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A computational model of inner speech supporting flexible goal-directed behaviour in Autism. Sci Rep 2022; 12:14198. [PMID: 35987942 PMCID: PMC9392752 DOI: 10.1038/s41598-022-18445-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 08/11/2022] [Indexed: 11/21/2022] Open
Abstract
Experimental and computational studies propose that inner speech boosts categorisation skills and executive functions, making human behaviour more focused and flexible. In addition, many clinical studies highlight a relationship between poor inner-speech and an executive impairment in autism spectrum condition (ASC), but contrasting findings are reported. Here we directly investigate the latter issue through a previously implemented and validated computational model of the Wisconsin Cards Sorting Tests. In particular, the model was applied to explore potential individual differences in cognitive flexibility and inner speech contribution in autistic and neurotypical participants. Our model predicts that the use of inner-speech could increase along the life-span of neurotypical participants but would be reduced in autistic ones. Although we found more attentional failures (i.e., wrong behavioural rule switches) in autistic children/teenagers and more perseverative behaviours in autistic young/older adults, only autistic children and older adults exhibited a lower performance (i.e., fewer consecutive correct rule switches) than matched control groups. Overall, our results corroborate the idea that the reduced use of inner speech could represent a disadvantage for autistic children and autistic older adults. Moreover, the results suggest that cognitive-behavioural therapies should focus on developing inner speech skills in autistic children as this could provide cognitive support throughout their whole life span.
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Sidtis JJ. Cerebral Blood Flow Is Not a Direct Surrogate of Behavior: Performance Models Suggest a Role for Functional Meta-Networks. Front Neurosci 2022; 16:771594. [PMID: 35242005 PMCID: PMC8885809 DOI: 10.3389/fnins.2022.771594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 01/26/2022] [Indexed: 11/13/2022] Open
Abstract
BackgroundFunctional brain imaging has become the dominant approach to the study of brain-behavior relationships. Unfortunately, the behavior half of the equation has been relegated to second-class status when it is not ignored completely. Different approaches to connectivity, based on temporally correlated physiological events across the brain, have ascended in place of behavior. A performance-based analysis has been developed as a simple, basic approach to incorporating specific performance measures obtained during imaging into the analysis of the imaging data identifying clinically relevant regions.MethodsThis paper contrasts performance-based lateralized regional cerebral blood flow (CBF) predictors of speech rate during Positron Emission Tomography with the values of these regions and their opposite hemisphere homologs in which a performance-based model was not applied. Five studies were examined: two that utilized normal speakers, one that utilized ataxic speakers, and two that examined Parkinsonian speakers.ResultsIn each study, the predictors were lateralized but the blood flow values that contributed to the performance-based analysis were bilateral. The speech-rate predictor regions were consistent with clinical studies on the effects of focal brain damage.ConclusionsThis approach has identified a basic, reproducible blood flow network that has predicted speech rate in multiple normal and neurologic groups. While the predictors are lateralized consistent with lesion data, the blood flow values of these regions are neither lateralized nor distinguished from their opposite hemisphere homologs in their magnitudes. The consistent differences between regional blood flow values and their corresponding regression coefficients in predicting performance suggests the presence of functional meta-networks that orchestrate the contributions of specific brain regions in support of mental and behavioral functions.
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Affiliation(s)
- John J. Sidtis
- Brain and Behavior Laboratory, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, United States
- Department of Psychiatry, New York University Langone School of Medicine, New York, NY, United States
- *Correspondence: John J. Sidtis,
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Skipper JI, Aliko S, Brown S, Jo YJ, Lo S, Molimpakis E, Lametti DR. Reorganization of the Neurobiology of Language After Sentence Overlearning. Cereb Cortex 2021; 32:2447-2468. [PMID: 34585723 PMCID: PMC9157312 DOI: 10.1093/cercor/bhab354] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/27/2021] [Accepted: 08/29/2021] [Indexed: 11/14/2022] Open
Abstract
It is assumed that there are a static set of "language regions" in the brain. Yet, language comprehension engages regions well beyond these, and patients regularly produce familiar "formulaic" expressions when language regions are severely damaged. These suggest that the neurobiology of language is not fixed but varies with experiences, like the extent of word sequence learning. We hypothesized that perceiving overlearned sentences is supported by speech production and not putative language regions. Participants underwent 2 sessions of behavioral testing and functional magnetic resonance imaging (fMRI). During the intervening 15 days, they repeated 2 sentences 30 times each, twice a day. In both fMRI sessions, they "passively" listened to those sentences, novel sentences, and produced sentences. Behaviorally, evidence for overlearning included a 2.1-s decrease in reaction times to predict the final word in overlearned sentences. This corresponded to the recruitment of sensorimotor regions involved in sentence production, inactivation of temporal and inferior frontal regions involved in novel sentence listening, and a 45% change in global network organization. Thus, there was a profound whole-brain reorganization following sentence overlearning, out of "language" and into sensorimotor regions. The latter are generally preserved in aphasia and Alzheimer's disease, perhaps explaining residual abilities with formulaic expressions in both.
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Affiliation(s)
| | - Sarah Aliko
- Experimental Psychology, University College London, London, UK.,London Interdisciplinary Biosciences Consortium, University College London, London, UK
| | - Stephen Brown
- Natural Sciences, University College London, London, UK
| | - Yoon Ju Jo
- Experimental Psychology, University College London, London, UK
| | - Serena Lo
- Speech and Language Sciences, University College London, London, UK
| | - Emilia Molimpakis
- Wellcome Centre for Human Neuroimaging, University College London, London, UK
| | - Daniel R Lametti
- Experimental Psychology, University College London, London, UK.,Department of Psychology, Acadia University, Nova Scotia, Canada
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Sidtis JJ, Gomez CM. Genotypic Differences in Networks Supporting Regional Predictors of Speech Rate in Spinocerebellar Ataxia: Preliminary Observations. Brain Connect 2021; 11:408-417. [PMID: 34030481 PMCID: PMC8388246 DOI: 10.1089/brain.2020.0972] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Background: Disordered speech production, dysarthria, is a common characteristic of the spinocerebellar ataxias (SCAs). Although dysarthric features differ across SCAs, a previous analysis revealed that a combination of regional cerebral blood flow (rCBF) in the left inferior frontal region and the right caudate predicted syllable rate, a pattern reported in normal speakers. This study examined the relationships between primary predictor brain regions and other areas of the brain in three SCA groups. The regions associated with the primary predictors are considered as elements of secondary networks since they are associated with regional speech predictors rather than directly with speech performance. Methods: Speech and rCBF data from 9 SCA1, 8 SCA5, and 5 SCA6 individuals were analyzed. Partial correlations were used to identify brain regions associated with the primary predictors. Results: Secondary networks differed across SCA genotypes. SCA1 and SCA6 demonstrated both positive and negative associations between primary and secondary areas, whereas the associations in the SCA5 genotype were only positive. The SCA5 associations were also largely bilaterally symmetrical. Both SCA1 and SCA5 demonstrated secondary associations with the right caudate, whereas the SCA6 group had no such associations. Conclusions: These results demonstrate that although primary aspects of a brain network may remain functional, pathophysiological processes associated with different SCA genotypes may express themselves in alterations of broader, secondary brain networks. These secondary networks may reflect generic functional associations with the primary predictor regions, compensatory activity in the presence of an SCA, SCA pathology, or some combination of these factors.
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Affiliation(s)
- John J Sidtis
- Brain and Behavior Laboratory, Geriatrics Division, The Nathan Kline Institute for Psychiatric Research, Orangeburg, New York, USA.,Department of Psychiatry, New York University Langone Medical Center, New York, New York, USA
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Sidtis JJ, Sidtis DVL, Dhawan V, Tagliati M, Eidelberg D. Stimulation of the Subthalamic Nucleus Changes Cortical-Subcortical Blood Flow Patterns During Speech: A Positron Emission Tomography Study. Front Neurol 2021; 12:684596. [PMID: 34122323 PMCID: PMC8187801 DOI: 10.3389/fneur.2021.684596] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 05/05/2021] [Indexed: 12/18/2022] Open
Abstract
Background: Deep brain stimulation of the subthalamic nucleus (STN-DBS) is an effective treatment for Parkinson's disease (PD) but can have an adverse effect on speech. In normal speakers and in those with spinocerebellar ataxia, an inverse relationship between regional cerebral blood flow (rCBF) in the left inferior frontal (IFG) region and the right caudate (CAU) is associated with speech rate. This pattern was examined to determine if it was present in PD, and if so, whether it was altered by STN-DBS. Methods: Positron Emission Tomography (PET) measured rCBF during speech in individuals with PD not treated with STN-DBS (n = 7), and those treated with bilateral STN-DBS (n = 7). Previously reported results from non-PD control subjects (n = 16) were reported for comparison. The possible relationships between speech rate during scanning and data from the left and right IFG and CAU head regions were investigated using a step-wise multiple linear regression to identify brain regions that interacted to predict speech rate. Results: The multiple linear regression analysis replicated previously reported predictive coefficients for speech rate involving the left IFG and right CAU regions. However, the relationships between these predictive coefficients and speech rates were abnormal in both PD groups. In PD who had not received STN-DBS, the right CAU coefficient decreased normally with increasing speech rate but the left IFG coefficient abnormally decreased. With STN-DBS, this pattern was partially normalized with the addition of a left IFG coefficient that increased with speech rate, as in normal controls, but the abnormal left IFG decreasing coefficient observed in PD remained. The magnitudes of both cortical predictive coefficients but not the CAU coefficient were exaggerated with STN-DBS. Conclusions: STN-DBS partially corrects the abnormal relationships between rCBF and speech rate found in PD by introducing a left IFG subregion that increases with speech rate, but the conflicting left IFG subregion response remained. Conflicting IFG responses may account for some of the speech problems observed after STN-DBS. Cortical and subcortical regions may be differentially affected by STN-DBS.
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Affiliation(s)
- John J Sidtis
- Brain and Behavior Laboratory, Geriatrics Department, Nathan Kline Institute, Orangeburg, NY, United States.,Department of Psychiatry, School of Medicine, New York University Langone, New York, NY, United States
| | - Diana Van Lancker Sidtis
- Brain and Behavior Laboratory, Geriatrics Department, Nathan Kline Institute, Orangeburg, NY, United States.,Department of Communicative Disorders and Sciences, New York University Steinhardt School, New York, NY, United States
| | - Vijay Dhawan
- Center for Neurosciences, The Feinstein Institute for Medical Research, Manhasset, NY, United States
| | - Michele Tagliati
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - David Eidelberg
- Center for Neurosciences, The Feinstein Institute for Medical Research, Manhasset, NY, United States
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A computational model of language functions in flexible goal-directed behaviour. Sci Rep 2020; 10:21623. [PMID: 33303842 PMCID: PMC7729881 DOI: 10.1038/s41598-020-78252-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 08/06/2020] [Indexed: 12/22/2022] Open
Abstract
The function of language in high-order goal-directed human cognition is an important topic at the centre of current debates. Experimental evidence shows that inner speech, representing a self-directed form of language, empowers cognitive processes such as working memory, perception, categorization, and executive functions. Here we study the relations between inner speech and processes like feedback processing and cognitive flexibility. To this aim we propose a computational model that controls an artificial agent who uses inner speech to internally manipulate its representations. The agent is able to reproduce human behavioural data collected during the solution of the Wisconsin Card Sorting test, a neuropsychological test measuring cognitive flexibility, both in the basic condition and when a verbal shadowing protocol is used. The components of the model were systematically lesioned to clarify the specific impact of inner speech on the agent’s behaviour. The results indicate that inner speech improves the efficiency of internal representation manipulation. Specifically, it makes the representations linked to specific visual features more disentangled, thus improving the agent’s capacity to engage/disengage attention on stimulus features after positive/negative action outcomes. Overall, the model shows how inner speech could improve goal-directed internal manipulation of representations and enhance behavioural flexibility.
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Stahl B, Gawron B, Regenbrecht F, Flöel A, Kotz SA. Formulaic Language Resources May Help Overcome Difficulties in Speech-Motor Planning after Stroke. PLoS One 2020; 15:e0233608. [PMID: 32497064 PMCID: PMC7272023 DOI: 10.1371/journal.pone.0233608] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 05/10/2020] [Indexed: 11/25/2022] Open
Abstract
Purpose Decades of research have explored communication in cerebrovascular diseases by focusing on formulaic expressions (e.g., “Thank you”—“You’re welcome”). This category of utterances is known for engaging primarily right-hemisphere frontotemporal and bilateral subcortical neural networks, explaining why left-hemisphere stroke patients with speech-motor planning disorders often produce formulaic expressions comparatively well. The present proof-of-concept study aims to confirm that using verbal cues derived from formulaic expressions can alleviate word-onset difficulties, one major symptom in apraxia of speech. Methods In a cross-sectional repeated-measures design, 20 individuals with chronic post-stroke apraxia of speech were asked to produce (i) verbal cues (e.g., /guː/) and (ii) subsequent German target words (e.g., “Tanz”) with critical onsets (e.g., /t/). Cues differed, most notably, in aspects of formulaicity (e.g., stereotyped prompt: /guː/, based on formulaic phrase “Guten Morgen”; unstereotyped prompt: /muː/, based on non-formulaic control word “Mutig”). Apart from systematic variation in stereotypy and communicative-pragmatic embeddedness possibly associated with holistic language processing, cues were matched for consonant-vowel structure, syllable-transition frequency, noun-verb classification, meter, and articulatory tempo. Results Statistical analyses revealed significant increases in correctly produced word onsets after verbal cues with distinct features of formulaicity (e.g., stereotyped versus unstereotyped prompts: p < 0.001), as reflected in large effect sizes (Cohen’s dz ≤ 2.2). Conclusions The current results indicate that using preserved formulaic language skills can relieve word-onset difficulties in apraxia of speech. This finding is consistent with a dynamic interplay of left perilesional and right intact language networks in post-stroke rehabilitation and may inspire new treatment strategies for individuals with apraxia of speech.
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Affiliation(s)
- Benjamin Stahl
- Department of Neurology, University Medicine Greifswald, Greifswald, Germany
- Department of Neurology, Charité Universitätsmedizin Berlin, Berlin, Germany
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
- Psychologische Hochschule Berlin, Berlin, Germany
- * E-mail:
| | - Bianca Gawron
- Department of Speech Science, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Frank Regenbrecht
- Clinic for Cognitive Neurology, University Hospital Leipzig, Leipzig, Germany
| | - Agnes Flöel
- Department of Neurology, University Medicine Greifswald, Greifswald, Germany
- Department of Neurology, Charité Universitätsmedizin Berlin, Berlin, Germany
- German Center for Neurodegenerative Diseases, Rostock and Greifswald, Germany
| | - Sonja A. Kotz
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
- Department of Neuropsychology and Psychopharmacology, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
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Sidtis JJ, Mubeen MA, Asaei A, Ardekani B, Van Lancker Sidtis D. Performance and Function Meet Structure: A White Matter Connection Tuned for Vocal Production. Brain Connect 2019; 8:628-636. [PMID: 30430846 PMCID: PMC6308290 DOI: 10.1089/brain.2018.0627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Contemporary imaging techniques have increased the potential for establishing how brain regions interact during spoken language. Some imaging methods report bilateral changes in brain activity during speech, whereas another approach finds that the relationship between individual variability in speech measures and individual variability in brain activity more closely resembles clinical observations. This approach has repeatedly demonstrated that speaking rate for phonological and lexical items can be predicted by an inverse relationship between cerebral blood flow in the left inferior frontal region and the right caudate nucleus. To determine whether morphology contributes to this relationship, we examined ipsilateral and contralateral white matter connections between these structures using diffusion tensor imaging, and we further assessed possible relationships between morphology and selected acoustic measures of participants' vocal productions. The ipsilateral connections between the inferior frontal regions and the caudate nuclei had higher average fractional anisotropy and mean diffusivity values than the contralateral connections. Neither contralateral connection between inferior frontal and caudate regions showed a significant advantage on any of the average morphology measures. However, individual differences in white matter morphology were significantly correlated with individual differences in vocal amplitude and frequency stability in the left frontal–right caudate connection. This cortical–striatal connection may be “tuned” for a role in the coordination of cortical and subcortical activity during speech. The structure–function relationship in this cortical-subcortical pathway supports the previous observation of a predictive pattern of cerebral blood flow during speech and may reflect a mechanism that ensures left-hemisphere control of the vocal expression of propositional language.
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Affiliation(s)
- John J Sidtis
- 1 Brain and Behavior Laboratory, Geriatrics Department, The Nathan Kline Institute for Psychiatric Research, Orangeburg, New York.,2 Department of Psychiatry, New York University Langone School of Medicine, New York, New York
| | - Muhammad Asim Mubeen
- 1 Brain and Behavior Laboratory, Geriatrics Department, The Nathan Kline Institute for Psychiatric Research, Orangeburg, New York
| | - Ali Asaei
- 1 Brain and Behavior Laboratory, Geriatrics Department, The Nathan Kline Institute for Psychiatric Research, Orangeburg, New York
| | - Babak Ardekani
- 3 Center for Biomedical Imaging and Neuromodulation, The Nathan Kline Institute for Psychiatric Research, Orangeburg, New York
| | - Diana Van Lancker Sidtis
- 1 Brain and Behavior Laboratory, Geriatrics Department, The Nathan Kline Institute for Psychiatric Research, Orangeburg, New York.,4 Department of Communicative Sciences and Disorders, New York University Steinhardt School, New York, New York
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Van Lancker Sidtis D, Sidtis JJ. Cortical-subcortical production of formulaic language: A review of linguistic, brain disorder, and functional imaging studies leading to a production model. Brain Cogn 2018; 126:53-64. [PMID: 30176549 PMCID: PMC6310163 DOI: 10.1016/j.bandc.2018.08.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 08/23/2018] [Accepted: 08/26/2018] [Indexed: 11/27/2022]
Abstract
Formulaic language forms about one-fourth of everyday talk. Formulaic (fixed expressions) and novel (grammatical language) differ in important characteristics. The features of idioms, slang, expletives, proverbs, aphorisms, conversational speech formulas, and other fixed expressions include ranges of length, flexible cohesion, memory storage, nonliteral and situation meaning, and affective content. Neurolinguistic observations in persons with focal brain damage or progressive neurological disease suggest that producing formulaic expressions can be achieved by interactions between the right hemisphere and subcortical structures. The known functional characteristics of these structures form a compatible substrate for production of formulaic expressions. Functional imaging using a performance-based analysis supported a right hemisphere involvement in producing conversational speech formulas, while indicating that the pause fillers, uh and um, engage the left hemisphere and function like lexical items. Together these findings support a dual-process model of language, whereby formulaic and grammatical language are modulated by different cerebral structures.
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Affiliation(s)
- Diana Van Lancker Sidtis
- Department of Communicative Sciences and Disorders, New York University Steinhardt School, New York, NY, USA; Brain and Behavior Laboratory, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA.
| | - John J Sidtis
- Brain and Behavior Laboratory, The Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA; Department of Psychiatry, New York University Langone School of Medicine, New York, NY, USA
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Sidtis DVL, Sidtis JJ. The Affective Nature of Formulaic Language: A Right-Hemisphere Subcortical Process. Front Neurol 2018; 9:573. [PMID: 30087650 PMCID: PMC6066536 DOI: 10.3389/fneur.2018.00573] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 06/25/2018] [Indexed: 11/13/2022] Open
Abstract
Formulaic expressions naturally convey affective content. The unique formal and functional characteristics of idioms, slang, expletives, proverbs, conversational speech formulas, and the many other conventional expressions in this repertory have been well-described: these include unitary form, conventionalized and non-literal meanings, and reliance on social context. Less highlighted, but potent, is the intrinsic presence of affective meaning. Expletives, for example, signal strong emotion. Idioms, too, inherently communicate emotional connotations, and conversational speech formulas allow for empathetic bonding and humor. The built-in affective content of formulaic expressions, in combination with their other unique characteristics, is compatible with the proposal that brain structures other than those representing grammatical language are in play in producing formulaic expressions. Evidence is presented for a dual process model of language, whereby a right hemisphere-subcortical system modulates formulaic language.
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Affiliation(s)
| | - John J Sidtis
- Communicative Sciences and Disorders, New York University, New York, NY, United States
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