scholarly journals Testing Conclusions From Functional Imaging of Working Memory with Data From Acute Stroke

2007 ◽  
Vol 18 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Lisa E. Philipose ◽  
Hannah Alphs ◽  
Vivek Prabhakaran ◽  
Argye E. Hillis
Keyword(s):  
Working Memory ◽  
Acute Stroke ◽  
Functional Imaging ◽  
Right Hemisphere ◽  
Spatial Working Memory ◽  
Verbal Working Memory ◽  
Stroke Patients ◽  
Imaging Results ◽  
Cortical Stroke ◽  
The Right

Functional imaging studies indicate that the left hemisphere mediates verbal working memory, while the right hemisphere mediates both verbal and spatial working memory. We evaluated acute stroke patients with working memory tests and imaging to identify whether unilateral dysfunction causes deficits in spatial and/or verbal working memory deficits. While left cortical stroke patients had verbal working memory impairments (p< 0.003), right cortical stroke patients had both verbal (p< 0.007) and spatial working memory (p< 0.03) impairments, confirming functional imaging results. Patients with transient ischemic stroke and patients with non-cortical stroke did not have significant deficits in working memory in either modality.

scholarly journals Validating Age-Related Functional Imaging Changes in Verbal Working Memory with Acute Stroke

2011 ◽  
Vol 24 (3) ◽  
pp. 187-199 ◽  
Author(s):  
Timothy B. Meier ◽  
Lin Naing ◽  
Lisa E. Thomas ◽  
Veena A. Nair ◽  
Argye E. Hillis ◽  
...  
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Acute Stroke ◽  
Functional Imaging ◽  
Memory Task ◽  
Recognition Task ◽  
Verbal Working Memory ◽  
Brain Regions ◽  
Stroke Patients ◽  
Younger Adults

Functional imaging studies consistently find that older adults recruit bilateral brain regions in cognitive tasks that are strongly lateralized in younger adults, a characterization known as the Hemispheric Asymmetry Reduction in Older Adults model. While functional imaging displays what brain areas are active during tasks, it cannot demonstrate what brain regions are necessary for task performance. We used behavioral data from acute stroke patients to test the hypothesis that older adults need both hemispheres for a verbal working memory task that is predominantly left-lateralized in younger adults. Right-handed younger (age ≥ 50,n= 7) and older adults (age > 50,n= 21) with acute unilateral stroke, as well as younger (n= 6) and older (n= 13) transient ischemic attack (TIA) patients, performed a self-paced verbal item-recognition task. Older patients with stroke to either hemisphere had a higher frequency of deficits in the verbal working memory task compared to older TIA patients. Additionally, the deficits in older stroke patients were mainly in retrieval time while the deficits in younger stroke patients were mainly in accuracy. These data suggest that bihemispheric activity is necessary for older adults to successfully perform a verbal working memory task.

scholarly journals Are visual working memory and episodic memory distinct processes? Insight from stroke patients by lesion-symptom mapping

2021 ◽  
Author(s):  
Selma Lugtmeijer ◽  
◽  
Linda Geerligs ◽  
Frank Erik de Leeuw ◽  
Edward H. F. de Haan ◽  
...  
Keyword(s):  
Working Memory ◽  
Episodic Memory ◽  
Visual Working Memory ◽  
Visual Memory ◽  
Right Hemisphere ◽  
Memory Task ◽  
Stroke Patients ◽  
Lesion Symptom Mapping ◽  
Criterion Setting ◽  
The Right

AbstractWorking memory and episodic memory are two different processes, although the nature of their interrelationship is debated. As these processes are predominantly studied in isolation, it is unclear whether they crucially rely on different neural substrates. To obtain more insight in this, 81 adults with sub-acute ischemic stroke and 29 elderly controls were assessed on a visual working memory task, followed by a surprise subsequent memory test for the same stimuli. Multivariate, atlas- and track-based lesion-symptom mapping (LSM) analyses were performed to identify anatomical correlates of visual memory. Behavioral results gave moderate evidence for independence between discriminability in working memory and subsequent memory, and strong evidence for a correlation in response bias on the two tasks in stroke patients. LSM analyses suggested there might be independent regions associated with working memory and episodic memory. Lesions in the right arcuate fasciculus were more strongly associated with discriminability in working memory than in subsequent memory, while lesions in the frontal operculum in the right hemisphere were more strongly associated with criterion setting in subsequent memory. These findings support the view that some processes involved in working memory and episodic memory rely on separate mechanisms, while acknowledging that there might also be shared processes.

scholarly journals The role of prefrontal cortex in working memory: examining the contents of consciousness

1998 ◽  
Vol 353 (1377) ◽  
pp. 1819-1828 ◽  
Author(s):  
◽  
S. M. Courtney ◽  
L. Petit ◽  
J. V. Haxby ◽  
L. G. Ungerleider
Keyword(s):  
Working Memory ◽  
Prefrontal Cortex ◽  
Visual Processing ◽  
Right Hemisphere ◽  
Functional Organization ◽  
Spatial Working Memory ◽  
Domain Specificity ◽  
Long Term Memory ◽  
Present Evidence ◽  
The Right

Working memory enables us to hold in our ‘mind's eye’ the contents of our conscious awareness, even in the absence of sensory input, by maintaining an active representation of information for a brief period of time. In this review we consider the functional organization of the prefrontal cortex and its role in this cognitive process. First, we present evidence from brain–imaging studies that prefrontal cortex shows sustained activity during the delay period of visual working memory tasks, indicating that this cortex maintains on–line representations of stimuli after they are removed from view. We then present evidence for domain specificity within frontal cortex based on the type of information, with object working memory mediated by more ventral frontal regions and spatial working memory mediated by more dorsal frontal regions. We also propose that a second dimension for domain specificity within prefrontal cortex might exist for object working memory on the basis of the type of representation, with analytic representations maintained preferentially in the left hemisphere and image–based representations maintained preferentially in the right hemisphere. Furthermore, we discuss the possibility that there are prefrontal areas brought into play during the monitoring and manipulation of information in working memory in addition to those engaged during the maintenance of this information. Finally, we consider the relationship of prefrontal areas important for working memory, both to posterior visual processing areas and to prefrontal areas associated with long–term memory.

scholarly journals Auditory Hallucinations in Acute Stroke

2005 ◽  
Vol 16 (4) ◽  
pp. 211-216 ◽  
Author(s):  
Yair Lampl ◽  
Mordechai Lorberboym ◽  
Ronit Gilad ◽  
Mona Boaz ◽  
Menachem Sadeh
Keyword(s):  
Acute Stroke ◽  
Cross Sectional Study ◽  
Auditory Hallucinations ◽  
Stroke Patients ◽  
Cross Sectional ◽  
Ischemic Lesion ◽  
Cortical Stroke ◽  
The Right ◽  
The Brain

Auditory hallucinations are uncommon phenomena which can be directly caused by acute stroke, mostly described after lesions of the brain stem, very rarely reported after cortical strokes. The purpose of this study is to determine the frequency of this phenomenon. In a cross sectional study, 641 stroke patients were followed in the period between 1996–2000. Each patient underwent comprehensive investigation and follow-up. Four patients were found to have post cortical stroke auditory hallucinations. All of them occurred after an ischemic lesion of the right temporal lobe. After no more than four months, all patients were symptom-free and without therapy. The fact the auditory hallucinations may be of cortical origin must be taken into consideration in the treatment of stroke patients. The phenomenon may be completely reversible after a couple of months.

scholarly journals Neural Systems for Visual Orienting and Their Relationships to Spatial Working Memory

2002 ◽  
Vol 14 (3) ◽  
pp. 508-523 ◽  
Author(s):  
Maurizio Corbetta ◽  
J. Michelle Kincade ◽  
Gordon L. Shulman
Keyword(s):  
Working Memory ◽  
Right Hemisphere ◽  
Spatial Working Memory ◽  
Inferior Frontal Gyrus ◽  
Blood Oxygen Level Dependent ◽  
Frontal Eye Field ◽  
Blood Oxygen Level ◽  
Visual Orienting ◽  
Dependent Signal ◽  
The Right

We investigated neural correlates of human visual orienting using event-related functional magnetic resonance imaging (fMRI). When subjects voluntarily directed attention to a peripheral location, we recorded robust and sustained signals uniquely from the intraparietal sulcus (IPs) and superior frontal cortex (near the frontal eye field, FEF). In the ventral IPs and FEF only, the blood oxygen level dependent signal was modulated by the direction of attention. The IPs and FEF also maintained the most sustained level of activation during a 7-sec delay, when subjects maintained attention at the peripheral cued location (working memory). Therefore, the IPs and FEF form a dorsal network that controls the endogenous allocation and maintenance of visuospatial attention. A separate right hemisphere network was activated by the detection of targets at unattended locations. Activation was largely independent of the target's location (visual field). This network included among other regions the right temporo-parietal junction and the inferior frontal gyrus. We propose that this cortical network is important for reorienting to sensory events.

scholarly journals The Role of Right Hemisphere in Language Is Executive Rather than Linguistic

2020 ◽  
Author(s):  
Weixi Kang ◽  
Afshin Azadikhah ◽  
Jie Mei
Keyword(s):  
Working Memory ◽  
Right Hemisphere ◽  
Verbal Working Memory ◽  
Neural Mechanisms ◽  
Supramarginal Gyrus ◽  
History Of Research ◽  
Growing Body ◽  
History Of ◽  
The Right

Despite a long history of research favors left lateralization of language, increasingevidence provides support to the claim that the right hemisphere also plays a role inlanguage. Although studies have indicated that the right hemisphere contributes tolanguage representation, the underlying neural mechanisms are partly investigated andremain elusive. In this review, we hypothesize that the right hemisphere is involved inlanguage but its contributions are more likely to be domain-general rather than linguistic.The present work provides a thorough review of the growing body of research that hasdemonstrated how the right hemisphere is related to language with a focus on specificneural mechanisms underlying various aspects of language, and discusses why somebrain regions of the right hemisphere such as supramarginal gyrus are essential fordomain-general processes (e.g., verbal working memory) involved in language, ratherthan directly contributing to language itself.

scholarly journals White Matter Integrity Correlates of the Reading Span

2021 ◽  
Author(s):  
Ekaterina V. Pechenkova ◽  
Yana R. Panikratova ◽  
Maria A. Fomina ◽  
Elena A. Mershina ◽  
Daria A. Bazhenova ◽  
...  
Keyword(s):  
Working Memory ◽  
White Matter ◽  
Right Hemisphere ◽  
Diffusion Tensor ◽  
Structural Connectivity ◽  
Verbal Working Memory ◽  
The Body ◽  
White Matter Integrity ◽  
Reading Span ◽  
The Right

Although working memory (WM) is crucial for intellectual abilities, not much is known about its brain underpinnings, especially the structural connectivity. We used diffusion tensor imaging (DTI) to look across the whole brain for the white matter integrity correlates of the individual differences in the reading span (verbal WM capacity during reading) in healthy adults. Right-handed healthy native Russian speakers (N = 67) underwent DTI on a 3T Philips Ingenia scanner. Verbal WM was assessed with the Daneman-Carpenter reading span test (Russian version). Fractional anisotropy maps from each participant were entered into the group tract-based spatial statistics analysis with the reading span as a covariate; the results were TFCE-corrected. After taking into account effects of age, sex, education and handedness, reading span positively correlated with the white matter integrity in multiple sites: the body, the genu and the splenium of corpus callosum; bilateral corona radiata (anterior, posterior, and superior); bilateral superior longitudinal fasciculus; several tracts in the right hemisphere only, including the internal and external capsule; bilateral superior parietal and frontal white matter. Although the left hemisphere is central for verbal processing, we revealed the important role of the right hemisphere white matter for the verbal WM capacity. Our finding indicates that larger verbal working memory span may originate from additional processing resources of the right hemisphere.

The correlation between apraxia and neglect in the right hemisphere: A voxel-based lesion-symptom mapping study in 138 acute stroke patients

Cortex ◽  
2020 ◽  
Vol 132 ◽  
pp. 166-179
Author(s):  
Andrea Dressing ◽  
Markus Martin ◽  
Lena-Alexandra Beume ◽  
Dorothee Kuemmerer ◽  
Horst Urbach ◽  
...  
Keyword(s):  
Acute Stroke ◽  
Right Hemisphere ◽  
Mapping Study ◽  
Stroke Patients ◽  
Lesion Symptom Mapping ◽  
The Right

scholarly journals White Matter Integrity in the Right Hemisphere Correlates with the Reading Span

2021 ◽  
Author(s):  
Ekaterina Pechenkova ◽  
Yana Panikratova ◽  
Maria Fomina ◽  
Elena Mershina ◽  
Daria Bazhenova ◽  
...  
Keyword(s):  
Working Memory ◽  
White Matter ◽  
Right Hemisphere ◽  
Diffusion Tensor ◽  
Structural Connectivity ◽  
Verbal Working Memory ◽  
The Body ◽  
White Matter Integrity ◽  
Reading Span ◽  
The Right

Although working memory (WM) is crucial for intellectual abilities, not much is known about its brain underpinnings, especially the structural connectivity. We used diffusion tensor imaging (DTI) to look across the whole brain for the white matter integrity correlates of the individual differences in the reading span (verbal WM capacity during reading) in healthy adults. Right-handed healthy native Russian speakers (N = 47) underwent DTI on a 3T Philips Ingenia scanner. Verbal WM was assessed with the Daneman-Carpenter reading span test (Russian version). Fractional anisotropy maps from each participant were entered into the group tract-based spatial statistics analysis with the reading span as a covariate; the results were TFCE-corrected. Reading span positively correlated with the white matter integrity in several sites of the right hemisphere: the body and the splenium of corpus callosum; the posterior limb of internal capsule; posterior corona radiata; and superior parietal white matter. Although the left hemisphere is central for verbal processing, we revealed the important role of the right hemisphere white matter for the verbal WM capacity. Our finding indicates that larger verbal working memory span may originate from additional processing resources of the right hemisphere.

scholarly journals Are visual working memory and episodic memory distinct processes? Insight from stroke patients by lesion-symptom mapping.

2021 ◽  
Author(s):  
Selma Lugtmeijer ◽  
Linda Geerligs ◽  
Frank Erik De Leeuw ◽  
Edward H. F. De Haan ◽  
Roy P. C. Kessels
Keyword(s):  
Working Memory ◽  
Episodic Memory ◽  
Visual Working Memory ◽  
Visual Memory ◽  
Right Hemisphere ◽  
Memory Task ◽  
Stroke Patients ◽  
Lesion Symptom Mapping ◽  
Criterion Setting ◽  
The Right

Abstract Working memory and episodic memory are two different processes, although the nature of their interrelationship is debated. As these processes are predominantly studied in isolation, it is unclear whether they crucially rely on different neural substrates. To obtain more insight in this, eighty-one adults with sub-acute ischemic stroke and twenty-nine elderly controls were assessed on a visual working memory task, followed by a surprise subsequent memory test for the same stimuli. Multivariate, atlas- and track-based lesion-symptom mapping (LSM) analyses were performed to identify anatomical correlates of visual memory. Behavioral results gave moderate evidence for independence between discriminability in working memory and subsequent memory, and strong evidence for a correlation in response bias on the two tasks in stroke patients. LSM analyses suggested there might be independent regions associated with working memory and episodic memory. Lesions in the right arcuate fasciculus were more strongly associated with discriminability in working memory than in subsequent memory, while lesions in the frontal operculum in the right hemisphere were more strongly associated with criterion setting in subsequent memory. These findings support the view that some processes involved in working memory and episodic memory rely on separate mechanisms, while acknowledging that there might also be shared processes.

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