scholarly journals Hippocampal function in schizophrenia and bipolar disorder

2009 ◽  
Vol 40 (5) ◽  
pp. 761-770 ◽  
Author(s):  
J. Hall ◽  
H. C. Whalley ◽  
K. Marwick ◽  
J. McKirdy ◽  
J. Sussmann ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
Temporal Cortex ◽  
Memory Task ◽  
Blood Oxygen Level Dependent ◽  
Brain Regions ◽  
Blood Oxygen Level ◽  
The Face ◽  
Healthy Control ◽  
Patient Groups ◽  
And Function

BackgroundThe hippocampus plays a central role in memory formation. There is considerable evidence of abnormalities in hippocampal structure and function in schizophrenia, which may differentiate it from bipolar disorder. However, no previous studies have compared hippocampal activation in schizophrenia and bipolar disorder directly.MethodFifteen patients with schizophrenia, 14 patients with bipolar disorder and 14 healthy comparison subjects took part in the study. Subjects performed a face–name pair memory task during functional magnetic resonance imaging (fMRI). Differences in blood oxygen level-dependent (BOLD) activity were determined during encoding and retrieval of the face–name pairs.ResultsThe patient groups showed significant differences in hippocampal and prefrontal cortex (PFC) activation during face–name pair learning. During encoding, patients with schizophrenia showed decreased anterior hippocampal activation relative to subjects with bipolar disorder, whereas patients with bipolar disorder showed decreased dorsal PFC activation relative to patients with schizophrenia. During retrieval, patients with schizophrenia showed greater activation of the dorsal PFC than patients with bipolar disorder. Patients with schizophrenia also differed from healthy control subjects in the activation of several brain regions, showing impaired superior temporal cortex activation during encoding and greater dorsal PFC activation during retrieval. These effects were evident despite matched task performance.ConclusionsPatients with schizophrenia showed deficits in hippocampal activation during a memory task relative to patients with bipolar disorder. The disorders were further distinguished by differences in PFC activation. The results demonstrate that these disorders can distinguished at a group level using non-invasive neuroimaging.

scholarly journals Brain reactivity using fMRI to insomnia stimuli in insomnia patients with discrepancy between subjective and objective sleep

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Young-Bo Kim ◽  
Nambeom Kim ◽  
Jae Jun Lee ◽  
Seo-Eun Cho ◽  
Kyoung-Sae Na ◽  
...  
Keyword(s):  
Brain Activity ◽  
Blood Oxygen Level Dependent ◽  
Brain Regions ◽  
Cognitive Distortion ◽  
Sleep Diary ◽  
Bold Signal ◽  
Blood Oxygen Level ◽  
General Anxiety ◽  
Sleep Deficit ◽  
Perception Of Sleep

AbstractSubjective–objective discrepancy of sleep (SODS) might be related to the distorted perception of sleep deficit and hypersensitivity to insomnia-related stimuli. We investigated differences in brain activation to insomnia-related stimuli among insomnia patients with SODS (SODS group), insomnia patients without SODS (NOSODS group), and healthy controls (HC). Participants were evaluated for subjective and objective sleep using sleep diary and polysomnography. Functional magnetic resonance imaging was conducted during the presentation of insomnia-related (Ins), general anxiety-inducing (Gen), and neutral (Neu) stimuli. Brain reactivity to the contrast of Ins vs. Neu and Gen vs. Neu was compared among the SODS (n = 13), NOSODS (n = 15), and HC (n = 16) groups. In the SODS group compared to other groups, brain areas including the left fusiform, bilateral precuneus, right superior frontal gyrus, genu of corpus callosum, and bilateral anterior corona radiata showed significantly increased blood oxygen level dependent (BOLD) signal in the contrast of Ins vs. Neu. There was no brain region with significantly increased BOLD signal in the Gen vs. Neu contrast in the group comparisons. Increased brain activity to insomnia-related stimuli in several brain regions of the SODS group is likely due to these individuals being more sensitive to sleep-related threat and negative cognitive distortion toward insomnia.

Effective Connectivity During an Avoidance-Based Pavlovian-to-Instrumental Transfer Task

2021 ◽  
Author(s):  
Daniel Petrie ◽  
Sy-Miin Chow ◽  
Charles Geier
Keyword(s):  
Effective Connectivity ◽  
A Priori ◽  
Transfer Task ◽  
Blood Oxygen Level Dependent ◽  
Brain Regions ◽  
Response Patterns ◽  
Multiple Model ◽  
Hemodynamic Response Function ◽  
Blood Oxygen Level ◽  
Psychological Phenomena

Pavlovian-to-instrumental transfer (PIT) refers to a phenomenon whereby a classically conditioned stimulus (CS) impacts the motivational salience of instrumental behavior. We examined behavioral response patterns and functional magnetic resonance imaging (fMRI) based effective connectivity during an avoidance-based PIT task. Eleven participants (8 females; Mage = 28.2, SD = 2.8, range = 25-32 years) completed the task. Effective connectivity between a priori brain regions engaged during the task was determined using hemodynamic response function group iterative multiple model estimation (HRF-GIMME). Behaviorally, participants exhibited specific PIT, a CS previously associated with a reinforcing outcome increased instrumental responding directed at the same outcome. We did not find evidence for general PIT; a CS did not significantly increase instrumental responding towards a different but related outcome. Using HRF-GIMME, we recovered effective connectivity maps among corticostriatal circuits engaged during the task. Group-level paths revealed directional effects from left putamen to right insula and from right putamen to right cingulate. Importantly, a direct effect of specific PIT stimuli on blood-oxygen-level-dependent (BOLD) activity in the left putamen was found. Results provide initial evidence of effective connectivity in key brain regions in an avoidance-based PIT task network. This study adds to the literature studying PIT effects in humans and employing GIMME models to understand how psychological phenomena are supported in the brain.

scholarly journals The Organization and Operation of Inferior Temporal Cortex

2018 ◽  
Vol 4 (1) ◽  
pp. 381-402 ◽  
Author(s):  
Bevil R. Conway
Keyword(s):  
Scene Perception ◽  
Temporal Cortex ◽  
Spatial Relationship ◽  
Inferior Temporal Cortex ◽  
Future Research ◽  
Functional Responses ◽  
Form And Function ◽  
High Acuity ◽  
The Face ◽  
And Function

Inferior temporal cortex (IT) is a key part of the ventral visual pathway implicated in object, face, and scene perception. But how does IT work? Here, I describe an organizational scheme that marries form and function and provides a framework for future research. The scheme consists of a series of stages arranged along the posterior-anterior axis of IT, defined by anatomical connections and functional responses. Each stage comprises a complement of subregions that have a systematic spatial relationship. The organization of each stage is governed by an eccentricity template, and corresponding eccentricity representations across stages are interconnected. Foveal representations take on a role in high-acuity object vision (including face recognition); intermediate representations compute other aspects of object vision such as behavioral valence (using color and surface cues); and peripheral representations encode information about scenes. This multistage, parallel-processing model invokes an innately determined organization refined by visual experience that is consistent with principles of cortical development. The model is also consistent with principles of evolution, which suggest that visual cortex expanded through replication of retinotopic areas. Finally, the model predicts that the most extensively studied network within IT—the face patches—is not unique but rather one manifestation of a canonical set of operations that reveal general principles of how IT works.

scholarly journals Working memory networks and activation patterns in schizophrenia and bipolar disorder: comparison with healthy controls

2014 ◽  
Vol 204 (4) ◽  
pp. 290-298 ◽  
Author(s):  
Christine Lycke Brandt ◽  
Tom Eichele ◽  
Ingrid Melle ◽  
Kjetil Sundet ◽  
Andrés Server ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
Working Memory ◽  
Large Scale ◽  
Psychotic Disorders ◽  
Brain Networks ◽  
Memory Task ◽  
Control Group ◽  
Healthy Controls ◽  
Activation Patterns ◽  
Patient Groups

BackgroundSchizophrenia and bipolar disorder are severe mental disorders with overlapping genetic and clinical characteristics, including cognitive impairments. An important question is whether these disorders also have overlapping neuronal deficits.AimsTo determine whether large-scale brain networks associated with working memory, as measured with functional magnetic resonance imaging (fMRI), are the same in both schizophrenia and bipolar disorder, and how they differ from those in healthy individuals.MethodPatients with schizophrenia (n = 100) and bipolar disorder (n = 100) and a healthy control group (n = 100) performed a 2-back working memory task while fMRI data were acquired. The imaging data were analysed using independent component analysis to extract large-scale networks of task-related activations.ResultsSimilar working memory networks were activated in all groups. However, in three out of nine networks related to the experimental task there was a graded response difference in fMRI signal amplitudes, where patients with schizophrenia showed greater activation than those with bipolar disorder, who in turn showed more activation than healthy controls. Secondary analysis of the patient groups showed that these activation patterns were associated with history of psychosis and current elevated mood in bipolar disorder.ConclusionsThe same brain networks were related to working memory in schizophrenia, bipolar disorder and controls. However, some key networks showed a graded hyperactivation in the two patient groups, in line with a continuum of neuronal abnormalities across psychotic disorders.

scholarly journals A Theoretical Investigation of the Relationship between Structural Equation Modeling and Partial Correlation in Functional MRI Effective Connectivity

2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Guillaume Marrelec ◽  
Habib Benali
Keyword(s):  
Structural Equation Modeling ◽  
Structural Equation ◽  
Partial Correlation ◽  
Effective Connectivity ◽  
Real Data ◽  
Blood Oxygen Level Dependent ◽  
Brain Regions ◽  
Equation Modeling ◽  
Blood Oxygen Level ◽  
Partial Correlations

An important field of blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI) is the investigation of effective connectivity, that is, the actions that a given set of regions exert on one another. We recently proposed a data-driven method based on the partial correlation matrix that could provide some insight regarding the pattern of functional interaction between brain regions as represented by structural equation modeling (SEM). So far, the efficiency of this approach was mostly based on empirical evidence. In this paper, we provide theoretical fundaments explaining why and in what measure structural equation modeling and partial correlations are related. This gives better insight regarding what parts of SEM can be retrieved by partial correlation analysis and what remains inaccessible. We illustrate the different results with real data.

scholarly journals Amphetamine modulates brain signal variability and working memory in younger and older adults

2015 ◽  
Vol 112 (24) ◽  
pp. 7593-7598 ◽  
Author(s):  
Douglas D. Garrett ◽  
Irene E. Nagel ◽  
Claudia Preuschhof ◽  
Agnieszka Z. Burzynska ◽  
Janina Marchner ◽  
...  
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Cognitive Aging ◽  
Memory Task ◽  
Blood Oxygen Level Dependent ◽  
Brain Dynamics ◽  
Blood Oxygen Level ◽  
Age Related ◽  
And Performance ◽  
Signal Variability

Better-performing younger adults typically express greater brain signal variability relative to older, poorer performers. Mechanisms for age and performance-graded differences in brain dynamics have, however, not yet been uncovered. Given the age-related decline of the dopamine (DA) system in normal cognitive aging, DA neuromodulation is one plausible mechanism. Hence, agents that boost systemic DA [such as d-amphetamine (AMPH)] may help to restore deficient signal variability levels. Furthermore, despite the standard practice of counterbalancing drug session order (AMPH first vs. placebo first), it remains understudied how AMPH may interact with practice effects, possibly influencing whether DA up-regulation is functional. We examined the effects of AMPH on functional-MRI–based blood oxygen level-dependent (BOLD) signal variability (SDBOLD) in younger and older adults during a working memory task (letter n-back). Older adults expressed lower brain signal variability at placebo, but met or exceeded young adult SDBOLD levels in the presence of AMPH. Drug session order greatly moderated change–change relations between AMPH-driven SDBOLD and reaction time means (RTmean) and SDs (RTSD). Older adults who received AMPH in the first session tended to improve in RTmean and RTSD when SDBOLD was boosted on AMPH, whereas younger and older adults who received AMPH in the second session showed either a performance improvement when SDBOLD decreased (for RTmean) or no effect at all (for RTSD). The present findings support the hypothesis that age differences in brain signal variability reflect aging-induced changes in dopaminergic neuromodulation. The observed interactions among AMPH, age, and session order highlight the state- and practice-dependent neurochemical basis of human brain dynamics.

scholarly journals Finger representations in primary somatosensory cortex are modulated during vibrotactile working memory

2021 ◽  
Author(s):  
Finn Rabe ◽  
Sanne Kikkert ◽  
Nicole Wenderoth
Keyword(s):  
Working Memory ◽  
Somatosensory Cortex ◽  
Pattern Analysis ◽  
Blood Oxygen Level Dependent ◽  
Brain Regions ◽  
Delay Period ◽  
Blood Oxygen Level ◽  
Secondary Somatosensory Cortex ◽  
Analysis Technique ◽  
Hand Area

It is well-established that vibrotactile stimulations elicit Blood-oxygen-level-dependent (BOLD) responses in somatotopically organized brain regions. Whether these somatotopic maps are modulated by working memory (WM) is still unknown. In our WM experiment, participants had to compare frequencies that were separated by a delay period. Vibrotactile stimuli were sequentially applied to either their right index or little finger. Using functional MRI, we investigated whether vibrotactile WM modulated neural activity in primary somatosensory (S1), an area that is known to contain individual finger representations. Our mass-univariate results revealed the well-described network of brain regions involved in WM. Interestingly, our mass-univariate results did not demonstrate S1 to be part of this network. However, when we parametrically modulated the time-binned regressors in our GLM we found that the delay activity in S1 and secondary somatosensory cortex (S2) was reflected in a U-shaped manner. Using multi-voxel pattern analysis (MVPA), an analysis technique that is more sensitive to subtle activity differences, we found finger-specific patterns of activation in the S1 hand area during the WM delay period. These results indicate that processes underlying WM modulate finger-specific representations during our discrimination task.

scholarly journals Complementary Maps for Location and Environmental Structure in CA1 and Subiculum

2021 ◽  
Author(s):  
Jacob M Olson ◽  
Alexander B Johnson ◽  
Lillian Chang ◽  
Emily L Tao ◽  
Xuefei Wang ◽  
...  
Keyword(s):  
Spatial Information ◽  
Dynamic Range ◽  
Spatial Working Memory ◽  
Activity Patterns ◽  
Memory Task ◽  
Structural Features ◽  
Brain Regions ◽  
Unique Role ◽  
Path Structure ◽  
And Function

AbstractThe dorsal subiculum lies among a network of interconnected brain regions that collectively map multiple spatial and orientational relationships between an organism and the boundaries and pathways composing its environment. A unique role of the subiculum in spatial information processing has yet to be defined despite reports of small neuron subpopulations that encode relationships to specific boundaries, axes of travel, or locations. We examined the activity patterns among populations of subiculum neurons during performance of a spatial working memory task performed within a complex network of interconnected pathways. Compared to neurons in hippocampal sub-region CA1, a major source of its afferents, subiculum neurons were far more likely to exhibit multiple firing fields at locations that were analogous with respect to path structure and function. Subiculum neuron populations were also found to exhibit a greater dynamic range in scale of spatial representation and for persistent patterns of spiking activity to be aligned to transitions between maze segments. Together, the findings indicate that the subiculum plays a unique role in spatial mapping, one that complements the location-specific firing of CA1 neurons with the encoding of emergent and recurring structural features of a complex path network.

Visuospatial planning in unmedicated major depressive disorder and bipolar disorder: distinct and common neural correlates

2016 ◽  
Vol 46 (11) ◽  
pp. 2313-2328 ◽  
Author(s):  
M. M. Rive ◽  
M. W. J. Koeter ◽  
D. J. Veltman ◽  
A. H. Schene ◽  
H. G. Ruhé
Keyword(s):  
Bipolar Disorder ◽  
Major Depressive Disorder ◽  
Executive Functioning ◽  
Depressive Disorder ◽  
Blood Oxygen Level Dependent ◽  
Blood Oxygen Level ◽  
Everyday Functioning ◽  
Major Depressive ◽  
State Dependent ◽  
Post Hoc

BackgroundCognitive impairments are an important feature of both remitted and depressed major depressive disorder (MDD) and bipolar disorder (BD). In particular, deficits in executive functioning may hamper everyday functioning. Identifying the neural substrates of impaired executive functioning would improve our understanding of the pathophysiology underlying these disorders, and may eventually aid in discriminating between MDD and BD, which is often difficult during depression and remission. To date, mostly medicated MDD and BD subjects have been investigated, which may have influenced results. Therefore, we investigated executive functioning in medication-free depressed and remitted MDD and BD subjects.MethodWe used the Tower of London (ToL) visuospatial planning task to assess behavioural performance and blood oxygen-level dependent responses in 35 healthy controls, 21 remitted MDD, 23 remitted BD, 19 depressed MDD and nine depressed BD subjects.ResultsVisuospatial planning per se was associated with increased frontostriatal activity in depressed BD compared to depressed MDD. In addition, post-hoc analyses indicated that visuospatial planning load was associated with increased parietal activity in depressed compared to remitted subjects, and BD compared to MDD subjects. Task performance did not significantly differ between groups.ConclusionsMore severely affected, medication-free mood disorder patients require greater parietal activity to perform in visuospatial planning, which may be compensatory to maintain relatively normal performance. State-dependent frontostriatal hyperactivity during planning may be a specific BD characteristic, providing clues for further characterization of differential pathophysiology in MDD v. BD. This could potentially provide a biomarker to aid in the differentiation of these disorders.

scholarly journals Training conquers multitasking costs by dividing task representations in the frontoparietal-subcortical system

2015 ◽  
Vol 112 (46) ◽  
pp. 14372-14377 ◽  
Author(s):  
K. G. Garner ◽  
Paul E. Dux
Keyword(s):  
Blood Oxygen Level Dependent ◽  
Brain Regions ◽  
Control Group ◽  
Blood Oxygen ◽  
Response Patterns ◽  
Resonance Imaging ◽  
Blood Oxygen Level ◽  
Training Outcomes ◽  
Multiple Tasks ◽  
Task Representations

Negotiating the information-rich sensory world often requires the concurrent management of multiple tasks. Despite this requirement, humans are thought to be poor at multitasking because of the processing limitations of frontoparietal and subcortical (FP-SC) brain regions. Although training is known to improve multitasking performance, it is unknown how the FP-SC system functionally changes to support improved multitasking. To address this question, we characterized the FP-SC changes that predict training outcomes using an individual differences approach. Participants (n = 100) performed single and multiple tasks in pre- and posttraining magnetic resonance imaging (fMRI) sessions interspersed by either a multitasking or an active-control training regimen. Multivoxel pattern analyses (MVPA) revealed that training induced multitasking improvements were predicted by divergence in the FP-SC blood oxygen level-dependent (BOLD) response patterns to the trained tasks. Importantly, this finding was only observed for participants who completed training on the component (single) tasks and their combination (multitask) and not for the control group. Therefore, the FP-SC system supports multitasking behavior by segregating constituent task representations.

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