Reductions in task positive neural systems occur with the passage of time and are associated with changes in ongoing thought

Cognition is dynamic and involves both the maintenance of and transitions between neurocognitive states. While recent research has identified some of the neural systems involved in sustaining task states, it is less well understood how intrinsic influences on cognition emerge over time. The current study uses fMRI and Multi-Dimensional Experience Sampling (MDES) to chart how cognition changes over time from moments in time when external attention was established. We found that the passage of time was associated with brain regions associated with external attention decreasing in activity over time. Comparing this pattern of activity to defined functional hierarchies of brain organization, we found that it could be best understood as movement away from systems involved in task performance. Moments where the participants described their thoughts as off-task showed a significant similarity to the task-negative end of the same hierarchy. Finally, the greater the similarity of a participant's neural dynamics to this hierarchy the faster their rate of increasing off-task thought over time. These findings suggest topographical changes in neural processing that emerge over time and those seen during off-task thought can both be understood as a common shift away from neural motifs seen during complex task performance

Out of focus – brain attention control deficits in adult ADHD

Modern environments are full of information, and place high demands on the attention control mechanisms that allow the selection of information from one (focused attention) or multiple (divided attention) sources, react to changes in a given situation (stimulus-driven attention), and allocate effort according to demands (task-positive and task-negative activity). We aimed to reveal how attention deficit hyperactivity disorder (ADHD) affects the brain functions associated with these attention control processes in constantly demanding tasks. Sixteen adults with ADHD and 17 controls performed adaptive visual and auditory discrimination tasks during functional magnetic resonance imaging (fMRI). Overlapping brain activity in frontoparietal saliency and default-mode networks, as well as in the somato-motor, cerebellar, and striatal areas were observed in all participants. In the ADHD participants, we observed exclusive activity enhancement in the brain areas typically considered to be primarily involved in other attention control functions: During auditory-focused attention, we observed higher activation in the sensory cortical areas of irrelevant modality and the default-mode network (DMN). DMN activity also increased during divided attention in the ADHD group, in turn decreasing during a simple button-press task. Adding irrelevant stimulation resulted in enhanced activity in the salience network. Finally, the irrelevant distractors that capture attention in a stimulus-driven manner activated dorsal attention networks and the cerebellum. Our findings suggest that attention control deficits involve the activation of irrelevant sensory modality, problems in regulating the level of attention on demand, and may encumber top-down processing in cases of irrelevant information. (C) 2018 Elsevier B.V. All rights reserved.Peer reviewe

Meaning in the noise: Neural signal variability in major depressive disorder

Clinical research has revealed aberrant activity and connectivity in default mode (DMN), frontoparietal (FPN), and salience (SN) network regions in major depressive disorder (MDD). Recent functional magnetic resonance imaging (fMRI) studies suggest that variability in brain activity, or blood oxygen level-dependent (BOLD) signal variability, may be an important novel predictor of psychopathology. However, to our knowledge, no studies have yet determined the relationship between resting-state BOLD signal variability and MDD nor applied BOLD signal variability features to the classification of MDD history using machine learning (ML). Thus, the current study had three aims: (i) to investigate the differences in the voxel-wise resting-state BOLD signal variability between varying depression histories; (ii) to examine the relationship between depressive symptom severity and resting-state BOLD signal variability; (iii) to explore the capability of resting-state BOLD signal variability to classify individuals by depression history. Using resting-state neuroimaging data for 79 women collected as a part of a larger NIH R01-funded study, we conducted (i) a one-way between-subjects ANCOVA, (ii) a multivariate multiple regression, and (iii) applied BOLD signal variability and average BOLD signal features to a supervised ML model. First, results indicated that individuals with any history of depression had significantly decreased BOLD signal variability in the left and right cerebellum and right parietal cortex in comparison to those with no depression history (pFWE \u3c .05). Second, and consistent with the results for depression history, depression severity was associated with reduced BOLD signal variability in the cerebellum. Lastly, a random forest model classified participant depression history with 76% accuracy, with BOLD signal variability features showing greater discriminative power than average BOLD signal features. These findings provide support for resting-state BOLD signal variability as a novel marker of neural dysfunction and implicate decreased neural signal variability as a neurobiological mechanism of depression

The disentanglement of the neural and experiential complexity of self-generated thoughts : A users guide to combining experience sampling with neuroimaging data

Human cognition is not limited to the processing of events in the external environment, and the covert nature of certain aspects of the stream of consciousness (e.g. experiences such as mind-wandering) provides a methodological challenge. Although research has shown that we spend a substantial amount of time focused on thoughts and feelings that are intrinsically generated, evaluating such internal states, purely on psychological grounds can be restrictive. In this review of the different methods used to examine patterns of ongoing thought, we emphasise how the process of triangulation between neuroimaging techniques, with self-reported information, is important for the development of a more empirically grounded account of ongoing thought. Specifically, we show how imaging techniques have provided critical information regarding the presence of covert states and can help in the attempt to identify different aspects of experience

Promoting Creativity Through Transcranial Direct Current Stimulation (tDCS) : a Critical Review

Creativity, meant as the ability to produce novel, original and suitable ideas, has received increased attention by research in the last years, especially from neuroaesthetics and social neuroscience. Besides the research conducted on the neural correlates of such capacities, previous work tried to answer the question of whether it is possible to enhance creativity through cognitive and neural stimulation. In particular, transcranial direct current stimulation (tDCS) has been applied to increase neuronal excitability in those areas related to creativity. However, being a complex construct that applies to a huge variety of situations, available results are often confusing and inconsistent. Thus, in the present critical review, after selecting original research articles investigating creativity with tDCS, results will be reviewed and framed according to the different effects of tDCS and its underlying mechanisms, which can be defined as follows: the promotion of self-focused attention; the disruption of inhibiting mechanisms; the enhancement of creative thinking; the promotion of artistic enactment. Finally, a theoretical perspective, the creative on/off model, will be provided to integrate the reported evidence with respect to both anatomical and functional issues and propose a cognitive explanation of the emergence of creative thinking

The effect of transcranial direct current stimulation on the interplay between executive control, behavioral variability and mind wandering: A registered report

Mind wandering (MW) is a mental phenomenon humans experience daily. Yet, we lack a complete understanding of the neural basis of this pervasive mental state. Over the past decade there has been an increase in publications using transcranial direct current stimulation (tDCS) to modulate the propensity to mind wander, but findings are diverse, and a satisfactory conclusion is missing. Recently, Boayue et al. (2020) reported successful reduction of mind wandering using high-definition tDCS (HD-tDCS) over the dorsolateral prefrontal cortex, providing preliminary evidence for the efficacy of HD-tDCS in interfering with mind wandering. The current study is a high-powered, pre-registered direct replication attempt of the effect found by Boayue et al. (2020). In addition, we investigated whether the effects of HD-tDCS on mind wandering would be prolonged and assessed the underlying processes of mind wandering using electroencephalography (EEG) and pupillometry during a finger-tapping random sequence generation task that requires the use of executive resources. We failed to find any evidence of the original effect of reduced MW during and after stimulation. When combining our data with the data from Boayue et al. (2020), the original effect of reduced MW caused by HD-tDCS disappeared. In addition, we observed increased occipital alpha power as task duration increased and increased midfrontal theta power preceding response patterns signaling high executive function use. Finally, tonic and phasic pupil size decreased as task duration increased yet, phasic responses were increased, while tonic responses were reduced preceding reports of MW. Additionally phasic pupil size also showed a tendency to be increased during periods of high executive function use. Importantly, none of the EEG or pupil measures were modulated by HD-tDCS. We conclude that HD-tDCS over the dorsolateral prefrontal cortex does not affect MW propensity and its neural signatures. Furthermore, we recommend that previously reported effects of tDCS on mind wandering and other cognitive functions should only be accepted after a successful pre-registered replication

The effect of transcranial direct current stimulation on the interplay between executive control, behavioral variability and mind wandering: A registered report

Mind wandering (MW) is a mental phenomenon humans experience daily. Yet, we lack a complete understanding of the neural basis of this pervasive mental state. Over the past decade there has been an increase in publications using transcranial direct current stimulation (tDCS) to modulate the propensity to mind wander, but findings are diverse, and a satisfactory conclusion is missing. Recently, Boayue et al. (2020) reported successful reduction of mind wandering using high-definition tDCS (HD-tDCS) over the dorsolateral prefrontal cortex, providing preliminary evidence for the efficacy of HD-tDCS in interfering with mind wandering. The current study is a high-powered, pre-registered direct replication attempt of the effect found by Boayue et al. (2020). In addition, we investigated whether the effects of HD-tDCS on mind wandering would be prolonged and assessed the underlying processes of mind wandering using electroencephalography (EEG) and pupillometry during a finger-tapping random sequence generation task that requires the use of executive resources. We failed to find any evidence of the original effect of reduced MW during and after stimulation. When combining our data with the data from Boayue et al. (2020), the original effect of reduced MW caused by HD-tDCS disappeared. In addition, we observed increased occipital alpha power as task duration increased and increased midfrontal theta power preceding response patterns signaling high executive function use. Finally, tonic and phasic pupil size decreased as task duration increased yet, phasic responses were increased, while tonic responses were reduced preceding reports of MW. Additionally phasic pupil size also showed a tendency to be increased during periods of high executive function use. Importantly, none of the EEG or pupil measures were modulated by HD-tDCS. We conclude that HD-tDCS over the dorsolateral prefrontal cortex does not affect MW propensity and its neural signatures. Furthermore, we recommend that previously reported effects of tDCS on mind wandering and other cognitive functions should only be accepted after a successful pre-registered replication

Self-referential Processing in the Adolescent Brain: Do Neural Self-Referential Processes Related to Adolescent Self-Concept Confer Risk for Depression?

Adolescence is an important developmental period in which self-concept stabilizes and depression develops. During early adolescence, self-concept becomes reliant on social comparison, leading to excessive self-focused attention that may contribute to risk for depression. Research has confirmed that negative global and social self-concept are closely related to the development of depressive symptoms during adolescence. Affective neuroscience studies demonstrate that there is a neural network underlying the processing of self-related information, yet little is known about how its function is associated with subjective feelings of self-concept and risk for depression in adolescence. The current study examined whether neural functioning during negative, compared to positive, self-referential processing is associated with early-adolescent girls’ ratings of global and social self-concept and depressive symptoms at two timepoints. The final sample included 39 girls (Myrs=12.18, SD=.77) who reported on their social and global self-concept using a questionnaire and during a functional neuroimaging task in which they responded whether they believed positive and negative personality trait words were true about them. Girls reported on depressive symptoms at the time of the scan and 6-months later. Results showed that greater social self-competence was related to greater neural activation when processing self-negative, relative to self-positive, adjectives in the PCC/precuneus, superior temporal gyrus/temporoparietal junction, and inferior parietal lobe. More positive self-perceptions during the imaging task were related to greater activation to self-positive>self-negative in the visual association area. More depressive symptoms at T1 were associated with greater activation to self-negative>self-positive in the caudate/putamen, dorsal anterior cingulate/supplementary motor area, and somatosensory cortex/inferior parietal cortex, while more symptoms at T2 were related to greater insula activation. Indirect effects analyses revealed that more negative self-perceptions during the fMRI task explained the positive association between dorsal medial prefrontal cortex activity in response to negative traits and depressive symptoms. This may suggest that youth with hyperactivation in the dMPFC during self-referential processing of negative traits may be excessively focused on negative self-related information. Findings highlight how differential neural processing of negative versus positive self-relevant information directly maps onto behavioral reports of self-concept during adolescence and how these brain-behavior associations may contribute to depression in early-adolescence

Neural correlates of self: the lower- and higher-order self-referential processing

The diploma thesis deals with the neural correlates of the human self. Specifically, it focuses on two types of neural processes that give rise to the self, namely on the lower- and higher- order self-referential processing (LO-SRP and HO-SRP). First, the thesis discusses selected classic and modern theories of the self, as well as selected phenomena and processes related to the self. The investigated processes are subsequently characterized in relation to these theoretical models and concepts. Next, the thesis presents a systematic overview of neuroimaging studies of the self to date and identifies brain areas that are potentially involved in LO-SRP and HO-SRP. In addition, the thesis describes neurocognitive models of the self, that try to explain various processes involved in the neural system of the self. The practical part of the work presents a research project that deals with the neural correlates of self-voice processing (LO-SRP) and processing of information about one's own person (HO-SRP) in healthy individuals. The study examines these processes in the auditory and mental domains. The results of the study provide evidence of the involvement of the default mode network and mirror neuron system in SRP. The study also identifies brain regions involved in LO-SRP and HO-SRP and some...Diplomová práce se zabývá neurálními koreláty lidského self. Konkrétně se zaměřuje na dva druhy neurálních procesů, které se podílí na vzniku self, a sice na sebereferenční zpracování informací (SRP) nižšího a vyššího řádu (LO-SRP a HO-SRP). Nejdříve práce pojednává o vybraných klasických a moderních teoriích self a také o vybraných fenoménech a procesech spojených se self. Zkoumané jevy jsou následně charakterizovány ve vztahu k těmto teoretickým modelům a pojmům. Dále práce uvádí systematický přehled dosavadních neurozobrazovacích studií self a identifikuje mozkové oblasti, které se potenciálně podílí na LO-SRP a HO-SRP. Navíc jsou v práci popsány neurokognitivní modely self, které se snaží vysvětlit různé procesy zapojené do neurálního systému self. Praktická část práce předkládá výzkumný projekt, který se zabývá neurálními koreláty zpracování vlastního hlasu (LO-SRP) a zpracování informací o vlastní osobě (HO-SRP) u zdravých jedinců. Studie zkoumá dané procesy ve sluchové a mentální doméně. Výsledky studie přináší důkazy o zapojení default mode sítě a systému zrcadlových neuronů do SRP. Studie také identifikuje mozkové oblasti, které se podílí na LO-SRP a HO-SRP a určité odlišnosti v neurálních základech daných procesů. Výsledky studie jsou diskutovány v kontextu předchozích výzkumů a je...Department of PsychologyKatedra psychologieFilozofická fakultaFaculty of Art