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Jha A, Diehl B, Strange B, Miserocchi A, Chowdhury F, McEvoy AW, Nachev P. Orienting to fear under transient focal disruption of the human amygdala. Brain 2022; 146:135-148. [PMID: 35104842 PMCID: PMC9825557 DOI: 10.1093/brain/awac032] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 10/28/2021] [Accepted: 01/08/2022] [Indexed: 01/13/2023] Open
Abstract
Responding to threat is under strong survival pressure, promoting the evolution of systems highly optimized for the task. Though the amygdala is implicated in 'detecting' threat, its role in the action that immediately follows-'orienting'-remains unclear. Critical to mounting a targeted response, such early action requires speed, accuracy, and resilience optimally achieved through conserved, parsimonious, dedicated systems, insured against neural loss by a parallelized functional organization. These characteristics tend to conceal the underlying substrate not only from correlative methods but also from focal disruption over time scales long enough for compensatory adaptation to take place. In a study of six patients with intracranial electrodes temporarily implanted for the clinical evaluation of focal epilepsy, we investigated gaze orienting to fear during focal, transient, unilateral direct electrical disruption of the amygdala. We showed that the amygdala is necessary for rapid gaze shifts towards faces presented in the contralateral hemifield regardless of their emotional expression, establishing its functional lateralization. Behaviourally dissociating the location of presented fear from the direction of the response, we implicated the amygdala not only in detecting contralateral faces, but also in automatically orienting specifically towards fearful ones. This salience-specific role was demonstrated within a drift-diffusion model of action to manifest as an orientation bias towards the location of potential threat. Pixel-wise analysis of target facial morphology revealed scleral exposure as its primary driver, and induced gamma oscillations-obtained from intracranial local field potentials-as its time-locked electrophysiological correlate. The amygdala is here reconceptualized as a functionally lateralized instrument of early action, reconciling previous conflicting accounts confined to detection, and revealing a neural organisation analogous to the superior colliculus, with which it is phylogenetically kin. Greater clarity on its role has the potential to guide therapeutic resection, still frequently complicated by impairments of cognition and behaviour related to threat, and inform novel focal stimulation techniques for the management of neuropsychiatric conditions.
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Affiliation(s)
- Ashwani Jha
- Correspondence to: Ashwani Jha UCL Queen Square Institute of Neurology, London, UK E-mail:
| | - Beate Diehl
- UCL Queen Square Institute of Neurology, London, UK
| | - Bryan Strange
- CTB-UPM and Department of Neuroimaging, Reina Sofia Centre for Alzheimer's Research, Madrid, Spain
| | | | | | | | - Parashkev Nachev
- Correspondence may also be addressed to: Parashkev Nachev E-mail:
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Culot C, Corlazzoli G, Fantini-Hauwel C, Gevers W. The relation between task-relatedness of anxiety and metacognitive performance. Conscious Cogn 2021; 94:103191. [PMID: 34388407 DOI: 10.1016/j.concog.2021.103191] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 07/27/2021] [Accepted: 08/06/2021] [Indexed: 11/19/2022]
Abstract
It is well established that anxiety influences a range of cognitive processes such as cognitive control or decision-making. What is less known is how anxiety influences the metacognitive evaluations individuals make about their own performance. The present study explored the importance of task-relatedness in the relation between anxiety and metacognitive awareness. More specifically, we hypothesized that induced anxiety would affect metacognitive performance in opposite directions depending solely on whether the threat is perceived as related or unrelated to the performance. We conducted two experiments to test this hypothesis. In both studies, electric shocks were administered randomly, regardless of participant's performance. In experiment 1, participants were informed that the shocks would be administered randomly, unrelated to performance. In experiment 2, participants were told that their metacognitive performance would influence the administration of the electric shocks (i.e. fewer electric shocks with better metacognitive performance). Our predictions were confirmed. Threat perceived as unrelated to metacognitive performance (Experiment 1) decreased metacognitive performance. Threat believed to be related to metacognitive performance resulted in improved performance (Experiment 2). These findings confirm that induced anxiety exerts a strong influence on metacognitive awareness while sparing first-order task performance. We furthermore demonstrate that the perceived relatedness of the anxiety determines whether metacognitive performance decreases or improves performance under threat.
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Affiliation(s)
- Catherine Culot
- Center for Research in Cognition and Neurosciences (CRCN) - Université Libre de Bruxelles (ULB), Brussels, Belgium; Neurosciences Institute (UNI), Université Libre de Bruxelles (ULB), Brussels, Belgium.
| | - Gaia Corlazzoli
- Center for Research in Cognition and Neurosciences (CRCN) - Université Libre de Bruxelles (ULB), Brussels, Belgium; Neurosciences Institute (UNI), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Carole Fantini-Hauwel
- Research center for experiMEntAl & clinical cogNitive psychopatholoGy (MEANING), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Wim Gevers
- Center for Research in Cognition and Neurosciences (CRCN) - Université Libre de Bruxelles (ULB), Brussels, Belgium; Neurosciences Institute (UNI), Université Libre de Bruxelles (ULB), Brussels, Belgium
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3
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Abstract
Initial evaluation structures (IESs) currently proposed as the earliest detectors of affective stimuli (e.g., amygdala, orbitofrontal cortex, or insula) are high-order structures (a) whose response latency cannot account for the first visual cortex emotion-related response (~80 ms), and (b) lack the necessary infrastructure to locally analyze the visual features that define emotional stimuli. Several thalamic structures accomplish both criteria. The lateral geniculate nucleus (LGN), a first-order thalamic nucleus that actively processes visual information, with the complement of the thalamic reticular nucleus (TRN) are proposed as core IESs. This LGN–TRN tandem could be supported by the pulvinar, a second-order thalamic structure, and by other extrathalamic nuclei. The visual thalamus, scarcely explored in affective neurosciences, seems crucial in early emotional evaluation.
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Affiliation(s)
- Luis Carretié
- Facultad de Psicología, Universidad Autónoma de Madrid, Spain
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4
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Asymmetric Behavior in Ptyodactylus guttatus: Can a Digit Ratio Reflect Brain Laterality? Symmetry (Basel) 2020. [DOI: 10.3390/sym12091490] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The digit ratio, an indicator of brain laterality, is the ratio of the second and fourth digits on the left (L24) or right foot (R24). Much of the research on the digit ratio and brain laterality focuses on primates, rather than other species such as reptiles. We tested whether the digit ratio in the gecko Ptyodactylus guttatus was associated with behaviors attributed to brain laterality. We examined risk-taking behavior (time spent under cover), foot preference (which foot was the first to start moving) and the side from which geckos bypassed an obstacle, in relation to the digit ratio. Geckos with longer fourth digits on their left hind foot (higher digit ratio) spent more time under cover. Geckos starting to move with their left leg were much more likely to bypass obstacles from the right side, and vice versa. This is the first evidence of laterality being associated with the digit ratio in reptiles. Comparisons among vertebrates are needed in order to decipher the evolutionary origin of the commonalities and peculiarities of brain asymmetry and disentangle the patterns and drivers of our evolutionary tree.
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Yuan M, Zhu H, Qiu C, Meng Y, Zhang Y, Shang J, Nie X, Ren Z, Gong Q, Zhang W, Lui S. Group cognitive behavioral therapy modulates the resting-state functional connectivity of amygdala-related network in patients with generalized social anxiety disorder. BMC Psychiatry 2016; 16:198. [PMID: 27296506 PMCID: PMC4906710 DOI: 10.1186/s12888-016-0904-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2015] [Accepted: 06/06/2016] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Amygdala is considered as the core pathogenesis of generalized social anxiety disorder (GSAD). However, it is still unclear whether effective group cognitive behavioral therapy (CBT) could modulate the function of amygdala-related network. We aimed to examine the resting-state functional connectivity (rsFC) of the amygdala before and after group CBT. METHODS Fifteen patients with GSAD were scanned on a 3T MR system before and after 8 weeks of group CBT. For comparison, nineteen healthy control participants also underwent baseline fMRI scanning. We used bilateral amygdala as seed regions and the rsFC maps of the right and left amygdala were created separately in a voxel-wise way. Clusters survived two-tailed Gaussian Random Field (GRF) correction at p <0.05 (voxel z value >2.3). RESULTS Compared with baseline, patients with CBT showed significantly decreased connectivity of the left amygdala with the right putamen, the left dorsal medial prefrontal cortex (dmPFC) and the right dorsal anterior cingulate cortex (dACC). Especially, the changes of the connectivity between the left amygdala and the dACC positively correlated with changes of the anxiety symptom in patients. Furthermore, in relative to controls, patients showed higher connectivity of left amygdala with dmPFC and dACC at baseline, while normal after CBT. CONCLUSIONS Short-term group CBT could down-regulate the abnormal higher connectivity of prefrontal-amygdala network, along with clinical improvement. This may provide a potential biomarker to monitor the treatment effect of CBT in GSAD patients.
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Affiliation(s)
- Minlan Yuan
- Mental Health Center, West China Hospital of Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041 China
| | - Hongru Zhu
- Mental Health Center, West China Hospital of Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041 China ,State Key Laboratory of Biotherapy, Psychiatric Laboratory, West China Hospital of Sichuan University, Chengdu, Sichuan China
| | - Changjian Qiu
- Mental Health Center, West China Hospital of Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041 China
| | - Yajing Meng
- Mental Health Center, West China Hospital of Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041 China ,State Key Laboratory of Biotherapy, Psychiatric Laboratory, West China Hospital of Sichuan University, Chengdu, Sichuan China
| | - Yan Zhang
- Mental Health Center, West China Hospital of Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041 China
| | - Jing Shang
- Mental Health Center, West China Hospital of Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041 China
| | - Xiaojing Nie
- Mental Health Center, West China Hospital of Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041 China
| | - Zhengjia Ren
- Mental Health Center, West China Hospital of Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041 China
| | - Qiyong Gong
- Department of Radiology, Huaxi MR Research Center (HMRRC), West China Hospital of Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041 China
| | - Wei Zhang
- Mental Health Center, West China Hospital of Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041, China. .,State Key Laboratory of Biotherapy, Psychiatric Laboratory, West China Hospital of Sichuan University, Chengdu, Sichuan, China.
| | - Su Lui
- Department of Radiology, Huaxi MR Research Center (HMRRC), West China Hospital of Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041, China. .,Radiology Department, the Second Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China.
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Almeida I, Soares SC, Castelo-Branco M. The Distinct Role of the Amygdala, Superior Colliculus and Pulvinar in Processing of Central and Peripheral Snakes. PLoS One 2015; 10:e0129949. [PMID: 26075614 PMCID: PMC4467980 DOI: 10.1371/journal.pone.0129949] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Accepted: 05/15/2015] [Indexed: 12/17/2022] Open
Abstract
Introduction Visual processing of ecologically relevant stimuli involves a central bias for stimuli demanding detailed processing (e.g., faces), whereas peripheral object processing is based on coarse identification. Fast detection of animal shapes holding a significant phylogenetic value, such as snakes, may benefit from peripheral vision. The amygdala together with the pulvinar and the superior colliculus are implicated in an ongoing debate regarding their role in automatic and deliberate spatial processing of threat signals. Methods Here we tested twenty healthy participants in an fMRI task, and investigated the role of spatial demands (the main effect of central vs. peripheral vision) in the processing of fear-relevant ecological features. We controlled for stimulus dependence using true or false snakes; snake shapes or snake faces and for task constraints (implicit or explicit). The main idea justifying this double task is that amygdala and superior colliculus are involved in both automatic and controlled processes. Moreover the explicit/implicit instruction in the task with respect to emotion is not necessarily equivalent to explicit vs. implicit in the sense of endogenous vs. exogenous attention, or controlled vs. automatic processes. Results We found that stimulus-driven processing led to increased amygdala responses specifically to true snake shapes presented in the centre or in the peripheral left hemifield (right hemisphere). Importantly, the superior colliculus showed significantly biased and explicit central responses to snake-related stimuli. Moreover, the pulvinar, which also contains foveal representations, also showed strong central responses, extending the results of a recent single cell pulvinar study in monkeys. Similar hemispheric specialization was found across structures: increased amygdala responses occurred to true snake shapes presented to the right hemisphere, with this pattern being closely followed by the superior colliculus and the pulvinar. Conclusion These results show that subcortical structures containing foveal representations such as the amygdala, pulvinar and superior colliculus play distinct roles in the central and peripheral processing of snake shapes. Our findings suggest multiple phylogenetic fingerprints in the responses of subcortical structures to fear-relevant stimuli.
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Affiliation(s)
- Inês Almeida
- Institute for Biomedical Imaging in Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Sandra C. Soares
- Institute for Biomedical Imaging in Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Education Department, University of Aveiro, Aveiro, Portugal
| | - Miguel Castelo-Branco
- Institute for Biomedical Imaging in Life Sciences (IBILI), Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- * E-mail:
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7
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Okon-Singer H, Hendler T, Pessoa L, Shackman AJ. The neurobiology of emotion-cognition interactions: fundamental questions and strategies for future research. Front Hum Neurosci 2015; 9:58. [PMID: 25774129 PMCID: PMC4344113 DOI: 10.3389/fnhum.2015.00058] [Citation(s) in RCA: 172] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 01/21/2015] [Indexed: 12/18/2022] Open
Abstract
Recent years have witnessed the emergence of powerful new tools for assaying the brain and a remarkable acceleration of research focused on the interplay of emotion and cognition. This work has begun to yield new insights into fundamental questions about the nature of the mind and important clues about the origins of mental illness. In particular, this research demonstrates that stress, anxiety, and other kinds of emotion can profoundly influence key elements of cognition, including selective attention, working memory, and cognitive control. Often, this influence persists beyond the duration of transient emotional challenges, partially reflecting the slower molecular dynamics of catecholamine and hormonal neurochemistry. In turn, circuits involved in attention, executive control, and working memory contribute to the regulation of emotion. The distinction between the 'emotional' and the 'cognitive' brain is fuzzy and context-dependent. Indeed, there is compelling evidence that brain territories and psychological processes commonly associated with cognition, such as the dorsolateral prefrontal cortex and working memory, play a central role in emotion. Furthermore, putatively emotional and cognitive regions influence one another via a complex web of connections in ways that jointly contribute to adaptive and maladaptive behavior. This work demonstrates that emotion and cognition are deeply interwoven in the fabric of the brain, suggesting that widely held beliefs about the key constituents of 'the emotional brain' and 'the cognitive brain' are fundamentally flawed. We conclude by outlining several strategies for enhancing future research. Developing a deeper understanding of the emotional-cognitive brain is important, not just for understanding the mind but also for elucidating the root causes of its disorders.
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Affiliation(s)
| | - Talma Hendler
- Functional Brain Center, Wohl Institute of Advanced Imaging, and School of Psychological Sciences, Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel AvivIsrael
| | - Luiz Pessoa
- Department of Psychology, Neuroscience and Cognitive Science Program, and Maryland Neuroimaging Center, University of Maryland, College Park, College Park, MDUSA
| | - Alexander J. Shackman
- Department of Psychology, Neuroscience and Cognitive Science Program, and Maryland Neuroimaging Center, University of Maryland, College Park, College Park, MDUSA
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8
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Viviani R. Emotion regulation, attention to emotion, and the ventral attentional network. Front Hum Neurosci 2013; 7:746. [PMID: 24223546 PMCID: PMC3819767 DOI: 10.3389/fnhum.2013.00746] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 10/18/2013] [Indexed: 01/15/2023] Open
Abstract
Accounts of the effect of emotional information on behavioral response and current models of emotion regulation are based on two opposed but interacting processes: automatic bottom-up processes (triggered by emotionally arousing stimuli) and top-down control processes (mapped to prefrontal cortical areas). Data on the existence of a third attentional network operating without recourse to limited-capacity processes but influencing response raise the issue of how it is integrated in emotion regulation. We summarize here data from attention to emotion, voluntary emotion regulation, and on the origin of biases against negative content suggesting that the ventral network is modulated by exposure to emotional stimuli when the task does not constrain the handling of emotional content. In the parietal lobes, preferential activation of ventral areas associated with “bottom-up” attention by ventral network theorists is strongest in studies of cognitive reappraisal. In conditions when no explicit instruction is given to change one's response to emotional stimuli, control of emotionally arousing stimuli is observed without concomitant activation of the dorsal attentional network, replaced by a shift of activation toward ventral areas. In contrast, in studies where emotional stimuli are placed in the role of distracter, the observed deactivation of these ventral semantic association areas is consistent with the existence of proactive control on the role emotional representations are allowed to take in generating response. It is here argued that attentional orienting mechanisms located in the ventral network constitute an intermediate kind of process, with features only partially in common with effortful and automatic processes, which plays an important role in handling emotion by conveying the influence of semantic networks, with which the ventral network is co-localized. Current neuroimaging work in emotion regulation has neglected this system by focusing on a bottom-up/top-down dichotomy of attentional control.
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Affiliation(s)
- Roberto Viviani
- Department of Psychiatry and Psychotherapy III, University of Ulm Ulm, Germany ; Institute of Psychology, University of Innsbruck Innsbruck, Austria
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9
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Hecht D. The neural basis of optimism and pessimism. Exp Neurobiol 2013; 22:173-99. [PMID: 24167413 PMCID: PMC3807005 DOI: 10.5607/en.2013.22.3.173] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2013] [Revised: 09/18/2013] [Accepted: 09/21/2013] [Indexed: 12/12/2022] Open
Abstract
Our survival and wellness require a balance between optimism and pessimism. Undue pessimism makes life miserable; however, excessive optimism can lead to dangerously risky behaviors. A review and synthesis of the literature on the neurophysiology subserving these two worldviews suggests that optimism and pessimism are differentially associated with the two cerebral hemispheres. High self-esteem, a cheerful attitude that tends to look at the positive aspects of a given situation, as well as an optimistic belief in a bright future are associated with physiological activity in the left-hemisphere (LH). In contrast, a gloomy viewpoint, an inclination to focus on the negative part and exaggerate its significance, low self-esteem as well as a pessimistic view on what the future holds are interlinked with neurophysiological processes in the right-hemisphere (RH). This hemispheric asymmetry in mediating optimistic and pessimistic outlooks is rooted in several biological and functional differences between the two hemispheres. The RH mediation of a watchful and inhibitive mode weaves a sense of insecurity that generates and supports pessimistic thought patterns. Conversely, the LH mediation of an active mode and the positive feedback it receives through its motor dexterity breed a sense of confidence in one's ability to manage life's challenges, and optimism about the future.
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Affiliation(s)
- David Hecht
- Institute of Cognitive Neuroscience, University College London, London, WC1N 3AR, United Kingdom
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10
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Vallortigara G. Core knowledge of object, number, and geometry: a comparative and neural approach. Cogn Neuropsychol 2012; 29:213-36. [PMID: 22292801 DOI: 10.1080/02643294.2012.654772] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Studies on the ontogenetic origins of human knowledge provide evidence for a small set of separable systems of core knowledge dealing with the representation of inanimate and animate objects, number, and geometry. Because core knowledge systems are evolutionarily ancient, they can be investigated from a comparative perspective, making use of various animal models. In this review, I discuss evidence showing precocious abilities in nonhuman species to represent (a) objects that move partly or fully out of view and their basic mechanical properties such as solidity, (b) the cardinal and ordinal/sequential aspects of numerical cognition and rudimentary arithmetic with small numerosities, and (c) the geometrical relationships among extended surfaces in the surrounding layout. Controlled rearing studies suggest that the abilities associated with core knowledge systems of objects, number, and geometry are observed in animals in the absence (or with very reduced) experience, supporting a nativistic foundation of such cognitive mechanisms. Animal models also promise a fresh approach to the issue of the neurobiological and genetic mechanisms underlying the expression of core knowledge systems.
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12
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Spatio-temporal indications of sub-cortical involvement in leftward bias of spatial attention. Neuroimage 2011; 54:3010-20. [DOI: 10.1016/j.neuroimage.2010.10.078] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 10/25/2010] [Accepted: 10/27/2010] [Indexed: 11/18/2022] Open
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13
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Hecht D. Depression and the hyperactive right-hemisphere. Neurosci Res 2010; 68:77-87. [PMID: 20603163 DOI: 10.1016/j.neures.2010.06.013] [Citation(s) in RCA: 134] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2010] [Revised: 06/24/2010] [Accepted: 06/28/2010] [Indexed: 12/21/2022]
Abstract
Depression is associated with an inter-hemispheric imbalance; a hyperactive right-hemisphere (RH) and a relatively hypoactive left-hemisphere (LH). Nevertheless, the underlying mechanisms which can explain why depression is associated with a RH dominance remain elusive. This article points out the potential links between functional cerebral asymmetries and specific symptoms and features of depression. There is evidence that the RH is selectively involved in processing negative emotions, pessimistic thoughts and unconstructive thinking styles--all which comprise the cognitive phenomenology of depression and in turn contribute to the elevated anxiety, stress and pain associated with the illness. Additionally, the RH mediates vigilance and arousal which may explain the sleep disturbances often reported in depression. The RH had also been linked with self-reflection, accounting for the tendency of depressed individuals to withdraw from their external environments and focus attention inward. Physiologically, RH activation is associated with hyprecortisolemia, which contributes to the deterioration of the immune system functioning and puts depressed patients at a greater risk of developing other illnesses, accounting for depression's high comorbidity with other diseases. Conversely, the LH is specifically involved in processing pleasurable experiences, and its relative attenuation is in line with the symptoms of anhedonia that characterize depression. The LH is also relatively more involved in decision-making processes, accounting for the indecisiveness that is often accompanied with depression.
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Affiliation(s)
- David Hecht
- Institute of Cognitive Neuroscience, University College London, 17 Queen Square, London WC1N3AR, UK.
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14
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Verleger R, Möller F, Kuniecki M, Śmigasiewicz K, Groppa S, Siebner HR. The left visual-field advantage in rapid visual presentation is amplified rather than reduced by posterior-parietal rTMS. Exp Brain Res 2010; 203:355-65. [DOI: 10.1007/s00221-010-2237-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Accepted: 03/24/2010] [Indexed: 12/01/2022]
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15
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Hecht D. Psychopathy and fearlessness: an interhemispheric imbalance perspective. Biol Psychiatry 2010; 67:e51-2. [PMID: 20031118 DOI: 10.1016/j.biopsych.2009.10.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 10/27/2009] [Accepted: 10/28/2009] [Indexed: 11/29/2022]
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van Wingen G, Mattern C, Verkes RJ, Buitelaar J, Fernández G. Testosterone reduces amygdala-orbitofrontal cortex coupling. Psychoneuroendocrinology 2010; 35:105-13. [PMID: 19782476 DOI: 10.1016/j.psyneuen.2009.09.007] [Citation(s) in RCA: 148] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 09/08/2009] [Accepted: 09/09/2009] [Indexed: 01/01/2023]
Abstract
Testosterone influences various aspects of affective behavior, which is mediated by different brain regions within the emotion circuitry. Previous neuroimaging studies have demonstrated that testosterone increases neural activity in the amygdala. To investigate whether this could be due to altered regulation of amygdala functioning which is thought to be mediated by the prefrontal cortex, we studied the effects of exogenous testosterone on the interaction between the amygdala and other brain regions. Healthy middle-aged women received a single nasal testosterone dose in a randomized, placebo-controlled, crossover manner, and performed an emotional face matching task while their brain activity was measured with functional MRI. The results show that testosterone rapidly reduced functional coupling of the amygdala with the orbitofrontal cortex, and enhanced amygdala coupling with the thalamus. This suggests that testosterone may reduce the regulatory control over the amygdala, or that testosterone shifts amygdala output away from the orbitofrontal cortex towards the thalamus. Testosterone also reduced functional coupling with the contralateral amygdala. Because interhemispheric amygdala coupling is lower in men than in women, this result suggests that circulating testosterone may contribute to this sexual dimorphism.
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Affiliation(s)
- Guido van Wingen
- Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands.
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