Visual Object Agnosia and Pure Word Alexia

Salvan, Carmen V.; Ulmer, John L.; DeYoe, Edgar A.; Wascher, Thomas C.; Mathews, Vincent P.; Lewis, James W.; Prost, Robert

doi:10.1097/00004728-200401000-00010

Cited by 22 publications

(4 citation statements)

References 12 publications

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“…ILF connects the occipital and the temporal lobes intrahemispherically (Nieuwenhuys et al, 2007). The temporal lobe is significant in processing semantic information of both verbal and visual language, while the occipital lobe serves as the core visual processing center of the human brain and is important in processing visual information (Salvan et al, 2004). As the major white matter tracts connecting the temporal and the occipital lobes, ILF facilitates the communication between the two lobes, and should thus play an important role in facilitating the identification of colors and inhibiting the meaning of the words in the Stroop test.…”

Section: Discussionmentioning

confidence: 99%

White matter integrity mediates decline in age-related inhibitory control

Tsapanou

Qolamreza

et al. 2018

Behavioural Brain Research

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Previous DTI studies have reported associations between white matter integrity and performance on the Stroop interference task. The current study aimed to add to these studies of inhibitory control by investigating how the differences in age and in white matter integrity relate to Stroop performance, and to examine whether the effect of age on Stroop performance is mediated by white matter integrity. 179 healthy adults from 20 to 80 years old were recruited in the study. DTI data were processed through TRACULA and the mean fractional anisotropy (FA) of 18 major white matter tracts were extracted and used for statistical analysis. Correlation analysis showed a strong negative relationship between age and the Stroop interference score (I). Higher I indicated better inhibitory control. Simple linear regression analyses indicated that most of the tracts showed negative relationships with age, and positive relationships with I. Moderation effect of age on the relationship between FA and I was tested on tracts that significantly predicted I after multiple comparison corrections, but none of these moderations were significant. Then we tested if these tracts mediated the effect of age on I and found significant indirect effects of age on I through the FA of the left corticospinal tract and through the right inferior longitudinal fasciculus. Our results highlight the role of a number of major white matter tracts in the processes supporting the Stroop inhibitory performance and further pinpointed the lower white matter integrity of specific tracts as contributors to the decrease in inhibitory control ability associated with the Stroop test in older age.

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Section: Discussionmentioning

confidence: 99%

White matter integrity mediates decline in age-related inhibitory control

Tsapanou

Qolamreza

et al. 2018

Behavioural Brain Research

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“…The fMRI rhyming task used for evaluating language laterality was similar to that described in Salvan et al ( 2004 ). The task presented visually rhyming and non-rhyming word pairs.…”

Section: Methodsmentioning

confidence: 99%

A preliminary fMRI study of a novel self-paced written fluency task: observation of left-hemispheric activation, and increased frontal activation in late vs. early task phases

Golestanirad

Das

Schweizer

et al. 2015

Front. Hum. Neurosci.

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Neuropsychological tests of verbal fluency are very widely used to characterize impaired cognitive function. For clinical neuroscience studies and potential medical applications, measuring the brain activity that underlies such tests with functional magnetic resonance imaging (fMRI) is of significant interest—but a challenging proposition because overt speech can cause signal artifacts, which tend to worsen as the duration of speech tasks becomes longer. In a novel approach, we present the group brain activity of 12 subjects who performed a self-paced written version of phonemic fluency using fMRI-compatible tablet technology that recorded responses and provided task-related feedback on a projection screen display, over long-duration task blocks (60 s). As predicted, we observed robust activation in the left anterior inferior and medial frontal gyri, consistent with previously reported results of verbal fluency tasks which established the role of these areas in strategic word retrieval. In addition, the number of words produced in the late phase (last 30 s) of written phonemic fluency was significantly less (p < 0.05) than the number produced in the early phase (first 30 s). Activation during the late phase vs. the early phase was also assessed from the first 20 s and last 20 s of task performance, which eliminated the possibility that the sluggish hemodynamic response from the early phase would affect the activation estimates of the late phase. The last 20 s produced greater activation maps covering extended areas in bilateral precuneus, cuneus, middle temporal gyrus, insula, middle frontal gyrus and cingulate gyrus. Among these areas, greater activation was observed in the bilateral middle frontal gyrus (Brodmann area BA 9) and cingulate gyrus (BA 24, 32) likely as part of the initiation, maintenance, and shifting of attentional resources. Consistent with previous pertinent fMRI literature involving overt and covert verbal responses, these findings highlight the promise and practicality of fMRI of written phonemic fluency.

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“…While left-hemispheric SLF fibers have been related to speech (Duffau et al 2002) and language comprehension (Tanabe et al 1987), right-hemispheric fibers have been related to the spatial-attention network (Doricchi and Tomaiuolo 2003). The inferior longitudinal fasciculi connect temporal to occipital lobes in each hemisphere and have been associated with higher-order visual functions such as object recognition (left-lateralized; Salvan et al 2004), face recognition, and visually evoked emotions (bilateral or right-lateralized; Bauer 1982; Habib 1986). The inferior fronto-occipital fasciculi connect visual association areas with the frontal eye fields, and there is some evidence that they mediate simultaneous perception intrahemipherically needed for selecting visual information in crowded scenes (right-lateralized or bilateral; Battelli et al 2003; Rizzo and Vecera 2002).…”

Section: Pathways Subserving Intra-and Interhemispheric Communicationmentioning

confidence: 99%

Contribution of Callosal Connections to the Interhemispheric Integration of Visuomotor and Cognitive Processes

2010

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In recent years, cognitive neuroscience has been concerned with the role of the corpus callosum and interhemispheric communication for lower-level processes and higher-order cognitive functions. There is empirical evidence that not only callosal disconnection but also subtle degradation of the corpus callosum can influence the transfer of information and integration between the hemispheres. The reviewed studies on patients with callosal degradation with and without disconnection indicate a dissociation of callosal functions: while anterior callosal regions were associated with interhemispheric inhibition in situations of semantic (Stroop) and visuospatial (hierarchical letters) competition, posterior callosal areas were associated with interhemispheric facilitation from redundant information at visuomotor and cognitive levels. Together, the reviewed research on selective cognitive functions provides evidence that the corpus callosum contributes to the integration of perception and action within a subcortico-cortical network promoting a unified experience of the way we perceive the visual world and prepare our actions.

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Visual Object Agnosia and Pure Word Alexia

Cited by 22 publications

References 12 publications

White matter integrity mediates decline in age-related inhibitory control

White matter integrity mediates decline in age-related inhibitory control

A preliminary fMRI study of a novel self-paced written fluency task: observation of left-hemispheric activation, and increased frontal activation in late vs. early task phases

Contribution of Callosal Connections to the Interhemispheric Integration of Visuomotor and Cognitive Processes

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