From “Oh, OK” to “Ah, yes” to “Aha!”: Hyper-systemizing and the rewards of insight\ud

Hyper-systemizers are individuals displaying an unusually strong bias toward systemizing, i.e. toward explaining events and solving problems by appeal to mechanisms that do not involve intentions or agency. Hyper-systemizing in combination with deficit mentalizing ability typically presents clinically as an autistic spectrum disorder; however, the development of hyper-systemizing in combination with normal-range mentalizing ability is not well characterized. Based on a review and synthesis of clinical, observational, experimental, and neurofunctional studies, it is hypothesized that repeated episodes of insightful problem solving by systemizing result in attentional and motivational sensitization toward further systemizing via progressive and chronic deactivation of the default network. This hypothesis is distinguished from alternatives, and its correlational and causal implications are discussed. Predictions of the default-deactivation model accessible to survey-based instruments, standard cognitive measures and neurofunctional methods are outlined, and evidence pertaining to them considered

Impact of Working Memory Load on fMRI Resting State Pattern in Subsequent Resting Phases

BACKGROUND: The default-mode network (DMN) is a functional network with increasing relevance for psychiatric research, characterized by increased activation at rest and decreased activation during task performance. The degree of DMN deactivation during a cognitively demanding task depends on its difficulty. However, the relation of hemodynamic responses in the resting phase after a preceding cognitive challenge remains relatively unexplored. We test the hypothesis that the degree of activation of the DMN following cognitive challenge is influenced by the cognitive load of a preceding working-memory task. METHODOLOGY/PRINCIPAL FINDINGS: Twenty-five healthy subjects were investigated with functional MRI at 3 Tesla while performing a working-memory task with embedded short resting phases. Data were decomposed into statistically independent spatio-temporal components using Tensor Independent Component Analysis (TICA). The DMN was selected using a template-matching procedure. The spatial map contained rest-related activations in the medial frontal cortex, ventral anterior and posterior cingulate cortex. The time course of the DMN revealed increased activation at rest after 1-back and 2-back blocks compared to the activation after a 0-back block. CONCLUSION/SIGNIFICANCE: We present evidence that a cognitively challenging working-memory task is followed by greater activation of the DMN than a simple letter-matching task. This might be interpreted as a functional correlate of self-evaluation and reflection of the preceding task or as relocation of cerebral resources representing recovery from high cognitive demands. This finding is highly relevant for neuroimaging studies which include resting phases in cognitive tasks as stable baseline conditions. Further studies investigating the DMN should take possible interactions of tasks and subsequent resting phases into account

Altered Relationship between Cortisol Response to Social Stress and Mediotemporal Function during Fear Processing in People at Clinical High Risk for Psychosis: A Preliminary Report

Evidence suggests that people at Clinical High Risk for Psychosis (CHR) have a blunted cortisol response to stress and altered mediotemporal activation during fear processing, which may be neuroendocrine–neuronal signatures of maladaptive threat responses. However, whether these facets are associated with each other and how this relationship is affected by cannabidiol treatment is unknown. We examined the relationship between cortisol response to social stress and mediotemporal function during fear processing in healthy people and in CHR patients. In exploratory analyses, we investigated whether treatment with cannabidiol in CHR individuals could normalise any putative alterations in cortisol-mediotemporal coupling. 33 CHR patients were randomised to 600 mg cannabidiol or placebo treatment. Healthy controls (n = 19) did not receive any drug. Mediotemporal function was assessed using a fearful face-processing functional magnetic resonance imaging paradigm. Serum cortisol and anxiety were measured immediately following the Trier Social Stress Test. The relationship between cortisol and mediotemporal blood-oxygen-level-dependent haemodynamic response was investigated using linear regression. In healthy controls, there was a significant negative relationship between cortisol and parahippocampal activation (p = 0.023), such that the higher the cortisol levels induced by social stress, the lower the parahippocampal activation (greater deactivation) during fear processing. This relationship differed significantly between the control and placebo groups (p = 0.033), but not between the placebo and cannabidiol groups (p = 0.67). Our preliminary findings suggest that the parahippocampal response to fear processing may be associated with the neuroendocrine (cortisol) response to experimentally induced social stress, and that this relationship may be altered in patients at clinical high risk for psychosis.</p

Auditory Selective Attention to Speech Modulates Activity in the Visual Word Form Area

Selective attention to speech versus nonspeech signals in complex auditory input could produce top-down modulation of cortical regions previously linked to perception of spoken, and even visual, words. To isolate such top-down attentional effects, we contrasted 2 equally challenging active listening tasks, performed on the same complex auditory stimuli (words overlaid with a series of 3 tones). Instructions required selectively attending to either the speech signals (in service of rhyme judgment) or the melodic signals (tone-triplet matching). Selective attention to speech, relative to attention to melody, was associated with blood oxygenation level–dependent (BOLD) increases during functional magnetic resonance imaging (fMRI) in left inferior frontal gyrus, temporal regions, and the visual word form area (VWFA). Further investigation of the activity in visual regions revealed overall deactivation relative to baseline rest for both attention conditions. Topographic analysis demonstrated that while attending to melody drove deactivation equivalently across all fusiform regions of interest examined, attending to speech produced a regionally specific modulation: deactivation of all fusiform regions, except the VWFA. Results indicate that selective attention to speech can topographically tune extrastriate cortex, leading to increased activity in VWFA relative to surrounding regions, in line with the well-established connectivity between areas related to spoken and visual word perception in skilled readers

반응 억제의 개인차와 관련한 대규모 휴지기 뇌네트워크의 특성

학위논문 (박사) -- 서울대학교 대학원 : 인문대학 협동과정 인지과학전공, 2020. 8. 이동수.Response inhibition is one of the essential cognitive functions and suppresses inappropriate responses for goal-directed behavior. When a brain is cognitively engaged, it enters a cognitive state that task-positive regions are activated, and the default mode network is deactivated (DMN). In contrast, DMN is activated, and task-positive regions are deactivated at rest. The transition between the states is important for the cognitive function, and recent studies have found that the salience network (SN) plays a crucial role in detecting and processing a salient signal and suppressing DMN at rest. It can be assumed that there exists optimized connectivity to perform response inhibition successfully and that it will also appear in resting-state requiring no cognitive effort. It was hypothesized that lower functional connectivity within SN and higher functional connectivity within DMN and greater anti-correlation between then is related to better response inhibition. The response inhibition of individuals was measured by the stop-signal task and the Stroop task. The correlation between intra-/inter-component functional connectivity derived from independent component analysis with dual regression and task performances were examined to test the hypothesis. The intra-/inter-component structural connectivity analysis using diffusion tensor imaging was conducted to provide a deeper understanding of functional connectivity. Topological characteristics of inter-component functional connectivity were also examined using the minimum spanning tree (MST) of each individual to provide a heuristic insight from the topological view. The results indicate that the functional connectivity within SN, but not DMN components, and the functional and structural connectivity between SN and DMN components are critical to elucidate individual differences in response inhibition. Higher structural connectivity but low functional connectivity of SN at rest was an important feature for superior response inhibition. The stronger structural connectivity and stronger anti-correlation between SN and DMN components were also indicative of better response inhibition. MST of a subject with the best performance showed direct connections between SN and anterior DMN/pDMN, whereas the MST of the one with the worst performance does not. These intra-/inter components connectivities reflect the organization of the brain that enables competent response inhibition and account for individual differences. This study might suggest that the individuals characteristics of large-scale network components at rest provide evidence to illustrate response inhibition of an individual without any experimental scan.반응 억제는 가장 주요한 인지 기능 중 하나이며 이상행동을 동반하는 다양한 정신 질환과도 깊은 관련이 있다. 따라서 이와 관련된 신경적 특성을 탐구하는 것은 매우 중요하다. 우리의 뇌는 어떠한 인지 기능을 수행할 때, 작업 관련 영역들을 활성화하고 자기 참조적 처리를 하는 디폴트 모드 네트워크 영역들은 비활성화한다. 휴지기에는 반대로 작업 관련 영역들은 비활성화하고 디폴트 모드 네트워크 영역은 활성화한다. 이처럼 인지 기능을 수행하기 위해서는 상태를 효율적으로 전환하는 것이 중요하다. 현출성 네트워크 (salience network)는 어떠한 과제를 할 때 중요한 자극을 탐지하여 처리하며 또한 디폴트 모드 네트워크의 활성을 억제하기 때문에 상태 간 전환에 핵심적인 역할을 하는 대규모 뇌네트워크이다. 따라서 이와 관련된 연결적 특성이 인지 기능과 밀접한 관련이 있으며, 그러한 특성은 휴지기의 연결성에도 반영되어 있을 것이라 가정하였다. 즉, 본 연구에서는 반응 억제의 개인차를 휴지기 대규모 뇌네트워크들의 특성을 통해 설명할 수 있을 것이며, 특히 현출성 네트워크의 낮은 기능적 연결성, 디폴트 모드 네트워크의 높은 기능적 연결성, 그리고 그 둘 간의 높은 기능적 역 상관 (anti-correlation)이 반응 억제에 우수한 사람들의 특징적인 휴지기 연결성일 것이라 가설을 세웠다. 개인의 반응 억제는 정지 신호 과제와 스트룹 과제를 통해 측정하였으며, 휴지기 대규모 뇌네트워크들의 특성들과 어떠한 상관을 갖는지 알아보았다. 즉, 기능적 뇌네트워크 내의 연결성과 두 뇌네트워크 간 연결성이 과제 수행과 어떠한 상관을 보이는지를 알아보았다. 또한 기능적 연결성에 대한 보다 깊은 이해를 위해 확산 텐서 영상과 트랙토그래피 기법을 사용하여 구조적 연결성과 반응 억제와의 상관을 알아보았다. 반응 억제와 관련된 토폴로지 특성 역시 함께 알아보기 위해 참여자들의 미니멈 스패닝 트리(MST: minimum spanning tree)를 계산하였다. 분석 결과, 현출성 네트워크, 그리고 현출성 네트워크와 디폴트 모드 네트워크 간의 연결성을 통해 반응 억제의 개인차를 설명할 수 있었다. 현출성 네트워크의 성분 내 구조적 연결성은 강하지만 휴지기의 기능적 연결성이 약한 참여자들일수록 반응 억제 수행이 우수했다. 현출성 네트워크와 디폴트 모드 네트워크 간의 구조적 연결성과 기능적 역 상관은 모두 높을수록 우수한 반응 억제를 보였다. 또한 두 네트워크 간 구조적 연결성이 높을수록 기능적 역 상관이 높은 것으로 나타났다. 토폴로지 분석에서는 가장 수행이 좋은 참여자의 MST는 현출성 네트워크와 디폴트 모드 네트워크들 간에 직접적인 연결이 관찰되었으나 수행이 가장 나쁜 참여자에서는 그러한 직접적인 연결이 관찰되지 않았다. 분석 결과, 휴지기의 현출성 네트워크 내 연결성, 그리고 현출성 네트워크와 디폴트 모드 네트워크 간의 기능적 역 상관과 구조적 연결성이 반응 억제의 개인 차이를 설명하였으나, 디폴트 모드 네트워크 내의 연결성은 그렇지 못했다. 이 연구는 과제 수행 중이 아닌 휴지기 동안의 뇌네트워크의 특성들을 통해 반응 억제의 개인차를 설명할 수 있음을 보여준다.1. Introduction 1 1.1. Response inhibition and its neural correlates 1 1.1.1. Cognitive tasks to measure response inhibition 1 1.1.2. The neural correlates of response inhibition 2 1.1.3. Response inhibition and resting-state brain 3 1.2. Investigations on large-scale networks underlying response inhibition 4 1.2.1. Resting-state networks and response inhibition 4 1.2.2. Structural connectivity 6 1.2.3. Topological characteristics 7 1.2.4. The aim of the present study 8 2. Methods 9 2.1. Subjects 9 2.2. Behavioral tasks to assess response inhibition 11 2.3. Brain imaging data acquisition and preprocessing 14 2.3.1. Resting-state fMRI 14 2.3.2. Diffusion tensor imaging 15 2.4. Resting-state networks and functional connectivity analysis 16 2.4.1. Group independent component analysis to identify resting-state networks 16 2.4.2. Dual regression to obtain subject-specific data of components 17 2.4.3. Estimation of subject-specific intra-/inter-component functional connectivity 21 2.5. Structural connectivity analysis 21 2.5.1. Structural connectivity and response inhibition 21 2.5.2. Relationship between functional connectivity and structural connectivity 22 2.6. Topological data analysis 25 2.6.1. Minimum spanning tree 25 3. Results 27 3.1. The performances of behavioral tasks 27 3.2. Intra-component connectivity and response inhibition 30 3.3. Inter-component connectivity and response inhibition 35 3.4. Relationship between functional connectivity and structural connectivity 41 3.5. Minimum spanning tree 43 4. Discussion 46 4.1. Resting-state network and cognition 46 4.2. Salience network and response inhibition 47 4.3. Connectivity and structural connectivity between SN and DMN 50 4.3.1. Functional connectivity between SN and DMN 50 4.3.2. Structural connectivity between SN and DMN 51 4.3.3. Topological characteristics between SN and DMN 53 4.4. Limitations of the study 54 5. Conclusion 56 References 57 국문 초록 70Docto

Specifically Progressive Deficits of Brain Functional Marker in Amnestic Type Mild Cognitive Impairment

Background: Deficits of the default mode network (DMN) have been demonstrated in subjects with amnestic type mild cognitive impairment (aMCI) who have a high risk of developing Alzheimer’s disease (AD). However, no longitudinal study of this network has been reported in aMCI. Identifying links between development of DMN and aMCI progression would be of considerable value in understanding brain changes underpinning aMCI and determining risk of conversion to AD. Methodology/Principal Findings: Resting-state fMRI was acquired in aMCI subjects (n = 26) and controls (n = 18) at baseline and after approximately 20 months follow up. Independent component analysis was used to isolate the DMN in each participant. Differences in DMN between aMCI and controls were examined at baseline, and subsequent changes between baseline and follow-up were also assessed in the groups. Posterior cingulate cortex/precuneus (PCC/PCu) hyper-functional connectivity was observed at baseline in aMCI subjects, while a substantial decrement of these connections was evident at follow-up in aMCI subjects, compared to matched controls. Specifically, PCC/PCu dysfunction was positively related to the impairments of episodic memory from baseline to follow up in aMCI group. Conclusions/Significance: The patterns of longitudinal deficits of DMN may assist investigators to identify and monitor the development of aMCI

Mind over chatter: plastic up-regulation of the fMRI alertness network by EEG neurofeedback

EEG neurofeedback (NFB) is a brain-computer interface (BCI) approach used to shape brain oscillations by means of real-time feedback from the electroencephalogram (EEG), which is known to reflect neural activity across cortical networks. Although NFB is being evaluated as a novel tool for treating brain disorders, evidence is scarce on the mechanism of its impact on brain function. In this study with 34 healthy participants, we examined whether, during the performance of an attentional auditory oddball task, the functional connectivity strength of distinct fMRI networks would be plastically altered after a 30-min NFB session of alpha-band reduction (n=17) versus a sham-feedback condition (n=17). Our results reveal that compared to sham, NFB induced a specific increase of functional connectivity within the alertness/salience network (dorsal anterior and mid cingulate), which was detectable 30 minutes after termination of training. Crucially, these effects were significantly correlated with reduced mind-wandering &#x27;on-task&#x27; and were coupled to NFB-mediated resting state reductions in the alpha-band (8-12 Hz). No such relationships were evident for the sham condition. Although group default-mode network (DMN) connectivity was not significantly altered following NFB, we observed a positive association between modulations of resting alpha amplitude and precuneal connectivity, both correlating positively with frequency of mind-wandering. Our findings demonstrate a temporally direct, plastic impact of NFB on large-scale brain functional networks, and provide promising neurobehavioral evidence supporting its use as a noninvasive tool to modulate brain function in health and disease

THE RELATIONSHIP BETWEEN THE DEFAULT MODE RESTING STATE NEURAL NETWORK, RESPIRATORY SINUS ARRHYTHMIA, AND SELF-FOCUSED COGNITION: AN EMPIRICAL ANALYSIS

Functional activity within the default mode resting state neural network (RSNN) and the resting respiratory sinus arrhythmia (RSA) may represent an integrated neural and peripheral cardiovascular index of the baseline, resting state in humans. Research also indicates that the integrated physiological baseline potentially formed by the default mode RSNN and resting RSA may be associated with self-focused cognition. We hypothesize that measures of default mode RSNN (namely functional connectivity strength), resting RSA, and self-focused cognition are, indeed, correlated and aim to demonstrate these relationships. Measures of default mode RSNN functional connectivity strength were derived using functional magnetic resonance imaging, measures of resting RSA were obtained via electrocardiogram, and self-focused cognition was assessed using survey methods. Although our results were largely unsupportive of our hypothesis, we present several possibly methodological confounds that may have impacted our findings, and we describe directions for future research