1
|
Bonandrini R, Gornetti E, Paulesu E. A meta-analytical account of the functional lateralization of the reading network. Cortex 2024; 177:363-384. [PMID: 38936265 DOI: 10.1016/j.cortex.2024.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 03/25/2024] [Accepted: 05/29/2024] [Indexed: 06/29/2024]
Abstract
The observation that the neural correlates of reading are left-lateralized is ubiquitous in the cognitive neuroscience and neuropsychological literature. Still, reading is served by a constellation of neural units, and the extent to which these units are consistently left-lateralized is unclear. In this regard, the functional lateralization of the fusiform gyrus is of particular interest, by virtue of its hypothesized role as a "visual word form area". A quantitative Activation Likelihood Estimation meta-analysis was conducted on activation foci from 35 experiments investigating silent reading, and both a whole-brain and a bayesian ROI-based approach were used to assess the lateralization of the data submitted to meta-analysis. Perirolandic areas showed the highest level of left-lateralization, the fusiform cortex and the parietal cortex exhibited only a moderate pattern of left-lateralization, while in the occipital, insular cortices and in the cerebellum the lateralization turned out to be the lowest observed. The relatively limited functional lateralization of the fusiform gyrus was further explored in a regression analysis on the lateralization profile of each study. The functional lateralization of the fusiform gyrus during reading was positively associated with the lateralization of the precentral and inferior occipital gyri and negatively associated with the lateralization of the triangular portion of the inferior frontal gyrus and of the temporal pole. Overall, the present data highlight how lateralization patterns differ within the reading network. Furthermore, the present data highlight how the functional lateralization of the fusiform gyrus during reading is related to the degree of functional lateralization of other language brain areas.
Collapse
Affiliation(s)
| | - Edoardo Gornetti
- Department of Psychology, University of Milano-Bicocca, Milan, Italy; Max Planck Institute for Psycholinguistics, Nijmegen, the Netherlands; The International Max Planck Research School for Language Sciences, Nijmegen, the Netherlands
| | - Eraldo Paulesu
- Department of Psychology, University of Milano-Bicocca, Milan, Italy; fMRI Unit, IRCCS Orthopedic Institute Galeazzi, Milan, Italy
| |
Collapse
|
2
|
Tao Y, Schubert T, Wiley R, Stark C, Rapp B. Cortical and Subcortical Mechanisms of Orthographic Word-form Learning. J Cogn Neurosci 2024; 36:1071-1098. [PMID: 38527084 DOI: 10.1162/jocn_a_02147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
We examined the initial stages of orthographic learning in real time as literate adults learned spellings for spoken pseudowords during fMRI scanning. Participants were required to learn and store orthographic word forms because the pseudoword spellings were not uniquely predictable from sound to letter mappings. With eight learning trials per word form, we observed changes in the brain's response as learning was taking place. Accuracy was evaluated during learning, immediately after scanning, and 1 week later. We found evidence of two distinct learning systems-hippocampal and neocortical-operating during orthographic learning, consistent with the predictions of dual systems theories of learning/memory such as the complementary learning systems framework [McClelland, J. L., McNaughton, B. L., & O'Reilly, R. C. Why there are complementary learning systems in the hippocampus and neocortex: Insights from the successes and failures of connectionist models of learning and memory. Psychological Review, 102, 419-457, 1995]. The bilateral hippocampus and the visual word form area (VWFA) showed significant BOLD response changes over learning, with the former exhibiting a rising pattern and the latter exhibiting a falling pattern. Moreover, greater BOLD signal increase in the hippocampus was associated with better postscan recall. In addition, we identified two distinct bilateral brain networks that mirrored the rising and falling patterns of the hippocampus and VWFA. Functional connectivity analysis revealed that regions within each network were internally synchronized. These novel findings highlight, for the first time, the relevance of multiple learning systems in orthographic learning and provide a paradigm that can be used to address critical gaps in our understanding of the neural bases of orthographic learning in general and orthographic word-form learning specifically.
Collapse
|
3
|
Purcell J, Wiley R, Won J, Callow D, Weiss L, Alfini A, Wei Y, Carson Smith J. Increased neural differentiation after a single session of aerobic exercise in older adults. Neurobiol Aging 2023; 132:67-84. [PMID: 37742442 DOI: 10.1016/j.neurobiolaging.2023.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 08/19/2023] [Accepted: 08/24/2023] [Indexed: 09/26/2023]
Abstract
Aging is associated with decreased cognitive function. One theory posits that this decline is in part due to multiple neural systems becoming dedifferentiated in older adults. Exercise is known to improve cognition in older adults, even after only a single session. We hypothesized that one mechanism of improvement is a redifferentiation of neural systems. We used a within-participant, cross-over design involving 2 sessions: either 30 minutes of aerobic exercise or 30 minutes of seated rest (n = 32; ages 55-81 years). Both functional Magnetic Resonance Imaging (fMRI) and Stroop performance were acquired soon after exercise and rest. We quantified neural differentiation via general heterogeneity regression. There were 3 prominent findings following the exercise. First, participants were better at reducing Stroop interference. Second, while there was greater neural differentiation within the hippocampal formation and cerebellum, there was lower neural differentiation within frontal cortices. Third, this greater neural differentiation in the cerebellum and temporal lobe was more pronounced in the older ages. These data suggest that exercise can induce greater neural differentiation in healthy aging.
Collapse
Affiliation(s)
- Jeremy Purcell
- Department of Kinesiology, University of Maryland, College Park, MD, USA; Maryland Neuroimaging Center, University of Maryland, College Park, MD, USA.
| | - Robert Wiley
- Department of Psychology, University of North Carolina at Greensboro, Greensboro, NC, USA
| | - Junyeon Won
- Department of Kinesiology, University of Maryland, College Park, MD, USA; Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, TX, USA
| | - Daniel Callow
- Department of Kinesiology, University of Maryland, College Park, MD, USA; Program in Neuroscience and Cognitive Science, University of Maryland, College Park, MD, USA
| | - Lauren Weiss
- Department of Kinesiology, University of Maryland, College Park, MD, USA; Program in Neuroscience and Cognitive Science, University of Maryland, College Park, MD, USA
| | - Alfonso Alfini
- National Center on Sleep Disorders Research, Division of Lung Diseases, National Heart, Lung, and Blood Institute, Bethesda, MD, USA
| | - Yi Wei
- Maryland Neuroimaging Center, University of Maryland, College Park, MD, USA
| | - J Carson Smith
- Department of Kinesiology, University of Maryland, College Park, MD, USA; Program in Neuroscience and Cognitive Science, University of Maryland, College Park, MD, USA.
| |
Collapse
|
4
|
Li R, Mukadam N, Kiran S. Functional MRI evidence for reorganization of language networks after stroke. HANDBOOK OF CLINICAL NEUROLOGY 2022; 185:131-150. [PMID: 35078595 DOI: 10.1016/b978-0-12-823384-9.00007-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
In this chapter, we review fMRI evidence for language reorganization in individuals with poststroke aphasia. Several studies in the current literature have utilized fMRI as a tool to understand patterns of functional reorganization in poststroke aphasia. Consistent with previous models that have been proposed to explain the trajectory of language recovery, differential patterns of language processing and language recovery have been identified across individuals with poststroke aphasia in different stages of recovery. Overall, a global network breakdown typically occurs in the early stages of aphasia recovery, followed by normalization in "traditional" left hemisphere language networks. Depending on individual characteristics, right hemisphere regions and bilateral domain-general regions may be further recruited. The main takeaway of this chapter is that poststroke aphasia recovery does not depend on individual neural regions, but rather involves a complex interaction among regions in larger networks. Many of the unresolved issues and contrastive findings in the literature warrant further research with larger groups of participants and standard protocols of fMRI implementation.
Collapse
Affiliation(s)
- Ran Li
- Department of Speech, Language and Hearing Sciences, Boston University, Boston, MA, United States
| | - Nishaat Mukadam
- Department of Speech, Language and Hearing Sciences, Boston University, Boston, MA, United States
| | - Swathi Kiran
- Department of Speech, Language and Hearing Sciences, Boston University, Boston, MA, United States.
| |
Collapse
|
5
|
Shea J, Wiley R, Moss N, Rapp B. Pseudoword spelling ability predicts response to word spelling treatment in acquired dysgraphia. Neuropsychol Rehabil 2020; 32:231-267. [PMID: 33047661 DOI: 10.1080/09602011.2020.1813596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Although rehabilitation of acquired dysgraphia can be quite effective, identifying predictors of responsiveness to treatment is useful for prognosis and individualization of treatment protocols. This study examined whether various features of treatment response were predicted by the integrity of one or more of the central cognitive components of spelling: orthographic long-term memory, orthographic working memory, and phoneme-grapheme conversion. Twenty dysgraphic individuals received 12 weeks of bi-weekly, individualized, lexically-based spelling rehabilitation using a spell-study-spell paradigm. Linear multiple regression modelling examined whether the type and severity of the dysgraphic deficit, assessed before rehabilitation, predicted the magnitude and rate of improvement, generalization to untrained items and maintenance of treatment gains. The results revealed that pseudoword spelling accuracy - indexing the integrity of the phoneme-grapheme conversion system - was the only factor examined that significantly predicted the rate of accuracy gains for trained words as well as the extent of generalization to untrained words. Pre-treatment pseudoword spelling accuracy also predicted retention of gains for trained and untrained words at 3-month follow-up. These findings reveal that the integrity of the phoneme-grapheme conversion system prior to dysgraphia rehabilitation may play a key role in rehabilitation-driven recovery, even when the treatment approach targets lexical rather than pseudoword spelling processes.
Collapse
Affiliation(s)
- Jennifer Shea
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD, USA
| | - Robert Wiley
- Department of Psychology, University of North Carolina Greensboro, Greensboro, NC, USA
| | - Natalie Moss
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD, USA
| | - Brenda Rapp
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD, USA
| |
Collapse
|
6
|
Tao Y, Rapp B. How functional network connectivity changes as a result of lesion and recovery: An investigation of the network phenotype of stroke. Cortex 2020; 131:17-41. [PMID: 32781259 PMCID: PMC9088558 DOI: 10.1016/j.cortex.2020.06.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 03/15/2020] [Accepted: 06/02/2020] [Indexed: 11/28/2022]
Abstract
This study, through a series of univariate and multivariate (classification) analyses, investigated fMRI task-based functional connectivity (FC) at pre- and post-treatment time-points in 18 individuals with chronic post-stroke dysgraphia. The investigation examined the effects of lesion and treatment-based recovery on functional organization, focusing on both inter-hemispheric (homotopic) and intra-hemispheric connectivity. The work confirmed, in the chronic stage, the "network phenotype of stroke injury" proposed by Siegel et al. (2016) consisting of abnormally low inter-hemispheric connectivity as well as abnormally high intra-hemispheric (ipsilesional) connectivity. In terms of recovery-based changes in FC, this study found overall hyper-normalization of these abnormal inter and intra-hemispheric connectivity patterns, suggestive of over-correction. Specifically, treatment-related homotopic FC increases were observed between left and right dorsal frontal-parietal regions. With regard to intra-hemispheric connections, recovery was dominated by increased ipsilateral connectivity between frontal and parietal regions along with decreased connectivity between the frontal regions and posterior parietal-occipital-temporal areas. Both inter and intra-hemispheric changes were associated with treatment-driven improvements in spelling performance. We suggest an interpretation according to which, with treatment, as posterior orthographic processing areas become more effective, executive control from frontal-parietal networks becomes less necessary.
Collapse
Affiliation(s)
- Yuan Tao
- Department of Cognitive Science, Johns Hopkins University, USA.
| | - Brenda Rapp
- Department of Cognitive Science, Johns Hopkins University, USA; Department of Neuroscience, Johns Hopkins University, USA; Department of Psychological and Brain Sciences, Johns Hopkins University, USA
| |
Collapse
|
7
|
Purcell JJ, Wiley RW, Rapp B. Re-learning to be different: Increased neural differentiation supports post-stroke language recovery. Neuroimage 2019; 202:116145. [PMID: 31479754 DOI: 10.1016/j.neuroimage.2019.116145] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 07/31/2019] [Accepted: 08/29/2019] [Indexed: 10/26/2022] Open
Abstract
Identifying the neural changes that support recovery of cognitive functions after a brain lesion is important to advance our understanding of human neuroplasticity, which, in turn, forms the basis for the development of effective treatments. To date, the preponderance of neuroimaging studies has focused on localizing changes in average brain activity associated with functional recovery. Here, we took a novel approach by evaluating whether cognitive recovery in chronic stroke is related to increases in the differentiation of local neural response patterns. This approach is supported by research indicating that, in the intact brain, local neural representations become more differentiated (dissimilar) with learning (Glezer et al., 2015). We acquired fMRI data before and after 21 individuals received approximately 12 weeks of behavioral treatment for written language impairment due to a left-hemisphere stroke. We used Local-Heterogeneity Regression Analysis (Purcell and Rapp, 2018) to measure local neural response differentiation associated with written language processing, assuming that greater heterogeneity in the pattern of activity across adjacent neural areas indicates more well-differentiated neural representations. First, we observed pre to post-treatment increases in local neural differentiation (Local-Hreg) in the ventral occipital-temporal cortex of the left hemisphere. Second, we found that, in this region, higher local neural response differentiation prior to treatment was associated with less severe written language impairment, and that it also predicted greater future responsiveness to treatment. Third, we observed that changes in neural differentiation were systematically related to performance changes for trained and untrained items. Fourth, we did not observe these brain-behavior relationships for mean BOLD responses, only for Local-Hreg. Thus, this is the first investigation to quantify changes in local neural differentiation in the recovery of a cognitive function and the first to demonstrate the clear behavioral relevance of these changes. We conclude that the findings provide strong support for the novel hypothesis that the local re-differentiation of neural representations can play a significant role in functional recovery after brain lesion.
Collapse
Affiliation(s)
- Jeremy J Purcell
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD, USA; Maryland Neuroimaging Center, University of Maryland, College Park, MD, USA.
| | - Robert W Wiley
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD, USA; Department of Psychology, University of North Carolina, Greensboro, NC, USA
| | - Brenda Rapp
- Department of Cognitive Science, Johns Hopkins University, Baltimore, MD, USA
| |
Collapse
|