Broca Area Research Articles

Presurgical brain mapping of the language network in pediatric patients with epilepsy using resting-state fMRI.

Epilepsy affects neural processing and often causes intra- or interhemispheric language reorganization, rendering localization solely based on anatomical landmarks (e.g., Broca's area) unreliable. Preoperative brain mapping is necessary to weigh the risk of resection with the risk of postoperative deficit. However, the use of conventional mapping methods (e.g., somatosensory stimulation, task-based functional MRI [fMRI]) in pediatric patients is technically difficult due to low compliance and their unique neurophysiology. Resting-state fMRI (rs-fMRI), a "task-free" technique based on the neural activity of the brain at rest, has the potential to overcome these limitations. The authors hypothesized that language networks can be identified from rs-fMRI by applying functional connectivity analyses. Cases in which both task-based fMRI and rs-fMRI were acquired as part of the preoperative clinical protocol for epilepsy surgery were reviewed. Task-based fMRI consisted of 2 language tasks and 1 motor task. Resting-state fMRI data were acquired while the patients watched an animated movie and were analyzed using independent component analysis (i.e., data-driven method). The authors extracted language networks from rs-fMRI data by performing a similarity analysis with functionally defined language network templates via a template-matching procedure. The Dice coefficient was used to quantify the overlap. Thirteen children underwent conventional task-based fMRI (e.g., verb generation, object naming), rs-fMRI, and structural imaging at 1.5T. The language components with the highest overlap with the language templates were identified for each patient. Language lateralization results from task-based fMRI and rs-fMRI mapping were comparable, with good concordance in most cases. Resting-state fMRI-derived language maps indicated that language was on the left in 4 patients (31%), on the right in 5 patients (38%), and bilateral in 4 patients (31%). In some cases, rs-fMRI indicated a more extensive language representation. Resting-state fMRI-derived language network data were identified at the patient level using a template-matching method. More than half of the patients in this study presented with atypical language lateralization, emphasizing the need for mapping. Overall, these data suggest that this technique may be used to preoperatively identify language networks in pediatric patients. It may also optimize presurgical planning of electrode placement and thereby guide the surgeon's approach to the epileptogenic zone.

Coil orientation affects pain sensation during single-pulse transcranial magnetic stimulation over Broca’s area

ObjectivePain sensation at the site of stimulation is a side effect of transcranial magnetic stimulation (TMS). The purpose of this study was to investigate how or whether the coil orientation affected TMS-induced pain on Broca’s area (BA) or primary motor cortex (M1). MethodsIn Experiment 1, we measured pain thresholds during single-pulse TMS delivered over BA or left M1 at seven coil orientation angles (−90° to 90°, in 30° increments) relative to the posterior-anterior (PA) orientation. In Experiment 2, we evaluated subjective pain intensity when delivering TMS at an intensity of 110% of the resting motor threshold, which is commonly used in conventional TMS studies. ResultsIn Experiment 1, we found a significant relationship between coil orientation and pain thresholds during BA stimulation but not M1 stimulation. During BA stimulation, pain thresholds were significantly lower when the coil orientation was 30° upward (−30° condition) relative to the PA orientation compared with 60° downward (60° condition). In Experiment 2, pain sensations were significantly stronger in the −30° condition compared with those in the 60° condition. We also confirmed that the averaged location of pain on the head in both conditions were more than 25 mm from the left lateral orbital rim. ConclusionsThe coil orientation of TMS over BA affects pain sensations. This might be attributable to the activation of nociceptors and nociceptive fibers in the muscle tissues above BA, rather than the orbicularis oculi muscle. SignificanceAlthough the influence of coil orientation on the TMS efficacy is unclear, this study suggests that manipulating the orientation of the TMS coil may be helpful in reducing pain when applying TMS to BA.

Effect of Repetitive Transcranial Magnetic Stimulation on Post-stroke Non-fluent Aphasia in Relation with Broca's Area.

This study investigated the differences in the effect of repetitive transcranial magnetic stimulation (rTMS) between patients with and without the involvement of Broca's area (IBA). The medical records of 20 stroke patients treated with rTMS for non-fluent aphasia were reviewed. Patients completed the Korean version of the Western Aphasia Battery (K-WAB) pre- and post-rTMS. Magnetic resonance T1-weighted images of the brain were analyzed using SPM12 software. Montreal Neurological Institute templates and Talairach coordinates were used to determine Broca's area involvement and segregate patients into 2 groups: IBA and non-IBA (NBA) groups. All statistical analyses were performed using the SPSS software. Twenty subjects were included in the study. The K-WAB scores revealed improvements in the total subjects and IBA and NBA groups. There were no statistical differences between the IBA and NBA groups in the ΔK-WAB scores of aphasia quotient, fluency, comprehension, repetition, and naming. The rTMS was positive for non-fluent aphasia patients, but there was no significant difference in effectiveness depending on the IBA. Further research with a larger number of patients is needed to identify the differences in the effect of rTMS on the IBA.

Психологические и психофизиологические механизмы обучения двигательным навыкам

The present review focuses on psychological and psychophysiological research in the study of motor training and the relationship of this process to the mirror neuron system underlying implicit training, or training by analogy. Our review shows that the most effective strategy for training a motor skill is a combination of physical repetition of the movement and observation of it, with the visual observation of the movement being as related as possible to the actual movement - the same environment, the movement should be congruent, the person performing the action should train the skill rather than perform it professionally. This strategy will be more effective in case of absence of any motor system impairment. In sports practice, the use of implicit training based on analogy (metaphor) for motor skill acquisition will be more effective and appropriate compared to classical implicit methods, especially in cases of motor system disorders, as well as at the older preschool and younger school ages, since the brain structures, critical for explicit training (training by instruction), finally mature by the age of 9-10. The system of mirror neurons, which includes, among others, the ventral premotor area and Broca area, is important in motor training, performing such functions as: recognition of movements, including complex polymodal actions performed by another person; it is the basis of mental representations of movements: motor representations, etc. In addition, it is involved in the recognition of action-related sentences. The mirror neuron system integrates observed actions of other people with the personal motor repertoire. The mirror neuron system underlies anticipation: the more professional are the athletes, the higher is the specialization of their mirror neuron system. The system of mirror neurons is the basis of motor training in childhood. An adult person is characterized by a wide repertoire of movements (motor archive), because during his life he gets mastered many movements and actions that are repeated many times and can be later included in mastering more complex actions. A child does not have such a wide motor repertoire; he has to master many movements from the beginning. The system of mirror neurons makes it possible to "mirror" movements similar to those in the human motor repertoire. As a child grows and develops, an archive of different motor programs and formed motor skills is accumulated. This means that children can gradually repeat, or "mirror", increasingly complex movements. Thus, the system of mirror neurons facilitates the process of purposeful movement formation in children of preschool and primary school age.

Paul Pierre Broca: his contribution to medicine

The article presents the main moments of the biography of the great 19th century anatomist, surgeon and anthropologist Paul Broca (1824-1880). The circumstances of his discovery of the motor center of oral speech, later called in his honor «Broca's area», in 1861 are described. His contributions to oncology, anthropology, and public health are briefly presented.

Corpus Callosum Diffusion Anisotropy and Hemispheric Lateralization of Language in Patients with Brain Arteriovenous Malformations.

Background: The corpus callosum (CC) plays a key role in mediating interhemispheric connectivity and developing functional hemispheric asymmetries. The purpose of this study was to investigate the changes in CC microstructure accompanying interhemispheric language reorganization in patients with brain arteriovenous malformations (AVMs). Methods: Forty-one patients with an unruptured AVM located in anatomically defined language areas underwent functional magnetic resonance imaging and diffusion tensor imaging. Hemispheric dominance in Broca's area (BA) and Wernicke's area (WA) was assessed separately. Right-sided or bilateral language dominance was classified as atypical lateralization. The CC was segmented into five subregions, and the mean fractional anisotropy (FA) was extracted. The relationship between callosal FA and language lateralization patterns was statistically analyzed. Results: We observed atypical language lateralization in 16 (39.0%) patients. Patients with atypical lateralization exhibited significantly higher mean FA values in the total CC (p = 0.002) and the anterior (p = 0.047), midanterior (p = 0.001), and midposterior (p = 0.043) subregions. Significant interaction effects of BA and WA lateralization were found for FA values in the total CC (p = 0.005) and the midanterior subregion (p = 0.004). Conclusions: These results indicate that AVM patients with atypical language lateralization exhibit higher callosal FA values, reflecting greater interhemispheric connectivity. Our findings contribute additional insights into the understanding of functional and structural plasticity of the human brain under pathological states. Impact statement Brain arteriovenous malformations (AVMs) are congenital lesions that frequently lead to interhemispheric language reorganization. In this study, by combining diffusion tensor imaging and functional magnetic resonance imaging, we investigated the relationship between callosal fractional anisotropy (FA) and language reorganization in patients with AVMs. We found that callosal FA was significantly higher in patients with atypical language lateralization, especially in those with crossed lateralization of Broca's and Wernicke's areas. This study demonstrated the remodeling of the corpus callosum microstructure accompanying language reorganization in AVM patients, providing insights into the structural and functional plasticity of the human brain associated with congenital cerebrovascular disease.

Common neural circuit for semantic-based articulation of numbers and words: A case study of a patient with Broca's aphasia

Studies have demonstrated that damage to Broca's area causes problems in phonological processing, but leaves semantic processing mostly preserved. The current investigation explored whether problems in phonological processing caused by injury to Broca's area extends to numbers. Patient LXM presented with an injury to the left anterior fronto-temporal cortex (including Broca's area). LXM completed a series of neuropsychological tests for general cognitive processing, mathematical processing, and language processing. LXM exhibited normal semantic processing but had difficulty in speech production for both words and numbers (e.g., reading characters and numbers, naming pictures, and reporting arithmetic facts). Broca's area is likely within the neuronal circuit governing semantic-based articulation of words and numbers. • This study provides direct evidence to support the association of phonological processes for numbers and words. • Systematic cognitive tests have been conducted, which clearly identify the deficits in phonological processes of patient. • The brain lesion is well documented with high-resolution MRI images.

BROCA’S APHASIA WORD PRODUCTION OF SODDERLAND IN "MY BEAUTIFUL BROKEN BRAIN" MOVIE

As a disorder that can hamper people's ability to use a language, aphasia is relatedto the damage that happened in the human brain. Some diseases that cause it arestroke, trauma, and brain hemorrhage. Complaints of aphasia sufferers can differfrom each other, and it is caused by the location of the disruption of languagefunction in the brain. Therefore, this study aims to analyze and observe difficultiesexperienced by Sodderland as the main character in My Beautiful Broken Brainmovie. Based on the analysis of mistakes made by Sodderland, the finding revealedthat she had difficulties in producing words, and it disturbs her interaction with thepeople around her. The errors produced are; lexical selection error, malapropism,substitution, shift, and omission. It also indicates some difficulties experienced byher; effortful speech, distortion of articulation, and stutter. Thus, the location ofbrain damage experienced by Sodderland was in the area of Broca so that sheexperienced a disruption that was dominant in language production. The articleends with some suggestions to help the people understand the difficulties peoplehave with this kind of disorder.

The Dynamics of Language Network Interactions in Lexical Selection: An Intracranial EEG Study.

Speaking in sentences requires selection from contextually determined lexical representations. Although posterior temporal cortex (PTC) and Broca's areas play important roles in storage and selection, respectively, of lexical representations, there has been no direct evidence for physiological interactions between these areas on time scales typical of lexical selection. Using intracranial recordings of cortical population activity indexed by high-gamma power (70-150Hz) modulations, we studied the causal dynamics of cortical language networks while epilepsy surgery patients performed a sentence completion task in which the number of potential lexical responses was systematically varied. Prior to completion of sentences with more response possibilities, Broca's area was not only more active, but also exhibited more local network interactions with and greater top-down influences on PTC, consistent with activation of, and competition between, more lexical representations. These findings provide the most direct experimental support yet for network dynamics playing a role in lexical selection among competing alternatives during speech production.

Decoding verbal working memory representations of Chinese characters from Broca's area

Representations of sensory working memory can be found across the entire neocortex. But how are verbal working memory (VWM) contents retained in the human brain? Here we used fMRI and multi-voxel pattern analyses to study Chinese native speakers (15 males, 13 females) memorizing Chinese characters. Chinese characters are uniquely suitable to study VWM because verbal encoding is encouraged by their complex visual appearance and monosyllabic pronunciation. We found that activity patterns in Broca's area and left premotor cortex carried information about the memorized characters. These language-related areas carried (1) significantly more information about cued characters than those not cued for memorization, (2) significantly more information on the left than the right hemisphere and (3) significantly more information about Chinese symbols than complex visual patterns which are hard to verbalize. In contrast, early visual cortex carries a comparable amount of information about cued and uncued stimuli and is thus unlikely to be involved in memory retention. This study provides evidence for verbal working memory maintenance in a distributed network of language-related brain regions, consistent with distributed accounts of WM. The results also suggest that Broca's area and left premotor cortex form the articulatory network which serves articulatory rehearsal in the retention of verbal working memory contents.

Functional reorganization of the reading network in the course of foreign language acquisition

During foreign language acquisition neural representations of native language and foreign language assimilate. In the reading network, this assimilation leads to a shift from effortful processing to automated reading. Longitudinal studies can track this transition and reveal dynamics that might not become apparent in behavior. Here, we report results from a longitudinal functional magnetic resonance imaging (fMRI) study, which tracked functional changes in the reading network of beginning learners of Greek over one year. We deliberately chose Greek as foreign language that would have similar orthographic transparency but a different alphabet than the native language (Polish). fMRI scans with lexical and semantic decision tasks were performed at five different time points (every ~3 months). Classical language areas (the left inferior frontal gyrus, the left precentral gyrus, and the bilateral supplementary motor cortex), and cognitive control areas (left inferior parietal lobe and bilateral anterior cingulate cortex) showed stronger activation after the first months of instruction as compared to the activation before instruction. This pattern occured in both tasks. Task-related activity in the reading network remained constant throughout the remaining 6 months of learning and was also present in a follow-up scan 3 months after the end of the course. A similar pattern was demonstrated by the analysis of convergence between foreign and native languages occurring within the first months of learning. Additionally, in the lexical task, the extent of spatial overlap, between foreign and native language in Broca's area increased constantly from the beginning till the end of training. Our findings support the notion that reorganization of language networks is achieved after a relatively short time of foreign language instruction. We also demonstrate that cognitive control areas are recruited in foreign language reading at low proficiency levels. No apparent changes in the foreign or native reading network occur after the initial 3 months of learning. This suggests that task demand might be more important than proficiency in regulating the resources needed for efficient foreign language reading.

Language Mapping With Magnetoencephalography: An Update on the Current State of Clinical Research and Practice With Considerations for Clinical Practice Guidelines.

Numerous studies have shown that language processing is not limited to a few brain areas. Visual or auditory stimuli activate corresponding cortical areas, then memory identifies the word or image, Wernicke's and Broca's areas support the processing for either reading/listening or speaking and many areas of the brain are recruited. Determining how a normal person processes language helps clinicians and scientist to understand how brain pathologies such as tumor or stroke can affect changes in language processing. Patients with epilepsy may develop atypical language organization. Over time, the chronic nature of epileptic activity, or changes from a tumor or stroke, can result in a shift of language processing area from the left to the right hemisphere, or re-routing of language pathways from traditional to non-traditional areas within the dominant left hemisphere. It is important to determine where these language areas are prior to brain surgery. MEG evoked responses reflecting cerebral activation of receptive and expressive language processing can be localized using several different techniques: Single equivalent current dipole, current distribution techniques or beamformer techniques. Over the past 20 years there have been at least 25 validated MEG studies that indicate MEG can be used to determine the dominant hemisphere for language processing. The use of MEG neuroimaging techniques is needed to reliably predict altered language networks in patients and to provide identification of language eloquent cortices for localization and lateralization necessary for clinical care.

Functional neuroanatomy of language without speech: An ALE meta-analysis of sign language.

Sign language (SL) conveys linguistic information using gestures instead of sounds. Here, we apply a meta‐analytic estimation approach to neuroimaging studies (N = 23; subjects = 316) and ask whether SL comprehension in deaf signers relies on the same primarily left‐hemispheric cortical network implicated in spoken and written language (SWL) comprehension in hearing speakers. We show that: (a) SL recruits bilateral fronto‐temporo‐occipital regions with strong left‐lateralization in the posterior inferior frontal gyrus known as Broca's area, mirroring functional asymmetries observed for SWL. (b) Within this SL network, Broca's area constitutes a hub which attributes abstract linguistic information to gestures. (c) SL‐specific voxels in Broca's area are also crucially involved in SWL, as confirmed by meta‐analytic connectivity modeling using an independent large‐scale neuroimaging database. This strongly suggests that the human brain evolved a lateralized language network with a supramodal hub in Broca's area which computes linguistic information independent of speech.

Higher temporal resolution multiband fMRI provides improved presurgical language maps.

We investigated the hypothesis that increasing fMRI temporal resolution using a multiband (MB) gradient echo-echo planar imaging (GRE-EPI) pulse sequence provides fMRI language maps of higher statistical quality than those acquired with a traditional GRE-EPI sequence. This prospective study enrolled 29 consecutive patients receiving language fMRI prior to a potential brain resection for tumor, AVM, or epilepsy. A 4-min rhyming task was performed at 3.0 Tesla with a traditional GRE-EPI pulse sequence (TR = 2000, TE = 30, matrix = 64/100%, slice = 4/0, FOV = 24, slices = 30, time points = 120) and an additional MB GRE-EPI pulse sequence with an acceleration factor of 6 (TR = 333, TE = 30, matrix 64/100%, slice = 4/0, FOV = 24, time points = 720). Spatially filtered t statistical maps were generated. Volumes of interest (VOIs) were drawn around activations at Broca's, dorsolateral prefrontal cortex, Wernicke's, and the visual word form areas. The t value maxima were measured for the overall brain and each of the VOIs. A paired t test was performed for the corresponding traditional and MB GRE-EPI measurements. The mean age of subjects was 42.6 years old (18-75). Sixty-two percent were male. The average overall brain t statistic maxima for the MB pulse sequence (t = 15.4) was higher than for the traditional pulse sequence (t = 9.3, p = < .0001). This also held true for Broca's area (p < 0.0001), Wernicke's area (p < .0001), dorsolateral prefrontal cortex (p < .0001), and the visual word form area (p < .0001). A MB GRE-EPI fMRI pulse sequence employing high temporal resolution provides clinical fMRI language maps of greater statistical significance than those obtained with a traditional GRE-EPI sequence.

The neural basis of language development: Changes in lateralization over age

We have long known that language is lateralized to the left hemisphere (LH) in most neurologically healthy adults. In contrast, findings on lateralization of function during development are more complex. As in adults, anatomical, electrophysiological, and neuroimaging studies in infants and children indicate LH lateralization for language. However, in very young children, lesions to either hemisphere are equally likely to result in language deficits, suggesting that language is distributed symmetrically early in life. We address this apparent contradiction by examining patterns of functional MRI (fMRI) language activation in children (ages 4 through 13) and adults (ages 18 through 29). In contrast to previous studies, we focus not on lateralization per se but rather on patterns of left-hemisphere (LH) and right-hemisphere (RH) activation across individual participants over age. Our analyses show significant activation not only in the LH language network but also in their RH homologs in all of the youngest children (ages 4 through 6). The proportion of participants showing significant RH activation decreases over age, with over 60% of adults lacking any significant RH activation. A whole-brain correlation analysis revealed an age-related decrease in language activation only in the RH homolog of Broca's area. This correlation was independent of task difficulty. We conclude that, while language is left-lateralized throughout life, the RH contribution to language processing is also strong early in life and decreases through childhood. Importantly, this early RH language activation may represent a developmental mechanism for recovery following early LH injury.

Clinical Feasibility of Combining Transcranial Direct Current Stimulation with Standard Aphasia Therapy.

Background:Transcranial direct current stimulation (tDCS) is a safe, portable, and inexpensive form of noninvasive brain stimulation that appears to augment the effects of concurrent therapy. However, several methodological issues in existing studies distance tDCS from current clinical practice. In this study, we offered (and administered) tDCS to individuals seeking typical behavioral aphasia therapy on an outpatient basis.Methods:We approached clients (n = 10) planning to receive standard aphasia therapy at a university clinic. Following a brief description of tDCS, we offered to provide stimulation during their therapy. Those interested and without contraindications participated in a double-blind, sham-controlled crossover study of tDCS paired with speech-language therapy provided twice weekly. Participants received active (2 mA) or sham tDCS during two eight-week therapy phases (separated by ten weeks) with the anode over Broca's area and the cathode on the contralateral forehead. Stimulation was provided for the first 20 minutes of each one-hour session. Prior to and following each phase, participants were video recorded telling the Cinderella narrative. Recordings were transcribed and analyzed for correct information units (CIUs).Results:Seven individuals (70%) were interested in and eligible for tDCS. Data from four participants who completed the study indicated a large effect size favoring active over sham tDCS (Cohen's d = 1.32). The participant with the most severe deficits did not benefit from therapy in either condition.Conclusion:There is potential for tDCS to enhance meaningful communication outcomes in standard clinical practice. Further investigation is needed to replicate findings and determine individual characteristics predictive of treatment response.

Asymmetry in the Cytoarchitecture of the Area 44 Homolog of the Brain of the Chimpanzee Pan troglodytes.

The evolution of the brain in apes and man followed a joint pathway stemming from common ancestors 5–10 million years ago. However, although apparently sharing similar organization and neurochemical properties, association areas of the isocortex remain one of the cornerstones of what sets humans aside from other primates. Brodmann’s area 44, the area of Broca, is known for its implication in speech, and thus indirectly is a key mark of human uniqueness. This latero-caudal part of the frontal lobe shows a marked functional asymmetry in humans, and takes part in other complex functions, including learning and imitation, tool use, music and contains the mirror neuron system (MNS). Since the main features in the cytoarchitecture of Broca’s area remains relatively constant in hominids, including in our closest relative, the chimpanzee Pan troglodytes, investigations on the finer structure, cellular organization, connectivity and eventual asymmetry of area 44 have a direct bearing on the understanding of the neural mechanisms at the base of our language. The semi-automated image analysis technology that we employed in the current study showed that the structure of the cortical layers of the chimpanzee contains elements of asymmetry that are discussed in relation to the corresponding human areas and the putative resulting disparity of function.

Evolutional and developmental anatomical architecture of the left inferior frontal gyrus

The left inferior frontal gyrus (IFG) including Broca's area is involved in the processing of many language subdomains, and thus, research on the evolutional and human developmental characteristics of the left IFG will shed light on how language emerges and maturates. In this study, we used diffusion magnetic resonance imaging (dMRI) and resting-state functional MRI (fMRI) to investigate the evolutional and developmental patterns of the left IFG in humans (age 6–8, age 11–13, and age 16–18 years) and macaques. Tractography-based parcellation was used to define the subcomponents of left IFG and consistently identified four subregions in both humans and macaques. This parcellation scheme for left IFG in human was supported by specific coactivation patterns and functional characterization for each subregion. During evolution and development, we found increased functional balance, amplitude of low frequency fluctuations, functional integration, and functional couplings. We also observed higher fractional anisotropy values, i.e. better myelination of dorsal and ventral white matter language pathways during evolution and development. We assume that the resting-state functional connectivity and task-related coactivation mapping are associated with hierarchical language processing. Our findings have shown the evolutional and human developmental patterns of left IFG, and will contribute to the understanding of how the human language evolves and how atypical language developmental disorders may occur.

Combined Brain-Perfusion SPECT and EEG Measurements Suggest Distinct Strategies for Speech Comprehension in CI Users With Higher and Lower Performance.

Cochlear implantation constitutes a successful therapy of inner ear deafness, with the majority of patients showing good outcomes. There is, however, still some unexplained variability in outcomes with a number of cochlear-implant (CI) users, showing major limitations in speech comprehension. The current study used a multimodal diagnostic approach combining single-photon emission computed tomography (SPECT) and electroencephalography (EEG) to examine the mechanisms underlying speech processing in postlingually deafened CI users (N = 21). In one session, the participants performed a speech discrimination task, during which a 96-channel EEG was recorded and the perfusions marker 99mTc-HMPAO was injected intravenously. The SPECT scan was acquired 1.5 h after injection to measure the cortical activity during the speech task. The second session included a SPECT scan after injection without stimulation at rest. Analysis of EEG and SPECT data showed N400 and P600 event-related potentials (ERPs) particularly evoked by semantic violations in the sentences, and enhanced perfusion in a temporo-frontal network during task compared to rest, involving the auditory cortex bilaterally and Broca’s area. Moreover, higher performance in testing for word recognition and verbal intelligence strongly correlated to the activation in this network during the speech task. However, comparing CI users with lower and higher speech intelligibility [median split with cutoff + 7.6 dB signal-to-noise ratio (SNR) in the Göttinger sentence test] revealed for CI users with higher performance additional activations of parietal and occipital regions and for those with lower performance stronger activation of superior frontal areas. Furthermore, SPECT activity was tightly coupled with EEG and cognitive abilities, as indicated by correlations between (1) cortical activation and the amplitudes in EEG, N400 (temporal and occipital areas)/P600 (parietal and occipital areas) and (2) between cortical activation in left-sided temporal and bilateral occipital/parietal areas and working memory capacity. These results suggest the recruitment of a temporo-frontal network in CI users during speech processing and a close connection between ERP effects and cortical activation in CI users. The observed differences in speech-evoked cortical activation patterns for CI users with higher and lower speech intelligibility suggest distinct processing strategies during speech rehabilitation with CI.

Mapping of the Language Network With Deep Learning.

Background: Pre-surgical functional localization of eloquent cortex with task-based functional MRI (T-fMRI) is part of the current standard of care prior to resection of brain tumors. Resting state fMRI (RS-fMRI) is an alternative method currently under investigation. Here, we compare group level language localization using T-fMRI vs. RS-fMRI analyzed with 3D deep convolutional neural networks (3DCNN).Methods: We analyzed data obtained in 35 patients with brain tumors that had both language T-fMRI and RS-MRI scans during pre-surgical evaluation. The T-fMRI data were analyzed using conventional techniques. The language associated resting state network was mapped using a 3DCNN previously trained with data acquired in >2,700 normal subjects. Group level results obtained by both methods were evaluated using receiver operator characteristic analysis of probability maps of language associated regions, taking as ground truth meta-analytic maps of language T-fMRI responses generated on the Neurosynth platform.Results: Both fMRI methods localized major components of the language system (areas of Broca and Wernicke). Word-stem completion T-fMRI strongly activated Broca's area but also several task-general areas not specific to language. RS-fMRI provided a more specific representation of the language system.Conclusion: 3DCNN was able to accurately localize the language network. Additionally, 3DCNN performance was remarkably tolerant of a limited quantity of RS-fMRI data.