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Neuropsychologia Feb 2022Developmental dyscalculia (DD) is a specific learning disability affecting the development of numerical and arithmetical skills. The origin of DD is typically attributed...
Developmental dyscalculia (DD) is a specific learning disability affecting the development of numerical and arithmetical skills. The origin of DD is typically attributed to the suboptimal functioning of key regions within the dorsal visual stream (parietal cortex) which support numerical cognition. While DD individuals are often impaired in visual numerosity perception, the extent to which they also show a wider range of visual dysfunctions is poorly documented. In the current study we measured sensitivity to global motion (translational and flow), 2D static form (Glass patterns) and 3D structure from motion in adults with DD and control subjects. While sensitivity to global motion was comparable across groups, thresholds for static form and structure from motion were higher in the DD compared to the control group, irrespective of associated reading impairments. Glass pattern sensitivity predicted numerical abilities, and this relation could not be explained by recently reported differences in visual crowding. Since global form sensitivity has often been considered an index of ventral stream function, our findings could indicate a cortical dysfunction extending beyond the dorsal visual stream. Alternatively, they would fit with a role of parietal cortex in form perception under challenging conditions requiring multiple element integration.
Topics: Adult; Dyscalculia; Form Perception; Humans; Mathematics; Motion Perception; Parietal Lobe; Visual Perception
PubMed: 34990696
DOI: 10.1016/j.neuropsychologia.2021.108140 -
Cerebellum & Ataxias 2017Mathematicians and scientists have struggled to adequately describe the of mathematics. Nobel laureates Albert Einstein and Eugene Wigner were perplexed by this issue,...
BACKGROUND
Mathematicians and scientists have struggled to adequately describe the of mathematics. Nobel laureates Albert Einstein and Eugene Wigner were perplexed by this issue, with Wigner concluding that the workability of mathematics in the real world is a mystery we cannot explain. In response to this classic enigma, the major purpose of this article is to provide a theoretical model of the ultimate origin of mathematics and "number sense" (as defined by S. Dehaene) that is proposed to involve the learning of inverse dynamics models through the collaboration of the cerebellum and the cerebral cortex (but prominently cerebellum-driven). This model is based upon (1) the modern definition of mathematics as the "science of patterns," (2) cerebellar sequence (pattern) detection, and (3) findings that the manipulation of numbers is automated in the cerebellum. This cerebro-cerebellar approach does necessarily conflict with mathematics or number sense models that focus on brain functions associated with especially the intraparietal sulcus region of the cerebral cortex. A direct corollary purpose of this article is to offer a cerebellar inner speech explanation for difficulty in developing "number sense" in developmental dyscalculia.
RESULTS
It is argued that during infancy the cerebellum learns (1) a first tier of internal models for a primitive physics that constitutes the foundations of visual-spatial working memory, and (2) a second (and more abstract) tier of internal models based on (1) that learns "number" and relationships among dimensions across the primitive physics of the first tier. Within this context it is further argued that difficulty in the early development of the second tier of abstraction (and "number sense") is based on the more demanding attentional requirements imposed on cerebellar inner speech executive control during the learning of cerebellar inverse dynamics models. Finally, it is argued that finger counting improves (does not originate) "number sense" by extending focus of attention in executive control of cerebellar inner speech.
DISCUSSION
It is suggested that (1) the origin of mathematics has historically been an enigma only because it is learned below the level of conscious awareness in cerebellar internal models, (2) understandings of the development of "number sense" and developmental dyscalculia can be advanced by first understanding the ultimate foundations of number and mathematics do not simply originate in the cerebral cortex, but rather in cerebro-cerebellar collaboration (predominately driven by the cerebellum).
CONCLUSION
It is concluded that difficulty with "number sense" results from the extended demands on executive control in learning inverse dynamics models associated with cerebellar inner speech related to the second tier of abstraction (numbers) of the infant's primitive physics.
PubMed: 28748095
DOI: 10.1186/s40673-017-0070-x -
Journal of Neurology, Neurosurgery, and... Nov 2016Existing literature suggests that the presence or absence of apraxia and associated parietal deficits may be clinically relevant in differential diagnosis of dementia...
INTRODUCTION
Existing literature suggests that the presence or absence of apraxia and associated parietal deficits may be clinically relevant in differential diagnosis of dementia syndromes.
AIM
This study investigated the profile of these features in Alzheimer's disease (AD) and frontotemporal dementia (FTD) spectrum disorders, at first presentation.
METHODS
Retrospective case note analysis was undertaken in 111 patients who presented to the Oxford Cognitive Disorders Clinic, Oxford, UK, including 29 amnestic AD, 12 posterior cortical atrophy (PCA), 12 logopenic primary progressive aphasia (lvPPA), 20 behavioural variant FTD (bvFTD), 7 non-fluent variant PPA (nfvPPA), 6 semantic variant PPA (svPPA) and 25 patients with subjective cognitive impairment (SCI). The clinical features of interest were: limb apraxia, apraxia of speech (AOS), and left parietal symptoms of dyslexia, dysgraphia, and dyscalculia.
RESULTS
The prevalence of limb apraxia was highest in PCA, amnestic AD, lvPPA and nfvPPA. AOS was only observed in nfvPPA. Associated parietal features were more prevalent in AD spectrum than FTD spectrum disorders. Group comparisons between key differential diagnostic challenges showed that lvPPA and nfvPPA could be significantly differentiated on the presence of left parietal features and AOS, and amnestic AD could be differentiated from bvFTD, svPPA and SCI by limb apraxia. Regression analysis showed that limb apraxia could successfully differentiate between AD and FTLD spectrum disorders with 83% accuracy.
DISCUSSION
Disease-specific profiles of limb apraxia and associated deficits can be observed. FTD and AD spectrum disorders can be difficult to differentiate due to overlapping cognitive symptoms, and measures of apraxia, in particular, appear to be a promising discriminator.
Topics: Aged; Alzheimer Disease; Apraxias; Diagnosis, Differential; Female; Follow-Up Studies; Frontotemporal Dementia; Humans; Male; Middle Aged; Retrospective Studies
PubMed: 27251676
DOI: 10.1136/jnnp-2015-312945 -
Frontiers in Human Neuroscience 2020Developmental dyscalculia (DD) is a learning disability affecting the acquisition of numerical-arithmetical skills. Affected people show persistent deficits in number...
Developmental dyscalculia (DD) is a learning disability affecting the acquisition of numerical-arithmetical skills. Affected people show persistent deficits in number processing, which are associated with aberrant brain activation and structure. Reduced gray matter has been reported in DD for the parietal cortex including the intraparietal sulcus (IPS), but also the frontal and occipito-temporal cortex. Furthermore, dyscalculics show white matter differences for instance in the inferior (ILF) and superior longitudinal fasciculus (SLF). However, the longitudinal development of these structural differences is unknown. Therefore, our goal was to investigate the developmental trajectory of gray and white matter in children with and without DD. In this longitudinal study, neuropsychological measures and T1-weighted structural images were collected twice with an interval of 4 years from 13 children with DD (8.2-10.4 years) and 10 typically developing (TD) children (8.0-10.4 years). Voxel-wise estimation of gray and white matter volumes was assessed using voxel-based morphometry for longitudinal data. The present findings reveal for the first time that DD children show persistently reduced gray and white matter volumes over development. Reduced gray matter was found in the bilateral inferior parietal lobes including the IPS, supramarginal gyri, left precuneus, cuneus, right superior occipital gyrus, bilateral inferior and middle temporal gyri, and insula. White matter volumes were reduced in the bilateral ILF and SLF, inferior fronto-occipital fasciculus (IFOF), corticospinal tracts, and right anterior thalamic radiation (ATR). Behaviorally, children with DD performed significantly worse in various numerical tasks at baseline and follow-up, corroborating persistent deficits in number processing. The present results are in line with the literature showing that children with DD have reduced gray and white matter volumes in the numerical network. Our study further sheds light on the trajectory of brain development, revealing that these known structural differences in the long association fibers and the adjacent regions of the temporal- and frontoparietal cortex persist in dyscalculic children from childhood into adolescence. In conclusion, our results underscore that DD is a persistent learning disorder accompanied by deficits in number processing and reduced gray and white matter volumes in number related brain areas.
PubMed: 32765241
DOI: 10.3389/fnhum.2020.00272 -
Frontiers in Psychiatry 2022The transition of teaching from in-person to Distance Learning (DL) due to the COVID-19 pandemic led to negative effects on students' psychological wellbeing and...
BACKGROUND
The transition of teaching from in-person to Distance Learning (DL) due to the COVID-19 pandemic led to negative effects on students' psychological wellbeing and academic achievement. The worst consequences have been experienced by students with so-called , as well as by their parents. However, very little emphasis has been placed on the effects of DL in students with Specific Learning Disorders (SLD). The present work aimed to evaluate the effects of DL during the COVID-19 lockdown in Italian students with SLD and in their parents.
METHODS
An online survey was administered to 92 students with SLD and their parents after the COVID-19 lockdown. The survey consisted of four sections: participants' demographic information; perceived stress related to general aspects (i.e., social and family determinants) as well as specific aspects related to DL; attitudes and feelings toward DL; and academic grades before and after DL.
RESULTS
Students with SLD perceived stress mainly from social isolation/distancing and DL ( always ≤ 0.0001), especially from online classes and oral exams ( always ≤ 0.0001). Students who did not benefit from appropriate accommodations (i.e., individualized teaching and learning methods) during DL perceived 3 times more DL-related stress than those who used them as in-person learning (OR = 3.00, CI 95%: 1.24-7.28, = 0.015). Girls perceived more stress from online lessons (OR = 0.40, CI 95%: 0.16-0.96, = 0.04) and use of devices (OR = 0.33, CI 95%: 0.14-0.80, = 0.015) than boys. Negative feelings (less motivation, reduced ability to understand lessons, interact, and stay focused) and positive feelings (less anxiety and more self-confidence with its own rate of learning) toward DL emerged. Higher academic grades also was observed after DL ( ≤ 0.0001). Lastly, strong and positive correlations emerged between students' and parents' perceived stress during DL ( always < 0.001).
IMPLICATIONS
The present study prompts special considerations for students with special educational needs not only when providing conventional instruction, but especially when it is necessary to suddenly modify teaching approaches.
PubMed: 36339862
DOI: 10.3389/fpsyt.2022.995484 -
Current Biology : CB Feb 2023The Venus flytrap Dionaea muscipula estimates prey nutrient content by counting trigger hair contacts initiating action potentials (APs) and calcium waves traveling all...
The Venus flytrap Dionaea muscipula estimates prey nutrient content by counting trigger hair contacts initiating action potentials (APs) and calcium waves traveling all over the trap. A first AP is associated with a subcritical rise in cytosolic calcium concentration, but when the second AP arrives in time, calcium levels pass the threshold required for fast trap closure. Consequently, memory function and decision-making are timed via a calcium clock. For higher numbers of APs elicited by the struggling prey, the Ca clock connects to the networks governed by the touch hormone jasmonic acid (JA), which initiates slow, hermetic trap sealing and mining of the animal food stock. Two distinct phases of trap closure can be distinguished within Dionaea's hunting cycle: (1) very fast trap snapping requiring two APs and crossing of a critical cytosolic Ca level and (2) JA-dependent slow trap sealing and prey processing induced by more than five APs. The Dionaea mutant DYSC is still able to fire touch-induced APs but does not snap close its traps and fails to enter the hunting cycle after prolonged mechanostimulation. Transcriptomic analyses revealed that upon trigger hair touch/AP stimulation, activation of calcium signaling is largely suppressed in DYSC traps. The observation that external JA application restored hunting cycle progression together with the DYSC phenotype and its transcriptional landscape indicates that DYSC cannot properly read, count, and decode touch/AP-induced calcium signals that are key in prey capture and processing.
Topics: Animals; Droseraceae; Action Potentials; Dyscalculia; Calcium
PubMed: 36693369
DOI: 10.1016/j.cub.2022.12.058 -
Frontiers in Psychology 2022Math difficulties (MD) manifest across various domain-specific and domain-general abilities. However, the existing cognitive profile of MD is incomplete and thus not...
Math difficulties (MD) manifest across various domain-specific and domain-general abilities. However, the existing cognitive profile of MD is incomplete and thus not applicable in typical settings such as schools or clinics. So far, no review has applied inclusion criteria according to DSM or ICD, summarized domain-specific abilities or examined the validity of response time scores for MD identification. Based upon stringent clinical criteria, the current meta-analysis included 34 studies which compared cognitive performances of a group with MD ( = 680) and a group without MD ( = 1565). Criteria according to DSM and ICD were applied to identify MD (percentile rank ≤ 16, age range 8-12 years, no comorbidities/low IQ). Effect sizes for 22 abilities were estimated and separated by their level and type of scoring (AC = accuracy, RT = response time). A cognitive profile of MD was identified, characterized by distinct weaknesses in: (a) computation (calculation [AC], fact retrieval [AC]), (b) number sense (quantity processing [AC], quantity-number linking [RT], numerical relations [AC]), and (c) visual-spatial short-term storage [AC]. No particular strength was found. Severity of MD, group differences in reading performance and IQ did not significantly moderate the results. Further analyses revealed that (a) effects are larger when dealing with numbers or number words than with quantities, (b) MD is not accompanied by any weakness in abilities typically assigned to reading, and (c) weaknesses in visual-spatial short-term storage emphasize the notion that number and space are interlinked. The need for high-quality studies investigating domain-general abilities is discussed.
PubMed: 35360597
DOI: 10.3389/fpsyg.2022.842391 -
Cerebral Cortex (New York, N.Y. : 1991) May 2023The purpose of this study is to identify consistencies across functional neuroimaging studies regarding common and unique brain regions/networks for individuals with... (Meta-Analysis)
Meta-Analysis
The purpose of this study is to identify consistencies across functional neuroimaging studies regarding common and unique brain regions/networks for individuals with reading difficulties (RD) and math difficulties (MD) compared to typically developing (TD) individuals. A systematic search of the literature, utilizing multiple databases, yielded 116 functional magnetic resonance imaging and positron emission tomography studies that met the criteria. Coordinates that directly compared TD with either RD or MD were entered into GingerALE (Brainmap.org). An activation likelihood estimate (ALE) meta-analysis was conducted to examine common and unique brain regions for RD and MD. Overall, more studies examined RD (n = 96) than MD (n = 20). Across studies, overactivation for reading and math occurred in the right insula and inferior frontal gyrus for atypically developing (AD) > TD comparisons, albeit in slightly different areas of these regions; however, inherent threshold variability across imaging studies could diminish overlying regions. For TD > AD comparisons, there were no similar or overlapping brain regions. Results indicate there were domain-specific differences for RD and MD; however, there were some similarities in the ancillary recruitment of executive functioning skills. Theoretical and practical implications for researchers and educators are discussed.
Topics: Humans; Reading; Dyslexia; Likelihood Functions; Brain; Cognition; Magnetic Resonance Imaging
PubMed: 36758954
DOI: 10.1093/cercor/bhad013 -
Journal of Alzheimer's Disease : JAD 2022The established causative mutations in the APP, PSEN1, and PSEN2 can explain less than 1%,Alzheimer's disease (AD) patients. Of the identified variants, the PSEN2...
BACKGROUND
The established causative mutations in the APP, PSEN1, and PSEN2 can explain less than 1%,Alzheimer's disease (AD) patients. Of the identified variants, the PSEN2 mutations are even less common.
OBJECTIVE
With the genetic study from the dementia cohort of Peking Union Medical College Hospital (PUMCH), we aim to illustrate the PSEN2 mutation spectrum and novel functionally validated mutations in Chinese AD patients.
METHODS
702 AD participants, aged 30-85, were identified in PUMCH dementia cohort. They all received history inquiry, physical examination, biochemical test, cognitive evaluation, brain CT/MRI, and next-generation DNA sequencing. Functional analysis was achieved by transfection of the HEK293 cells with plasmids harboring the wild-type PSEN2 or candidate mutations.
RESULTS
Nine PSEN2 rare variants were found, including two reported (M239T, R62C) and seven novel variants (N141S, I368F, L396I, G117X, I146T, S147N, H220Y). The HEK293 cells transfected with the PSEN2 N141S, M239T, I368F plasmids showed higher Aβ42 and Aβ42/Aβ40 levels relative to the wild-type PSEN2. The PSEN2 L396I, G117X, S147N, H220Y, and R62C did not alter Aβ42, Aβ40 levels, or Aβ42/Aβ40 ratio. 1.9%,(13/702) subjects harbored rare PSEN2 variants. 0.4%,(3/702) subjects carried pathogenic/likely pathogenic PSEN2 mutations. The three subjects with the functionally validated PSEN2 mutations were all familial early-onset AD patients. The common symptoms included amnesia and mental symptom. Additionally, the M239T mutation carrier presented with dressing apraxia, visuospatial agraphia, dyscalculia and visual mislocalization.
CONCLUSION
The PSEN2 N141S, M239T, and I368F are functionally validated mutations.
Topics: Alzheimer Disease; Amyloid beta-Protein Precursor; HEK293 Cells; Humans; Mutation; Presenilin-2
PubMed: 35491795
DOI: 10.3233/JAD-220194 -
Frontiers in Psychology 2022This paper summarizes a theory of cognitive development and elaborates on its educational implications. The theory postulates that development occurs in cycles along...
This paper summarizes a theory of cognitive development and elaborates on its educational implications. The theory postulates that development occurs in cycles along multiple fronts. Cognitive competence in each cycle comprises a different profile of executive, inferential, and awareness processes, reflecting changes in developmental priorities in each cycle. Changes reflect varying needs in representing, understanding, and interacting with the world. Interaction control dominates episodic representation in infancy; attention control and perceptual awareness dominate in realistic representations in preschool; inferential control and awareness dominate rule-based representation in primary school; truth and validity control and precise self-evaluation dominate in principle-based thought in adolescence. We demonstrate that the best predictors of school learning in each cycle are the cycle's cognitive priorities. Also learning in different domains, e.g., language and mathematics, depends on an interaction between the general cognitive processes dominating in each cycle and the state of the representational systems associated with each domain. When a representational system is deficient, specific learning difficulties may emerge, e.g., dyslexia and dyscalculia. We also discuss the educational implications for evaluation and learning at school.
PubMed: 36248549
DOI: 10.3389/fpsyg.2022.954971