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.

The anatomy of human emotion

2012 ◽  
pp. 257-262
Author(s):  
R. J. Dolan
Keyword(s):  
Emotional Processing ◽  
Functional Neuroimaging ◽  
Brain Activity ◽  
Mental States ◽  
Brain Regions ◽  
Emotional States ◽  
Psychological States ◽  
General Utility ◽  
Positron Emission ◽  
Emotional System

Emotions, uniquely among mental states, are characterized by psychological and somatic referents. The former embody the subjectivity of all psychological states. The latter are evident in objectively measurable stereotyped behavioural patterns of facial expression, comportment, and states of autonomic arousal. These include unique patterns of response associated with discrete emotional states, as for example seen in the primary emotions of fear, anger, or disgust often thought of as emotion proper. Emotional states are also unique among psychological states in exerting global effects on virtually all aspects of cognition including attention, perception, and memory. Emotion also exerts biasing influences on high level cognition including the decision-making processes that guide extended behaviour. An informed neurobiological account of emotion needs to incorporate how these wide ranging effects are mediated. Although much of what we can infer about emotional processing in the human brain is derived from clinic-pathological correlations, the advent of high resolution, non-invasive functional neuroimaging techniques such as functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) has greatly expanded this knowledge base. This is particularly the case for emotion, as opposed to other areas of cognition, where normative studies have provided a much richer account of the underlying neurobiology than that available on the basis of observations from pathology as in classical neuropsychology. Emotion has historically been considered to reflect the product of activity within the limbic system of the brain. The general utility of the concept of a limbic-based emotional system is limited by a lack of a consensus as to its precise anatomical extent and boundaries, coupled with knowledge that emotion-related brain activity is, to a considerable degree, configured by behavioural context. What this means is that brain regions engaged by, for example, an emotion of fear associated with seeing a snake can have both distinct and common features with an emotion of fear associated with a fearful recollection. Consequently, within this framework emotional states are not unique to any single brain region but are expressed in widespread patterns of brain activity, including activity within early sensory cortices, shaped by the emotion eliciting context. This perspective emphasizes a global propagation of emotional signals as opposed to a perspective of circumscribed limbic-mediated emotion-related activity.

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.

scholarly journals Electrophysiological Evidence of Dissociation Between Explicit Encoding and Fast Mapping of Novel Spoken Words

2021 ◽  
Vol 12 ◽  
Author(s):  
Yury Shtyrov ◽  
Margarita Filippova ◽  
Evgeni Blagovechtchenski ◽  
Alexander Kirsanov ◽  
Elizaveta Nikiforova ◽  
...  
Keyword(s):  
Learning Strategies ◽  
Functional Neuroimaging ◽  
Brain Activity ◽  
Cognitive Strategies ◽  
Task Demands ◽  
Event Related Potential ◽  
Fast Mapping ◽  
Learning Session ◽  
Word Acquisition ◽  
Spoken Words

Existing behavioral, neuropsychological and functional neuroimaging data suggest that at least two major cognitive strategies are used for new word learning: fast mapping (FM) via context-dependent inference and explicit encoding (EE) via direct instruction. However, these distinctions remain debated at both behavioral and neurophysiological levels, not least due to confounds related to diverging experimental settings. Furthermore, the neural dynamics underpinning these two putative processes remain poorly understood. To tackle this, we designed a paradigm presenting 20 new spoken words in association with pictures in either FM or EE settings, closely matched for auditory and visual features and overall task demands. We tested word acquisition using a range of behavioral measures as well as passive event-related potential (ERP) responses, an established measure of word memory trace activation, and compared brain activity elicited by novel FM and EE words before and after the learning session. Behavioral data obtained in free recall, recognition and semantic word-picture matching tasks indicated successful acquisition of new words after just 10 exposures. Crucially, we found no behavioral evidence of different acquisition outcomes between FM and EE learning. ERP data, which exhibited the main response peaks at ~170, 250, and 520 ms, also indicated successful learning, with statistically different responses between novel and familiar words present only before, but not after the training, suggesting rapid formation of new neural memory circuits matching in activation those for previously known words. Furthermore, already at the earliest peak, we found different topographic distributions for the two learning types, with left-lateralized FM dynamics, suggestive of core language system involvement, and more diffuse activity for EE items, possibly suggesting the role of attention/executive control network. A similar effect also manifested later, at ~520 ms. Our data suggest that while both EE and FM learning can be successful for rapid word acquisition at the behavioral level, the diverging electrophysiological patterns suggest a dissociation between the neural systems underpinning these learning strategies.

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.

Large Scale Neurocognitive Networks Underlying Episodic Memory

2000 ◽  
Vol 12 (1) ◽  
pp. 163-173 ◽  
Author(s):  
Lars Nyberg ◽  
Jonas Persson ◽  
Reza Habib ◽  
Endel Tulving ◽  
Anthony R. McIntosh ◽  
...  
Keyword(s):  
Episodic Memory ◽  
Large Scale ◽  
Functional Neuroimaging ◽  
Brain Activity ◽  
Activity Patterns ◽  
Brain Regions ◽  
Target Density ◽  
Functional Connections ◽  
Positron Emission ◽  
Episodic Encoding

Large-scale networks of brain regions are believed to mediate cognitive processes, including episodic memory. Analyses of regional differences in brain activity, measured by functional neuroimaging, have begun to identify putative components of these networks. To more fully characterize neurocognitive networks, however, it is necessary to use analytical methods that quantify neural network interactions. Here, we used positron emission tomography (PET) to measure brain activity during initial encoding and subsequent recognition of sentences and pictures. For each type of material, three recognition conditions were included which varied with respect to target density (0%, 50%, 100%). Analysis of large-scale activity patterns identified a collection of foci whose activity distinguished the processing of sentences vs. pictures. A second pattern, which showed strong prefrontal cortex involvement, distinguished the type of cognitive process (encoding or retrieval). For both pictures and sentences, the manipulation of target density was associated with minor activation changes. Instead, it was found to relate to systematic changes of functional connections between material-specific regions and several other brain regions, including medial temporal, right prefrontal and parietal regions. These findings provide evidence for large-scale neural interactions between material-specific and process-specific neural substrates of episodic encoding and retrieval.

scholarly journals Characterisation of the Contribution of the GABA-Benzodiazepine α1 Receptor Subtype to [11C]Ro15-4513 PET Images

2012 ◽  
Vol 32 (4) ◽  
pp. 731-744 ◽  
Author(s):  
James FM Myers ◽  
Lula Rosso ◽  
Ben J Watson ◽  
Sue J Wilson ◽  
Nicola J Kalk ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
A Priori ◽  
Benzodiazepine Receptor ◽  
Brain Regions ◽  
Complex Model ◽  
Receptor Subtype ◽  
Receptor Subtypes ◽  
Time Activity ◽  
Positron Emission ◽  
The Impact

This positron emission tomography (PET) study aimed to further define selectivity of [11C]Ro15-4513 binding to the GABARα5 relative to the GABARα1 benzodiazepine receptor subtype. The impact of zolpidem, a GABARα1-selective agonist, on [11C]Ro15-4513, which shows selectivity for GABARα5, and the nonselective benzodiazepine ligand [11C]flumazenil binding was assessed in humans. Compartmental modelling of the kinetics of [11C]Ro15-4513 time-activity curves was used to describe distribution volume ( VT) differences in regions populated by different GABA receptor subtypes. Those with low α5 were best fitted by one-tissue compartment models; and those with high α5 required a more complex model. The heterogeneity between brain regions suggested spectral analysis as a more appropriate method to quantify binding as it does not a priori specify compartments. Spectral analysis revealed that Zolpidem caused a significant VT decrease (~10%) in [11C]flumazenil, but no decrease in [11C]Ro15-4513 binding. Further analysis of [11C]Ro15-4513 kinetics revealed additional frequency components present in regions containing both α1 and α5 subtypes compared with those containing only α1. Zolpidem reduced one component (mean ± s.d.: 71% ± 41%), presumed to reflect α1-subtype binding, but not another (13% ± 22%), presumed to reflect α5. The proposed method for [11C]Ro15-4513 analysis may allow more accurate selective binding assays and estimation of drug occupancy for other nonselective ligands.

scholarly journals A neurocognitive investigation of the impact of socializing with a robot on empathy for pain

2019 ◽  
Vol 374 (1771) ◽  
pp. 20180034 ◽  
Author(s):  
Emily S. Cross ◽  
Katie A. Riddoch ◽  
Jaydan Pratts ◽  
Simon Titone ◽  
Bishakha Chaudhury ◽  
...  
Keyword(s):  
Social Relationships ◽  
Functional Neuroimaging ◽  
Region Of Interest ◽  
Brain Regions ◽  
Social Robot ◽  
Human Robot Interaction ◽  
Functional Region ◽  
Repetition Suppression ◽  
Empathy For Pain ◽  
The Impact

To what extent can humans form social relationships with robots? In the present study, we combined functional neuroimaging with a robot socializing intervention to probe the flexibility of empathy, a core component of social relationships, towards robots. Twenty-six individuals underwent identical fMRI sessions before and after being issued a social robot to take home and interact with over the course of a week. While undergoing fMRI, participants observed videos of a human actor or a robot experiencing pain or pleasure in response to electrical stimulation. Repetition suppression of activity in the pain network, a collection of brain regions associated with empathy and emotional responding, was measured to test whether socializing with a social robot leads to greater overlap in neural mechanisms when observing human and robotic agents experiencing pain or pleasure. In contrast to our hypothesis, functional region-of-interest analyses revealed no change in neural overlap for agents after the socializing intervention. Similarly, no increase in activation when observing a robot experiencing pain emerged post-socializing. Whole-brain analysis showed that, before the socializing intervention, superior parietal and early visual regions are sensitive to novel agents, while after socializing, medial temporal regions show agent sensitivity. A region of the inferior parietal lobule was sensitive to novel emotions, but only during the pre-socializing scan session. Together, these findings suggest that a short socialization intervention with a social robot does not lead to discernible differences in empathy towards the robot, as measured by behavioural or brain responses. We discuss the extent to which long-term socialization with robots might shape social cognitive processes and ultimately our relationships with these machines. This article is part of the theme issue ‘From social brains to social robots: applying neurocognitive insights to human–robot interaction’.

Auditory verbal hallucinations: neuroimaging and treatment

2016 ◽  
Vol 47 (2) ◽  
pp. 199-208 ◽  
Author(s):  
M. M. Bohlken ◽  
K. Hugdahl ◽  
I. E. C. Sommer
Keyword(s):  
Functional Neuroimaging ◽  
Brain Activity ◽  
Neural Correlates ◽  
Brain Regions ◽  
Behavioural Therapy ◽  
Special Focus ◽  
Comprehensive Overview ◽  
Auditory Verbal Hallucinations ◽  
Research Areas ◽  
Control Functions

Auditory verbal hallucinations (AVH) are a frequently occurring phenomenon in the general population and are considered a psychotic symptom when presented in the context of a psychiatric disorder. Neuroimaging literature has shown that AVH are subserved by a variety of alterations in brain structure and function, which primarily concentrate around brain regions associated with the processing of auditory verbal stimuli and with executive control functions. However, the direction of association between AVH and brain function remains equivocal in certain research areas and needs to be carefully reviewed and interpreted. When AVH have significant impact on daily functioning, several efficacious treatments can be attempted such as antipsychotic medication, brain stimulation and cognitive–behavioural therapy. Interestingly, the neural correlates of these treatments largely overlap with brain regions involved in AVH. This suggests that the efficacy of treatment corresponds to a normalization of AVH-related brain activity. In this selected review, we give a compact yet comprehensive overview of the structural and functional neuroimaging literature on AVH, with a special focus on the neural correlates of efficacious treatment.

scholarly journals A neurocognitive investigation of the impact of socialising with a robot on empathy for pain

2018 ◽  
Author(s):  
Emily S. Cross ◽  
Katie A. Riddoch ◽  
Jaydan Pratts ◽  
Simon Titone ◽  
Bishakha Chaudhury ◽  
...  
Keyword(s):  
Social Relationships ◽  
Functional Neuroimaging ◽  
Region Of Interest ◽  
Brain Regions ◽  
Social Robot ◽  
Functional Region ◽  
Repetition Suppression ◽  
Before And After ◽  
Empathy For Pain ◽  
The Impact

To what extent can humans form social relationships with robots? In the present study, we combined functional neuroimaging with a robot socialising intervention to probe the flexibility of empathy, a core component of social relationships, toward robots. Twenty-six individuals underwent identical fMRI sessions before and after being issued a social robot to take home and interact with over the course of a week. While undergoing fMRI, participants observed videos of a human actor or a robot experiencing pain or pleasure in response to electrical stimulation. Repetition suppression of activity in the pain network, a collection of brain regions associated with empathy and emotional responding, was measured to test whether socialising with a social robot leads to greater overlap in neural mechanisms when observing human and robotic agents experiencing pain or pleasure. In contrast to our hypothesis, functional region-of-interest analyses revealed no change in neural overlap for agents after the socialising intervention. Similarly, no increase in activation when observing a robot experiencing pain emerged post-socialising. Whole-brain analysis showed that, before the socialising intervention, superior parietal and early visual regions are sensitive to novel agents, while after socialising, medial temporal regions show agent sensitivity. A region of the inferior parietal lobule was sensitive to novel emotions, but only during the pre-socialising scan session. Together, these findings suggest that a short socialisation intervention with a social robot does not lead to discernible differences in empathy toward the robot, as measured by behavioural or brain responses. We discuss the extent to which longer term socialisation with robots might shape social cognitive processes and ultimately our relationships with these machines.

Functional Neuroimaging Studies in Obsessive-Compulsive Disorder: Overview and Synthesis

2017 ◽  
Author(s):  
Brian P. Brennan ◽  
Scott L. Rauch
Keyword(s):  
Obsessive Compulsive Disorder ◽  
Functional Neuroimaging ◽  
Critical Role ◽  
Resting State Fmri ◽  
Brain Regions ◽  
Obsessive Compulsive ◽  
Compulsive Disorder ◽  
Additional Information ◽  
Positron Emission ◽  
Cortical Circuit

Studies using functional neuroimaging have played a critical role in the current understanding of the neurobiology of obsessive-compulsive disorder (OCD). Early studies using positron emission tomography (PET) identified a core cortico-striatal-thalamo-cortical circuit that is dysfunctional in OCD. Subsequent studies using behavioral paradigms in conjunction with functional magnetic resonance imaging (fMRI) have provided additional information about the neural substrates underlying specific psychological processes relevant to OCD. More recently, studies utilizing resting state fMRI have identified abnormal functional connectivity within intrinsic brain networks including the default mode and frontoparietal networks in OCD patients. Although these studies, as a whole, clearly substantiate the model of cortico-striatal-thalamo-cortical circuit dysfunction in OCD and support the continued investigation of neuromodulatory treatments targeting these brain regions, there is also growing evidence that brain regions outside this core circuit, particularly frontoparietal regions involved in cognitive control processes, may also play a significant role in the pathophysiology of OCD.

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