1
|
Purg N, Starc M, Slana Ozimič A, Kraljič A, Matkovič A, Repovš G. Neural Evidence for Different Types of Position Coding Strategies in Spatial Working Memory. Front Hum Neurosci 2022; 16:821545. [PMID: 35517989 PMCID: PMC9067305 DOI: 10.3389/fnhum.2022.821545] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 03/14/2022] [Indexed: 11/19/2022] Open
Abstract
Sustained neural activity during the delay phase of spatial working memory tasks is compelling evidence for the neural correlate of active storage and maintenance of spatial information, however, it does not provide insight into specific mechanisms of spatial coding. This activity may reflect a range of processes, such as maintenance of a stimulus position or a prepared motor response plan. The aim of our study was to examine neural evidence for the use of different coding strategies, depending on the characteristics and demands of a spatial working memory task. Thirty-one (20 women, 23 ± 5 years) and 44 (23 women, 21 ± 2 years) participants performed a spatial working memory task while we measured their brain activity using fMRI in two separate experiments. Participants were asked to remember the position of a briefly presented target stimulus and, after a delay period, to use a joystick to indicate either the position of the remembered target or an indicated non-matching location. The task was designed so that the predictability of the response could be manipulated independently of task difficulty and memory retrieval process. We were particularly interested in contrasting conditions in which participants (i) could use prospective coding of the motor response or (ii) had to rely on retrospective sensory information. Prospective motor coding was associated with activity in somatomotor, premotor, and motor cortices and increased integration of brain activity with and within the somatomotor network. In contrast, retrospective sensory coding was associated with increased activity in parietal regions and increased functional connectivity with and within secondary visual and dorsal attentional networks. The observed differences in activation levels, dynamics of differences over trial duration, and integration of information within and between brain networks provide compelling evidence for the use of complementary spatial working memory strategies optimized to meet task demands.
Collapse
Affiliation(s)
- Nina Purg
- Department of Psychology, Faculty of Arts, University of Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
- *Correspondence: Nina Purg
| | - Martina Starc
- Department of Psychology, Faculty of Arts, University of Ljubljana, Ljubljana, Slovenia
| | - Anka Slana Ozimič
- Department of Psychology, Faculty of Arts, University of Ljubljana, Ljubljana, Slovenia
| | - Aleksij Kraljič
- Department of Psychology, Faculty of Arts, University of Ljubljana, Ljubljana, Slovenia
| | - Andraž Matkovič
- Department of Psychology, Faculty of Arts, University of Ljubljana, Ljubljana, Slovenia
| | - Grega Repovš
- Department of Psychology, Faculty of Arts, University of Ljubljana, Ljubljana, Slovenia
| |
Collapse
|
2
|
Cohen AL, Soussand L, Corrow SL, Martinaud O, Barton JJS, Fox MD. Looking beyond the face area: lesion network mapping of prosopagnosia. Brain 2019; 142:3975-3990. [PMID: 31740940 PMCID: PMC6906597 DOI: 10.1093/brain/awz332] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 08/29/2019] [Accepted: 09/09/2019] [Indexed: 12/31/2022] Open
Abstract
Damage to the right fusiform face area can disrupt the ability to recognize faces, a classic example of how damage to a specialized brain region can disrupt a specialized brain function. However, similar symptoms can arise from damage to other brain regions, and face recognition is now thought to depend on a distributed brain network. The extent of this network and which regions are critical for facial recognition remains unclear. Here, we derive this network empirically based on lesion locations causing clinically significant impairments in facial recognition. Cases of acquired prosopagnosia were identified through a systematic literature search and lesion locations were mapped to a common brain atlas. The network of brain regions connected to each lesion location was identified using resting state functional connectivity from healthy participants (n = 1000), a technique termed lesion network mapping. Lesion networks were overlapped to identify connections common to lesions causing prosopagnosia. Reproducibility was assessed using split-half replication. Specificity was assessed through comparison with non-specific control lesions (n = 135) and with control lesions associated with symptoms other than prosopagnosia (n = 155). Finally, we tested whether our facial recognition network derived from clinically evident cases of prosopagnosia could predict subclinical facial agnosia in an independent lesion cohort (n = 31). Our systematic literature search identified 44 lesions causing prosopagnosia, only 29 of which intersected the right fusiform face area. However, all 44 lesion locations fell within a single brain network defined by connectivity to the right fusiform face area. Less consistent connectivity was found to other face-selective regions. Surprisingly, all 44 lesion locations were also functionally connected, through negative correlation, with regions in the left frontal cortex. This connectivity pattern was highly reproducible and specific to lesions causing prosopagnosia. Positive connectivity to the right fusiform face area and negative connectivity to left frontal regions were independent predictors of prosopagnosia and predicted subclinical facial agnosia in an independent lesion cohort. We conclude that lesions causing prosopagnosia localize to a single functionally connected brain network defined by connectivity to the right fusiform face area and to left frontal regions. Implications of these findings for models of facial recognition deficits are discussed.
Collapse
Affiliation(s)
- Alexander L Cohen
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
- Berenson-Allen Center for Non-Invasive Brain Stimulation and Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
- Computational Radiology Laboratory, Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Louis Soussand
- Berenson-Allen Center for Non-Invasive Brain Stimulation and Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | | | - Olivier Martinaud
- Department of Neurology Neuropsychology and Imaging of Human Memory, Caen-Normandy University, PSL Research University, EPHE, INSERM, Caen University Hospital, Caen, France
| | - Jason J S Barton
- Departments of Medicine (Neurology), Ophthalmology and Visual Sciences, Psychology, University of British Columbia, Canada
| | - Michael D Fox
- Berenson-Allen Center for Non-Invasive Brain Stimulation and Division of Cognitive Neurology, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
- Athinoula A. Martinos Centre for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
3
|
Atherton KE, Filippini N, Zeman AZJ, Nobre AC, Butler CR. Encoding-related brain activity and accelerated forgetting in transient epileptic amnesia. Cortex 2018; 110:127-140. [PMID: 29861041 PMCID: PMC6335262 DOI: 10.1016/j.cortex.2018.04.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 04/06/2018] [Accepted: 04/30/2018] [Indexed: 12/25/2022]
Abstract
The accelerated forgetting of newly learned information is common amongst patients with epilepsy and, in particular, in the syndrome of transient epileptic amnesia (TEA). However, the neural mechanisms underlying accelerated forgetting are poorly understood. It has been hypothesised that interictal epileptiform activity during longer retention intervals disrupts normally established memory traces. Here, we tested a distinct hypothesis-that accelerated forgetting relates to the abnormal encoding of memories. We studied a group of 15 patients with TEA together with matched, healthy control subjects. Despite normal performance on standard anterograde memory tasks, patients showed accelerated forgetting of a word list over one week. We used a subsequent memory paradigm to compare encoding-related brain activity in patients and controls. Participants studied a series of visually presented scenes whilst undergoing functional MRI scanning. Recognition memory for these scenes was then probed outside the scanner after delays of 45 min and of 4 days. Patients showed poorer memory for the scenes compared with controls. In the patients but not the controls, subsequently forgotten stimuli were associated with reduced hippocampal activation at encoding. Furthermore, patients demonstrated reduced deactivation of posteromedial cortex regions upon viewing subsequently remembered stimuli as compared to subsequently forgotten ones. These data suggest that abnormal encoding-related activity in key memory areas of the brain contributes to accelerated forgetting in TEA. We propose that abnormally encoded memory traces may be particularly vulnerable to interference from subsequently encountered material and hence be forgotten more rapidly. Our results shed light on the mechanisms underlying memory impairment in epilepsy, and offer support to the proposal that accelerated forgetting may be a useful marker of subtle dysfunction in memory-related brain systems.
Collapse
Affiliation(s)
- Kathryn E Atherton
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK; Department of Experimental Psychology and Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, UK
| | - Nicola Filippini
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Adam Z J Zeman
- Cognitive & Behavioural Neurology, University of Exeter Medical School, Exeter, UK
| | - Anna C Nobre
- Department of Experimental Psychology and Oxford Centre for Human Brain Activity, Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Oxford, UK
| | - Christopher R Butler
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK.
| |
Collapse
|
4
|
Ravishankar M, Morris A, Burgess A, Khatib D, Stanley JA, Diwadkar VA. Cortical-hippocampal functional connectivity during covert consolidation sub-serves associative learning: Evidence for an active "rest" state. Brain Cogn 2017; 131:45-55. [PMID: 29054542 DOI: 10.1016/j.bandc.2017.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 09/22/2017] [Indexed: 01/18/2023]
Abstract
We studied modulation of undirected functional connectivity (uFC) in cortical-hippocampal sub-networks during associative learning. Nineteen healthy individuals were studied (fMRI acquired on a Siemens Verio 3T), and uFC was studied between nodes in a network of regions identified by standard activation models based on bivariate correlational analyses of time series data. The paradigm alternated between Memory Encoding, Rest and Retrieval. "Rest" intervals promoted covert consolidation. Over the task, performance was broadly separable into linear (Early) and asymptomatic (Late) regimes, with late performance reflecting successful memory consolidation. Significant modulation of uFC was observed during periods of covert consolidation. The sub-networks which were modulated constituted connections between frontal regions such as the dorsal prefrontal cortex (dPFC) and dorsal anterior cingulate cortex (dACC), the medial temporal lobe (hippocampus, HPC), the superior parietal cortex (SPC) and the fusiform gyrus (FG). uFC patterns were dynamic in that sub-networks modulated during Early learning (dACC ↔ SPC, dACC ↔ FG, dPFC ↔ HPC) were not identical to those modulated during Late learning (dACC ↔ HPC, dPFC ↔ FG, FG ↔ SPC). Covert consolidation exerts systematic effects, and these results add to emerging evidence for the constructive role of the brain's "resting state" in potentiating action.
Collapse
Affiliation(s)
- Mathura Ravishankar
- Dept of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, USA
| | - Alexandra Morris
- Dept of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, USA
| | - Ashley Burgess
- Dept of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, USA
| | - Dalal Khatib
- Dept of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, USA
| | - Jeffrey A Stanley
- Dept of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, USA
| | - Vaibhav A Diwadkar
- Dept of Psychiatry & Behavioral Neurosciences, Wayne State University School of Medicine, USA.
| |
Collapse
|
5
|
Sreenivasan K, Zhuang X, Banks SJ, Mishra V, Yang Z, Deshpande G, Cordes D. Olfactory Network Differences in Master Sommeliers: Connectivity Analysis Using Granger Causality and Graph Theoretical Approach. Brain Connect 2017; 7:123-136. [PMID: 28125912 DOI: 10.1089/brain.2016.0458] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Previous studies investigating the differences in olfactory processing and judgments between trained sommeliers and controls have shown increased activations in brain regions involving higher level cognitive processes in sommeliers. However, there is little information about the influence of expertise on causal connectivity and topological properties of the connectivity networks between these regions. Therefore, the current study focuses on addressing these questions in a functional magnetic resonance imaging (fMRI) study of olfactory perception in Master Sommeliers. fMRI data were acquired from Master Sommeliers and control participants during different olfactory and nonolfactory tasks. Mean time series were extracted from 90 different regions of interest (ROIs; based on Automated Anatomical Labeling atlas). The underlying neuronal variables were extracted using blind hemodynamic deconvolution and then input into a dynamic multivariate autoregressive model to obtain connectivity between every pair of ROIs as a function of time. These connectivity values were then statistically compared to obtain paths that were significantly different between the two groups. The obtained connectivity matrices were further studied using graph theoretical methods. In sommeliers, significantly greater connectivity was observed in connections involving the precuneus, caudate, putamen, and several frontal and temporal regions. The controls showed increased connectivity from the left hippocampus to the frontal regions. Furthermore, the sommeliers exhibited significantly higher small-world topology than the controls. These findings are significant, given that learning about neuroplasticity in adulthood in these regions may then have added clinical importance in diseases such as Alzheimer's and Parkinson's where early neurodegeneration is isolated to regions important in smell.
Collapse
Affiliation(s)
| | - Xiaowei Zhuang
- 1 Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, Nevada
| | - Sarah J Banks
- 1 Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, Nevada
| | - Virendra Mishra
- 1 Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, Nevada
| | - Zhengshi Yang
- 1 Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, Nevada
| | - Gopikrishna Deshpande
- 2 Department of Electrical and Computer Engineering, AU MRI Research Center, Auburn University , Auburn, Alabama
- 3 Department of Psychology, Auburn University , Auburn, Alabama
- 4 Alabama Advanced Imaging Consortium, Auburn University and University of Alabama Birmingham , Birmingham, Alabama
| | - Dietmar Cordes
- 1 Cleveland Clinic Lou Ruvo Center for Brain Health, Las Vegas, Nevada
- 5 Department of Psychology and Neuroscience, University of Colorado, Boulder, Colorado
| |
Collapse
|
6
|
Kizilirmak JM, Thuerich H, Folta-Schoofs K, Schott BH, Richardson-Klavehn A. Neural Correlates of Learning from Induced Insight: A Case for Reward-Based Episodic Encoding. Front Psychol 2016; 7:1693. [PMID: 27847490 PMCID: PMC5088210 DOI: 10.3389/fpsyg.2016.01693] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 10/13/2016] [Indexed: 12/03/2022] Open
Abstract
Experiencing insight when solving problems can improve memory formation for both the problem and its solution. The underlying neural processes involved in this kind of learning are, however, thus far insufficiently understood. Here, we conceptualized insight as the sudden understanding of a novel relationship between known stimuli that fits into existing knowledge and is accompanied by a positive emotional response. Hence, insight is thought to comprise associative novelty, schema congruency, and intrinsic reward, all of which are separately known to enhance memory performance. We examined the neural correlates of learning from induced insight with functional magnetic resonance imaging (fMRI) using our own version of the compound-remote-associates-task (CRAT) in which each item consists of three clue words and a solution word. (Pseudo-)Solution words were presented after a brief period of problem-solving attempts to induce either sudden comprehension (CRA items) or continued incomprehension (control items) at a specific time point. By comparing processing of the solution words of CRA with control items, we found induced insight to elicit activation of the rostral anterior cingulate cortex/medial prefrontal cortex (rACC/mPFC) and left hippocampus. This pattern of results lends support to the role of schema congruency (rACC/mPFC) and associative novelty (hippocampus) in the processing of induced insight. We propose that (1) the mPFC not only responds to schema-congruent information, but also to the detection of novel schemata, and (2) that the hippocampus responds to a form of associative novelty that is not just a novel constellation of familiar items, but rather comprises a novel meaningful relationship between the items—which was the only difference between our insight and no insight conditions. To investigate episodic long-term memory encoding, we compared CRA items whose solution word was recognized 24 h after encoding to those with forgotten solutions. We found activation in the left striatum and parts of the left amygdala, pointing to a potential role of brain reward circuitry in the encoding of the solution words. We propose that learning from induced insight mainly relies on the amygdala evaluating the internal value (as an affective evaluation) of the suddenly comprehended information, and striatum-dependent reward-based learning.
Collapse
Affiliation(s)
- Jasmin M Kizilirmak
- Cognitive Neuroscience Lab, Institute of Psychology, University of Hildesheim Hildesheim, Germany
| | - Hannes Thuerich
- Memory and Consciousness Research Group, Department of Neurology, Otto-von-Guericke University of Magdeburg Magdeburg, Germany
| | - Kristian Folta-Schoofs
- Cognitive Neuroscience Lab, Institute of Psychology, University of Hildesheim Hildesheim, Germany
| | - Björn H Schott
- Leibniz Institute for Neurobiology, Department of Behavioral NeurologyMagdeburg, Germany; Department of Psychiatry, Charité University HospitalBerlin, Germany
| | - Alan Richardson-Klavehn
- Memory and Consciousness Research Group, Department of Neurology, Otto-von-Guericke University of Magdeburg Magdeburg, Germany
| |
Collapse
|
7
|
Nejad-Davarani SP, Chopp M, Peltier S, Li L, Davoodi-Bojd E, Lu M, Bagher-Ebadian H, Budaj J, Gallagher D, Ding Y, Hearshen D, Jiang Q, Cerghet M. Resting state fMRI connectivity analysis as a tool for detection of abnormalities in five different cognitive networks of the brain in Multiple Sclerosis patients. ACTA ACUST UNITED AC 2016; 2:464-471. [PMID: 29170718 PMCID: PMC5697978 DOI: 10.15761/ccrr.1000s1001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Objectives Cognitive dysfunction is present in at least half of patients with Multiple Sclerosis. The purpose of this study was to examine functional connectivity abnormalities in patients with multiple sclerosis (MS) using resting state fMRI (rsfMRI). Methods Conventional MRI, rsfMRI and diffusion tensor imaging (DTI) data was acquired from 10 patients with relapsing-remitting multiple sclerosis (RRMS) and 20 healthy controls. Cross-correlation of the resting state average signal among the voxels in each brain region of the five cognitive networks: default mode network (DMN), attention, verbal memory, memory, and visuospatial working memory network, was calculated. Voxelwise analyses were used to investigate fractional anisotropy (FA) of white matter tracts. The normalized gray matter (GM), white matter and thalamus volumes were calculated. Results Compared to controls, significant deficit in MS patients at each of five networks, attention (p=0.026), DMN (p=0.004), verbal memory (p<0.001), memory (p=0.001), visuospatial working memory (p=0.003) was found. Significant reduction (p=0.034) in the normalized GM volume and asymmetry in thalamus volume (p=0.041) was detected in MS patients compared to controls. Conclusion Wide spread of functional abnormalities are present within different cognitive networks in patients with RRMS, suggesting that DMN may not be sufficient for measurement of MS cognitive impairment. Larger and longitudinal studies should ascertain whether rsfMRI of cognitive networks and changes in GM and thalamus volume can be used as tools for assessment of cognition in clinical trials in MS.
Collapse
Affiliation(s)
- Siamak P Nejad-Davarani
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA.,Department of Biomedical engineering, University of Michigan, Ann Arbor, MI, USA.,Department of Radiology, University of Michigan, Ann Arbor, MI, USA
| | - Michael Chopp
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| | - Scott Peltier
- Department of Biomedical engineering, University of Michigan, Ann Arbor, MI, USA
| | - Lian Li
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| | | | - Mei Lu
- Biostatistics and Research Epidemiology, Henry Ford Hospital, Detroit, MI, USA
| | | | - John Budaj
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| | - David Gallagher
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| | - Yue Ding
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| | - David Hearshen
- Department of Radiology, Henry Ford Hospital, Detroit, MI, USA
| | - Quan Jiang
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| | - Mirela Cerghet
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| |
Collapse
|
8
|
Woodcock EA, Wadehra S, Diwadkar VA. Network Profiles of the Dorsal Anterior Cingulate and Dorsal Prefrontal Cortex in Schizophrenia During Hippocampal-Based Associative Memory. Front Syst Neurosci 2016; 10:32. [PMID: 27092063 PMCID: PMC4823313 DOI: 10.3389/fnsys.2016.00032] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/23/2016] [Indexed: 01/04/2023] Open
Abstract
Schizophrenia is a disorder characterized by brain network dysfunction, particularly during behavioral tasks that depend on frontal and hippocampal mechanisms. Here, we investigated network profiles of the regions of the frontal cortex during memory encoding and retrieval, phases of processing essential to associative memory. Schizophrenia patients (n = 12) and healthy control (HC) subjects (n = 10) participated in an established object-location associative memory paradigm that drives frontal-hippocampal interactions. Network profiles were modeled of both the dorsal prefrontal (dPFC) and the dorsal anterior cingulate cortex (dACC) as seeds using psychophysiological interaction analyses, a robust framework for investigating seed-based connectivity in specific task contexts. The choice of seeds was motivated by previous evidence of involvement of these regions during associative memory. Differences between patients and controls were evaluated using second-level analyses of variance (ANOVA) with seed (dPFC vs. dACC), group (patients vs. controls), and memory process (encoding and retrieval) as factors. Patients showed a pattern of exaggerated modulation by each of the dACC and the dPFC during memory encoding and retrieval. Furthermore, group by memory process interactions were observed within regions of the hippocampus. In schizophrenia patients, relatively diminished modulation during encoding was associated with increased modulation during retrieval. These results suggest a pattern of complex dysfunctional network signatures of critical forebrain regions in schizophrenia. Evidence of dysfunctional frontal-medial temporal lobe network signatures in schizophrenia is consistent with the illness' characterization as a disconnection syndrome.
Collapse
Affiliation(s)
- Eric A Woodcock
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of MedicineDetroit, MI, USA; Translational Neuroscience Program, Wayne State University School of MedicineDetroit, MI, USA
| | - Sunali Wadehra
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine Detroit, MI, USA
| | - Vaibhav A Diwadkar
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of MedicineDetroit, MI, USA; Translational Neuroscience Program, Wayne State University School of MedicineDetroit, MI, USA
| |
Collapse
|
9
|
Silverstein BH, Bressler SL, Diwadkar VA. Inferring the Dysconnection Syndrome in Schizophrenia: Interpretational Considerations on Methods for the Network Analyses of fMRI Data. Front Psychiatry 2016; 7:132. [PMID: 27536253 PMCID: PMC4971389 DOI: 10.3389/fpsyt.2016.00132] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 07/15/2016] [Indexed: 12/28/2022] Open
Abstract
Schizophrenia has long been considered one of the most intractable psychiatric conditions. Its etiology is likely polygenic, and its symptoms are hypothesized to result from complex aberrations in network-level neuronal activity. While easily identifiable by psychiatrists based on clear behavioral signs, the biological substrate of the disease remains poorly understood. Here, we discuss current trends and key concepts in the theoretical framework surrounding schizophrenia and critically discuss network approaches applied to neuroimaging data that can illuminate the correlates of the illness. We first consider a theoretical framework encompassing basic principles of brain function ranging from neural units toward perspectives of network function. Next, we outline the strengths and limitations of several fMRI-based analytic methodologies for assessing in vivo brain network function, including undirected and directed functional connectivity and effective connectivity. The underlying assumptions of each approach for modeling fMRI data are treated in some quantitative detail, allowing for assessment of the utility of each for generating inferences about brain networks relevant to schizophrenia. fMRI and the analyses of fMRI signals provide a limited, yet vibrant platform from which to test specific hypotheses about brain network dysfunction in schizophrenia. Carefully considered and applied connectivity measures have the power to illuminate loss or change of function at the network level, thus providing insight into the underlying neurobiology which gives rise to the emergent symptoms seen in the altered cognition and behavior of schizophrenia patients.
Collapse
Affiliation(s)
- Brian H Silverstein
- Department of Psychiatry and Behavioral Neurosciences, Brain Imaging Research Division, Wayne State University , Detroit, MI , USA
| | - Steven L Bressler
- Center for Complex Systems and Brain Sciences, Florida Atlantic University , Boca Raton, FL , USA
| | - Vaibhav A Diwadkar
- Department of Psychiatry and Behavioral Neurosciences, Brain Imaging Research Division, Wayne State University , Detroit, MI , USA
| |
Collapse
|
10
|
Rifkin-Graboi A, Kong L, Sim LW, Sanmugam S, Broekman BFP, Chen H, Wong E, Kwek K, Saw SM, Chong YS, Gluckman PD, Fortier MV, Pederson D, Meaney MJ, Qiu A. Maternal sensitivity, infant limbic structure volume and functional connectivity: a preliminary study. Transl Psychiatry 2015; 5:e668. [PMID: 26506054 PMCID: PMC4930120 DOI: 10.1038/tp.2015.133] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 07/02/2015] [Accepted: 07/22/2015] [Indexed: 11/30/2022] Open
Abstract
Mechanisms underlying the profound parental effects on cognitive, emotional and social development in humans remain poorly understood. Studies with nonhuman models suggest variations in parental care affect the limbic system, influential to learning, autobiography and emotional regulation. In some research, nonoptimal care relates to decreases in neurogenesis, although other work suggests early-postnatal social adversity accelerates the maturation of limbic structures associated with emotional learning. We explored whether maternal sensitivity predicts human limbic system development and functional connectivity patterns in a small sample of human infants. When infants were 6 months of age, 20 mother-infant dyads attended a laboratory-based observational session and the infants underwent neuroimaging at the same age. After considering age at imaging, household income and postnatal maternal anxiety, regression analyses demonstrated significant indirect associations between maternal sensitivity and bilateral hippocampal volume at six months, with the majority of associations between sensitivity and the amygdala demonstrating similar indirect, but not significant results. Moreover, functional analyses revealed direct associations between maternal sensitivity and connectivity between the hippocampus and areas important for emotional regulation and socio-emotional functioning. Sensitivity additionally predicted indirect associations between limbic structures and regions related to autobiographical memory. Our volumetric results are consistent with research indicating accelerated limbic development in response to early social adversity, and in combination with our functional results, if replicated in a larger sample, may suggest that subtle, but important, variations in maternal care influence neuroanatomical trajectories important to future cognitive and emotional functioning.
Collapse
Affiliation(s)
- A Rifkin-Graboi
- Integrative Neuroscience Program, Singapore Institute for Clinical Sciences, Singapore, Singapore,Integrative Neuroscience Program, Singapore Institute for Clinical Sciences, Brenner Centre for Molecular Medicine 30 Medical Drive, Singapore 117609, Singapore. E-mail:
| | - L Kong
- Department of Biomedical Engineering and Clinical Imaging Research Center, National University of Singapore, Singapore, Singapore
| | - L W Sim
- Integrative Neuroscience Program, Singapore Institute for Clinical Sciences, Singapore, Singapore
| | - S Sanmugam
- Integrative Neuroscience Program, Singapore Institute for Clinical Sciences, Singapore, Singapore
| | - B F P Broekman
- Integrative Neuroscience Program, Singapore Institute for Clinical Sciences, Singapore, Singapore,Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore, Singapore
| | - H Chen
- Department of Psychological Medicine, KK Women's and Children's Hospital, Duke-National University of Singapore, Singapore, Singapore
| | - E Wong
- Integrative Neuroscience Program, Singapore Institute for Clinical Sciences, Singapore, Singapore
| | - K Kwek
- Department of Maternal Fetal Medicine, KK Women's and Children's Hospital, Singapore, Singapore
| | - S-M Saw
- Department of Epidemiology, Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
| | - Y-S Chong
- Integrative Neuroscience Program, Singapore Institute for Clinical Sciences, Singapore, Singapore,Department of Obstetrics & Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, National University Health System, Singapore, Singapore
| | - P D Gluckman
- Human Development, Singapore Institute for Clinical Sciences, Singapore, Singapore,Liggins Institute, University of Auckland, Auckland, New Zealand
| | - M V Fortier
- Department of Diagnostic and Interventional Imaging, KK Women's and Children's Hospital, Singapore, Singapore
| | - D Pederson
- Department of Psychology, University of Western Ontario, London, Ontario, Canada
| | - M J Meaney
- Integrative Neuroscience Program, Singapore Institute for Clinical Sciences, Singapore, Singapore,Department of Neurosciences, Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada,Sackler Program for Epigenetics and Psychobiology, Douglas Mental Health University Institute, McGill University, Montreal, Quebec, Canada
| | - A Qiu
- Integrative Neuroscience Program, Singapore Institute for Clinical Sciences, Singapore, Singapore,Department of Biomedical Engineering and Clinical Imaging Research Center, National University of Singapore, Singapore, Singapore,Department of Biomedical Engineering, National University of Singapore, 9 Engineering Drive 1, Block EA #03-12, Singapore 117576, Singapore. E-mail:
| |
Collapse
|
11
|
Woodcock EA, White R, Diwadkar VA. The dorsal prefrontal and dorsal anterior cingulate cortices exert complementary network signatures during encoding and retrieval in associative memory. Behav Brain Res 2015; 290:152-60. [DOI: 10.1016/j.bbr.2015.04.050] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 04/23/2015] [Accepted: 04/28/2015] [Indexed: 01/10/2023]
|
12
|
Hutcheson NL, Sreenivasan KR, Deshpande G, Reid MA, Hadley J, White DM, Ver Hoef L, Lahti AC. Effective connectivity during episodic memory retrieval in schizophrenia participants before and after antipsychotic medication. Hum Brain Mapp 2014; 36:1442-57. [PMID: 25504918 DOI: 10.1002/hbm.22714] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 11/07/2014] [Accepted: 12/01/2014] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Impairment in episodic memory is one of the most robust findings in schizophrenia. Disruptions of fronto-temporal functional connectivity that could explain some aspects of these deficits have been reported. Recent work has identified abnormal hippocampal function in unmedicated patients with schizophrenia (SZ), such as increased metabolism and glutamate content that are not always seen in medicated SZ. For these reasons, we hypothesized that altered fronto-temporal connectivity might originate from the hippocampus and might be partially restored by antipsychotic medication. METHODS Granger causality methods were used to evaluate the effective connectivity between frontal and temporal regions in 21 unmedicated SZ and 20 matched healthy controls (HC) during performance of an episodic memory retrieval task. In 16 SZ, effective connectivity between these regions was evaluated before and after 1-week of antipsychotic treatment. RESULTS In HC, significant effective connectivity originating from the right hippocampus to frontal regions was identified. Compared to HC, unmedicated SZ showed significant altered fronto-temporal effective connectivity, including reduced right hippocampal to right medial frontal connectivity. After 1-week of antipsychotic treatment, connectivity more closely resembled the patterns observed in HC, including increased effective connectivity from the right hippocampus to frontal regions. CONCLUSIONS These results support the notion that memory disruption in schizophrenia might originate from hippocampal dysfunction and that medication restores some aspects of fronto-temporal dysconnectivity. Patterns of fronto-temporal connectivity could provide valuable biomarkers to identify new treatments for the symptoms of schizophrenia, including memory deficits.
Collapse
Affiliation(s)
- Nathan L Hutcheson
- Department of Psychiatry and Behavioral Neurobiology, The University of Alabama at Birmingham, Birmingham, Alabama
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Lückmann HC, Jacobs HI, Sack AT. The cross-functional role of frontoparietal regions in cognition: internal attention as the overarching mechanism. Prog Neurobiol 2014; 116:66-86. [DOI: 10.1016/j.pneurobio.2014.02.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 02/03/2014] [Accepted: 02/03/2014] [Indexed: 10/25/2022]
|