Left BA Research Articles

Scalp acupuncture targets for neurological disorders：evidence from neuroimaging studies (part 2).

Scalp acupuncture is a method of treating diseases by dividing and stimulating the corresponding function-oriented cortical scalp areas. It is a commonly used therapy for neurological disorders. However, the specific target selection for scalp acupuncture remains to be explored. This manuscript aims to initiate an attempt to develop/identify scalp acupuncture targets based on neuroimaging findings and noninvasive brain stimulation. Neurosynth-based meta-analysis of neuroimaging studies was conducted to identify brain stimulation targets of neurological disorders. The identified target regions were further projected to the scalp. The traditional acupoints and 10-20 EEG system were referenced for the localization of these targets. In this study, the "mild cognitive impairment" (MCI), "Alzheimer's disease" (AD) and "dementia" were used as the retrieval terms respectively, and a unity detection method was used to generate brain maps, with the default FDR (false discovery rate, P<0.01) threshold of Neurosynth set for subsequent exploration of various disease-related brain regions. The literature search was conducted on July 30, 2022. The localization and manipulation suggestions of neuroimage-based scalp acupuncture targets for MCI, AD, and dementia were introduced in the present paper (part 2). Here are 3 target examples for each of these 3 diseases due to word limitation. 1) MCI：Based on the 81 papers retrieved, we identified 6 potential scalp acupuncture points for MCI, their corresponding brain regions, brain functions and the possible resultant effects of the scalp target acupoint stimulation respectively are as below. MCI1：the orbital part of the left inferior frontal gyrus (left Brodmann area ［BA］47), related to semantic coding, working memory and episodic memory, improving semantic coding and memory function；MCI2：the anterior motor area/left anterior central gyrus (left BA6), the motor center area, improving MCI motor function；MCI3：the left medial temporal gyrus (left BA21), related to the processing of speech, visual space, language and word understanding, improving language and memory. 2) AD：Based on the 196 papers retrieved, we found 6 potential scalp acupuncture targets for AD, their corresponding brain regions and brain functions of the 3 example targets respectively are as below. AD1：the left medial temporal gyrus (left BA21), participating in language and semantic processing, sentence and word generation, intent expression, deductive reasoning；AD2：the left angular gyrus (left BA39), related to semantic processing, word reading and comprehension, memory retrieval, attention and spatial cognition, reasoning, etc.；AD3：the left fusiform/suboccipital gyrus (left BA37), related to semantic classification, text generation, sign language, phonology processing, etc. 3) Dementia：Based on the 142 papers retrieved, we found 4 potential scalp acupuncture targets for dementia, their corresponding brain regions, brain functions and the possible targets of the proposed scalp stimulation respectively are as below. D1 and D2：the left inferior frontal gyrus (i.e., left BA46, and left BA47, respectively), being closely related to working memory, emotional response regulation, melody and other processing processes, may be suitable for treating memory decline and advanced executive dysfunction in patients with dementia；D3：the left medial temporal gyrus (left BA21), an important brain region for various sensory integration, cognitive processing and memory functions, and emotional processing, may be suitable for temporal dementia. We identified scalp acupuncture targets for several common neurological disorders based on neuroimaging findings and noninvasive brain stimulation. The proposed targets may also be used for treating these disorders using nerve/brain stimulation methods.

Structural Neuroplasticity Effects of Singing in Chronic Aphasia.

Singing-based treatments of aphasia can improve language outcomes, but the neural benefits of group-based singing in aphasia are unknown. Here, we set out to determine the structural neuroplasticity changes underpinning group-based singing-induced treatment effects in chronic aphasia. Twenty-eight patients with at least mild nonfluent poststroke aphasia were randomized into two groups that received a 4-month multicomponent singing intervention (singing group) or standard care (control group). High-resolution T1 images and multishell diffusion-weighted MRI data were collected in two time points (baseline/5 months). Structural gray matter (GM) and white matter (WM) neuroplasticity changes were assessed using language network region of interest-based voxel-based morphometry (VBM) and quantitative anisotropy-based connectometry, and their associations to improved language outcomes (Western Aphasia Battery Naming and Repetition) were evaluated. Connectometry analyses showed that the singing group enhanced structural WM connectivity in the left arcuate fasciculus (AF) and corpus callosum as well as in the frontal aslant tract (FAT), superior longitudinal fasciculus, and corticostriatal tract bilaterally compared with the control group. Moreover, in VBM, the singing group showed GM volume increase in the left inferior frontal cortex (Brodmann area 44) compared with the control group. The neuroplasticity effects in the left BA44, AF, and FAT correlated with improved naming abilities after the intervention. These findings suggest that in the poststroke aphasia group, singing can bring about structural neuroplasticity changes in left frontal language areas and in bilateral language pathways, which underpin treatment-induced improvement in speech production.

Morphological evolution of language-relevant brain areas.

Human language is supported by a cortical network involving Broca's area, which comprises Brodmann Areas 44 and 45 (BA44 and BA45). While cytoarchitectonic homolog areas have been identified in nonhuman primates, it remains unknown how these regions evolved to support human language. Here, we use histological data and advanced cortical registration methods to precisely compare the morphology of BA44 and BA45 in humans and chimpanzees. We found a general expansion of Broca's areas in humans, with the left BA44 enlarging the most, growing anteriorly into a region known to process syntax. Together with recent functional and receptorarchitectural studies, our findings support the conclusion that BA44 evolved from an action-related region to a bipartite system, with a posterior portion supporting action and an anterior portion supporting syntactic processes. Our findings add novel insights to the longstanding debate on the relationship between language and action, and the evolution of Broca's area.

Dissociating Language and Thought in Human Reasoning.

What is the relationship between language and complex thought? In the context of deductive reasoning there are two main views. Under the first, which we label here the language-centric view, language is central to the syntax-like combinatorial operations of complex reasoning. Under the second, which we label here the language-independent view, these operations are dissociable from the mechanisms of natural language. We applied continuous theta burst stimulation (cTBS), a form of noninvasive neuromodulation, to healthy adult participants to transiently inhibit a subregion of Broca's area (left BA44) associated in prior work with parsing the syntactic relations of natural language. We similarly inhibited a subregion of dorsomedial frontal cortex (left medial BA8) which has been associated with core features of logical reasoning. There was a significant interaction between task and stimulation site. Post hoc tests revealed that performance on a linguistic reasoning task, but not deductive reasoning task, was significantly impaired after inhibition of left BA44, and performance on a deductive reasoning task, but not linguistic reasoning task, was decreased after inhibition of left medial BA8 (however not significantly). Subsequent linear contrasts supported this pattern. These novel results suggest that deductive reasoning may be dissociable from linguistic processes in the adult human brain, consistent with the language-independent view.

Decreasing distance from tumor to the language network causes language deficit.

Preoperative language deficits are associated with alterations in the language networks of patients with gliomas. This study investigated how gliomas affect language performance by altering the language network. Ninety patients with lower-grade gliomas were included, and their preoperative language performance was evaluated using the Western Aphasia Battery. We also calculated the topological properties based on resting state functional magnetic resonance imaging. All patients were classified according to aphasia quotient (AQ) into the aphasia (AQ < 93.8), mild anomia (AQ > 93.8 and naming section <9.8), and normal groups (AQ > 93.8). The shortest distance from the tumor to the language network (SDTN) was evaluated to identify the effect on language performance induced by the tumor. One-way analysis of variance and post hoc analysis with Sidak correction were used to analyze the differences in topological properties among the three groups. Causal mediation analysis was used to identify indirectly affected mediators. Compared with the mild anomia group, longer shortest path length (p=.0016), lower vulnerability (p=.0331), and weaker nodal efficiencies of three nodes (right caudal Brodmann area [BA] 45, right caudal BA 22, and left BA 41/42, all p < .05) were observed in the aphasia group. The SDTN mediated nodal degree centrality and nodal vulnerability (left rostroventral BA 39), which negatively affected the AQs. Conventional language eloquent and mirrored areas participated in the language network alterations induced by gliomas. The SDTN was a mediator that affected the preoperative language status in patients with gliomas.

Revisiting the relation between syntax, action, and left BA44.

Among the many lines of research that have been exploring how embodiment contributes to cognition, one focuses on how the neural substrates of language may be shared, or at least closely coupled, with those of action. This paper revisits a particular proposal that has received considerable attention—namely, that the forms of hierarchical sequencing that characterize both linguistic syntax and goal-directed action are underpinned partly by common mechanisms in left Brodmann area (BA) 44, a cortical region that is not only classically regarded as part of Broca’s area, but is also a core component of the human Mirror Neuron System. First, a recent multi-participant, multi-round debate about this proposal is summarized together with some other relevant findings. This review reveals that while the proposal is supported by a variety of theoretical arguments and empirical results, it still faces several challenges. Next, a narrower application of the proposal is discussed, specifically involving the basic word order of subject (S), object (O), and verb (V) in simple transitive clauses. Most languages are either SOV or SVO, and, building on prior work, it is argued that these strong syntactic tendencies derive from how left BA44 represents the sequential-hierarchical structure of goal-directed actions. Finally, with the aim of clarifying what it might mean for syntax and action to have “common” neural mechanisms in left BA44, two different versions of the main proposal are distinguished. Hypothesis 1 states that the very same neural mechanisms in left BA44 subserve some aspects of hierarchical sequencing for syntax and action, whereas Hypothesis 2 states that anatomically distinct but functionally parallel neural mechanisms in left BA44 subserve some aspects of hierarchical sequencing for syntax and action. Although these two hypotheses make different predictions, at this point neither one has significantly more explanatory power than the other, and further research is needed to elaborate and test them.

Characterising the unity and diversity of executive functions in a within-subject fMRI study

Behavioural studies investigating the relationship between Executive Functions (EFs) demonstrated evidence that different EFs are correlated with each other, but also that they are partially independent from each other. Neuroimaging studies investigating such an interrelationship with respect to the functional neuroanatomical correlates are sparse and have revealed inconsistent findings. To address this question, we created four tasks derived from the same basic paradigm, one each for updating, inhibition, switching, and dual-tasking. We assessed brain activity through functional magnetic resonance imaging (fMRI) in twenty-nine participants while they performed the four EF tasks plus control tasks. For the analysis, we first determined the neural correlates of each EF by subtracting the respective control tasks from the EF tasks. We tested for unity in EF tasks by calculating the conjunction across these four “EF-minus-control” contrasts. This identified common areas including left lateral frontal cortices [middle and superior frontal gyrus (BA 6)], medial frontal cortices (BA 8) as well as parietal cortices [inferior and superior parietal lobules (BA 39/7)]. We also observed areas activated by two or three EF tasks only, such as frontoparietal areas [e.g., SFG (BA8) right inferior parietal lobule (BA 40), left precuneus (BA 7)], and subcortical regions [bilateral thalamus (BA 50)]. Finally, we found areas uniquely activated for updating [bilateral MFG (BA 8) and left supramarginal gyrus (BA 39)], inhibition (left IFG BA 46), and dual-tasking [left postcentral gyrus (BA 40)]. These results demonstrate that the functional neuroanatomical correlates of the four investigated EFs show unity as well as diversity.

Hemispheric Difference of Regional Brain Function Exists in Patients With Acute Stroke in Different Cerebral Hemispheres: A Resting-State fMRI Study.

ObjectiveTo explore the different compensatory mechanisms of brain function between the patients with brain dysfunction after acute ischemic stroke (AIS) in the dominant hemisphere and the non-dominant hemisphere based on Resting-state Functional Magnetic Resonance Imaging (Rs-fMRI).MethodsIn this trial, 15 healthy subjects (HS) were used as blank controls. In total, 30 hemiplegic patients with middle cerebral artery acute infarction of different dominant hemispheres were divided into the dominant hemisphere group (DH) and the non-dominant hemisphere group (NDH), scanned by a 3.0 T MRI scanner, to obtain the amplitude of low-frequency fluctuations (ALFF) and regional homogeneity (ReHo) and compare the differences.ResultsCompared with the HS, increased ALFF values in the brain areas, such as the bilateral midbrain, were observed in DH. Meanwhile decreased ReHo values in the brain areas, such as the right postcentral gyrus (BA3), were also observed. Enhanced ALFF values in the brain areas, such as the left BA6, and enhanced ReHo values in the brain areas, such as the left precuneus, were observed in the NDH. The ALFF and ReHo values of the right BA9 and precentral gyrus were both increased. Compared with DH, the NDH group showed lower ALFF values in the left supplementary motor area and lower ReHo values in the right BA10.ConclusionAfter acute infarction in the middle cerebral artery of the dominant hemisphere, a compensation mechanism is triggered in brain areas of the ipsilateral cortex regulating motor-related pathways, while some brain areas related to cognition, sensation, and motor in the contralateral cortex are suppressed, and the connection with the peripheral brain regions is weakened. After acute infarction in the middle cerebral artery of the non-dominant hemisphere, compensatory activation appears in motor control-related brain areas of the dominant hemisphere. After acute middle cerebral artery infarction in the dominant hemisphere, compared with the non-dominant hemisphere, functional specificity in the bilateral supplementary motor area weakens. After acute middle cerebral artery infarction in different hemispheres, there are hemispheric differences in the compensatory mechanism of brain function.

The role of a critical left fronto-temporal network with its right-hemispheric homologue in syntactic learning based on word category information

Word category information (WCI) is proposed to be fundamental for syntactic learning and processing. However, it remains largely unclear how left-hemispheric key regions for language, including BA 44 in the inferior frontal gyrus (IFG) and superior temporal gyrus (STG), interact with their right-hemispheric homologues to support the WCI-based syntactic learning. To address this question, this study employed a unified structural equation modeling (uSEM) approach to explore both the intra- and inter-hemispheric effective connectivity among these areas, to specify the neural underpinnings of handling WCI for syntactic learning. Modeling results identified a distinctive intra-left hemispheric connection from left BA 44 to left STG, a more integrated intra-right hemispheric network, and a particular frontal right-to-left hemispheric connectivity pattern for WCI-based syntactic learning. Further analyses revealed a selective positive correlation between task performance and the lagged effect in left BA 44. These results converge on a critical left fronto-temporal language network with left BA 44 and its connectivity to left STG for WCI-based syntactic learning, which is also facilitated in a domain-general fashion by the right homologues. Together, these results provide novel insights into crucial neural network(s) for syntactic learning on the basis of WCI.

Non-classical behavior of the default mode network regions during an information processing task

The default mode network (DMN) efficient deactivation and suppressed functional connectivity (FC) during goal-directed tasks, which require attentional resources, have been considered essential to healthy brain cognition. However, recent studies have shown that DMN regions do not always show the expected behavior. Then, we aimed to investigate the functional activation and connectivity of DMN nodes in young, healthy controls during a goal-directed task. We used an adaptation of the symbol digit modalities test (SDMT) to evaluate the information processing speed (IPS). Twenty-four subjects (10 women, age: 29 ± 7years) underwent two functional Magnetic Resonance Imaging experiments: one during resting-state and one during a block-designed SDMT paradigm. We superimposed the templates of the DMN on the group activation map and observed the reorganization of the network. For the posterior cingulate cortex (PCC) node of the DMN, which is spatially extensive, comprising the precuneus (dorsal portion) and the posterior cingulate gyrus (PCG, ventral portion), the extent of each region was different between conditions, suggesting different functional roles for them. Therefore, for the functional connectivity (FC) analysis, we split the DMN-PCC region into two regions: left precuneus (BA 7) and PCG. The left precuneus (BA 7) was positively correlated with the left lingual gyrus (BA 17), a task-positive region, and negatively associated with the DMN nodes when comparing task performance with the resting-state condition. The other DMN regions presented the classical antagonistic role during the attentional task. In conclusion, we found that the activation and functional connectivity of the DMN is, in general, suppressed during the information processing. However, the left precuneus BA 7 presented a context-dependent modulatory behavior, working as a transient in-between hub connecting the DMN to task-positive areas. Such findings support studies that show increased activation and excitatory functional connectivity of DMN portions during goal-directed tasks. Moreover, our results may contribute to defining more precise functional correlates of IPS deficits in a wide range of clinical and neurological diseases.

Abstract 26: Neurologic Functional Connectivity In Unicoronal Craniosynostosis: A Side-based Comparison

Purpose: Unicoronal synostosis has been associated with impaired reading, language, and social function. Functional MRI (fMRI) can evaluate brain connectivity in targeted brain regions to compare imaging analysis to previously published clinical performance. fMRI was used in this study to compare brain function connectivity in unicoronal synostosis (UCS) and compare outcomes by cerebral dominance (left versus right-sided UCS). Methods: Twelve adolescents with surgically treated UCS, 7 right-sided and 5 left-sided, were individually matched to age, gender and handedness controls. Resting state fMRI was acquired in a 3T Siemens TIM Trio scanner (Erlangen, Germany). Data was collected with intrinsic connectivity distribution and seed-connectivity analysis with BioImage Suite (Yale School of Medicine). Region of interest (ROI) analysis was performed based on Brodmann’s areas (BA) related to emotional, executive, language, motor and visuo-spatial function, left BA5, 6, 7, 18, 19, 37, 39, and 44. BA5, 6, 7 are areas of the frontal and parietal cortex important for visuomotor coordination and complex movement. BA18, 19 are areas of the occipital lobe related to visual information processing. BA 37, 39, and 44 are areas of the fusiform, angular gyri and temporal lobe important for language function. P<0.05 was significant. Results: Compared to controls, all UCS patients demonstrated decreased connectivity in left BA7, bilateral BA39, and right BA41 (p<0.01)), which are areas of the parietal and temporal cortices responsible for vision, language function, and motor coordination. Right UCS patients demonstrated increased connectivity in right BA17, BA18, BA19, BA20, BA36 when compared to controls (p<0.05). In the ROI analysis, right UCS exhibited decreased connectivity between the anterior cingulate cortex and right BA18, 19, and 37 compared to controls (p<0.05). The increased connectivity in BA17-20 (visual processing regions) supports our previous neurocognitive study results of increased visual perception abilities in right UCS patients. The subsequent decreased connectivity between BA18-19 and the anterior cingulate cortex (a section of which is implicated in complex motor coordination) is supported by neurocognitive data that shows decreased visual-motor integration ability in right UCS. This decreased connectivity between the aforementioned areas and the anterior cingulate gyrus despite increased intrinsic connectivity may also imply discordance in connecting emotion and executive function to language and visual information in right UCS patients. Connectivity between the left parahippocampus and right BA36, 37, and 54 was increased (p<0.05). Compared to controls and right UCS, left UCS demonstrated decreased connectivity between left BA6 and left BA17 and 18 (p<0.05). Left UCS patients did not demonstrate significantly different intrinsic or seed-based connectivity to right UCS or controls otherwise. Conclusion: Unilateral coronal synostosis had decreased connectivity and greater potential for neurocognitive dysfunction in regions associated with memory, visual information processing, and motor function. Moreover, left-sided UCS had decreased connectivity in circuits crucial in complex motor movement when compared to right-sided UCS. This study provides data suggestive of long-term sequelae of UCS that varies by sidedness, which may underlie the different phenotypes of neurocognitive impairment found in previous cognitive analyses.

Retrieval of semantic knowledge in language pre-surgical mapping. A MEG study.

Retrieval of semantic knowledge in language pre-surgical mapping. A MEG study.

Neural Correlates of Syntax and Proto-Syntax: Evolutionary Dimension.

The present fMRI study tested predictions of the evolution-of-syntax framework which analyzes certain structures as remnants (“fossils”) of a non-hierarchical (non-recursive) proto-syntactic stage in the evolution of language (Progovac, 2015, 2016). We hypothesized that processing of these structures, in comparison to more modern hierarchical structures, will show less activation in the brain regions that are part of the syntactic network, including Broca’s area (BA 44 and 45) and the basal ganglia, i.e., the network bolstered in the line of descent of humans through genetic mutations that contributed to present-day dense neuronal connectivity among these regions. Fourteen healthy native English-speaking adults viewed written stimuli consisting of: (1) full sentences (FullS; e.g., The case is closed); (2) Small Clauses (SC; e.g., Case closed); (3) Complex hierarchical compounds (e.g., joy-killer); and (4) Simple flat compounds (e.g., kill-joy). SC (compared to FullS) resulted in reduced activation in the left BA 44 and right basal ganglia. Simple (relative to complex) compounds resulted in increased activation in the inferior temporal gyrus and the fusiform gyrus (BA 37/19), areas implicated in visual and semantic processing. We discuss our findings in the context of current theories regarding the co-evolution of language and the brain.

Motor and language deficits correlate with resting state functional magnetic resonance imaging networks in patients with brain tumors

Background and purposeEvidence of pre-operative resting state functional magnetic resonance (RS-fMRI) validation by correlating it with clinical pre-operative status in brain tumor patients is scarce. Our aim was to validate the functional relevance of RS-fMRI by investigating the association between RS-fMRI and pre-operative motor and language function performance in patients with brain tumor. Materials and methodsSixty-nine patients with brain tumors were prospectively recruited. Patients with tumors near precentral gyrus (n = 49) underwent assessment for apparent (paresis) and subtle (finger tapping) deficits. Patients with left frontal tumors in the vicinity of the inferior frontal gyrus (n = 29) underwent assessment for gross (aphasia) and mild language (phonological verbal fluency) deficits. RS-fMRI results were extracted by spatial independent component analysis (ICA). ResultsMotor group: paretic patients showed significantly (P = 0.01) decreased BOLD signal in ipsilesional precentral gyrus when compared to contralesional one. Significantly (P < 0.01) lower BOLD signal was also observed in ipsilesional precentral gyrus of paretics when compared with the non-paretics. In asymptomatic patients, a strong positive correlation (r = 0.68, P < 0.01) between ipsilesional motor cortex BOLD signal and contralesional finger tapping performance was observed. Language group: patients with aphasia showed significantly (P = 0.01) decreased RS-fMRI BOLD signal in left BA 44 when compared with non- aphasics. In asymptomatic patients, a strong positive correlation (r = 0.72, P < 0.01) between BA 44 BOLD signal and phonological fluency performance was observed. ConclusionsOur results showed that RS-fMRI BOLD signal of motor and language networks were significantly affected by the tumors implying the usefulness of the method for assessment of the underlying functions in brain tumors patients.

Translational validity of PASAT and the effect of fatigue and mood in patients with relapsing remitting MS: A functional MRI study.

Paced Auditory Serial Addition Test (PASAT) is used for assessment of information processing speed, attention, and working memory, which are the most frequently affected cognitive domains in multiple sclerosis (MS) patients, and may be significantly affected by fatigue. However, the effect of fatigue and mood on the PASAT performance in MS patients translationally validated by fMRI has not been studied yet. The aim of this study is to investigate the translational validity of the PASAT, using fMRI during a paced visual serial addition test (PVSAT) paradigm in patients with relapsing remitting MS (RRMS) and to assess the impact of fatigue and mood on test performance. Fourteen patients with RRMS in remission and 14 healthy controls, matched by sex, age, and educational status, were enrolled in the study. The subjects underwent a standard neurological examination, neuropsychological evaluation with the PASAT 3', fMRI scanning with a PVSAT paradigm, and Beck Depression Inventory. All patients were assessed by the Modified Fatigue Impact Scale. Paced Auditory Serial Addition Test score was lower in patients (41.4±15.5 vs 51.6±7.5, P=.035). A moderate negative correlation (P=-0.563, P=0.036) was found between PASAT and MIFS scores. The fMRI scanning showed significant activations in several clusters that differed between patients and controls. The patient group presented wider cluster activation; Brodmann area (BA) 6-bilaterally; left BA7, 8, and 9; and right BA40, while controls presented with activations in left BA6 and BA44. Significant negative correlations between PASAT score and cortical activations in left BA23, right BA32, and left BA7 were observed in patients only. Our results show that poorer performance on the PASAT is associated with higher activation in areas connected with working memory, attention, and emotional processes during the fMRI assessment with PVSAT paradigm, which provides evidence for the translational validity of the PASAT in patients with RRMS.

The Effectiveness Of ‘Experiential Emotion Regulation’ Versus ‘Cognitive Defusion’: An fMRI Study

The Effectiveness Of ‘Experiential Emotion Regulation’ Versus ‘Cognitive Defusion’: An fMRI Study

Proper name retrieval and structural integrity of cerebral cortex in midlife: A cross-sectional study

There is currently little understanding on whether retrieval of proper names differs in midlife compared to young adulthood and if so, whether the age differences in this ability are associated with differences in structural integrity of the cerebral cortex. To answer these questions, we studied retrieval of proper names in 115 cognitively healthy middle-aged persons (49.7, ±3.2), comparing their performance on a tip-of-the-tongue (TOT) task with that of 68 young persons (25.4, ±3.5) from the Cam-Can data repository (http://www.mrc-cbu.cam.ac.uk/datasets/camcan/). Grey matter (GM) density and cortical thickness were used as indices of structural integrity of the cerebral cortex. The middle-aged (MA) group experienced more TOTs during proper names retrieval than young adults (YA), (t = 3.789, p < .005) and had considerably less GM density and cortical thickness across a range of brain areas bilaterally. Small clusters in left BA 45 and right BA 44 (cortical thickness) and in right BA 40 (volumetry) revealed group differences when accounting for TOTs. However, we observed no correlations between MA’s TOT scores and GM volumes or cortical thickness of the brain regions typically reported as implicated in retrieval of proper names: left anterior temporal lobe, left insula, and left superior and middle temporal gyri.

Connectivity of the hippocampus and Broca's area during acquisition of a novel grammar

Following Opitz and Friederici (2003) suggesting interactions of the hippocampal system and the prefrontal cortex as the neural mechanism underlying novel grammar learning, the present fMRI study investigated functional connectivity of bilateral BA 44/45 and the hippocampus during an artificial grammar learning (AGL) task. Our results, contrary to the previously reported interactions, demonstrated parallel (but separate) contributions of both regions, each with their own interactions, to the process of novel grammar acquisition. The functional connectivity pattern of Broca's area pointed to the importance of coherent activity of left frontal areas around the core language processing region for successful grammar learning. Furthermore, connectivity patterns of left and right hippocampi (predominantly with occipital areas) were found to be a strong predictor of high performance on the task. Finally, increasing functional connectivity over time of both left and right BA 44/45 with the right posterior cingulate cortex and the right temporo-parietal areas points to the importance of multimodal and attentional processes supporting novel grammar acquisition. Moreover, it highlights the right-hemispheric involvement in initial stages of L2 learning. These latter interactions were found to operate irrespective of the task performance, making them an obligatory mechanism accompanying novel grammar learning.

Lights from the Dark: Neural Responses from a Blind Visual Hemifield.

Here we present evidence that a hemianopic patient with a lesion of the left primary visual cortex (V1) showed an unconscious above-chance orientation discrimination with moving rather than static visual gratings presented to the blind hemifield. The patient did not report any perceptual experience of the stimulus features except for a feeling that something appeared in the blind hemifield. Interestingly, in the lesioned left hemisphere, following stimulus presentation to the blind hemifield, we found an event-related potential (ERP) N1 component at a post-stimulus onset latency of 180–260 ms and a source generator in the left BA 19. In contrast, we did not find evidence of the early visual components C1 and P1 and of the later component P300. A positive component (P2a) was recorded between 250 and 320 ms after stimulus onset frontally in both hemispheres. Finally, in the time range 320–440 ms there was a negative peak in right posterior electrodes that was present only for the moving condition. In sum, there were two noteworthy results: Behaviorally, we found evidence of above chance unconscious (blindsight) orientation discrimination with moving but not static stimuli. Physiologically, in contrast to previous studies, we found reliable ERP components elicited by stimuli presented to the blind hemifield at various electrode locations and latencies that are likely to index either the perceptual report of the patient (N1 and P2a) or, the above-chance unconscious performance with moving stimuli as is the case of the posterior ERP negative component. This late component can be considered as the neural correlate of a kind of blindsight enabling feature discrimination only when stimuli are moving and that is subserved by the intact right hemisphere through interhemispheric transfer.

The impact of obesity on the parameters of cardiovascular remodeling, cerebral blood flow and autonomic regulation of cardiac rhythm in hypertensive patients

Objective. The aim of this study was to assess autonomic regulation disturbances, disorders of systemic, brain and intra-cardiac hemodynamics and to find out the features of vascular and cardiac remodeling in patients with arterial hypertension associated with obesity. Materials and Methods. The study involved 82 patients with stage II hypertension combined with obesity (39 men and 43 women) and 18 (12 men and 6 women) patients with essential hypertension with normal body weight. All the patients underwent general clinical examination, ECG Holter monitoring with heart rate variability analysis, 24h ABPM, duplex echocardiography and pulsed-wave Doppler of extracranial vessels. Results. Patients with essential hypertension associated with obesity have significantly higher average daily SBP by 9.4 % (p = 0.036), average DBP by 12.1 % (p = 0.027) and hypertension time index by 83.3 % (p = 0.012), diastolic size of LA by 11.1 % (p = 0.007), IVSTd by 23.7 % (p = 0.001), LVMI by 14.3 % (p = 0.022) and reduced volume-mass index of LV by 18.8 % (p = 0.013). In patients with essential hypertension with obesity we observed a significant decrease in Vmax in the left CCA by 16.5 % (p = 0.003) and in the right CCA by 12.6 % (p = 0.046), Vmean in the left CCA by 16.8 % (p = 0.001) and in the right CCA by 14.4 % (p = 0.009), reduced Vmax by 19.1 % (p = 0.002) and Vmean by 21.9% (p = 0.002) in the right ICA. Levels of Vmax and Vmean in the left MCA in hypertensive patients with obesity were lower by 10.2% (p = 0.043) and 12.5 % (p = 0.044), while the index of vascular reactivity sensitive to hypercapnia in the left MCA was lower by 14.6 % (p = 0.015). In overweighed patients with hypertension the linear Vmax in the left VA was lower by 13.9 % (p = 0.015) and Vmean 14.5 % (p = 0.013), in the right VA Vmax and Vmean were lower by 17.7 % (p = 0.011) and 25.8 % (p = 0.003). In group with hypertension and obesity Vmean in BA showed a reduction by 17.3 % (p = 0.021), and index of reactivity sensitive to hypercapnia by 23.1 % (p = 0.002). Hypertensive patients with obesity and with normal body weight did not differ by temporal and spectral parameters of HRV. Index LF/HF in both groups exceeded 2 cu. Conclusions. The presence of obesity in patients with essential hypertension is accompanied by significantly higher average SBP and DBP, daily hypertension time index according to 24h ABPM, a significant increase in diastolic LA size, IVSTd, LVMI and decrease of LV volume-mass index, decreased blood flow in CCA, right ICA, left MCA, both VA and BA, index of vascular reactivity sensitive to hypercapnia in the left MCA and BA. In patients with essential hypertension regardless of whether obese or of normal body weight sympathetic part of the autonomic nervous system prevails.