Clinical outcomes of peripheral nerve interfaces for rehabilitation in paralysis and amputation: a literature review.

Peripheral nerve interfaces (PNIs) are electrical systems designed to integrate with peripheral nerves in patients, such as following central nervous system (CNS) injuries to augment or replace CNS control and restore function. We review the literature for clinical trials and studies containing clinical outcome measures to explore the utility of human applications of PNIs. We discuss the various types of electrodes currently used for PNI systems and their functionalities and limitations. We discuss important design characteristics of PNI systems, including biocompatibility, resolution and specificity, efficacy, and longevity, to highlight their importance in the current and future development of PNIs. The clinical outcomes of PNI systems are also discussed. Finally, we review relevant PNI clinical trials that were conducted, up to the present date, to restore the sensory and motor function of upper or lower limbs in amputees, spinal cord injury patients, or intact individuals and describe their significant findings. This review highlights the current progress in the field of PNIs and serves as a foundation for future development and application of PNI systems.

Treatment of Intrathecal Drug Pump Flipping Using Fascial Flaps: A Technical Description and Case Series.

BACKGROUND AND OBJECTIVES: Intrathecal drug therapy is a common treatment for dystonia, pain, and spasticity using implanted pump and catheter systems. Standardized management of intrathecal drug pump (ITDP) migration and flipping has not been well established in the literature. This study reports the use of soft tissue to address less common pump complications such as pump flipping, migration, and difficulty in medication refill. METHODS: A retrospective chart review of intrathecal pump cases performed by two surgeons between February 2020 and August 2022 was conducted. Patients with complications such as pump flipping, migration, or challenges in medication refill treated with soft tissue flaps were included. Patient demographics, comorbidities, and perioperative data were collected. RESULTS: A total of five patients with ITDP complicated by pump flipping, migration, malposition, or difficulty in medication refill that were treated using fascial flaps were included in the study. Three technical considerations when revising ITDP complications are secure pump anchoring, reliable wound closure, and ease of pump medication refill. Cases 1 and 2 demonstrate the technique of secure pump anchoring with a rectus fascial flap. Cases 3 and 4 show a technique to achieve reliable vascularized wound closure, and case 5 describes a technique to solve an uncommon problem of a thick subcutaneous abdominal tissue preventing the refill of the ITDP medication. CONCLUSION: Soft tissue flaps may serve as a treatment option for patients with uncommon ITDP complications. De-epithelialized dermal fasciocutaneous or fascial flaps may be developed to anchor the pump more securely. Cross-discipline collaboration may further delineate the technique, benefits, and outcomes of this approach.

Spinal cord stimulation for chronic pain treatment following sacral chordoma resection: illustrative case.

BACKGROUND: Cancer-related or postoperative pain can occur following sacral chordoma resection. Despite a lack of current recommendations for cancer pain treatment, spinal cord stimulation (SCS) has demonstrated effectiveness in addressing cancer-related pain. OBSERVATIONS: A 76-year-old female with a sacral chordoma underwent anterior osteotomies and partial en bloc sacrectomy. She subsequently presented with chronic pain affecting both buttocks and posterior thighs and legs, significantly impeding her daily activities. She underwent a staged epidural SCS paddle trial and permanent system placement using intraoperative neuromonitoring. The utilization of percutaneous leads was not viable because of her history of spinal fluid leakage, multiple lumbosacral surgeries, and previous complex plastic surgery closure. The patient reported a 62.5% improvement in her lower-extremity pain per the modified Quadruple Visual Analog Scale and a 50% improvement in the modified Pain and Sleep Questionnaire 3-item index during the SCS trial. Following permanent SCS system placement and removal of her externalized lead extenders, she had an uncomplicated postoperative course and reported notable improvements in her pain symptoms. LESSONS: This case provides a compelling illustration of the successful treatment of chronic pain using SCS following radical sacral chordoma resection. Surgeons may consider this treatment approach in patients presenting with refractory pain following spinal tumor resection.

Internal iliac artery aneurysm masquerading as a sciatic nerve schwannoma: illustrative case.

BACKGROUND: Schwannomas are common peripheral nerve sheath tumors. Imaging techniques such as magnetic resonance imaging (MRI) and computed tomography (CT) can help to distinguish schwannomas from other types of lesions. However, there have been several reported cases describing the misdiagnosis of aneurysms as schwannomas. OBSERVATIONS: A 70-year-old male with ongoing pain despite spinal fusion surgery underwent MRI. A lesion was noted along the left sciatic nerve, which was believed to be a sciatic nerve schwannoma. During the surgery for planned neurolysis and tumor resection, the lesion was noted to be pulsatile. Electromyography mapping and intraoperative ultrasound confirmed vascular pulsations and turbulent flow within the aneurysm, so the surgery was aborted. A formal CT angiogram revealed the lesion to be an internal iliac artery (IIA) branch aneurysm. The patient underwent coil embolization with complete obliteration of the aneurysm. LESSONS: The authors report the first case of an IIA aneurysm misdiagnosed as a sciatic nerve schwannoma. Surgeons should be aware of this potential misdiagnosis and potentially use other imaging modalities to confirm the lesion before proceeding with surgery.

Response to Letter Regarding "Predictive Value of Preoperative Serum Albumin in Patients With Metastatic Spine Diseases: A Statistical Comment".

We thank the authors for their interest in and commentary on "Preoperative Serum Albumin Level Predicts Length of Stay and Perioperative Adverse Events Following Vertebral Corpectomy and Posterior Stabilization for Metastatic Spine Disease." We appreciate the opportunity to respond to their comments herein.

Magnetic Resonance-Guided Stereotaxy for Infusions to the Pig Brain.

The overall goal of this procedure is to perform stereotaxy in the pig brain with real-time magnetic resonance (MR) visualization guidance to provide precise infusions. The subject was positioned prone in the MR bore for optimal access to the top of the skull with the torso raised, the neck flexed, and the head inclined downward. Two anchor pins anchored on the bilateral zygoma held the head steady using the head holder. A magnetic resonance imaging (MRI) flex-coil was placed rostrally across the head holder so that the skull was accessible for the intervention procedure. A planning grid placed on the scalp was used to determine the appropriate entry point of the cannula. The stereotactic frame was secured and aligned iteratively through software projection until the projected radial error was less than 0.5 mm. A hand drill was used to create a burr hole for insertion of the cannula. A gadolinium-enhanced co-infusion was used to visualize the infusion of a cell suspension. Repeated T1-weighted MRI scans were registered in real time during the agent delivery process to visualize the volume of gadolinium distribution. MRI-guided stereotaxy allows for precise and controlled infusion into the pig brain, with concurrent monitoring of cannula insertion accuracy and determination of the agent volume of distribution.

Preoperative Serum Albumin Level Predicts Length of Stay and Perioperative Adverse Events Following Vertebral Corpectomy and Posterior Stabilization for Metastatic Spine Disease.

STUDY DESIGN: Retrospective review of a prospectively collected national database. OBJECTIVES: To determine the association between preoperative serum albumin levels and perioperative adverse events (AEs) following vertebral corpectomy and posterior stabilization for metastatic spine disease. METHODS: The 2010 to 2019 American College of Surgeons' National Surgical Quality Improvement (ACS-NSQIP) database was used to identify all patients undergoing vertebral corpectomy and posterior stabilization for metastatic spine disease. Receiver operative characteristic (ROC) curve analysis was used to determine preoperative serum albumin cut-off values for predicting perioperative AEs. Low preoperative serum albumin was defined as serum albumin below this cut-off value. RESULTS: A total of 301 patients were included in the study. ROC curve analysis demonstrated serum albumin < 3.25 g/dL as a cut-off value for predicting perioperative AEs. The low serum albumin group had a higher overall perioperative AEs (P = .041), longer post-operative LOS (P < .001), higher 30-day reoperation rate (P = .014), and a higher in-hospital mortality rate (P = .046). Multivariate analysis demonstrated that low preoperative serum albumin was associated with higher perioperative AEs. CONCLUSIONS: Low serum albumin level is associated with higher perioperative AEs, longer postoperative LOS, and higher rates of 30-day reoperation and in-hospital mortality among patients undergoing vertebral corpectomy and posterior stabilization for metastatic spine disease. Strategies to improve preoperative nutritional status in patients undergoing this procedure may improve these perioperative outcome measures within this surgical population. LEVEL OF EVIDENCE: III.

Incorporating Intraoperative Mechanomyography to Peripheral Nerve Decompression Surgery.

BACKGROUND: Mechanomyography (MMG) is a novel intraoperative tool to detect and quantify nerve activity with high sensitivity as compared with traditional electromyographic recordings. MMG reflects the mechanical vibrations of single motor units detected through accelerometer sensors after direct motor neuron stimulation. OBJECTIVE: To determine the feasibility of applying intraoperative MMG during peripheral nerve surgery. METHODS: A total of 20 consecutive patients undergoing surgical decompression of the ulnar nerve at the cubital tunnel or common peroneal nerve at the fibular head were included in this study. Intraoperatively, the common peroneal and ulnar nerves were directly stimulated through the MMG electrode probe starting at 0.1 mA threshold and increasing by 0.1 mA increments until target muscle activity was noted. The lowest threshold current required to elicit a muscle response was recorded before decompression and after proximal and distal nerve decompression. RESULTS: Of the patients, 80% (16/20) had MMG signals detected and recorded. Four patients were unable to have MMG signal detected despite direct nerve visualization and complete neurolysis. The mean predecompression stimulus threshold was 1.59 ± 0.19 mA. After surgical decompression, improvement in the mean MMG stimulus threshold was noted (0.47 ± 0.03 mA, P = .0002). Postoperatively, all patients endorsed symptomatic improvement with no complications. CONCLUSION: MMG may provide objective guidance for the intraoperative determination of the extent of nerve decompression. Lower stimulus thresholds may represent increased sparing of axonal tissue. Future work should focus on validating normative values of MMG stimulus thresholds in various nerves and establishing clinical associations with functional outcomes.

Improvement in sagittal alignment and mechanical low-back pain following deep brain stimulation for Parkinson's disease: illustrative case.

BACKGROUND: Parkinson's disease (PD) is a common neurogenerative disease marked by the characteristic triad of bradykinesia, rigidity, and tremor. A significant percentage of patients with PD also demonstrate postural abnormalities (camptocormia) that limit ambulation and accelerate degenerative pathologies of the spine. Although deep brain stimulation (DBS) is a well-established treatment for the motor fluctuations and tremor seen in PD, the efficacy of DBS on postural abnormalities in these patients is less clear. OBSERVATIONS: The authors present a patient with a history of PD and prior lumbosacral fusion who underwent bilateral subthalamic nucleus DBS and experienced immediate improvement in sagittal alignment and subjective relief of mechanical low-back pain. LESSONS: DBS may improve postural abnormalities seen in PD and potentially delay or reduce the need for spinal deformity surgery.

An EEG-Based Investigation of the Effect of Perceived Observation on Visual Memory in Virtual Environments.

The presence of external observers has been shown to affect performance on cognitive tasks, but the parameters of this impact for different types of tasks and the underlying neural dynamics are less understood. The current study examined the behavioral and brain activity effects of perceived observation on participants' visual working memory (VWM) in a virtual reality (VR) classroom setting, using the task format as a moderating variable. Participants (n = 21) were equipped with a 57-channel EEG cap, and neural data were collected as they completed two VWM tasks under two observation conditions (observed and not observed) in a within-subjects experimental design. The "observation" condition was operationalized through the addition of a static human avatar in the VR classroom. The avatar's presence was associated with a significant effect on extending the task response time, but no effect was found on task accuracy. This outcome may have been due to a ceiling effect, as the mean participant task scores were quite high. EEG data analysis supported the behavioral findings by showing consistent differences between the no-observation and observation conditions for one of the VWM tasks only. These neural differences were identified in the dorsolateral prefrontal cortex (dlPFC) and the occipital cortex (OC) regions, with higher theta-band activity occurring in the dlPFC during stimulus encoding and in the OC during response selection when the "observing" avatar was present. These findings provide evidence that perceived observation can inhibit performance during visual tasks by altering attentional focus, even in virtual contexts.

Brain-to-brain communication during musical improvisation: a performance case study.

Understanding and predicting others' actions in ecological settings is an important research goal in social neuroscience. Here, we deployed a mobile brain-body imaging (MoBI) methodology to analyze inter-brain communication between professional musicians during a live jazz performance. Specifically, bispectral analysis was conducted to assess the synchronization of scalp electroencephalographic (EEG) signals from three expert musicians during a three-part 45 minute jazz performance, during which a new musician joined every five minutes. The bispectrum was estimated for all musician dyads, electrode combinations, and five frequency bands. The results showed higher bispectrum in the beta and gamma frequency bands (13-50 Hz) when more musicians performed together, and when they played a musical phrase synchronously. Positive bispectrum amplitude changes were found approximately three seconds prior to the identified synchronized performance events suggesting preparatory cortical activity predictive of concerted behavioral action. Moreover, a higher amount of synchronized EEG activity, across electrode regions, was observed as more musicians performed, with inter-brain synchronization between the temporal, parietal, and occipital regions the most frequent. Increased synchrony between the musicians' brain activity reflects shared multi-sensory processing and movement intention in a musical improvisation task.

Acute aortic occlusion leading to spinal cord ischemia in a 73-year-old: A case report.

Background: Cauda equina syndrome (CES) is typically caused by a compressive etiology from a herniated disk, tumor, or fracture of the spine compressing the thecal sac. Here, we report a CES mimic - acute aortic occlusion (AAO), a rare disease that is associated with high morbidity and mortality. AAO can compromise spinal cord blood supply and leads to spinal cord ischemia. Case Description: Our patient presented with an acute onset of bilateral lower extremity pain and weakness with bowel/bladder incontinence, a constellation of symptoms concerning for CES. However, on initial imaging, there was no compression of his thecal sac to explain his symptomology. Further, investigation revealed an AAO. The patient underwent an emergent aortic thrombectomy with resolution of symptoms. Conclusion: AAO can mimic CES and should be considered in one's differential diagnosis when imaging is negative for any spinal compressive etiologies.

Comparing physiological responses during cognitive tests in virtual environments vs. in identical real-world environments.

Immersive virtual environments (VEs) are increasingly used to evaluate human responses to design variables. VEs provide a tremendous capacity to isolate and readily adjust specific features of an architectural or product design. They also allow researchers to safely and effectively measure performance factors and physiological responses. However, the success of this form of design-testing depends on the generalizability of response measurements between VEs and real-world contexts. At the current time, there is very limited research evaluating the consistency of human response data across identical real and virtual environments. Rendering tools were used to precisely replicate a real-world classroom in virtual space. Participants were recruited and asked to complete a series of cognitive tests in the real classroom and in the virtual classroom. Physiological data were collected during these tests, including electroencephalography (EEG), electrocardiography (ECG), electrooculography (EOG), galvanic skin response (GSR), and head acceleration. Participants' accuracy on the cognitive tests did not significantly differ between the real classroom and the identical VE. However, the participants answered the tests more rapidly in the VE. No significant differences were found in eye blink rate and heart rate between the real and VR settings. Head acceleration and GSR variance were lower in the VE setting. Overall, EEG frequency band-power was not significantly altered between the real-world classroom and the VE. Analysis of EEG event-related potentials likewise indicated strong similarity between the real-world classroom and the VE, with a single exception related to executive functioning in a color-mismatch task.

A Roadmap Towards Standards for Neurally Controlled End Effectors.

The control and manipulation of various types of end effectors such as powered exoskeletons, prostheses, and 'neural' cursors by brain-machine interface (BMI) systems has been the target of many research projects. A seamless "plug and play" interface between any BMI and end effector is desired, wherein similar user's intent cause similar end effectors to behave identically. This report is based on the outcomes of an IEEE Standards Association Industry Connections working group on End Effectors for Brain-Machine Interfacing that convened to identify and address gaps in the existing standards for BMI-based solutions with a focus on the end-effector component. A roadmap towards standardization of end effectors for BMI systems is discussed by identifying current device standards that are applicable for end effectors. While current standards address basic electrical and mechanical safety, and to some extent, performance requirements, several gaps exist pertaining to unified terminologies, data communication protocols, patient safety and risk mitigation.

Characterization of the Stages of Creative Writing With Mobile EEG Using Generalized Partial Directed Coherence.

Two stages of the creative writing process were characterized through mobile scalp electroencephalography (EEG) in a 16-week creative writing workshop. Portable dry EEG systems (four channels: TP09, AF07, AF08, TP10) with synchronized head acceleration, video recordings, and journal entries, recorded mobile brain-body activity of Spanish heritage students. Each student's brain-body activity was recorded as they experienced spaces in Houston, Texas ("Preparation" stage), and while they worked on their creative texts ("Generation" stage). We used Generalized Partial Directed Coherence (gPDC) to compare the functional connectivity among both stages. There was a trend of higher gPDC in the Preparation stage from right temporo-parietal (TP10) to left anterior-frontal (AF07) brain scalp areas within 1-50 Hz, not reaching statistical significance. The opposite directionality was found for the Generation stage, with statistical significant differences (p < 0.05) restricted to the delta band (1-4 Hz). There was statistically higher gPDC observed for the inter-hemispheric connections AF07-AF08 in the delta and theta bands (1-8 Hz), and AF08 to TP09 in the alpha and beta (8-30 Hz) bands. The left anterior-frontal (AF07) recordings showed higher power localized to the gamma band (32-50 Hz) for the Generation stage. An ancillary analysis of Sample Entropy did not show significant difference. The information transfer from anterior-frontal to temporal-parietal areas of the scalp may reflect multisensory interpretation during the Preparation stage, while brain signals originating at temporal-parietal toward frontal locations during the Generation stage may reflect the final decision making process to translate the multisensory experience into a creative text.

Assaying neural activity of children during video game play in public spaces: a deep learning approach.

OBJECTIVE: Understanding neural activity patterns in the developing brain remains one of the grand challenges in neuroscience. Developing neural networks are likely to be endowed with functionally important variability associated with the environmental context, age, gender, and other variables. Therefore, we conducted experiments with typically developing children in a stimulating museum setting and tested the feasibility of using deep learning techniques to help identify patterns of brain activity associated with different conditions. APPROACH: A four-channel dry EEG-based Mobile brain-body imaging data of children at rest and during videogame play (VGP) was acquired at the Children's Museum of Houston. A data-driven approach based on convolutional neural networks (CNN) was used to describe underlying feature representations in the EEG and their ability to discern task and gender. The variability of the spectral features of EEG during the rest condition as a function of age was also analyzed. MAIN RESULTS: Alpha power (7-13 Hz) was higher during rest whereas theta power (4-7 Hz) was higher during VGP. Beta (13-18 Hz) power was the most significant feature, higher in females, when differentiating between males and females. Using data from both temporoparietal channels to classify between VGP and rest condition, leave-one-subject-out cross-validation accuracy of 67% was obtained. Age-related changes in EEG spectral content during rest were consistent with previous developmental studies conducted in laboratory settings showing an inverse relationship between age and EEG power. SIGNIFICANCE: These findings are the first to acquire, quantify and explain brain patterns observed during VGP and rest in freely behaving children in a museum setting using a deep learning framework. The study shows how deep learning can be used as a data driven approach to identify patterns in the data and explores the issues and the potential of conducting experiments involving children in a natural and engaging environment.

Deployment of Mobile EEG Technology in an Art Museum Setting: Evaluation of Signal Quality and Usability.

Electroencephalography (EEG) has emerged as a powerful tool for quantitatively studying the brain that enables natural and mobile experiments. Recent advances in EEG have allowed for the use of dry electrodes that do not require a conductive medium between the recording electrode and the scalp. The overall goal of this research was to gain an understanding of the overall usability and signal quality of dry EEG headsets compared to traditional gel-based systems in an unconstrained environment. EEG was used to collect Mobile Brain-body Imaging (MoBI) data from 432 people as they experienced an art exhibit in a public museum. The subjects were instrumented with either one of four dry electrode EEG systems or a conventional gel electrode EEG system. Each of the systems was evaluated based on the signal quality and usability in a real-world setting. First, we describe the various artifacts that were characteristic of each of the systems. Second, we report on each system's usability and their limitations in a mobile setting. Third, to evaluate signal quality for task discrimination and characterization, we employed a data driven clustering approach on the data from 134 of the 432 subjects (those with reliable location tracking information and usable EEG data) to evaluate the power spectral density (PSD) content of the EEG recordings. The experiment consisted of a baseline condition in which the subjects sat quietly facing a white wall for 1 min. Subsequently, the participants were encouraged to explore the exhibit for as long as they wished (piece-viewing). No constraints were placed upon the individual in relation to action, time, or navigation of the exhibit. In this freely-behaving approach, the EEG systems varied in their capacity to record characteristic modulations in the EEG data, with the gel-based system more clearly capturing stereotypical alpha and beta-band modulations.

Powered exoskeletons for bipedal locomotion after spinal cord injury.

OBJECTIVE: Powered exoskeletons promise to increase the quality of life of people with lower-body paralysis or weakened legs by assisting or restoring legged mobility while providing health benefits across multiple physiological systems. Here, a systematic review of the literature on powered exoskeletons addressed critical questions: What is the current evidence of clinical efficacy for lower-limb powered exoskeletons? What are the benefits and risks for individuals with spinal cord injury (SCI)? What are the levels of injury considered in such studies? What are their outcome measures? What are the opportunities for the next generation exoskeletons? APPROACH: A systematic search of online databases was performed to identify clinical trials and safety or efficacy studies with lower-limb powered exoskeletons for individuals with SCI. Twenty-two studies with eight powered exoskeletons thus selected, were analyzed based on the protocol design, subject demographics, study duration, and primary/secondary outcome measures for assessing exoskeleton's performance in SCI subjects. MAIN RESULTS: Findings show that the level of injury varies across studies, with T10 injuries being represented in 45.4% of the studies. A categorical breakdown of outcome measures revealed 63% of these measures were gait and ambulation related, followed by energy expenditure (16%), physiological improvements (13%), and usability and comfort (8%). Moreover, outcome measures varied across studies, and none had measures spanning every category, making comparisons difficult. SIGNIFICANCE: This review of the literature shows that a majority of current studies focus on thoracic level injury as well as there is an emphasis on ambulatory-related primary outcome measures. Future research should: 1) develop criteria for optimal selection and training of patients most likely to benefit from this technology, 2) design multimodal gait intention detection systems that engage and empower the user, 3) develop real-time monitoring and diagnostic capabilities, and 4) adopt comprehensive metrics for assessing safety, benefits, and usability.

Your Brain on Art: Emergent Cortical Dynamics During Aesthetic Experiences.

The brain response to conceptual art was studied with mobile electroencephalography (EEG) to examine the neural basis of aesthetic experiences. In contrast to most studies of perceptual phenomena, participants were moving and thinking freely as they viewed the exhibit The Boundary of Life is Quietly Crossed by Dario Robleto at the Menil Collection-Houston. The brain activity of over 400 subjects was recorded using dry-electrode and one reference gel-based EEG systems over a period of 3 months. Here, we report initial findings based on the reference system. EEG segments corresponding to each art piece were grouped into one of three classes (complex, moderate, and baseline) based on analysis of a digital image of each piece. Time, frequency, and wavelet features extracted from EEG were used to classify patterns associated with viewing art, and ranked based on their relevance for classification. The maximum classification accuracy was 55% (chance = 33%) with delta and gamma features the most relevant for classification. Functional analysis revealed a significant increase in connection strength in localized brain networks while subjects viewed the most aesthetically pleasing art compared to viewing a blank wall. The direction of signal flow showed early recruitment of broad posterior areas followed by focal anterior activation. Significant differences in the strength of connections were also observed across age and gender. This work provides evidence that EEG, deployed on freely behaving subjects, can detect selective signal flow in neural networks, identify significant differences between subject groups, and report with greater-than-chance accuracy the complexity of a subject's visual percept of aesthetically pleasing art. Our approach, which allows acquisition of neural activity "in action and context," could lead to understanding of how the brain integrates sensory input and its ongoing internal state to produce the phenomenon which we term aesthetic experience.

A Novel Experimental and Analytical Approach to the Multimodal Neural Decoding of Intent During Social Interaction in Freely-behaving Human Infants.

Understanding typical and atypical development remains one of the fundamental questions in developmental human neuroscience. Traditionally, experimental paradigms and analysis tools have been limited to constrained laboratory tasks and contexts due to technical limitations imposed by the available set of measuring and analysis techniques and the age of the subjects. These limitations severely limit the study of developmental neural dynamics and associated neural networks engaged in cognition, perception and action in infants performing "in action and in context". This protocol presents a novel approach to study infants and young children as they freely organize their own behavior, and its consequences in a complex, partly unpredictable and highly dynamic environment. The proposed methodology integrates synchronized high-density active scalp electroencephalography (EEG), inertial measurement units (IMUs), video recording and behavioral analysis to capture brain activity and movement non-invasively in freely-behaving infants. This setup allows for the study of neural network dynamics in the developing brain, in action and context, as these networks are recruited during goal-oriented, exploration and social interaction tasks.