive and produce speech undergoes important changes in late adulthood. The goal of the present study was to characterize functional and structural age-related differences in the cortical network that support speech perception and production, using magnetic resonance imaging, as well as the relationship between functional and structural age-related changes occurring in this network. We asked young and older adults to observe videos of a speaker producing single words (perception), and to observe and repeat the words produced (production). Results show a widespread bilateral network of brain activation for Perception and Production that was not correlated with age. In addition, several regions did show age-related change (auditory cortex, planum temporale, superior temporal sulcus, premotor cortices, SMA-proper). Examination of the relationship between brain signal and regional and global gray matter volume and cortical thickness revealed a complex set of relationships between structure and function, with some regions showing a relationship between structure and function and some not. The present results provide novel findings about the neurobiology of aging and verbal communication.

Frontal and temporal contributions to understanding the iconic co-speech gestures that accompany speech

In everyday conversation, listeners often rely on a speaker's gestures to clarify any ambiguities in the verbal message. Using fMRI during naturalistic story comprehension, we examined which brain regions in the listener are sensitive to speakers' iconic gestures. We focused on iconic gestures that contribute information not found in the speaker's talk, compared with those that convey information redundant with the speaker's talk. We found that three regions-left inferior frontal gyrus triangular (IFGTr) and opercular (IFGOp) portions, and left posterior middle temporal gyrus (MTGp)--responded more strongly when gestures added information to nonspecific language, compared with when they conveyed the same information in more specific language; in other words, when gesture disambiguated speech as opposed to reinforced it. An increased BOLD response was not found in these regions when the nonspecific language was produced without gesture, suggesting that IFGTr, IFGOp, and MTGp are involved in integrating semantic information across gesture and speech. In addition, we found that activity in the posterior superior temporal sulcus (STSp), previously thought to be involved in gesture-speech integration, was not sensitive to the gesture-speech relation. Together, these findings clarify the neurobiology of gesture-speech integration and contribute to an emerging picture of how listeners glean meaning from gestures that accompany speech.

Fragmentation and unpredictability of early-life experience in mental disorders

Maternal sensory signals in early life play a crucial role in programming the structure and function of the developing brain, promoting vulnerability or resilience to emotional and cognitive disorders. In rodent models of early-life stress, fragmentation and unpredictability of maternally derived sensory signals provoke persistent cognitive and emotional dysfunction in offspring. Similar variability and inconsistency of maternal signals during both gestation and early postnatal human life may influence development of emotional and cognitive functions, including those that underlie later depression and anxiety.

Epidural cortical stimulation and aphasia therapy

BACKGROUND

There are several methods of delivering cortical brain stimulation to modulate cortical excitability and interest in their application as an adjuvant strategy in aphasia rehabilitation after stroke is growing. Epidural cortical stimulation, although more invasive than other methods, permits high frequency stimulation of high spatial specificity to targeted neuronal populations.

AIMS

First, we review evidence supporting the use of epidural cortical stimulation for upper limb recovery after focal cortical injury in both animal models and human stroke survivors. These data provide the empirical and theoretical platform underlying the use of epidural cortical stimulation in aphasia. Second, we summarize evidence for the application of epidural cortical stimulation in aphasia. We describe the procedures and primary outcomes of a safety and feasibility study (Cherney, Erickson & Small, 2010), and provide previously unpublished data regarding secondary behavioral outcomes from that study.

MAIN CONTRIBUTION

In a controlled study comparing epidural cortical stimulation plus language treatment (CS/LT) to language treatment alone (LT), eight stroke survivors with nonfluent aphasia received intensive language therapy for 6 weeks. Four of these participants also underwent surgical implantation of an epidural stimulation device which was activated only during therapy sessions. Behavioral data were collected before treatment, immediately after treatment, and at 6 and 12 weeks following the end of treatment. The effect size for the primary outcome measure, the Western Aphasia Battery Aphasia Quotient, was benchmarked as moderate from baseline to immediately post-treatment, and large from baseline to the 12-week follow-up. Similarly, effect sizes obtained at the 12-week follow-up for the Boston Naming Test, the Communicative Effectiveness Index, and for correct information units on a picture description task were greater than those obtained immediately post treatment. When effect sizes were compared for individual subject pairs on discourse measures of content and rate, effects were typically larger for the investigational subjects receiving CS/LT than for the control subjects receiving LT alone. These analyses support previous findings regarding therapeutic efficacy of CS/LT compared to LT i.e. epidural stimulation of ipsilesional premotor cortex may augment behavioral speech-language therapy, with the largest effects after completion of therapy.

CONCLUSIONS

Continued investigation of epidural cortical stimulation in combination with language training in post-stroke aphasia should proceed cautiously. Carefully planned studies that customize procedures to individual profiles are warranted. Information from research on non-invasive methods of CS/LT may also inform future studies of epidural cortical stimulation.

Gesture's Neural Language

When people talk to each other, they often make arm and hand movements that accompany what they say. These manual movements, called “co-speech gestures,” can convey meaning by way of their interaction with the oral message. Another class of manual gestures, called “emblematic gestures” or “emblems,” also conveys meaning, but in contrast to co-speech gestures, they can do so directly and independent of speech. There is currently significant interest in the behavioral and biological relationships between action and language. Since co-speech gestures are actions that rely on spoken language, and emblems convey meaning to the effect that they can sometimes substitute for speech, these actions may be important, and potentially informative, examples of language–motor interactions. Researchers have recently been examining how the brain processes these actions. The current results of this work do not yet give a clear understanding of gesture processing at the neural level. For the most part, however, it seems that two complimentary sets of brain areas respond when people see gestures, reflecting their role in disambiguating meaning. These include areas thought to be important for understanding actions and areas ordinarily related to processing language. The shared and distinct responses across these two sets of areas during communication are just beginning to emerge. In this review, we talk about the ways that the brain responds when people see gestures, how these responses relate to brain activity when people process language, and how these might relate in normal, everyday communication.