The role of disrupted functional connectivity in aphasia

Meier, Erin L.

doi:10.1016/b978-0-12-823384-9.00005-0

Cited by 2 publications

(2 citation statements)

References 191 publications

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“…The fusiform gyrus appears to fulfill a role uniquely critical to naming, integrating lexical retrieval with semantic content 11,12 . Prior studies have demonstrated the impact of lesions resulting in aphasia on language network connectivity, 13,14 and have begun to appreciate the impacts of treatment 15 . In a recent scoping review, Klingbeil et al 16 .…”

Section: Introductionmentioning

confidence: 99%

“…11,12 Prior studies have demonstrated the impact of lesions resulting in aphasia on language network connectivity, 13,14 and have begun to appreciate the impacts of treatment. 15 In a recent scoping review, Klingbeil et al 16 identified four rsfMRI studies of aphasia treatment that examined rsFC change in a total of 39 patients. [17][18][19][20] No single study had considered more than a dozen patients, and all four were conducted in the chronic phase (a minimum of 7 months after stroke).…”

Section: Introductionmentioning

confidence: 99%

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Subacute aphasia recovery is associated with resting‐state connectivity within and beyond the language network

Stockbridge

Faria

Fridriksson

et al. 2023

Ann Clin Transl Neurol

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ObjectiveTo examine changes to connectivity after aphasia treatment in the first 3 months after stroke.MethodsTwenty people experiencing aphasia within the first 3 months of stroke completed MRI before and immediately following 15 hours of language treatment. They were classified based on their response to treatment on a naming test of nouns as either high responders (10% improvement or more), or low responders (<10% improvement). Groups were similar in age, gender distribution, education, days since stroke, stroke volume, and baseline severity. Resting‐state functional connectivity analysis was limited to the connectivity of the left fusiform gyrus with the bilateral inferior frontal gyrus, supramarginal gyrus, angular gyrus, and superior, middle, and inferior temporal gyrus, based on previous studies showing the importance of left fusiform gyrus in naming performance.ResultsBaseline ipsilateral connectivity between the left fusiform gyrus and the language network was similar between high and low responders to therapy when controlling for stroke volume. Following therapy, change in connectivity was significantly greater among high responders between the left fusiform gyrus and the ipsilateral and contralateral pars triangularis, ipsilateral pars opercularis and superior temporal gyrus, and contralateral angular gyrus when compared with low responders.InterpretationAn account of these findings incorporates primarily proximal connectivity restoration, but also potentially reflects select contralateral compensatory reorganization. The latter is often associated with chronic recovery, reflecting the transitional nature of the subacute period.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Subacute aphasia recovery is associated with resting‐state connectivity within and beyond the language network

Stockbridge

Faria

Fridriksson

et al. 2023

Ann Clin Transl Neurol

View full text Add to dashboard Cite

show abstract

Temporopolar regions of the human brain

Mesulam

2022

Brain

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Following prolonged neglect during the formative decades of behavioural neurology, the temporopolar region has become a site of vibrant research on the neurobiology of cognition and conduct. This turnaround can be attributed to increasing recognition of neurodegenerative diseases that target temporopolar regions for peak destruction. The resultant syndromes include behavioural dementia, associative agnosia, semantic forms of primary progressive aphasia and semantic dementia. Clinicopathological correlations show that object naming and word comprehension are critically dependent on the language-dominant (usually left) temporopolar region, whereas behavioural control and non-verbal object recognition display a more bilateral representation with a rightward bias. Neuroanatomical experiments in macaques and neuroimaging in humans show that the temporoparietal region sits at the confluence of auditory, visual and limbic streams of processing at the downstream (deep) pole of the ‘what’ pathway. The functional neuroanatomy of this region revolves around three axes, an anterograde horizontal axis from unimodal to heteromodal and paralimbic cortex; a radial axis where visual (ventral), auditory (dorsal) and paralimbic (medial) territories encircle temporopolar cortex and display hemispheric asymmetry; and a vertical depth-of-processing axis for the associative elaboration of words, objects and interoceptive states. One function of this neural matrix is to support the transformation of object and word representations from unimodal percepts to multimodal concepts. The underlying process is likely to start at canonical gateways that successively lead to generic (superordinate), specific (basic) and unique levels of recognition. A first sign of left temporopolar dysfunction takes the form of taxonomic blurring where boundaries among categories are preserved but not boundaries among exemplars of a category. Semantic paraphasias and coordinate errors in word–picture verification tests are consequences of this phenomenon. Eventually, boundaries among categories are also blurred and comprehension impairments become more profound. The medial temporopolar region belongs to the amygdalocentric component of the limbic system and stands to integrate exteroceptive information with interoceptive states underlying social interactions. Review of the pertinent literature shows that word comprehension and conduct impairments caused by temporopolar strokes and temporal lobectomy are far less severe than those seen in temporopolar atrophies. One explanation for this unexpected discrepancy invokes the miswiring of residual temporopolar neurons during the many years of indolently progressive neurodegeneration. According to this hypothesis, the temporopolar regions become not only dysfunctional but also sources of aberrant outputs that interfere with the function of areas elsewhere in the language and paralimbic networks, a juxtaposition not seen in lobectomy or stroke.

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The role of disrupted functional connectivity in aphasia

Cited by 2 publications

References 191 publications

Subacute aphasia recovery is associated with resting‐state connectivity within and beyond the language network

Subacute aphasia recovery is associated with resting‐state connectivity within and beyond the language network

Temporopolar regions of the human brain

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