Limbic Lobe Research Articles

Neural substrates of excessive daytime sleepiness in early drug naïve Parkinson's disease: A resting state functional MRI study

IntroductionExcessive daytime sleepiness (EDS) is a common non-motor symptom in Parkinson's disease (PD), but its neuropathology remains elusive due to the limited studies and the inclusion of medicated patients. This current study examined the neural substrates of EDS in drug naïve PD patients. MethodsA total of 76 PD patients in the early disease stages were recruited; 16 of them had EDS, while the remaining 60 did not. Resting state functional magnetic resonance imaging (rs-fMRI) was used to determine group differences (patients with EDS vs. patients without EDS) in spontaneous neural activity indicated by regional homogeneity (ReHo). Additionally, functional connectivity (FC) of the regions showing group differences in ReHo with the entire brain was performed. ResultsReHo analysis controlling for gray matter volume, age, gender, general cognition, depression, postural instability gait difficulty, and rapid eye movement sleep behavior disorder showed decreased ReHo in the left cerebellum and inferior frontal gyrus, but increased ReHo in the left paracentral lobule in PD-EDS patients, compared with patients without EDS. FC analysis controlling for the same variables as in the analysis of ReHo revealed that the three regions showing ReHo differences had decreased FC with regions in the frontal, temporal, insular and limbic lobes and cerebellum in PDs with EDS. ConclusionWhile decreases in ReHo and FC were found, increases in ReHo were also noted, implying both neural downregulation and compensatory mechanisms in early PD patients with EDS. Longitudinal studies are warranted to clarify the long-term impact of EDS in PD.

A Reduced Gray Matter Volume in Patients with Bipolar II Disorder in a Japanese Sample: A Comparison with Schizophrenia

Objective: Neuroimaging studies of bipolar disorders have provided an insight into the pathophysiology, and have raised an issue of a shared change with schizophrenia and the normalizing effect of lithium on the alteration. Despite the classification of the bipolar disorders into the bipolar I disorder (BP-I) and bipolar II disorder (BP-II), the patients with BP-II have only been involved in a limited number of the neuroimaging studies. There is minimal information about the direct comparison between BP-II and schizophrenia. Methods: All patients were diagnosed using DSM-5 criteria. A cross-sectional study was carried out to compare the regional brain volumes among the patients with BP-II taking lithium (BP-II-On, n=17) and not taking it (BP-II-Off, n=22), the patients with schizophrenia (n=35) and healthy controls (n=36). The MRI data were processed using Statistical Parametric Mapping 8 and the divided brain areas were defined by an automated anatomical labeling. Results: A significant reduction in the gray matter volume of the frontal, temporal and limbic lobes was similarly observed in BP-II-off and schizophrenia patients when compared to the controls. The brain volume of BP-II-On had significantly decreased in the temporal lobe, but not in either the frontal or limbic lobe. The less pronounced reduction of BP-II-On was also observed in the sub-regions of the prefrontal and limbic cortices, such as the anterior cingulate cortex. Conclusion: The present study suggests that there was a similarity in the distribution pattern of the decreased gray matter volume in the brain between BP-II and schizophrenia, placing an emphasis on the lithium effect that putatively normalized the abnormality in the anterior frontal and limbic brain areas of BP-II. However, further studies are required to replicate the results in a larger cohort and to confirm the lithium effect in a longitudinal study.

Locally Estimated Hemodynamic Response Function and Activation Detection Sensitivity in Heroin-Cue Reactivity Study.

Introduction:A fixed hemodynamic response function (HRF) is commonly used for functional magnetic resonance imaging (fMRI) analysis. However, HRF may vary from region to region and subject to subject. We investigated the effect of locally estimated HRF (in functionally homogenous parcels) on activation detection sensitivity in a heroin cue reactivity study.Methods:We proposed a novel exploratory method for brain parcellation based on a probabilistic model to segregate the brain into spatially connected and functionally homogeneous components. Then, we estimated HRF and detected activated regions in response to an experimental task in each parcel using a joint detection estimation (JDE) method. We compared the proposed JDE method with the general linear model (GLM) that uses a fixed HRF and is implemented in FEAT (as a part of FMRIB Software Library, version 4.1).Results:1) Regions detected by JDE are larger than those detected by fixed HRF, 2) In group analysis, JDE found areas of activation not detected by fixed HRF. It detected drug craving a priori “regions-of-interest” in the limbic lobe (anterior cingulate cortex [ACC], posterior cingulate cortex [PCC] and cingulate gyrus), basal ganglia, especially striatum (putamen and head of caudate), and cerebellum in addition to the areas detected by the fixed HRF method, 3) JDE obtained higher Z-values of local maxima compared to those obtained by fixed HRF.Conclusion:In our study of heroin cue reactivity, our proposed method (that estimates HRF locally) outperformed the conventional GLM that uses a fixed HRF.

Pulsed arterial spin labeling effectively and dynamically observes changes in cerebral blood flow after mild traumatic brain injury.

Cerebral blood flow is strongly associated with brain function, and is the main symptom and diagnostic basis for a variety of encephalopathies. However, changes in cerebral blood flow after mild traumatic brain injury remain poorly understood. This study sought to observe changes in cerebral blood flow in different regions after mild traumatic brain injury using pulsed arterial spin labeling. Our results demonstrate maximal cerebral blood flow in gray matter and minimal in the white matter of patients with mild traumatic brain injury. At the acute and subacute stages, cerebral blood flow was reduced in the occipital lobe, parietal lobe, central region, subcutaneous region, and frontal lobe. Cerebral blood flow was restored at the chronic stage. At the acute, subacute, and chronic stages, changes in cerebral blood flow were not apparent in the insula. Cerebral blood flow in the temporal lobe and limbic lobe diminished at the acute and subacute stages, but was restored at the chronic stage. These findings suggest that pulsed arterial spin labeling can precisely measure cerebral blood flow in various brain regions, and may play a reference role in evaluating a patient's condition and judging prognosis after traumatic brain injury.

Incomplete Hippocampal Inversion: A Comprehensive MRI Study of Over 2000 Subjects.

The incomplete-hippocampal-inversion (IHI), also known as malrotation, is an atypical anatomical pattern of the hippocampus, which has been reported in healthy subjects in different studies. However, extensive characterization of IHI in a large sample has not yet been performed. Furthermore, it is unclear whether IHI are restricted to the medial-temporal lobe or are associated with more extensive anatomical changes. Here, we studied the characteristics of IHI in a community-based sample of 2008 subjects of the IMAGEN database and their association with extra-hippocampal anatomical variations. The presence of IHI was assessed on T1-weighted anatomical magnetic resonance imaging (MRI) using visual criteria. We assessed the association of IHI with other anatomical changes throughout the brain using automatic morphometry of cortical sulci. We found that IHI were much more frequent in the left hippocampus (left: 17%, right: 6%, χ2−test, p < 10−28). Compared to subjects without IHI, subjects with IHI displayed morphological changes in several sulci located mainly in the limbic lobe. Our results demonstrate that IHI are a common left-sided phenomenon in normal subjects and that they are associated with morphological changes outside the medial temporal lobe.

Regional homogeneity alterations differentiate between tremor dominant and postural instability gait difficulty subtypes of Parkinson's disease.

Parkinson's disease (PD) can be classified into the tremor dominant (TD) subtype and the postural instability gait difficulty (PIGD) subtype, which present with different clinical courses and prognoses. However, the symptom-specific intrinsic neural mechanisms underlying the subtypes of PD still remain elusive. In the current study, we utilized resting-state fMRI (rs-fMRI) combined with the regional homogeneity (ReHo) method to investigate the modulations of neural activity in 13 patients with predominantly PIGD (p-PIGD) and 15 patients with predominantly TD (p-TD) in the resting state. Compared with healthy controls, the p-PIGD and the p-TD groups both displayed ReHo changes in the default mode network (DMN). By contrast, the p-TD group exhibited more ReHo alterations in the cerebellum involved in the cerebello-thalamo-cortical (CTC) loops, whilst the p-PIGD group in extensive cortical and sub-cortical areas, including the frontal, parietal, occipital, temporal, limbic lobes, basal ganglia and thalamus, which are involved in the striatal-thalamo-cortical (STC) loops. Direct comparison between the two groups showed significant ReHo alterations in the primary visual cortex. Our findings underscore the differential involvement of the STC and CTC circuits underlying the two subtypes of PD. Moreover, relatively widespread neural activity abnormality, especially in the motor-related regions as well as the visual network, is apparently a characteristic feature of PIGD symptoms. This study could shed light on the underlying pathophysiology and clinical heterogeneity of PD presentation.

Brain mediators of systemic oxidative stress on perceptual impairments in Parkinson's disease.

BackgroundParkinson’s disease (PD) is well documented to be associated with elevated systemic oxidative stress and perceptual impairments. Furthermore, the striatum and extrastriatal cortical areas, which are involved in the coordination of perceptual functions, are impaired at an early stage of the disease. However, the possible pathophysiology involved in perceptual impairments remains unclear. This raises the possibility that structural abnormalities might mediate the relationship between oxidative stress and perceptual impairments.MethodsWe explored the differences between 27 patients with PD and 25 healthy controls in terms of serum oxidative stress, perceptual functions, and regional gray matter. A single-level three-variable mediation model was used to investigate the possible relationships between serum oxidative stress, regional gray matter volume, and different domains of perceptual functioning.ResultsThe results demonstrate that increased serum oxidative stress (as indicated by thiobarbituric acid reactive substances) was associated with declined perceptual functioning in PD patients. We further explored significant gray matter volume reductions in the bilateral temporal gyri (middle temporal gyrus and fusiform gyrus), bilateral frontal gyri, limbic lobe (hippocampus and uncus), left inferior parietal lobule, right caudate nucleus, and insula in PD. Further mediation analysis showed that gray matter volumes in the middle temporal gyrus, inferior parietal lobule, hippocampus, and insula served as brain mediators between elevated serum oxidative stress and perceptual impairments.ConclusionsThese results suggest that higher oxidative stress levels adversely impact perceptual functions by causing temporal and mesolimbic abnormalities.Electronic supplementary materialThe online version of this article (doi:10.1186/s12967-015-0749-9) contains supplementary material, which is available to authorized users.

Fuzzy approximate entropy analysis of resting state fMRI signal complexity across the adult life span

In this study, we present a method for measuring functional magnetic resonance imaging (fMRI) signal complexity using fuzzy approximate entropy (fApEn) and compare it with the established sample entropy (SampEn). Here we use resting state fMRI dataset of 86 healthy adults (41 males) with age ranging from 19 to 85 years. We expect the complexity of the resting state fMRI signals measured to be consistent with the Goldberger/Lipsitz model for robustness where healthier (younger) and more robust systems exhibit more complexity in their physiological output and system complexity decrease with age. The mean whole brain fApEn demonstrated significant negative correlation (r = −0.472, p<0.001) with age. In comparison, SampEn produced a non-significant negative correlation (r = −0.099, p = 0.367). fApEn also demonstrated a significant (p < 0.05) negative correlation with age regionally (frontal, parietal, limbic, temporal and cerebellum parietal lobes). There was no significant correlation regionally between the SampEn maps and age. These results support the Goldberger/Lipsitz model for robustness and have shown that fApEn is potentially a sensitive new method for the complexity analysis of fMRI data.

Auditory P3a and P3b neural generators in schizophrenia: An adaptive sLORETA P300 localization approach

The present study investigates the neural substrates underlying cognitive processing in schizophrenia (Sz) patients. To this end, an auditory 3-stimulus oddball paradigm was used to identify P3a and P3b components, elicited by rare-distractor and rare-target tones, respectively. Event-related potentials (ERP) were recorded from 31 Sz patients and 38 healthy controls. The P3a and P3b brain-source generators were identified by time-averaging of low-resolution brain electromagnetic tomography (LORETA) current density images. In contrast with the commonly used fixed window of interest (WOI), we proposed to apply an adaptive WOI, which takes into account subjects' P300 latency variability. Our results showed different P3a and P3b source activation patterns in both groups. P3b sources included frontal, parietal and limbic lobes, whereas P3a response generators were localized over bilateral frontal and superior temporal regions. These areas have been related to the discrimination of auditory stimulus and to the inhibition (P3a) or the initiation (P3b) of motor response in a cognitive task. In addition, differences in source localization between Sz and control groups were observed. Sz patients showed lower P3b source activity in bilateral frontal structures and the cingulate. P3a generators were less widespread for Sz patients than for controls in right superior, medial and middle frontal gyrus. Our findings suggest that target and distractor processing involves distinct attentional subsystems, both being altered in Sz. Hence, the study of neuroelectric brain information can provide further insights to understand cognitive processes and underlying mechanisms in Sz.

Comparative anatomy of the cerebral convolutions: The great limbic lobe and the limbic fissure in the mammalian series.

Journal of Comparative NeurologyVolume 523, Issue 17 p. 2501-2554 Review Comparative anatomy of the cerebral convolutions: The great limbic lobe and the limbic fissure in the mammalian series BY Paul Broca, Paul BrocaSearch for more papers by this author BY Paul Broca, Paul BrocaSearch for more papers by this author First published: 18 July 2015 https://doi.org/10.1002/cne.23856Citations: 9 Translated by Donna Furlani; technical revision by Patrick R. Hof and Luiz Pessoa Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume523, Issue171 December 2015Pages 2501-2554 RelatedInformation

A Decrease in the Volume of Gray Matter as a Risk Factor for Postoperative Delirium Revealed by an Atlas-based Method

Delirium is a common syndrome in older patients after surgery. Although an atrophic change in the whole brain may be a potential risk factor for postoperative delirium, the anatomically specific change related to the vulnerability still remains a significant issue. Prospective study. University hospital. 116 consecutive patients who underwent elective cardiac operations. Before the surgery, magnetic resonance imaging (MRI) was evaluated. The MRI data were processed to calculate the absolute volumes of the predefined region of interest using Statistical Parametrical Mapping 8 with an atlas-based method. The evaluated volume was expressed as the fraction (%) of the total intracranial volume. Postoperative delirium was diagnosed according to the DSM-IV criteria for delirium. Delirium developed in 19 of 116 patients (16.4%) with an age range from 58 to 84 years. Based on a comparison with the age-controlled non-delirium patients (over 57 years; n = 65), a statistically significant reduction in the gray matter volume of the delirium patients was observed in the defined gyri of the temporal and limbic lobes. Moreover, a moderate value (>0.8) of area under the curve to predict postoperative delirium was revealed by receiver operating characteristic curve analysis of the gyri of temporal lobe. The decreased volume of gray matter could be associated with the vulnerability to delirium after surgery. The atlas-based method would be a potential tool to pre-screen the brain structure of individual patients for the prediction of postoperative delirium.

From Paul Broca's great limbic lobe to the limbic system.

Paul Broca's concept of the "great limbic lobe" has had a huge impact on neuroscience. In this commentary, which accompanies the first English translation of the original paper, we comment on Broca's contribution and its influence on the understanding of the brain bases of emotion.

P21. Susceptibility-weighted imaging provides insight into white matter damage in amyotrophic lateral sclerosis

Background Amyotrophic lateral sclerosis (ALS) is the most common adult-onset motor neuron disease. ALS is currently regarded as a multisystem disease, where pathological processes clearly extend beyond the motor system. Several disease mechanisms are involved, including protein aggregation, increases in reactive oxygen species levels, calcium disturbances, mitochondrial degeneration and neuroinflammatory processes. Similar to other neurodegenerative disorders magnetic resonance imaging markers, indicative of excess iron levels, have been reported in the brains of patients with ALS and ALS animal models. Here we employed a statistical analysis of susceptibility-weighted imaging (SWI) to assess patients with ALS, to answer the question whether SWI is able to detect typical ALS white matter disturbances. Materials & Methods We analysed the SWI of white matter in a cohort of 30 patients with ALS and 30 healthy age-matched controls. Scans were obtained on a 1.5 Tesla Siemens Sonata scanner. SWI images were calculated based on magnitude and phase data. Homodyne filtering of the complex-valued GRE data was performed to correct raw phase images for phase wraps and for background phase contributions. To this end, the complex-valued GRE data are divided in image domain with a complex-valued low-pass filtered copy of the GRE data and the arc tangent is taken to yield corrected phase images. The low-pass filtering was carried out by slice-wise multiplication of the GRE data with a 2D Hanning window in the Fourier domain using a width of 25% of the data matrix size. Since a left-handed MRI system was used during the study, the corrected phase images, , were converted according to Haacke et al. (2004) to create weighted phase images, , with enhanced paramagnetic structures such as iron-laden tissue and venous vessels. The sensitivity toward paramagnetic structures of the magnitude images was then amplified by multiplying the magnitude with the weighted phase images yielding the so called susceptibility weighted images. Preprocessing of SWI was then done using SPM8 (Wellcome Trust Centre for Neuroimaging, UCL, London, UK) and the VBM8 toolbox with MATLAB R2009b (TheMathworks, Natick, USA) as mathematical framework. After coregistration of the SWI images on their corresponding T1 images, these SWI maps were normalized into MNI space by using the warps from DARTEL normalization of the T1 images. Images were finally smoothed with a 4 mm FWHM Gaussian kernel. Group comparison of ALS patients and healthy controls for the whole brain was performed in SPM8 using the model ’compare populations: one scan/subject (ANCOVA)’ with age and sex as nuisance variable. Results Signal alterations were found in the corpus callosum; along the corticospinal tract (subcortical motor cortex, posterior limb of the internal capsule and brainstem levels) and in the subgyral regions of frontal, parietal, temporal, occipital and limbic lobes. Conclusion SWI of the white matter is capable of assessing iron and myelin disturbances. The SWI patterns observed in this study indicate that widespread iron disturbances occur in patients with ALS and correlate with disease severity. Moreover SWI detects the hallmark white matter changes in ALS, suggesting that SWI could serve as biomarker.

Susceptibility-weighted imaging provides insight into white matter damage in amyotrophic lateral sclerosis.

BackgroundAmyotrophic lateral sclerosis (ALS) is a fatal, progressive neurodegenerative disorder, characterised by widespread white matter damage. There is growing evidence that disturbances in iron metabolism contribute to white matter alterations.Materials & MethodsWe analysed the data of susceptibility-weighted imaging (SWI) of white matter in a cohort of 27 patients with ALS and 30 healthy age-matched controls.ResultsSignal alterations were found on SWI in the corpus callosum; along the corticospinal tract (subcortical motor cortex, posterior limb of the internal capsule and brainstem levels) and in the subgyral regions of frontal, parietal, temporal, occipital and limbic lobes. Alterations of white matter in the corpus callosum correlated with disease severity as assessed by the revised ALS functional rating scale.ConclusionSWI is capable of indicating iron and myelin disturbances in white matter of ALS patients. The SWI patterns observed in this study suggest that widespread alterations due to iron disturbances occur in patients with ALS and correlate with disease severity.

Functional correlates of t-Tau, p-Tau and Aβ₁₋₄₂ amyloid cerebrospinal fluid levels in Alzheimer's disease: a ¹⁸F-FDG PET/CT study.

The aim of the study was to investigate the relationships between cerebrospinal fluid (CSF) levels of t-Tau, p-Tau and amyloid-β (Aβ₁₋₄₂) amyloid peptide and fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) brain distribution in a group of patients with Alzheimer's disease. The study included 81 newly diagnosed Alzheimer's disease patients according to the NINCDS-ADRDA criteria. The mean (±SD) age of the patients was 70 (±6) years; 44 were male and 37 were female. All patients underwent a CSF assay and MRI before ¹⁸F-FDG PET scanning. The relationships were evaluated by means of statistical parametric mapping (SPM8). Increased t-Tau CSF levels were related to reduced glucose consumption in a wide portion of the right frontal lobe [Brodmann area (BA 47)] and limbic lobe bilaterally (BA 31,32), whereas no areas of increased ¹⁸F-FDG uptake related to t-Tau levels were detected. Elevated p-Tau concentrations in CSF were related to increased glucose consumption in both the right and the left limbic lobe and in the left frontal lobe (BA 32 and 8). We did not find any specific cortical area of reduced glucose consumption being related to low levels of Aβ₁₋₄₂ in CSF, whereas a spawn of ¹⁸F-FDG uptake was detectable in BA 18,19 and in the right cerebellum. The results of our study suggest that reduced Aβ₁₋₄₂ concentrations in CSF are related to a wide cortical dysfunction, whereas t-Tau and p-Tau are related to more selective cortical metabolic patterns that mainly involve the cingulate cortex.

Brain process for perception of the "out of the body" tactile illusion for virtual object interaction.

“Out of the body” tactile illusion refers to the phenomenon in which one can perceive tactility as if emanating from a location external to the body without any stimulator present there. Taking advantage of such a tactile illusion is one way to provide and realize richer interaction feedback without employing and placing actuators directly at all stimulation target points. However, to further explore its potential, it is important to better understand the underlying physiological and neural mechanism. As such, we measured the brain wave patterns during such tactile illusion and mapped out the corresponding brain activation areas. Participants were given stimulations at different levels with the intention to create veridical (i.e., non-illusory) and phantom sensations at different locations along an external hand-held virtual ruler. The experimental data and analysis indicate that both veridical and illusory sensations involve, among others, the parietal lobe, one of the most important components in the tactile information pathway. In addition, we found that as for the illusory sensation, there is an additional processing resulting in the delay for the ERP (event-related potential) and involvement by the limbic lobe. These point to regarding illusion as a memory and recognition task as a possible explanation. The present study demonstrated some basic understanding; how humans process “virtual” objects and the way associated tactile illusion is generated will be valuable for HCI (Human-Computer Interaction).

Changes in regional cerebral blood flow are associated with endothelial dysfunction markers in cocaine-dependent patients under recent abstinence.

Cocaine is a known risk factor for several vascular ischemic events. The underlying mechanisms leading to the complications are not fully understood, although thrombus formation and accelerated atherosclerosis are prominent findings. Evidence of endothelial dysfunction (ED), a key phenomenon in the pathogenesis of atherogenesis, has been demonstrated in cocaine-dependent individuals. Abnormal regional cerebral blood flow (rCBF) is a common finding among chronic cocaine users. The aim of this study was to evaluate whether brain perfusion changes were associated with ED markers in cocaine-dependent individuals. Circulating endothelial cells (CECs), soluble intercellular cell adhesion molecule, and the chemokine regulated on activation normal T cells expressed and secreted were measured in 27 DSM-IV (Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition) cocaine-dependents patients. Regional cerebral blood flow was assessed using single-photon emission computed tomography at baseline (after recent cocaine consumption) and after 4 weeks of strict abstinence under standard benzodiazepine or antipsychotic therapy. We used statistical parametric mapping analysis to evaluate the covariates. Endothelial cell damage/activation markers were significantly higher in cocaine-dependent individuals after recent consumption and were reduced after 1-month abstinence (P < 0.05). Global rCBF exhibited no significant difference between baseline and after abstinence. When regional perfusion was analyzed in association with ED covariates, significant differences were observed in bilateral cortical areas, including the limbic lobes. We demonstrated an association between systemic ED markers and rCBF in cocaine-dependent patients. These findings suggest that vascular injury may play a role in the pathogenesis of abnormal rCBF.

Enhanced Neuroactivation during Working Memory Task in Postmenopausal Women Receiving Hormone Therapy: A Coordinate-Based Meta-Analysis.

Background and Aim: Hormone therapy (HT) has long been thought beneficial for controlling menopausal symptoms and human cognition. Studies have suggested that HT has a positive association with working memory, but no consistent relationship between HT and neural activity has been shown in any cognitive domain. The purpose of this meta-analysis was to assess the convergence of findings from published randomized control trials studies that examined brain activation changes in postmenopausal women.Methods: A systematic search for fMRI studies of neural responses during working memory tasks in postmenopausal women was performed. Studies were excluded if they were not treatment studies and did not contain placebo or blank controls. For the purpose of the meta-analysis, 8 studies were identified, with 103 postmenopausal women taking HT and 109 controls.Results: Compared with controls, postmenopausal women who took HT increased activation in the left frontal lobe, including superior frontal gyrus (BA 8), right middle frontal gyrus (BA 9), anterior lobe, paracentral lobule (BA 7), limbic lobe, and anterior cingulate (BA 32). Additionally, decreased activation is noted in the right limbic lobe, including parahippocampal gyrus (BA 28), left parietal lobe, and superior parietal lobule (BA 7). All regions were significant at p ≤ 0.05 with correction for multiple comparisons.Conclusion: Hormone treatment is associated with BOLD signal activation in key anatomical areas during fMRI working memory tasks in healthy hormone-treated postmenopausal women. A positive correlation between activation and task performance suggests that hormone use may benefit working memory.

49. Inter-areal frontal lobe communication during rest: A depth eeg connectivity study

Purpose This study investigated functional connectivity in the human limbic system, frontal and temporal lobe and their relationship in pharmacoresistant patients with temporal lobe epilepsy (TLE). We worked with interictal recordings in resting state and investigated whether there exists a relationship between specific brain structures and frequency bands. Methods We studied five pharmacoresistant patients with TLE, who were candidates for surgery and had established deep electrodes in the pre-surgery examination (the detection of epileptic zone). The deep electrode recordings from epileptic zones and non-epileptic structures of the brain we divided into eleven areas based on their anatomical locations which are cross correlated with each other and we identified the relationship between them. We worked with interictal recordings in resting state. We considered a significant correlation to be a correlation value bigger than ± 0.5 and lasts longer than 30 percent of 10-min interval. We complemented correlation with graphs (tentative graphical views of correlations) and coherence. Results In the tested structures the link occurred predominantly in alpha. It was shown that there exist the relationship between specific structures and particular frequency bands. We also discovered that this relationship was not affected by epilepsy. Conclusions Interareal communication within the frontal lobe during rest appears to be structured and complex. The resting state comprises ongoing communications on various levels: the whole brain, interlobar, regional and subregional levels. The hub structures known to assure the large scale communication in the RSNs have the hub properties also in interlobar and regional interactions. While the very slow oscillation on the brain level have been largely studied by the RSN fMRI, the more rapid lobar and sublobar communications are not well understood and need further research.

Acupuncture for ischemic stroke: cerebellar activation may be a central mechanism following Deqi.

The needling sensation of Deqi during acupuncture is a key factor of influencing acupuncture outcome. Recent studies have mainly focused on the brain function effects of Deqi in a physiological state. Functional magnetic resonance imaging (fMRI) on the effects of acupuncture at Waiguan (SJ5) in pathological and physiological states is controversial. In this study, 12 patients with ischemic stroke received acupuncture at Waiguan (SJ5) and simultaneously underwent fMRI scanning of the brain, with imaging data of the activated areas obtained. Based on the patient's sensation, imaging data were allocated to either the Deqi group or non-Deqi group. In the Deqi group, the activated/deactivated areas were the left superior temporal gyrus (BA39)/right anterior lobe of the cerebellum and left thalamus. In the non-Deqi group, the activated areas included the medial frontal gyrus of the right frontal lobe (BA11), right limbic lobe (BA30, 35), and left frontal lobe (BA47), while the only deactivated area was the right parietal lobe (BA40). Compared with the non-Deqi group, the Deqi group exhibited marked activation of the right anterior lobe of the cerebellum and right limbic lobe (BA30). These findings confirm that the clinical effect of Deqi during acupuncture is based on brain functional changes. Cerebellar activation may be one of the central mechanisms of acupuncture in the treatment of ischemic stroke.