scholarly journals Occipital Cortex of Blind Individuals Is Functionally Coupled with Executive Control Areas of Frontal Cortex

2015 ◽  
Vol 27 (8) ◽  
pp. 1633-1647 ◽  
Author(s):  
Ben Deen ◽  
Rebecca Saxe ◽  
Marina Bedny
Keyword(s):  
Working Memory ◽  
Functional Connectivity ◽  
Sentence Comprehension ◽  
Memory Load ◽  
Memory Task ◽  
Occipital Cortex ◽  
Memory Systems ◽  
Functional Responses ◽  
Congenitally Blind ◽  
Blind Individuals

In congenital blindness, the occipital cortex responds to a range of nonvisual inputs, including tactile, auditory, and linguistic stimuli. Are these changes in functional responses to stimuli accompanied by altered interactions with nonvisual functional networks? To answer this question, we introduce a data-driven method that searches across cortex for functional connectivity differences across groups. Replicating prior work, we find increased fronto-occipital functional connectivity in congenitally blind relative to blindfolded sighted participants. We demonstrate that this heightened connectivity extends over most of occipital cortex but is specific to a subset of regions in the inferior, dorsal, and medial frontal lobe. To assess the functional profile of these frontal areas, we used an n-back working memory task and a sentence comprehension task. We find that, among prefrontal areas with overconnectivity to occipital cortex, one left inferior frontal region responds to language over music. By contrast, the majority of these regions responded to working memory load but not language. These results suggest that in blindness occipital cortex interacts more with working memory systems and raise new questions about the function and mechanism of occipital plasticity.

Working memory training in congenitally blind individuals results in an integration of occipital cortex in functional networks

2018 ◽  
Vol 348 ◽  
pp. 31-41 ◽  
Author(s):  
Helene Gudi-Mindermann ◽  
Johanna M. Rimmele ◽  
Guido Nolte ◽  
Patrick Bruns ◽  
Andreas K. Engel ◽  
...  
Keyword(s):  
Working Memory ◽  
Occipital Cortex ◽  
Working Memory Training ◽  
Memory Training ◽  
Functional Networks ◽  
Congenitally Blind ◽  
Blind Individuals

scholarly journals Reduced Left Lateralization of Language in Congenitally Blind Individuals

2017 ◽  
Vol 29 (1) ◽  
pp. 65-78 ◽  
Author(s):  
Connor Lane ◽  
Shipra Kanjlia ◽  
Hilary Richardson ◽  
Anne Fulton ◽  
Akira Omaki ◽  
...  
Keyword(s):  
Language Processing ◽  
Reading Ability ◽  
Sentence Comprehension ◽  
Memory Task ◽  
Developmental Factors ◽  
Two Samples ◽  
Congenitally Blind ◽  
Cortical Regions ◽  
Blind Individuals ◽  
Language Network

Language processing depends on a left-lateralized network of frontotemporal cortical regions. This network is remarkably consistent across individuals and cultures. However, there is also evidence that developmental factors, such as delayed exposure to language, can modify this network. Recently, it has been found that, in congenitally blind individuals, the typical frontotemporal language network expands to include parts of “visual” cortices. Here, we report that blindness is also associated with reduced left lateralization in frontotemporal language areas. We analyzed fMRI data from two samples of congenitally blind adults (n = 19 and n = 13) and one sample of congenitally blind children (n = 20). Laterality indices were computed for sentence comprehension relative to three different control conditions: solving math equations (Experiment 1), a memory task with nonwords (Experiment 2), and a “does this come next?” task with music (Experiment 3). Across experiments and participant samples, the frontotemporal language network was less left-lateralized in congenitally blind than in sighted individuals. Reduction in left lateralization was not related to Braille reading ability or amount of occipital plasticity. Notably, we observed a positive correlation between the lateralization of frontotemporal cortex and that of language-responsive occipital areas in blind individuals. Blind individuals with right-lateralized language responses in frontotemporal cortices also had right-lateralized occipital responses to language. Together, these results reveal a modified neurobiology of language in blindness. Our findings suggest that, despite its usual consistency across people, the neurobiology of language can be modified by nonlinguistic experiences.

Abnormal prefrontal activity subserving attentional control of emotion in remitted depressed patients during a working memory task with emotional distracters

2011 ◽  
Vol 42 (1) ◽  
pp. 29-40 ◽  
Author(s):  
R. Kerestes ◽  
C. D. Ladouceur ◽  
S. Meda ◽  
P. J. Nathan ◽  
H. P. Blumberg ◽  
...  
Keyword(s):  
Working Memory ◽  
Attentional Control ◽  
Memory Load ◽  
Memory Task ◽  
Region Of Interest ◽  
Blood Oxygen Level Dependent ◽  
Emotional Information ◽  
Working Memory Load ◽  
Depressed Patients ◽  
The Right

BackgroundPatients with major depressive disorder (MDD) show deficits in processing of facial emotions that persist beyond recovery and cessation of treatment. Abnormalities in neural areas supporting attentional control and emotion processing in remitted depressed (rMDD) patients suggests that there may be enduring, trait-like abnormalities in key neural circuits at the interface of cognition and emotion, but this issue has not been studied systematically.MethodNineteen euthymic, medication-free rMDD patients (mean age 33.6 years; mean duration of illness 34 months) and 20 age- and gender-matched healthy controls (HC; mean age 35.8 years) performed the Emotional Face N-Back (EFNBACK) task, a working memory task with emotional distracter stimuli. We used blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to measure neural activity in the dorsolateral (DLPFC) and ventrolateral prefrontal cortex (VLPFC), orbitofrontal cortex (OFC), ventral striatum and amygdala, using a region of interest (ROI) approach in SPM2.ResultsrMDD patients exhibited significantly greater activity relative to HC in the left DLPFC [Brodmann area (BA) 9/46] in response to negative emotional distracters during high working memory load. By contrast, rMDD patients exhibited significantly lower activity in the right DLPFC and left VLPFC compared to HC in response to positive emotional distracters during high working memory load. These effects occurred during accurate task performance.ConclusionsRemitted depressed patients may continue to exhibit attentional biases toward negative emotional information, reflected by greater recruitment of prefrontal regions implicated in attentional control in the context of negative emotional information.

scholarly journals Declined functional connectivity of white matter during rest and working memory tasks associates with cognitive impairments in schizophrenia

2020 ◽  
Author(s):  
Yurui Gao ◽  
Muwei Li ◽  
Anna S Huang ◽  
Adam W Anderson ◽  
Zhaohua Ding ◽  
...  
Keyword(s):  
Working Memory ◽  
White Matter ◽  
Functional Connectivity ◽  
Resting State ◽  
Spatial Working Memory ◽  
Cognitive Impairments ◽  
Memory Task ◽  
Brain Network ◽  
Blood Oxygenation ◽  
Cerebral Peduncle

BACKGROUND: Schizophrenia, characterized by cognitive impairments, arises from a disturbance of brain network. Pathological changes in white matter (WM) have been indicated as playing a role in disturbing neural connectivity in schizophrenia. However, deficits of functional connectivity (FC) in individual WM bundles in schizophrenia have never been explored; neither have cognitive correlates with those deficits. METHODS: Resting-state and spatial working memory task fMRI images were acquired on 67 healthy subjects and 84 patients with schizophrenia. The correlations in blood-oxygenation-level-dependent (BOLD) signals between 46 WM and 82 gray matter regions were quantified, analyzed and compared between groups under three scenarios (i.e., resting state, retention period and entire time of a spatial working memory task). Associations of FC in WM with cognitive assessment scores were evaluated for three scenarios. RESULTS: FC deficits were significant (p<.05) in external capsule, cingulum, uncinate fasciculus, genu and body of corpus callosum under all three scenarios. Deficits were also present in the anterior limb of the internal capsule and cerebral peduncle in task scenario. Decreased FCs in specific WM bundles associated significantly (p<.05) with cognitive impairments in working memory, processing speed and/or cognitive control. CONCLUSIONS: Decreases in FC are evident in several WM bundles in patients with schizophrenia and are significantly associated with cognitive impairments during both rest and working memory tasks. Furthermore, working memory tasks expose FC deficits in more WM bundles and more cognitive associates in schizophrenia than resting state does.

scholarly journals Changes in thalamocortical connectivity as a potential mechanism of cross-modal plasticity in congenitally blind individuals

2018 ◽  
Author(s):  
Theo Marins ◽  
Maite Russo ◽  
Erika Rodrigues ◽  
jorge Moll ◽  
Daniel Felix ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Cortical Thickness ◽  
Visual Information ◽  
Brain Plasticity ◽  
Temporal Cortex ◽  
Occipital Cortex ◽  
Brain Structures ◽  
Congenitally Blind ◽  
Blind Individuals ◽  
Neuroimaging Techniques

ABSTRACTEvidence of cross-modal plasticity in blind individuals has been reported over the past decades showing that non-visual information is carried and processed by classical “visual” brain structures. This feature of the blind brain makes it a pivotal model to explore the limits and mechanisms of brain plasticity. However, despite recent efforts, the structural underpinnings that could explain cross-modal plasticity in congenitally blind individuals remain unclear. Using advanced neuroimaging techniques, we mapped the thalamocortical connectivity and assessed cortical thickness and integrity of white matter of congenitally blind individuals and sighted controls to test the hypothesis that aberrant thalamocortical pattern of connectivity can pave the way for cross-modal plasticity. We described a direct occipital takeover by the temporal projections from the thalamus, which would carry non-visual information (e.g. auditory) to the visual cortex in congenitally blinds. In addition, the amount of thalamo-occipital connectivity correlated with the cortical thickness of primary visual cortex (V1), supporting a probably common (or related) reorganization phenomena. Our results suggest that aberrant thalamocortical connectivity as one possible mechanism of cross-modal plasticity in blinds, with potential impact on cortical thickness of V1.SIGNIFICANT STATEMENTCongenitally blind individuals often develop greater abilities on spared sensory modalities, such as increased acuity in auditory discrimination and voice recognition, when compared to sighted controls. These functional gains have been shown to rely on ‘visual’ cortical areas of the blind brain, characterizing the phenomenon of cross-modal plasticity. However, its anatomical underpinnings in humans have been unsuccessfully pursued for decades. Recent advances of non-invasive neuroimaging techniques allowed us to test the hypothesis of abnormal thalamocortical connectivity in congenitally blinds. Our results showed an expansion of the thalamic connections to the temporal cortex over those that project to the occipital cortex, which may explain, the cross-talk between the visual and auditory systems in congenitally blind individuals.

scholarly journals Contralateral Delay Activity Tracks Fluctuations in Working Memory Performance

2018 ◽  
Vol 30 (9) ◽  
pp. 1229-1240 ◽  
Author(s):  
Kirsten C. S. Adam ◽  
Matthew K. Robison ◽  
Edward K. Vogel
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Memory Load ◽  
Memory Performance ◽  
Memory Task ◽  
Memory Storage ◽  
Alpha Power ◽  
Working Memory Load ◽  
Contralateral Delay Activity ◽  
Trial Performance

Neural measures of working memory storage, such as the contralateral delay activity (CDA), are powerful tools in working memory research. CDA amplitude is sensitive to working memory load, reaches an asymptote at known behavioral limits, and predicts individual differences in capacity. An open question, however, is whether neural measures of load also track trial-by-trial fluctuations in performance. Here, we used a whole-report working memory task to test the relationship between CDA amplitude and working memory performance. If working memory failures are due to decision-based errors and retrieval failures, CDA amplitude would not differentiate good and poor performance trials when load is held constant. If failures arise during storage, then CDA amplitude should track both working memory load and trial-by-trial performance. As expected, CDA amplitude tracked load (Experiment 1), reaching an asymptote at three items. In Experiment 2, we tracked fluctuations in trial-by-trial performance. CDA amplitude was larger (more negative) for high-performance trials compared with low-performance trials, suggesting that fluctuations in performance were related to the successful storage of items. During working memory failures, participants oriented their attention to the correct side of the screen (lateralized P1) and maintained covert attention to the correct side during the delay period (lateralized alpha power suppression). Despite the preservation of attentional orienting, we found impairments consistent with an executive attention theory of individual differences in working memory capacity; fluctuations in executive control (indexed by pretrial frontal theta power) may be to blame for storage failures.

Effects of a secondary task and working memory load on multisensory hand position

2012 ◽  
Vol 25 (0) ◽  
pp. 58
Author(s):  
Katrina Quinn ◽  
Francia Acosta-Saltos ◽  
Jan W. de Fockert ◽  
Charles Spence ◽  
Andrew J. Bremner
Keyword(s):  
Working Memory ◽  
Visual Information ◽  
Secondary Task ◽  
Memory Load ◽  
Memory Task ◽  
Hand Position ◽  
Working Memory Load ◽  
The Individual ◽  
Task Conditions ◽  
Relative Weighting

Information about where our hands are arises from different sensory modalities; chiefly proprioception and vision. These inputs differ in variability from situation to situation (or task to task). According to the idea of ‘optimal integration’, the information provided by different sources is combined in proportion to their relative reliabilities, thus maximizing the reliability of the combined estimate. It is uncertain whether optimal multisensory integration of multisensory contributions to limb position requires executive resources. If so, then it should be possible to observe effects of secondary task performance and/or working memory load (WML) on the relative weighting of the senses under conditions of crossmodal sensory conflict. Alternatively, an integrated signal may be affected by upstream influences of WML or a secondary task on the reliabilities of the individual sensory inputs. We examine these possibilities in two experiments which examine effects of WML on reaching tasks in which bisensory visual-proprioceptive (Exp. 1), and unisensory proprioceptive (Exp. 2) cues to hand position are provided. WML increased visual capture under conditions of visual-proprioceptive conflict, regardless of the direction of visual-proprioceptive conflict, and the degree of load imposed. This indicates that task-switching (rather than WML load) leads to an increased reliance on visual information regardless of its task-specific reliability (Exp. 1). This could not be explained due to an increase in the variability of proprioception under secondary working memory task conditions (Exp. 2). We conclude that executive resources are involved in the relative weighting of visual and proprioceptive cues to hand position.

scholarly journals Working Memory and the Suppression of Reflexive Saccades

2002 ◽  
Vol 14 (1) ◽  
pp. 95-103 ◽  
Author(s):  
Jason P. Mitchell ◽  
C. Neil Macrae ◽  
Iain D. Gilchrist
Keyword(s):  
Working Memory ◽  
Memory Load ◽  
Critical Role ◽  
Memory Task ◽  
Behavioral Responses ◽  
Error Rates ◽  
Antisaccade Task ◽  
Working Memory Load ◽  
Reflexive Saccades ◽  
Back Task

Conscious behavioral intentions can frequently fail under conditions of attentional depletion. In attempting to trace the cognitive origin of this effect, we hypothesized that failures of action control—specifically, oculomotor movement—can result from the imposition of fronto-executive load. To evaluate this prediction, participants performed an antisaccade task while simultaneously completing a working-memory task that is known to make variable demands on prefrontal processes (n-back task, see Jonides et al., 1997). The results of two experiments are reported. As expected, antisaccade error rates were increased in accordance with the fronto-executive demands of the n-back task (Experiment 1). In addition, the debilitating effects of working-memory load were restricted to the inhibitory component of the antisaccade task (Experiment 2). These findings corroborate the view that working memory operations play a critical role in the suppression of prepotent behavioral responses.

Relation of working memory to off-line and real-time sentence processing in children with specific language impairment

2000 ◽  
Vol 21 (1) ◽  
pp. 117-148 ◽  
Author(s):  
JAMES W. MONTGOMERY
Keyword(s):  
Working Memory ◽  
Real Time ◽  
Sentence Processing ◽  
Language Impairment ◽  
Specific Language Impairment ◽  
Sentence Comprehension ◽  
Memory Task ◽  
Load Condition ◽  
Specific Language ◽  
Processing Task

In this study we examined the influence of working memory on the off-line and real-time sentence comprehension/processing of children with specific language impairment (SLI). A total of 12 children with SLI, 12 normally developing children matched for chronological age (CA), and 12 children matched for receptive syntax (RS) completed three tasks. In the working memory task, children recalled as many words as possible under three processing load conditions varying in the number of mental operations (i.e., no load, single load, dual load). In the off-line comprehension task, children listened to linguistically nonredundant and redundant sentences. In the real-time sentence processing task, children monitored sentences for the occurrence of a target word appearing at the beginning, middle, or end of a test sentence and pushed a response pad as quickly as possible upon hearing the target. In the memory task, SLI children recalled fewer words in the dual-load condition relative to CA peers, who showed no condition effect. The SLI and RS groups performed similarly overall; however, both groups recalled fewer words in the dual-load condition than in the other conditions. In the off-line task, the SLI group comprehended fewer sentences of both types relative to the CA controls and fewer redundant sentences relative to themselves and to the RS controls. A significant correlation between working memory and sentence comprehension was found for the SLI group and control groups. For the on-line task, between-group analyses revealed that the SLI group yielded an overall slower word recognition reaction time than the CA and RS groups. Working memory and sentence processing were not correlated for any group. Results were interpreted to suggest that SLI children have a more limited functional working memory capacity than their CA peers. Children with SLI also appear to have greater difficulty managing their working memory resources relative to both age peers and younger children when performing a conventional off-line sentence comprehension task but not a real-time sentence processing task.

scholarly journals Learning to suppress a distractor is not affected by working memory load

2019 ◽  
Vol 27 (1) ◽  
pp. 96-104 ◽  
Author(s):  
Ya Gao ◽  
Jan Theeuwes
Keyword(s):  
Working Memory ◽  
High Probability ◽  
Spatial Working Memory ◽  
Memory Load ◽  
Working Memory Capacity ◽  
Memory Task ◽  
Automatic Process ◽  
Long Term Memory ◽  
Working Memory Load ◽  
Statistical Regularities

AbstractWhere and what we attend to is not only determined by our current goals but also by what we have encountered in the past. Recent studies have shown that people learn to extract statistical regularities in the environment resulting in attentional suppression of high-probability distractor locations, effectively reducing capture by a distractor. Here, we asked whether this statistical learning is dependent on working memory resources. The additional singleton task in which one location was more likely to contain a distractor was combined with a concurrent visual working memory task (Experiment 1) and a spatial working memory task (Experiment 2). The result showed that learning to suppress this high-probability location was not at all affected by working memory load. We conclude that learning to suppress a location is an implicit and automatic process that does not rely on visual or spatial working memory capacity, nor on executive control resources. We speculate that extracting regularities from the environment likely relies on long-term memory processes.

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