scholarly journals The effect of task demands on the neural patterns generated by novel instruction encoding

2021 ◽  
Author(s):  
Alberto Sobrado ◽  
Ana F. Palenciano ◽  
Carlos González-García ◽  
María Ruz
Keyword(s):  
Brain Activity ◽  
Brain Regions ◽  
Task Demands ◽  
Neural Representation ◽  
Stimulus Category ◽  
Related Information ◽  
Multiple Dimensions ◽  
Organizational Patterns ◽  
Task Sets ◽  
The Impact

AbstractVerbal instructions allow fast and optimal implementation of novel behaviors. Previous research has shown that different control-related variables organize neural activity in frontoparietal regions during the preparation of novel instructed task sets. Little is known, however, about how such variables organize brain activity under different task demands. In this study, we assessed the impact of implementation and memorization demands in the neural representation of novel instructions. We combined functional Magnetic Resonance Imaging (fMRI) with an instruction-following paradigm to compare the effect of three relevant control-related variables (integration of dimensions, response complexity, and stimulus category) across demands, and to explore the degree of overlap between these. Our results reveal, first, that the implementation and memorization of novel instructions share common neural patterns in several brain regions. Importantly, they also suggest that the preparation to implement instructions results in a strengthened coding of relevant control-related information in frontoparietal areas compared to their mere memorization. Overall, our study shows how the content of novel instructions proactively shapes brain activity based on multiple dimensions and how these organizational patterns are strengthened during implementation demands.

scholarly journals Functional neuroimaging of psychiatric disorders: exploring hidden behaviour

2004 ◽  
Vol 34 (4) ◽  
pp. 577-581 ◽  
Author(s):  
P. C. FLETCHER
Keyword(s):  
Functional Neuroimaging ◽  
Brain Activity ◽  
Cognitive Strategies ◽  
Healthy Person ◽  
Brain Regions ◽  
Task Demands ◽  
Unrealistic Expectation ◽  
Positron Emission ◽  
The Impact ◽  
Function Mapping

From the outset, people have had high expectations of functional neuroimaging. Many will have been disappointed. After roughly a decade of widespread use, even an enthusiastic advocate must be diffident about the impact of the two most frequently used techniques – positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) – upon clinical psychiatry. Perhaps this disappointment arises from an unrealistic expectation of what these techniques are able to tell us about the workings of the normal and the disordered brain. Anyone who hoped for intricate and unambiguous region-to-function mapping was always going to be disappointed. This expectation presupposes, among other things, a thorough understanding of the cognitive functions that are to be mapped onto the brain regions. This understanding, however, while developing, is still rudimentary. Mapping disorder along comparable lines is even more complex since it demands two levels of understanding. The first is of the healthy region-to-function mapping, the second of the disordered region-to-function mapping, which immediately demands a consideration of the nature of the function in the disordered state. After all, someone with schizophrenia, when confronted with a psychological task, might tackle it in a very different way, in terms of the cognitive strategies used, from a healthy person confronted with the same task. The observation that brain activity differs across the two individuals would only be interpretable insofar as one thoroughly understood the processes that each individual invoked in response to the task demands.

scholarly journals Bi-Hemispheric Engagement in the Retrieval of Autobiographical Episodes

2005 ◽  
Vol 16 (4) ◽  
pp. 203-210 ◽  
Author(s):  
Marie M. P. Vandekerckhove ◽  
Hans J. Markowitsch ◽  
Markus Mertens ◽  
Friedrich G. Woermann
Keyword(s):  
Autobiographical Memory ◽  
Brain Activity ◽  
Brain Regions ◽  
Retrosplenial Cortex ◽  
Task Demands ◽  
Related Information ◽  
Memory Integration ◽  
Interactive Network ◽  
Dorsolateral Prefrontal ◽  
The Brain

Functional magnetic resonance imaging (fMRI) was used to study the neural correlates of neutral, stressful, negative and positive autobiographical memories. The brain activity produced by these different kinds of episodic memory did not differ significantly, but a common pattern of activation for different kinds of autobiographical memory was revealed that included (1) largely bilateral portions of the medial and superior temporal lobes, hippocampus and parahippocampus, (2) portions of the ventral, medial, superior and dorsolateral prefrontal cortex, (3) the anterior and posterior cingulate, including the retrosplenial, cortex, (4) the parietal cortex, and (5) portions of the cerebellum. The brain regions that were mainly activated constituted an interactive network of temporal and prefrontal areas associated with structures of the extended limbic system. The main bilateral activations with left-sided preponderance probably reflected reactivation of complex semantic and episodic self-related information representations that included previously experienced contexts. In conclusion, the earlier view of a strict left versus right prefrontal laterality in the retrieval of semantic as opposed to episodic autobiographical memory, may have to be modified by considering contextual variables such as task demands and subject variables. Consequently, autobiographical memory integration should be viewed as based on distributed bi-hemispheric neural networks supporting multi-modal, emotionally coloured components of personal episodes.

scholarly journals Computational mechanisms for neural representation of words

2021 ◽  
Author(s):  
Ze Fu ◽  
Xiaosha Wang ◽  
Xiaoying Wang ◽  
Huichao Yang ◽  
Jiahuan Wang ◽  
...  
Keyword(s):  
Neural Network ◽  
Brain Activity ◽  
Inferior Frontal Gyrus ◽  
Activity Patterns ◽  
Explanatory Power ◽  
Word Meaning ◽  
Brain Regions ◽  
Neural Representation ◽  
Space Representation ◽  
Neural Representations

A critical way for humans to acquire, represent and communicate information is through language, yet the underlying computation mechanisms through which language contributes to our word meaning representations are poorly understood. We compared three major types of word computation mechanisms from large language corpus (simple co-occurrence, graph-space relations and neural-network-vector-embedding relations) in terms of the association of words’ brain activity patterns, measured by two functional magnetic resonance imaging (fMRI) experiments. Word relations derived from a graph-space representation, and not neural-network-vector-embedding, had unique explanatory power for the neural activity patterns in brain regions that have been shown to be particularly sensitive to language processes, including the anterior temporal lobe (capturing graph-common-neighbors), inferior frontal gyrus, and posterior middle/inferior temporal gyrus (capturing graph-shortest-path). These results were robust across different window sizes and graph sizes and were relatively specific to language inputs. These findings highlight the role of cumulative language inputs in organizing word meaning neural representations and provide a mathematical model to explain how different brain regions capture different types of language-derived information.

scholarly journals Neuroscience Research on Human Visual Path Integration: Empirical Overview and Strategic Considerations

2021 ◽  
Author(s):  
Jimmy Y. Zhong
Keyword(s):  
Path Integration ◽  
Hippocampal Formation ◽  
Brain Activity ◽  
Brain Regions ◽  
Neural Basis ◽  
Age Related ◽  
Neuroscience Research ◽  
Integration Strategies ◽  
The Impact ◽  
The Brain

Over the past two decades, many neuroimaging studies have attempted uncover the brain regions and networks involved in path integration and identify the underlying neurocognitive mechanisms. Although these studies made inroads into the neural basis of path integration, they have yet to offer a full disclosure of the functional specialization of the brain regions supporting path integration. In this paper, I reviewed notable neuroscientific studies on visual path integration in humans, identified the commonalities and discrepancies in their findings, and incorporated fresh insights from recent path integration studies. Specifically, this paper presented neuroscientific studies performed with virtual renditions of the triangle/path completion task and addressed whether or not the hippocampus is necessary for human path integration. Based on studies that showed evidence supporting and negating the involvement of the hippocampal formation in path integration, this paper introduces the proposal that the use of different path integration strategies may determine the extent to which the hippocampus and entorhinal cortex are engaged during path integration. To this end, recent studies that investigated the impact of different path integration strategies on behavioral performance and functional brain activity were discussed. Methodological concerns were raised with feasible recommendations for improving the experimental design of future strategy-related path integration studies, which can cover cognitive neuroscience research on age-related differences in the role of the hippocampal formation in path integration and Bayesian modelling of the interaction between landmark and self-motion cues. The practical value of investigating different path integration strategies was also discussed briefly from a biomedical perspective.

scholarly journals The Impact of Sports-Related Concussions on the Language System

2018 ◽  
Vol 1 (1) ◽  
pp. 36-46
Author(s):  
Patrick S Ledwidge
Keyword(s):  
Brain Activity ◽  
Brain Regions ◽  
Functional Brain Imaging ◽  
Long Term Effects ◽  
Brain Potentials ◽  
Language System ◽  
Induced Changes ◽  
The Impact ◽  
Language Network

Sports-related Concussions (SRC) and their potential long-term effects are a growing concern among athletes and their families. Research utilizing functional brain imaging/recording techniques (e.g., fMRI, ERP) seeks to explain how neurocognitive brain activity changes in the days and years following SRC. Although language deficits are documented following non-sports related concussion there remains a striking lack of research on how SRCs may influence the language system and their supporting neural mechanisms. Neuroimaging findings, however, demonstrate that SRCs alter structural and functional pathways within the frontotemporal language network. Brain regions included in this network generate language-related event-related brain potentials (ERPs), including the N400 and P600. ERPs have been used to demonstrate long-term neurocognitive alterations associated with concussion and may also provide objective and robust markers of SRC-induced changes to the language system.

scholarly journals Asymmetric effective connectivity within frontoparietal motor network underlying motor imagery and motor execution

2020 ◽  
Author(s):  
Takeshi Ogawa ◽  
Hideki Shimobayashi ◽  
Jun-ichiro Hirayama ◽  
Motoaki Kawanabe
Keyword(s):  
Motor Imagery ◽  
Primary Motor Cortex ◽  
Brain Activity ◽  
Effective Connectivity ◽  
Premotor Cortex ◽  
Brain Regions ◽  
Neural Representation ◽  
Motor Execution ◽  
Positive Effects ◽  
Motor Network

AbstractBoth imagery and execution of motor controls consist of interactions within a neuronal network, including frontal motor-related regions and posterior parietal regions. To reveal neural representation in the frontoparietal motor network, several approaches have been proposed: one is decoding of actions/modes related to motor control from the spatial pattern of brain activity; another is to estimate effective connectivity, which means a directed association between two brain regions within motor regions. However, a motor network consisting of multiple brain regions has not been investigated to illustrate network representation depending on motor imagery (MI) or motor execution (ME). Here, we attempted to differentiate the frontoparietal motor-related networks based on the effective connectivity in the MI and ME conditions. We developed a delayed sequential movement and imagery (dSMI) task to evoke brain activity associated with data under ME and MI in functional magnetic resonance imaging (fMRI) scanning. We applied a linear non-Gaussian acyclic causal model to identify effective connectivity among the frontoparietal motor-related brain regions for each condition. We demonstrated higher effective connectivity from the contralateral dorsal premotor cortex (dPMC) to the primary motor cortex (M1) in ME than in MI. We mainly identified significant direct effects of dPMC and ventral premotor cortex (vPMC) to the parietal regions. In particular, connectivity from the dPMC to the superior parietal lobule (SPL) in the same hemisphere showed significant positive effects across all conditions. Instead, interlateral connectivities from vPMC to SPL showed significantly negative effects across all conditions. Finally, we found positive effects from A1 to M1 in the same hemisphere, such as the audio motor pathway. These results indicated that sources of motor command originated from d/vPMC and influenced M1 as achievements of ME and MI, and the parietal regions as integration of somatosensory and visual representation during finger tapping. In addition, sequential sounds may functionally facilitate temporal motor processes.

scholarly journals The role of superstition of cognitive control during neurofeedback training

2021 ◽  
Author(s):  
Doris Groessinger ◽  
Florian Ph.S Fischmeister ◽  
Mathias Witte ◽  
Karl Koschutnig ◽  
Manuel Ninaus ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Associative Learning ◽  
Real Time ◽  
Ventral Striatum ◽  
Psychiatric Symptoms ◽  
Brain Activity ◽  
Training Session ◽  
Brain Regions ◽  
Neurofeedback Training ◽  
The Impact

Background: Real-time fMRI neurofeedback is growing in reputation as a means to alter brain activity patterns and alleviate psychiatric symptoms. Activity in ventral striatum structures is considered an index of training efficacy. fMRI response in these brain regions indicates neurofeedback-driven associative learning. Here we investigated the impact of mere superstition of control as observed during neurofeedback training on patterns of fMRI activation. Methods: We examined the brain activations of a large sample of young participants (n = 97, 50 female, age range 18-54yrs) in a simple fMRI task. Participants saw a display similar to that typically used for real-time fMRI. They were instructed to watch the bars' movements or to control them with their own brain activity. Bar movements were not connected with brain activity of participants in any way and perceptions of control were superstitious. After the pretended control condition, they rated how well they were able to control the bars' movements. Results: Strong activation in the basal ganglia and ventral striatum as well as in large portions of the anterior insula, supplementary motor area, and the middle frontal gyrus due to the superstition of brain control. Conclusions: The superstition of control over one's own brain activity in a pretended neurofeedback training session activates the same neural networks as neurofeedback-driven learning. Therefore, activity in the basal ganglia and ventral striatum cannot be taken as evidence for neurofeedback-driven associative learning unless its effects are proven to supersede those elicited by appropriate sham conditions.

scholarly journals Blue Light Stimulates Cognitive Brain Activity in Visually Blind Individuals

2013 ◽  
Vol 25 (12) ◽  
pp. 2072-2085 ◽  
Author(s):  
Gilles Vandewalle ◽  
Olivier Collignon ◽  
Joseph T. Hull ◽  
Véronique Daneault ◽  
Geneviève Albouy ◽  
...  
Keyword(s):  
Blue Light ◽  
Ganglion Cells ◽  
Brain Activity ◽  
Memory Task ◽  
Brain Regions ◽  
Human Cognition ◽  
Brain Functions ◽  
And Performance ◽  
Blind Individuals ◽  
The Impact

Light regulates multiple non-image-forming (or nonvisual) circadian, neuroendocrine, and neurobehavioral functions, via outputs from intrinsically photosensitive retinal ganglion cells (ipRGCs). Exposure to light directly enhances alertness and performance, so light is an important regulator of wakefulness and cognition. The roles of rods, cones, and ipRGCs in the impact of light on cognitive brain functions remain unclear, however. A small percentage of blind individuals retain non-image-forming photoreception and offer a unique opportunity to investigate light impacts in the absence of conscious vision, presumably through ipRGCs. Here, we show that three such patients were able to choose nonrandomly about the presence of light despite their complete lack of sight. Furthermore, 2 sec of blue light modified EEG activity when administered simultaneously to auditory stimulations. fMRI further showed that, during an auditory working memory task, less than a minute of blue light triggered the recruitment of supplemental prefrontal and thalamic brain regions involved in alertness and cognition regulation as well as key areas of the default mode network. These results, which have to be considered as a proof of concept, show that non-image-forming photoreception triggers some awareness for light and can have a more rapid impact on human cognition than previously understood, if brain processing is actively engaged. Furthermore, light stimulates higher cognitive brain activity, independently of vision, and engages supplemental brain areas to perform an ongoing cognitive process. To our knowledge, our results constitute the first indication that ipRGC signaling may rapidly affect fundamental cerebral organization, so that it could potentially participate to the regulation of numerous aspects of human brain function.

scholarly journals Effects of Dopaminergic Drugs on Cognitive Control Processes Vary by Genotype

2020 ◽  
Vol 32 (5) ◽  
pp. 804-821 ◽  
Author(s):  
Daniella J. Furman ◽  
Robert L. White ◽  
Jenna Naskolnakorn ◽  
Jean Ye ◽  
Andrew Kayser ◽  
...  
Keyword(s):  
Cognitive Control ◽  
D2 Receptor ◽  
Drug Effects ◽  
Task Demands ◽  
System Component ◽  
Comt Genotype ◽  
Dopaminergic Drugs ◽  
Control Processes ◽  
Task Sets ◽  
The Impact

Dopamine (DA) has been implicated in modulating multiple cognitive control processes, including the robust maintenance of task sets and memoranda in the face of distractors (cognitive stability) and, conversely, the ability to switch task sets or update the contents of working memory when it is advantageous to do so (cognitive flexibility). In humans, the limited specificity of available pharmacological probes has posed a challenge for understanding the mechanisms by which DA, acting on multiple receptor families across the PFC and striatum, differentially influences these cognitive processes. Using a within-subject, placebo-controlled design, we contrasted the impact of two mechanistically distinct DA drugs, tolcapone (an inhibitor of catechol- O-methyltransferase [COMT], a catecholamine inactivator) and bromocriptine (a DA agonist with preferential affinity for the D2 receptor), on the maintenance and switching of task rules. Given previous work demonstrating that drug effects on behavior are dependent on baseline DA tone, participants were stratified according to genetic polymorphisms associated with cortical (COMT Val158Met) and striatal (Taq1A) DA system function. Our results were partially consistent with an inverted-U-shaped relationship between tolcapone and robust rule maintenance (interaction with COMT genotype) and between bromocriptine and cued rule switching (interaction with Taq1A genotype). However, when task instructions were ambiguous, a third relationship emerged to explain drug effects on spontaneous task switching (interaction of COMT genotype and bromocriptine). Together, this pattern of results suggests that the effects of DA drugs vary not only as a function of the DA system component upon which they act but also on subtle differences in task demands and context.

The role of neuroimaging in understanding the impact of neuroplasticity after CNS damage

2020 ◽  
pp. 185-198
Author(s):  
Nick S. Ward
Keyword(s):  
Functional Neuroimaging ◽  
Recovery Of Function ◽  
Brain Activity ◽  
Complete Recovery ◽  
Brain Regions ◽  
Functional Brain Imaging ◽  
Brain Organization ◽  
Brain Reorganization ◽  
Invasive Techniques ◽  
The Impact

After stroke, there is little restitution of neural tissue, but reorganization of surviving neural networks appears to be important for recovery of function. Non-invasive techniques such as functional magnetic resonance imaging and magnetoencephalography allow some aspects of this brain reorganization to be studied in humans. For example, early after stroke there appears to be an upregulation in task-related activity which diminishes with time, but more particularly with recovery. Those with the most complete recovery tend to have the most ‘normal’ activation patter, and those with less complete recovery tend to rely on additional brain regions. Disruption of activity in these additional regions can impair performance in stroke patients suggesting that these new patterns of brain activity can support what recovered function there is. In other words, this reorganization is functionally relevant. Advances in functional neuroimaging now allow the study of alterations in connections between brain regions. Understanding how brain organization is related to anatomical damage, as well as impairment and recovery that can take place over weeks and months following stroke opens the way for functional brain imaging to become a clinically useful tool in rehabilitation, particularly in our ability to predict outcomes and response to novel therapies. Understanding the dynamic process of systems level reorganization will allow greater understanding of the mechanisms of recovery and potentially improve our ability to deliver effective restorative therapy.

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