Left Hemisphere Inferior Research Articles

학습장애 위험아동의 인지 및 감성 활성화를 위한 뇌 기반 기초연산 프로그램의 기본 방향

Objectives The purpose of this study is to develop a brain-based basic operations program for children at risk for learning disabilities, extract core elements of basic operations, and examine related cognitive and emotion brain regions to suggest a desirable basic direction for designing a basic operations program. Methods For that purpose, the literature research method was mainly used. Analyzing the Korean, Finnish, and US curriculum and NCTM (2000) numbers and operational criteria to extract the core elements of basic operations for the lower grades of elementary school, Prior literature was analyzed to explore the basic directions of programs that could analyze and activate cognitive and emotional brain regions associated with it. Results First, as a result of analyzing the mathematics and curriculum of Korea, Finland, and the United States and the numbers and arithmetic standards of NCTM (2000), we were able to extract 14 basic operational core elements such as numbers recognition, centuries, quantity discrimination, composition/decomposition, number system, addition meaning, subtraction meaning, multiplication meaning, operations characteristics, operations relations, approximation of operations result, addition fluency, subtraction fluency, multiplication fluency. Secondly, the results of considering the related cognitive brain regions by classifying the core elements of basic operations into the major categories “numbers” and “operations”. In the large category “numbers”, both hemispheres are generally involved, and the core center is the intraparietal sulcus, parietal lobe, left hemisphere angular gyrus and left hemisphere inferior frontal gyrus(including Broca's center), In the large category “operations”, it was found that the frontal lobe and the parietal lobe share a common circuit, while multiple brain regions that play a unique role in each operations are connected. The emotion brain region was handled by the amygdala of the limbic system and the frontal lobe of the right hemisphere. As the basic direction of the basic operations program considered based on the related cognitive and emotion brain areas (1) Education that activates the interaction between the frontal lobe and the parietal lobe (2) Education that activates the interaction between the amygdala and the frontal lobe (3) Education that integrates cognition and sensitivity was presented. Conclusions we proposed the concept and practice a basic operations program based on the development of cognitive and emotion.

Conceptual Closure Elicited by Event Boundary Transitions Affects Commercial Communication Effectiveness.

While our experience of the world may appear continuous, recent evidence suggests that our experience is automatically segmented and encoded into long-term memory as a set of discrete events. Event segmentation is an important process in long-term memory encoding with evidence pointing to experiences occurring around event boundaries being better recognized subsequently. Neuroimaging studies have shown increased activity in the hippocampus and other nodes of the default mode network (DMN) when encountering an event boundary. We have previously demonstrated that the steady state topography (SST) measure of brain activity at a left inferior frontal scalp sites is correlated with the strength of long-term memory encoding. More recently, we have noted that event boundaries occurring in naturalistic stimuli such as television advertising trigger a transient drop in activity at the inferior frontal scalp sites, an effect we have termed Conceptual Closure. In this study, SST measures of brain activity were recorded in 50 male participants as they viewed a first-person journey through a 10-room virtual art gallery. We hypothesized that the transition from one room to another would serve as an event boundary which would triggers increased hippocampal and DMN activity while correspondingly decreasing activity in task positive networks in the vicinity of the inferior frontal cortex thus eliciting Conceptual Closure. A permutation test confirmed the hypothesis in that the appearance of the door between gallery rooms was associated with Conceptual Closure in that we observed a significant drop in brain activity at the left hemisphere inferior frontal scalp site at this point in time. Finally, we illustrate the real-world impact of Conceptual Closure by considering the commercial effectiveness of a television advertisement that exhibited Conceptual Closure at points of branding. The television advertisement was broadcast before and after it was re-edited to minimize Conceptual Closure at the time the advertising brand was being featured. Minimizing Conceptual Closure at the time of branding and key message was associated with significant increased commercial effectiveness of the advertisement.

Differential neurocognitive network perturbation in amnestic and aphasic Alzheimer disease.

To determine if Alzheimer disease (AD) is associated with aphasic rather than amnestic dementias in certain circumstances related in part to perturbations in different networks. Three groups were investigated: 14 participants suspected of having the neuropathology of AD based on clinically diagnosed amnestic dementia of the Alzheimer type (DAT), 26 individuals with primary progressive aphasia (PPA) with either a positive 18F-florbetapir amyloid PET scan or confirmed AD at autopsy, and 26 neurologically intact controls. The groups were compared using rs-fMRI. Seeds included the left hemisphere inferior frontal gyrus (IFG) for the language network, the left hippocampus for the episodic memory network, and the left posterior cingulate for the default mode network (DMN). Greater connectivity perturbations were found from the hippocampus for the DAT group and from the IFG for the PPA group. Furthermore, connectivity alterations in the PPA group were more asymmetric and favored the language-dominant left hemisphere. Loss of connectivity from the DMN seed was of a similar magnitude in the PPA and DAT groups. Despite the presumptive common underlying neuropathology of amyloid plaques and neurofibrillary tangles, the 2 groups displayed 2 different patterns of network perturbation, each concordant with the clinical presentation and the anatomy of neurodegeneration.

White matter correlates of creative cognition in a normal cohort

Creative cognition, as measured through divergent thinking (DT), offers insight into one’s ability to generate novel ideas. Relatively little work has been done exploring the relationship between creative idea generation tasks and white matter integrity via fractional anisotropy (FA). Our previous work has shown that higher scores on DT tasks were related to reduced fractional anisotropy (FA) within the left hemisphere anterior thalamic radiation (Jung et al., 2010). However, Takeuchi et al., 2010, found positive correlations with FA and DT tasks in the prefrontal cortex and genu of the corpus callosum. The present study assessed subjects studying or working in science, technology, engineering and mathematics (STEM; N ​= ​178) for correlations in white matter FA, as related to a measure of DT. Healthy normal subjects aged (16–32 years, mean age ​= ​22.0 ​± ​3.8; F ​= ​89/178). Three idea generation DT measures were scored by three raters (α ​= ​0.71) using the consensual assessment technique, from which a composite creativity index (CCI) was derived. We found that CCI was inversely related to FA (all p ​< ​0.05, controlling for age, sex, and full scale intelligence, and corrected for multiple comparisons using family wise error), within the left hemisphere inferior frontal gyrus, inferior fronto-occipital fasciculus, cingulate gyrus, inferior longitudinal fasciculus, and right hemisphere uncinate fasciculus. These results are consistent with our previous findings, implicating lower FA in white matter regions linking broad cortical networks, now established in a much larger sample of normal healthy subjects.

Differential associations of metabolic risk factors on cortical thickness in metabolic syndrome.

ObjectiveMetabolic syndrome (MetS) refers to a cluster of risk factors for cardiovascular disease, including obesity, hypertension, dyslipidemia, and hyperglycemia. While sizable prior literature has examined associations between individual risk factors and quantitative measures of cortical thickness (CT), only very limited research has investigated such measures in MetS. Furthermore, the relative contributions of these risk factors to MetS-related effects on brain morphology have not yet been studied. The primary goal of this investigation was to examine how MetS may affect CT. A secondary goal was to explore the relative contributions of individual risk factors to regional alterations in CT, with the potential to identify risk factor combinations that may underlie structural changes.MethodsEighteen participants with MetS (mean age = 59.78 years) were age-matched with 18 healthy control participants (mean age = 60.50 years). CT measures were generated from T1-weighted images and groups were contrasted using whole-brain general linear modeling. A follow-up multivariate partial least squares correlation (PLS) analysis, including the full study sample with complete risk factor measurements (N = 53), was employed to examine which risk factors account for variance in group structural differences.ResultsParticipants with MetS demonstrated significantly reduced CT in left hemisphere inferior parietal, rostral middle frontal, and lateral occipital clusters and in a right hemisphere precentral cluster. The PLS analysis revealed that waist circumference, high-density lipoprotein cholesterol (HDL-C), triglycerides, and glucose were significant contributors to reduced CT in these clusters. In contrast, diastolic blood pressure showed a significantly positive association with CT while systolic blood pressure did not emerge as a significant contributor. Age was not associated with CT.ConclusionThese results indicate that MetS can be associated with regionally specific reductions in CT. Importantly, a novel link between a risk factor profile comprising indices of obesity, hyperglycemia, dyslipidemia and diastolic BP and localized alterations in CT emerged. While the pathophysiological mechanisms underlying these associations remain incompletely understood, these findings may be relevant for future investigations of MetS and might have implications for treatment approaches that focus on specific risk factor profiles with the aim to reduce negative consequences on the structural integrity of the brain.

The Location and Effects of Visual Hemisphere-Specific Stimulation on Reading Fluency in Children With the Characteristics of Dyslexia

Fluency is used as an indicator of reading proficiency. Many students with reading disabilities are unable to benefit from typical interventions. This study is designed to replicate Lorusso, Facoetti, Paganoni, Pezzani, and Molteni’s (2006) work using FlashWord, a computer program that tachistoscopically presents words in the right or left visual hemi-field in English and locates through fMRI imaging the processing areas involved in fluency development. Our participants were 15 students who were ages 8 to 19 years and had reading disabilities randomly assigned to Intervention (n = 9) and Delayed Intervention (n = 6) groups. Functional imaging studies focused on analyzing activations in the left hemisphere (LH) superior temporal gyrus, the inferior frontal gyrus, and the LH inferior occipito-temporal/fusiform area (visual-word form area [VWFA]). Analysis of intervention data showed that 6 of the 9 Intervention group participants (67%) achieved levels of automatic processing and increased their reading rate by an average of 20 words per minute after participating in the FlashWord intervention. Analyses of fMRI group activation maps and mean activation levels in regions of interest document processing changes in VWFA activations that could be related to the increase in reading speed and confirm these locations as essential to developing fluency.

GABRB1 Single Nucleotide Polymorphism Associated with Altered Brain Responses (but not Performance) during Measures of Impulsivity and Reward Sensitivity in Human Adolescents.

Variations in genes encoding several GABAA receptors have been associated with human drug and alcohol abuse. Among these, a number of human studies have suggested an association between GABRB1, the gene encoding GABAA receptor β1 subunits, with Alcohol dependence (AD), both on its own and comorbid with other substance dependence and psychiatric illnesses. In the present study, we hypothesized that the GABRB1 genetically-associated increased risk for developing alcoholism may be associated with impaired behavioral control and altered sensitivity to reward, as a consequence of altered brain function. Exploiting the IMAGEN database (Schumann et al., 2010), we explored in a human adolescent population whether possession of the minor (T) variant of the single nucleotide polymorphism (SNP) rs2044081 is associated with performance of tasks measuring aspects of impulsivity, and reward sensitivity that are implicated in drug and alcohol abuse. Allelic variation did not associate with altered performance in either a stop-signal task (SST), measuring one aspect of impulsivity, or a monetary incentive delay (MID) task assessing reward anticipation. However, increased functional magnetic resonance imaging (fMRI) blood-oxygen-level dependent (BOLD) response in the right hemisphere inferior frontal gyrus (IFG), left hemisphere caudate/insula and left hemisphere inferior temporal gyrus (ITG) during MID performance was higher in the minor (T) allelic group. In contrast, during SST performance, the BOLD response found in the right hemisphere supramarginal gyrus, right hemisphere lingual and left hemisphere inferior parietal gyrus indicated reduced responses in the minor genotype. We suggest that β1-containing GABAA receptors may play a role in excitability of brain regions important in controlling reward-related behavior, which may contribute to susceptibility to addictive behavior.

Disruption of contralateral inferior parietal cortex by 1 Hz repetitive TMS modulates body sway following unpredictable removal of sway-related fingertip feedback

Contact with an earth-fixed reference augments sway-related feedback and leads to sway reduction during upright standing. We investigated the effect of repetitive transcranial magnetic stimulation (rTMS) over the left hemisphere inferior parietal gyrus (IPG) as well as middle frontal gyrus (MFG) on the progression of sway following right-hand finger tip contact onset and removal. In two experimental sessions, 12 adults received 20min of 1Hz rTMS stimulation at 110% passive motor threshold over the left MFG and left IPG, respectively. Before and after each stimulation interval, participants’ body sway was assessed in terms of antero–posterior Center-of-Pressure (CoP) velocity. Passive touch onset and removal were timed at random intervals by controlling the vertical position of a contact plate. Progression of sway was evaluated across 6s before to 6s after each contact event. Following both contact onset and removal, a temporary increase in sway above baseline without contact was observed. After removal overshoot was especially prominent. While steady-state sway was not altered by stimulation, rTMS over the left IPG reduced overshoot compared to pre-stimulation; thus, improving sway progression on haptic deprivation. We discuss our finding in the light of altered transient postural disorientation due to intermodal sensory conflict, illusion of backwards falling and tactile attention capture.

The relationship between phonological and auditory processing and brain organization in beginning readers

We employed brain–behavior analyses to explore the relationship between performance on tasks measuring phonological awareness, pseudoword decoding, and rapid auditory processing (all predictors of reading (dis)ability) and brain organization for print and speech in beginning readers. For print-related activation, we observed a shared set of skill-correlated regions, including left hemisphere temporoparietal and occipitotemporal sites, as well as inferior frontal, visual, visual attention, and subcortical components. For speech-related activation, shared variance among reading skill measures was most prominently correlated with activation in left hemisphere inferior frontal gyrus and precuneus. Implications for brain-based models of literacy acquisition are discussed.

Individual Differences in Verbal Abilities Associated with Regional Blurring of the Left Gray and White Matter Boundary

Blurring of the cortical gray and white matter border on MRI is associated with normal aging, pathological aging, and the presence of focal cortical dysplasia. However, it remains unclear whether normal variations in signal intensity contrast at the gray and white matter junction reflect the functional integrity of subjacent tissue. This study explores the relationship between verbal abilities and gray and white matter contrast (GWC) in healthy human adults. Participants were scanned at 3 T MRI and administered standardized measures of verbal expression and verbal working memory. GWC was estimated by calculating the non-normalized T1 image intensity contrast above and below the cortical gray/white matter interface. Spherical averaging and whole-brain correlational analyses were performed. Sulcal regions exhibited higher contrast compared to gyral regions. We found a strongly lateralized and regionally specific profile with reduced verbal expression abilities associated with blurring in left hemisphere inferior frontal cortex and temporal pole. Reduced verbal working memory was associated with blurring in widespread left frontal and temporal cortices. Such lateralized and focal results provide support for GWC as a measure of regional functional integrity and highlight its potential role in probing the neuroanatomical substrates of cognition in healthy and diseased populations.

Evidence of Left Inferior Frontal–Premotor Structural and Functional Connectivity Deficits in Adults Who Stutter

The neurophysiological basis for stuttering may involve deficits that affect dynamic interactions among neural structures supporting fluid speech processing. Here, we examined functional and structural connectivity within corticocortical and thalamocortical loops in adults who stutter. For functional connectivity, we placed seeds in the left and right inferior frontal Brodmann area 44 (BA44) and in the ventral lateral nucleus (VLN) of the thalamus. Subject-specific seeds were based on peak activation voxels captured during speech and nonspeech tasks using functional magnetic resonance imaging. Psychophysiological interaction (PPI) was used to find brain regions with heightened functional connectivity with these cortical and subcortical seeds during speech and nonspeech tasks. Probabilistic tractography was used to track white matter tracts in each hemisphere using the same seeds. Both PPI and tractrography supported connectivity deficits between the left BA44 and the left premotor regions, while connectivity among homologous right hemisphere structures was significantly increased in the stuttering group. No functional connectivity differences between BA44 and auditory regions were found between groups. The functional connectivity results derived from the VLN seeds were less definitive and were not supported by the tractography results. Our data provide strongest support for deficient left hemisphere inferior frontal to premotor connectivity as a neural correlate of stuttering.

Aberrant spatiotemporal activation profiles associated with math difficulties in children: A magnetic source imaging study.

The study investigates the relative degree and timing of cortical activation in parietal, temporal, and frontal regions during simple arithmetic tasks in children who experience math difficulties. Real-time brain activity was measured with magnetoencephalography during simple addition and numerosity judgments in students with math difficulties and average or above average reading skills (MD group, N = 14), students with below average scores on both math and basic reading tests (MD/RD group, N = 16) and students with above average scores on standardized math tests (control group, N = 25). Children with MD showed increased degree of neurophysiological activity in inferior and superior parietal regions in the right hemisphere compared to both controls and MD/RD students. Left hemisphere inferior parietal regions did not show the expected task-related changes and showed activity at a significant temporal delay. MD students also showed increased early engagement of prefrontal cortices. Taken together, these findings may indicate increased reliance on a network of right hemisphere parietal (and possibly frontal areas as well) for simple math calculations in students who experience math difficulties but perform within normal range in reading.

Übersicht über Bildgebungs- befunde zum phonologischen Defizit der Lese-Rechtschreibstörung bei Kindern und Erwachsenen: Grundlegende Defizite oder Anzeichen von Kompensation?

Early neuroimaging studies exploring the neurobiological correlates of the phonological deficit in dyslexia were restricted to adult probands with dyslexia due to the exposure to radioactivity in the course of PET measurements. The differences in activation between normal adult readers and adults with dyslexia recorded in these studies left open the issue of whether or not these are indeed fundamental activation deficits or only a reflection of lifelong experience with poor reading and writing skills and thus should be interpreted as a sign of compensation. Development of fMRI in recent years has enabled the investigation of children with dyslexia in order to explore the neurobiological activation patterns that underlie dyslexia. On the whole, the imaging findings in children and adults with dyslexia indicate that the left-hemisphere inferior frontal differences in activation, as well as the dorsal and ventral temporal differences in activation observed in all age groups during the processing of phonological language tasks are to be regarded as a fundamental biological deficit in dyslexia. Right-hemisphere differences in activation, which in German-speaking areas are observable in adults but only rarely in children with dyslexia, might, on the other hand, be regarded as a sign of developmental compensation.

An fMRI investigation of syllable sequence production

Fluent speech comprises sequences that are composed from a finite alphabet of learned words, syllables, and phonemes. The sequencing of discrete motor behaviors has received much attention in the motor control literature, but relatively little has been focused directly on speech production. In this paper, we investigate the cortical and subcortical regions involved in organizing and enacting sequences of simple speech sounds. Sparse event-triggered functional magnetic resonance imaging (fMRI) was used to measure responses to preparation and overt production of non-lexical three-syllable utterances, parameterized by two factors: syllable complexity and sequence complexity. The comparison of overt production trials to preparation only trials revealed a network related to the initiation of a speech plan, control of the articulators, and to hearing one's own voice. This network included the primary motor and somatosensory cortices, auditory cortical areas, supplementary motor area (SMA), the precentral gyrus of the insula, and portions of the thalamus, basal ganglia, and cerebellum. Additional stimulus complexity led to increased engagement of the basic speech network and recruitment of additional areas known to be involved in sequencing non-speech motor acts. In particular, the left hemisphere inferior frontal sulcus and posterior parietal cortex, and bilateral regions at the junction of the anterior insula and frontal operculum, the SMA and pre-SMA, the basal ganglia, anterior thalamus, and the cerebellum showed increased activity for more complex stimuli. We hypothesize mechanistic roles for the extended speech production network in the organization and execution of sequences of speech sounds.