Aerobic exercise improves verbal working memory sub-processes in adolescents: behavioral evidence from an N-back task

Background

Studies on the effects of aerobic exercise on working memory (WM) have mainly concentrated on the overall effects, yet there is little knowledge on how moderate intensity aerobic exercise impacts the sub-processes of verbal WM (VWM) in adolescents. To address this gap, two experiments were conducted to explore the influence of aerobic exercise on the maintenance and updating sub-processes of VWM.

Methods

In Experiment 1, a mixed experimental design of 2 (exercise habit: high vs. low) × 3 (memory load: 0-back vs. 1-back vs. 2-back) was used to compare VWM and its sub-processes in 40 adolescents. In Experiment 2, a 2 (group: intervention vs. control) × 3 (time point: pretest vs. 1st post-test vs. 18th post-test) × 3 (memory load: 0-back vs. 1-back vs. 2-back) mixed experimental design was used to investigate the acute and long-term effects of moderate intensity aerobic exercise on VWM and its sub-processes in 24 adolescents with low exercise habits.

Results

The results of Experiment 1 showed that VWM performance and its sub-processes in the high exercise habit group were better than those in the low exercise habit group. The results of Experiment 2 showed that the effects of the long-term exercise intervention were superior to those of the acute exercise intervention, and both were superior to the pretest. Meanwhile, it was found that aerobic exercise intervention had a greater effect size on the updating sub-process of VWM.

Conclusion

In conclusion, the results indicated that moderate intensity aerobic exercise could enhance the performance of VWM and its sub-processes in adolescents, and long-term intervention showed greater improvement effects compared to acute intervention, especially in the updating sub-process of VWM.

The impact of early and late blindness on language and verbal working memory: A brain-constrained neural model

Neural circuits related to language exhibit a remarkable ability to reorganize and adapt in response to visual deprivation. Particularly, early and late blindness induce distinct neuroplastic changes in the visual cortex, repurposing it for language and semantic processing. Interestingly, these functional changes provoke a unique cognitive advantage - enhanced verbal working memory, particularly in early blindness. Yet, the underlying neuromechanisms and the impact on language and memory-related circuits remain not fully understood. Here, we applied a brain-constrained neural network mimicking the structural and functional features of the frontotemporal-occipital cortices, to model conceptual acquisition in early and late blindness. The results revealed differential expansion of conceptual-related neural circuits into deprived visual areas depending on the timing of visual loss, which is most prominent in early blindness. This neural recruitment is fundamentally governed by the biological principles of neural circuit expansion and the absence of uncorrelated sensory input. Critically, the degree of these changes is constrained by the availability of neural matter previously allocated to visual experiences, as in the case of late blindness. Moreover, we shed light on the implication of visual deprivation on the neural underpinnings of verbal working memory, revealing longer reverberatory neural activity in 'blind models' as compared to the sighted ones. These findings provide a better understanding of the interplay between visual deprivations, neuroplasticity, language processing and verbal working memory.

The impact of spatial and verbal working memory load on semantic relatedness judgements

Studies using a relatedness judgement task have found differences between prime-target word pairs that vary in the degree of semantic relatedness. However, the influence of working memory load on semantic processing in this task and the role of the type of working memory task have not yet been investigated. The present study therefore investigated for the first time the effect of working memory load (low vs. high) and working memory type (verbal vs. spatial) on semantic relatedness judgements. Semantically strongly related (e.g., hip - KNEE), weakly related (e.g., muscle - KNEE) and unrelated (e.g., office - KNEE) Polish word pairs were presented in an experiment involving a dual working memory and semantic relatedness task. The data revealed that, relative to semantically unrelated word pairs, responses were faster for strongly related pairs but slower for weakly related pairs. Importantly, the verbal working memory task decreased facilitation for strongly related pairs and increased inhibition for weakly related pairs relative to the spatial working memory task. Furthermore, working memory load impacted only weakly related pairs in the verbal but not in the spatial working memory task. These results show that working memory type and load influence semantic relatedness judgements, but the direction and size of the impact depend on the strength of semantic relations.

Heterogeneity and overlap in the continuum of linguistic profile of logopenic and semantic variants of primary progressive aphasia: a Profile Analysis based on Multidimensional Scaling study

BACKGROUND

Primary progressive aphasia (PPA) diagnostic criteria underestimate the complex presentation of semantic (sv) and logopenic (lv) variants, in which symptoms partially overlap, and mixed clinical presentation (mixed-PPA) and heterogenous profile (lvPPA +) are frequent. Conceptualization of similarities and differences of these clinical conditions is still scarce.

METHODS

Lexical, semantic, phonological, and working memory errors from nine language tasks of sixty-seven PPA were analyzed using Profile Analysis based on Multidimensional Scaling, which allowed us to create a distributed representation of patients' linguistic performance in a shared space. Patients had been studied with [18F] FDG-PET. Correlations were performed between metabolic and behavioral data.

RESULTS

Patients' profiles were distributed across a continuum. All PPA, but two, presented a lexical retrieval impairment, in terms of reduced production of verbs and nouns. svPPA patients occupied a fairly clumped space along the continuum, showing a preponderant semantic deficit, which correlated to fusiform gyrus hypometabolism, while only few presented working memory deficits. Adjacently, lvPPA + presented a semantic impairment combined with phonological deficits, which correlated with metabolism in the anterior fusiform gyrus and posterior middle temporal gyrus. Starting from the shared phonological deficit side, a large portion of the space was occupied by all lvPPA, showing a combination of phonological, lexical, and working memory deficits, with the latter correlating with posterior temporo-parietal hypometabolism. Mixed PPA did not show unique profile, distributing across the space.

DISCUSSION

Different clinical PPA entities exist but overlaps are frequent. Identifying shared and unique clinical markers is critical for research and clinical practice. Further research is needed to identify the role of genetic and pathological factors in such distribution, including also higher sample size of less represented groups.

Truthful yet misleading: Elementary second-order deception in school-age children and its sociocognitive correlates

In highly competitive contexts, deceptive intentions might be transparent, so conveying only false information to the opponent can become a predictable strategy. In such situations, alternating between truths and lies (second-order lying behavior) represents a less foreseeable option. The current study investigated the development of 8- to 10-year-old children's elementary second-order deception in relation to their attribution of ignorance (first- and second-order ignorance) and executive functions (inhibitory control, shifting ability, and verbal working memory). An adapted version of the hide-and-seek paradigm was used to assess children's second-order lie-telling, in which children were asked to hide a coin in either of their hands. Unlike the standard paradigm, the opponent did not consistently look for the coin in the location indicated by the children, so children needed to switch between telling simple lies and truths (elementary second-order lies about the coin location) to successfully deceive the recipient. The results showed that older children were less likely to tell elementary second-order lies. However, across the sample, when children decided to lie, this ability was positively related to their second-order ignorance attribution and their verbal working memory. Moreover, we obtained preliminary evidence for the presence of a habituation effect in second-order lying, with children being more accurate and having less variability in their truthful-to-deceive responses (this being the more frequently elicited response) than when telling lies to deceive. Our findings could have implications for understanding the mechanisms underlying children's ability to alternate between truths and lies to deceive.

Lexico-syntactic constraints influence verbal working memory in sentence-like lists

We test predictions from the language emergent perspective on verbal working memory that lexico-syntactic constraints should support both item and order memory. In natural language, long-term knowledge of lexico-syntactic patterns involving part of speech, verb biases, and noun animacy support language comprehension and production. In three experiments, participants were presented with randomly generated dative-like sentences or lists in which part of speech, verb biases, and animacy of a single word were manipulated. Participants were more likely to recall words in the correct position when presented with a verb over a noun in the verb position, a good dative verb over an intransitive verb in the verb position, and an animate noun over an inanimate noun in the subject noun position. These results demonstrate that interactions between words and their context in the form of lexico-syntactic constraints influence verbal working memory.

Sequential syntactic knowledge supports item but not order recall in verbal working memory

Previous studies have shown that psycholinguistic effects such as lexico-semantic knowledge effects mainly determine item recall in verbal working memory (WM). However, we may expect that syntactic knowledge, involving knowledge about word-level sequential aspects of language, should also impact serial-order aspects of recall in WM. Evidence for this assumption is scarce and inconsistent and has been conducted in language with deterministic syntactic rules. In languages such as French, word position is determined in a probabilistic manner: an adjective is placed before or after a noun, depending on its lexico-semantic properties. We exploited this specificity of the French language for examining the impact of syntactic positional knowledge on both item and serial order recall in verbal WM. We presented lists with adjective-noun pairs for immediate serial recall, the adjectives being in regular or irregular position relative to the nouns. We observed increased recall performance when adjectives occurred in regular position; this effect was observed for item recall but not order recall scores. We propose an integration of verbal WM and syntactic processing models to account for this finding by assuming that the impact of syntactic knowledge on serial-order WM recall is indirect and mediated via syntax-dependent item-retrieval processes.

Production of Sentential Negation in German and Italian Non-fluent Aphasia

The ability of persons with non-fluent aphasia (PWAs) to produce sentential negation has been investigated in several languages, but only in small samples. Accounts of (morpho)syntactic impairment in PWAs have emphasized various factors, such as whether the negative marker blocks or interferes with verb movement, the position of the Negation Phrase in the syntactic hierarchy or the interpretability of negation. This study investigates the ability of German- and Italian-speaking PWAs to construct negative sentences, as well as the role of verbal working memory (WM) capacity and education in task performance and production of sentential negation. German and Italian differ in the syntactic properties of the negative markers that are relevant here (nicht and non, respectively). A sentence anagram task tapping into the construction of negative and affirmative declarative sentences was administered to 9 German- and 7 Italian-speaking PWAs, and to 14 German- and 11 Italian-speaking age- and education-matched healthy volunteers. We fitted generalized linear mixed-effects models to the datasets. There was no significant difference between negative and affirmative sentences in either group of PWAs. There was a main effect of verbal WM capacity on task performance, but no interaction between verbal WM capacity and production of negative vs. affirmative sentences. Education did not affect task performance. The results are discussed in light of different linguistically-informed accounts of (morpho)syntactic impairment in non-fluent aphasia.

The role of left temporo-parietal and inferior frontal cortex in comprehending syntactically complex sentences: A brain stimulation study

BACKGROUND AND OBJECTIVES

Syntactic competence relies on a left-lateralized network converging on hubs in inferior-frontal and posterior-temporal cortices. We address the question whether anodal transcranial direct current stimulation (a-tDCS) over these hubs can modulate comprehension of sentences, whose syntactic complexity systematically varied along the factors embedding depths and canonicity. Semantic content and length of the sentences were kept identical and forced choice picture matching was required after the full sentence had been presented.

METHODS

We used a single-blind, within-subject, sham-controlled design, applying a-tDCS targeting left posterior tempo-parietal (TP) and left inferior frontal cortex (FC). Stimulation sites were determined by individual neuro-navigation. 20 participants were included of whom 19 entered the analysis. Results were analysed using (generalized) mixed models. In a pilot-experiment in another group of 20 participants we validated the manipulation of syntactic complexity by the two factors embedding depth and argument-order.

RESULTS

Reaction times increased and accuracy decreased with higher embedding depth and non-canonical argument order in both experiments. Notably a-tDCS over TP enhanced sentence-to-picture matching, while FC-stimulation showed no consistent effect. Moreover, the analysis disclosed a session effect, indicating improvements of task performance especially regarding speed.

CONCLUSIONS

We conclude that the posterior 'hub' of the neuronal network affording syntactic analysis represents a 'bottleneck', likely due to working-memory capacity and the challenges of mapping semantic to syntactic information allowing for role assignment. While this does not challenge the role of left inferior-frontal cortex for syntax processing and novel-grammar learning, the application of highly established syntactic rules during sentence comprehension may be considered optimized, thus not augmentable by a-tDCS in the uncompromised network.

SIGNIFICANCE STATEMENT

Anodal transcranial direct current stimulation (a-tDCS) over left temporo-parietal cortex enhances comprehension of complex sentences in uncompromised young speakers. Since a-tDCS over left frontal cortex did not elicit any change, the 'bottleneck' for the understanding of complex sentences seems to be the posterior, temporo-parietal rather than the anterior inferior-frontal 'hub' of language processing. Regarding the attested role of inferior-frontal cortex in syntax processing, we suggest that its function is optimized in competent young speakers, preventing further enhancement by (facilitatory) tDCS. Results shed light on the functional anatomy of syntax processing during sentence comprehension; moreover, they open perspectives for research in the lesioned language network of people with syntactic deficits due to aphasia.

Shape features of working memory-related deep-brain regions differentiate high and low community functioning in schizophrenia

We have previously shown that schizophrenia (SCZ) participants with high community functioning demonstrate better verbal working memory (vWM) performance relative to those with low community functioning. In the present study, we investigated whether neuroanatomical differences in regions supporting vWM also exist between schizophrenia groups that vary on community functioning. Utilizing magnetic resonance imaging, shape features of deep-brain nuclei known to be involved in vWM were calculated in samples of high functioning (HF-SCZ, n = 23) and low functioning schizophrenia participants (LF-SCZ, n = 18), as well as in a group of healthy control participants (CON, n = 45). Large deformation diffeomorphic metric mapping was employed to characterize surface anatomy of the caudate nucleus, globus pallidus, hippocampus, and thalamus. Statistical analyses involved linear mixed-effects models and vertex-wise contrast mapping to assess between-group differences in structural shape features, and Pearson correlations to evaluate relationships between shape metrics and vWM performance. We found significant between-group main effects in deep-brain surface anatomy across all structures. Post-hoc comparisons revealed HF-SCZ and LF-SCZ groups significantly differed on both caudate and hippocampal shape, however, significant correlations with vWM were only observed in hippocampal shape for both SCZ groups. Specifically, more abnormal hippocampal deformation was associated with lower vWM suggesting hippocampal shape is both a neural substrate for vWM deficits and a potential biomarker to predict or monitor the efficacy of cognitive rehabilitation. These findings add to a growing body of literature related to functional outcomes in schizophrenia by demonstrating unique shape patterns across the spectrum of community functioning in SCZ.

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Deep-brain abnormalities are present in patients regardless of functional severity.

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Caudate and hippocampal shape differ between community functioning-based groups.

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Verbal working memory relates to hippocampal shape in both patient groups.

Components of language processing and their long-term and working memory storage in the brain

There is a consensus that the temporal lobes are involved in representing various types of information critical for language processing, including phonological (i.e., speech sound), semantic (meaning), and orthographic (spelling) representations. An important question is whether the same regions that represent our long-term knowledge of phonology, semantics, and orthography are used to support the maintenance of these types of information in working memory (WM) (for instance, maintaining semantic information during sentence comprehension), or whether regions outside the temporal lobes provide the neural basis for WM maintenance in these domains. This review focuses on the issue of whether temporal lobe regions support WM for phonological information, with a brief discussion of related findings in the semantic and orthographic domains. Across all three domains, evidence from lesion-symptom mapping and functional neuroimaging indicates that parietal or frontal regions are critical for supporting WM, with different regions supporting WM in the three domains. The distinct regions in different domains argue against these regions as playing a general attentional role. The findings imply an interaction between the temporal lobe regions housing the long-term memory representations in these domains and the frontal and parietal regions needed to maintain these representations over time.

Visuospatial working memory and the construction of a spatial situation model in listening comprehension: An examination using a spatial tapping task

The present study investigated how visuospatial working memory (VSWM) is involved in the construction of a spatial situation model for spatial passages presented auditorily. A simple spatial tapping condition, a complex tapping condition as a target-tracking task, and a control condition, were used to analyze the role of VSWM. To understand how individuals who differ in verbal working memory (VWM) capacity (determined with a listening span test) process spatial text during dual-task performance, individual differences in VWM capacity were analyzed. In two experiments, the participants listened to a spatial text at the same time as performing a spatial concurrent task or no concurrent task. The results of the free recall test in Experiment 1 showed that there were no differences between the tapping conditions in the high VWM capacity group; the low VWM capacity group had a lower performance in both spatial tapping tasks compared to the control condition. The results of the map drawing test in Experiment 2 showed that complex spatial tapping impaired performance in comparison to simple spatial tapping and the control condition in the high VWM capacity group; in the low VWM capacity group, both spatial tapping tasks impaired recall performance. In addition, the participants with high VWM capacity demonstrated better performance. Overall, the results suggest that individuals with high VWM capacity have more resources to process verbal and spatial information than those with low VWM capacity, indicating that VWM capacity is related to the degree of the involvement of VSWM.

Eye-movements reveal the serial position of the attended item in verbal working memory

The problem of how the mind can retain sequentially organized information has a long research tradition that remains unresolved. While various computational models propose a mechanism of binding serial order information to position markers, the representational nature and processes that operate on these position markers are not clear. Recent behavioral work suggests that space is used to mark positions in serial order and that this process is governed by spatial attention. Based on the assumption that brain areas controlling spatial attention are also involved in saccadic planning, we continuously tracked the eye-movements as a direct measure of the spatial attention during retrieval from a verbal WM sequence. Participants memorized a sequence of auditory numbers. During retention, they heard a number-cue that did or did not belong to the memorized set. After this number-cue, a target-beep could be presented to which they had to respond if the number-cue belonged to the memorized sequence. In Experiment 1, the target-beep was either presented to the left or right ear, and in Experiment 2 bilaterally (removing any spatial aspect). We tested the hypothesis that systematic eye-movements are made when people retrieve items of sequences of auditory words and found that the retrieval of begin items resulted in leftward eye-movements and the retrieval of end items in rightward eye-movements. These observations indicate that the oculomotor system is also involved in the serial order processes in verbal WM thereby providing a promising novel approach to get insight into abstract cognitive processes.

The role of working memory and visual processing in prototype category learning

To investigate whetherworking memory and visual processing havethe same role or differentrolesin A/B and A/not A prototype category learning,the present study adoptedan A/Bor A/not A category learningtask in control and dual conditions. The results of Experiment 1 showed that an additional dual visual working memory taskrather thanadualverbal working memory task reduced accuracy of the A/B task, whereasnodual tasksinfluencedaccuracy of the A/not A task. The results of Experiment 2 revealed that an additionaldual visual processing task impairedaccuracy of the A/B task, whereas the dual visual processing task did not influence accuracy of the A/not Atask. These results indicate that visual working memory and visual processing play different roles in A/B and A/not A prototype category learning, andsupport that thesetwo types of prototype category learning are mediated by differentmemory systems.

Treatment of verbal short-term memory abilities to improve language function in aphasia: A case series treatment study

Recent approaches to interventions for aphasia have incorporated verbal short-term memory (STM) and working memory (WM) components. We investigated whether a treatment involving repetition of word sequences after a response delay would improve tolerance of increased verbal STM load in repetition and, consequently, improve performance on repetition and other language tasks. Eight individuals with aphasia participated. We used a single subject design with outcome measures on near-transfer tasks closely related to the treatment task and far-transfer tasks more distantly related to the treatment task. We minimized repeated presentation of stimuli in all phases of treatment to control for confounding effects of repeated exposure of treated items. Four participants demonstrated modest acquisition effects. On outcome measures, we observed improvements by some participants on near-transfer tasks, (repetition of concrete and abstract word strings and verbal spans) and far-transfer tasks (naming and discourse). Some participants demonstrated a significant decline in word repetition accuracy after a response delay before treatment, indicating difficulty in maintaining activation of linguistic representations. It was these participants who showed the most improvement on outcome measures. More studies are needed to determine who will respond to this treatment and what factors might influence the effectiveness of this treatment approach.

Comparing verbal working memory load in auditory and visual modalities using functional near-infrared spectroscopy

The verbal identity n-back task is commonly used to assess verbal working memory (VWM) capacity. Only three studies have compared brain activation during the n-back when using auditory and visual stimuli. The earliest study, a positron emission tomography study of the 3-back, found no differences in VWM-related brain activation between n-back modalities. In contrast, two subsequent functional magnetic resonance imaging (fMRI) studies of the 2-back found that auditory VWM was associated with greater left dorsolateral prefrontal cortex (DL-PFC) activation than visual VWM, perhaps suggesting that auditory VWM requires more cognitive effort than its visual counterpart. The current study aimed to assess whether DL-PFC activation (i.e., cognitive effort) differs by VWM modality. To do this, 16 younger adults completed an auditory and visual n-back, both at four levels of VWM load. Concurrently, activation of the PFC was measured using functional near-infrared spectroscopy (fNIRS), a silent neuroimaging method. We found that DL-PFC activation increased with VWM load, but it was not affected by VWM modality or the interaction between load and modality. This supports the view that both VWM modalities require similar cognitive effort, and perhaps that previous fMRI results were an artefact of scanner noise. We also found that, across conditions, DL-PFC activation was positively correlated with reaction time. This may further support DL-PFC activation as an index of cognitive effort, and fNIRS as a method to measure it.

The Effects of Phonological Short Term Memory on Lexical and Grammatical Production Skills in Persian Children with Developmental Language Disorder

The deficit in verbal working memory (vWM) skills has been frequently reported in children with developmental language disorder (DLD) and may contribute to their problems in language. This study aimed to compare the phonological short-term memory (pSTM) and linguistic skills between Persian-speaking children with DLD and typical language development (TLD) to explore the role that pSTM plays in lexical and grammatical problems of children with DLD. This study included 32 Persian-speaking children who were divided into two groups of DLD (n = 16) and TLD (n = 16) within the age range from 6 to 8 years. The Persian non-word repetition test was employed as the measure of pSTM. Lexical and grammatical indices were extracted from narrative generations. Independent-samples t test was used to analyze the group-related differences in vWM, lexical, and grammatical skills. Moreover, the one-way ANCOVA analysis by controlling for NWR was utilized as the covariate to investigate the effects of vWM on linguistic performances. According to the results, the children with DLD scored significantly lower on NWR task and all lexical and grammatical measures, compared to TLD children (P < 0.01, d > 1). The group-related differences disappeared after controlling for NWR (P > 0.05). The results show that Persian-speaking children with DLD experience significant difficulties in pSTM skills, which affect their lexical and grammatical performances.

Decoding verbal working memory representations of Chinese characters from Broca's area

Representations of sensory working memory can be found across the entire neocortex. But how are verbal working memory (VWM) contents retained in the human brain? Here we used fMRI and multi-voxel pattern analyses to study Chinese native speakers (15 males, 13 females) memorizing Chinese characters. Chinese characters are uniquely suitable to study VWM because verbal encoding is encouraged by their complex visual appearance and monosyllabic pronunciation. We found that activity patterns in Broca's area and left premotor cortex carried information about the memorized characters. These language-related areas carried (1) significantly more information about cued characters than those not cued for memorization, (2) significantly more information on the left than the right hemisphere and (3) significantly more information about Chinese symbols than complex visual patterns which are hard to verbalize. In contrast, early visual cortex carries a comparable amount of information about cued and uncued stimuli and is thus unlikely to be involved in memory retention. This study provides evidence for verbal working memory maintenance in a distributed network of language-related brain regions, consistent with distributed accounts of WM. The results also suggest that Broca's area and left premotor cortex form the articulatory network which serves articulatory rehearsal in the retention of verbal working memory contents.

Visual and verbal working memory loads interfere with scene-viewing

Working memory is thought to be divided into distinct visual and verbal subsystems. Studies of visual working memory frequently use verbal working memory tasks as control conditions and/or use articulatory suppression to ensure that visual load is not transferred to verbal working memory. Using these verbal tasks relies on the assumption that the verbal working memory load will not interfere with the same processes as visual working memory. In the present study, participants maintained a visual or verbal working memory load as they simultaneously viewed scenes while their eye movements were recorded. Because eye movements and visual working memory are closely linked, we anticipated the visual load would interfere with scene-viewing (and vice versa), while the verbal load would not. Surprisingly, both visual and verbal memory loads interfered with scene-viewing behavior, while eye movements during scene-viewing did not significantly interfere with performance on either memory task. These results suggest that a verbal working memory load can interfere with eye movements in a visual task.

Cognition in offspring of parents with psychotic and non-psychotic severe mental illness

BACKGROUND

Cognitive impairment is a feature of severe mental illness (SMI; schizophrenia, bipolar disorder, major depressive disorder). Psychotic forms of SMI may be associated with greater cognitive impairment, but it is unclear if this differential impairment pre-dates illness onset or whether it reflects a consequence of the disorder. To establish if there is a developmental impairment related to familial risk of psychotic SMI, we investigated cognition in offspring of parents with psychotic and non-psychotic SMI.

METHOD

Participants included 360 children and youth (mean age 11.10, SD 4.03, range 6-24), including 68 offspring of parents with psychotic SMI, 193 offspring of parents with non-psychotic SMI, and 99 offspring of control parents. The cognitive battery assessed a range of functions using standardized tests and executive function tasks from the Cambridge Automated Neuropsychological Test Battery.

RESULTS

Compared to controls, offspring of parents with psychotic SMI performed worse on overall cognition (β = -0.32; p < 0.001) and 6 of 15 cognitive domains, including verbal intelligence, verbal working memory, processing speed, verbal learning and memory, verbal fluency, and sustained attention. Offspring of parents with non-psychotic SMI performed worse than controls on 3 of the 15 domain specific cognitive tests, including verbal intelligence, visual memory and decision-making.

CONCLUSIONS

Widespread mild-to-moderate cognitive impairments are present in young offspring at familial risk for transdiagnostic psychotic SMI. Offspring at familial risk for non-psychotic SMI showed fewer and more specific impairments in the domains of verbal intelligence, visual memory and decision-making.

Neuromagnetic speech discrimination responses are associated with reading-related skills in dyslexic and typical readers

Poor neural speech discrimination has been connected to dyslexia, and may represent phonological processing deficits that are hypothesized to be the main cause for reading impairments. Thus far, neural speech discrimination impairments have rarely been investigated in adult dyslexics, and even less by examining sources of neuromagnetic responses. We compared neuromagnetic speech discrimination in dyslexic and typical readers with mismatch fields (MMF) and determined the associations between MMFs and reading-related skills. We expected weak and atypically lateralized MMFs in dyslexic readers, and positive associations between reading-related skills and MMF strength. MMFs were recorded to a repeating pseudoword /ta-ta/ with occasional changes in vowel identity, duration, or syllable frequency from 43 adults, 21 with confirmed dyslexia. Phonetic (vowel and duration) changes elicited left-lateralized MMFs in the auditory cortices. Contrary to our hypothesis, MMF source strengths or lateralization did not differ between groups. However, better verbal working memory was associated with stronger left-hemispheric MMFs to duration changes across groups, and better reading was associated with stronger right-hemispheric late MMFs across speech-sound changes in dyslexic readers. This suggests a link between neural speech processing and reading-related skills, in line with previous work. Furthermore, our findings suggest a right-hemispheric compensatory mechanism for language processing in dyslexia. The results obtained promote the use of MMFs in investigating reading-related brain processes.

The evolution of theory of mind (ToM) within the evolution of cerebellar sequence detection in stone-tool making and language: implications for studies of higher-level cognitive functions in degenerative cerebellar atrophy

INTRODUCTION

Within the context of Clausi, Olivito, Lupo, Siciliano, Bozzali and Leggio's (Cell Neurosci 12:510, 2019) insightful study of how prediction of theory of mind (ToM) is compromised in degenerative cerebellar atrophy, this article describes how prediction can also be understood as the cerebro-cerebellar system's capacity to rapidly shift attention to manipulate cause-and-effect relationships embedded in language.

METHOD

The evolution of the capacity of ToM is described within the evolution of stone-tool making, language, and the origin of the phonological loop in verbal working memory. Specifically, it is argued that this evolutionary framework offers a way to get further inside the prediction process by illuminating how sub-vocal speech evolved during stone-tool evolution due to its adaptive refinement of early human ability to manipulate and hold in memory progressively more detailed cause-and-effect relationships in the origin of verbal working memory.

CONCLUSION

The addition of sub-vocal speech/cause-and-effect relationship to the analysis of prediction provides an evolutionary model of the mechanisms of ToM, which, in turn, brings forward additional cerebro-cerebellar mechanisms which can (1) further support Clausi, Olivito, Lupo et al's findings and (2) shed light on additional mechanisms that might further clarify what might be behind cerebellar dysfunction in the construction of ToM. Problems encountered by cerebellar degenerative atrophy patients with the Faux pas test and Advanced ToM task with unexpected events may stem from a combination of an inability (1) of their cerebellar internal models to rapidly switch attention among cause-and-effect elements of the stories and (2) to extend cerebellar internal models to the prediction of the resulting similar but unexpected events. That is, with both (1) and (2) occurring at the same time, alternative meanings of causes and effects might be missed in both automatic and consciously manipulated sub-vocal verbal working memory. A method to measure sub-vocal speech in this context is suggested.

The effect of working memory maintenance on long-term memory

Initially inspired by the Atkinson and Shiffrin model, researchers have spent a half century investigating whether actively maintaining an item in working memory (WM) leads to improved subsequent long-term memory (LTM). Empirical results have been inconsistent, and thus the answer to the question remains unclear. We present evidence from 13 new experiments as well as a meta-analysis of 61 published experiments. Both the new experiments and meta-analysis show clear evidence that increased WM maintenance of a stimulus leads to superior recognition for that stimulus in subsequent LTM tests. This effect appears robust across a variety of experimental design parameters, suggesting that the variability in prior results in the literature is probably due to low power and random chance. The results support theories on which there is a close link between WM and LTM mechanisms, while challenging claims that this relationship is specific to verbal memory and evolved to support language acquisition.

Early cochlear implantation: Verbal working memory, vocabulary, speech intelligibility and participant variables

OBJECTIVES

The purpose of this study was to compare performance in the areas of verbal working memory (VWM), vocabulary skills, and speech intelligibility between children with cochlear implants (CIs) and children with typical development (TD). The correlations between participant variables and the scores of children with CIs in VWM and the measures of language were examined. Also, it was important to identify which variables predict VWM in children with CIs.

METHODS

A total of 59 children participated in this study with the study group being comprised of 31 children who had received a CI and the control group being comprised of 28 children with TD. The assessment techniques utilized in this study were the backward digit span (BDS), non-word repetition, speech intelligibility, and vocabulary skills.

RESULTS

The study results revealed significant differences in the non-word repetition, speech intelligibility, and vocabulary tasks. The results all favored the typically developing children while the findings for the BDS were equal for both groups.

DISCUSSION

In children with CIs the results for VWM observed in this study are believed to be related to the modality of assessment presentation, prior vocabulary knowledge, and familiarity with the presented material. The results from this study also revealed that the variables which predicted VWM in children with CIs were speech perception, duration of CI use, and vocabulary knowledge.

Cerebellar contributions to sequence prediction in verbal working memory

Verbal working memory is one of the most studied non-motor functions with robust cerebellar involvement. While the superior cerebellum (lobule VI) has been associated with articulatory control, the inferior cerebellum (lobule VIIIa) has been linked to phonological storage. The present study was aimed to elucidate the differential roles of these regions by investigating whether the cerebellum might contribute to verbal working memory via predictions based on sequence learning/detection. 19 healthy adult subjects completed an fMRI-based Sternberg task which included repeating and novel letter sequences that were phonologically similar or dissimilar. It was hypothesized that learning a repeating sequence of study letters would reduce phonological storage demand and associated right inferior cerebellar activations and that this effect would be modulated by phonological similarity of the study letters. Specifically, while increased phonological storage demand due to high phonological similarity was expected to be reflected in increased right inferior cerebellar activations for similar relative to dissimilar study letters, the reduction in activation for repeating relative to novel sequences was expected to be more profound for phonologically similar than for dissimilar study letters, especially at higher memory load. Results confirmed the typical effects of cognitive load (5 vs. 2 study letters) and phonological similarity in several cerebellar and neocortical brain regions as well as in behavioral data (accuracy and response time). Importantly, activations in superior and inferior cerebellar regions were differentially modulated as a function of similarity and sequence novelty, indicating that particularly lobule VIIIa may contribute to verbal working memory by generating predictions of letter sequences that reduce the likelihood of phonological loop failure before stored items need to be retrieved. The present study is consistent with other investigations that support prediction, which can be based on sequence learning or detection, as an overarching cerebellar function.

Executive Skills and Academic Achievement in the Dystrophinopathies

OBJECTIVES

To examine academic performance in dystrophinopathy as a function of dystrophin gene mutation position as well as intellectual function, executive skills, socioeconomic status (SES), behavior, and physical ability.

METHODS

In a cross-sectional study, boys with dystrophinopathy (ages 5-17; n=50) completed tests of academics (Woodcock-Johnson-III: spelling, reading, calculation and total scores), executive functioning (selective attention/inhibitory control, set shifting, working memory, and processing speed), single word comprehension and nonverbal reasoning. Motor skills were assessed and parents provided demographic information and child behavioral assessments. Dystrophin gene mutation positions were dichotomized into groups (upstream versus downstream of exon 43, location of isoforms previously linked to intellectual impairment). Genetic mutation groups were compared on measures of academic achievement, and multiple regression analyses examined unique and joint contributions of executive skills, intelligence quotient (IQ), SES, motor abilities, behavior, and mutation positions to academic outcomes.

RESULTS

Academic performance was slightly, yet significantly, lower than IQ and varied as a function of dystrophin gene position, wherein boys possessing the downstream mutation exhibited greater impairment than boys with the upstream mutation. Digit span forward (indexing verbal span), but no other measure of executive function, contributed significant variance to total academic achievement, spelling and calculation.

CONCLUSIONS

Weak academic performance is associated with dystrophinopathy and is more common in downstream mutations. A specific deficit in verbal span may underlie inefficiencies observed in children with dystrophinopathy and may drive deficits impacting academic abilities. (JINS, 2018, 24, 928-938).

Intelligence test at preschool-age predicts reading difficulty among school-aged very low birth weight infants in Japan

OBJECTIVE

To elucidate whether the results of an intelligence test at preschool age are predictive of reading difficulty (RD) at school age among very low birth weight infants (VLBWI).

METHODS

Subjects were 48 Japanese children whose birth weight was <1500 g and who regularly visited a follow-up clinic. All subjects completed the Wechsler Intelligence Scale for Children-III (WISC-III) during the last grade of kindergarten, and four reading tasks during the second to fourth grade of elementary school. All participants had a full-scale intelligence quotient score of 85 or higher. Subjects with a standard deviation reading time score greater than 2.0 in two or more tasks were considered to have RD. We evaluated the associations between each WISC-III score and RD using logistic regression analyses. Furthermore, we performed receiver operating characteristic (ROC) analysis to determine a cutoff WISC-III score predictive of RD.

RESULTS

In the mutually-adjusted model, the adjusted odds ratio per 1 score increase of freedom from distractibility (FD) was 0.832 (95% confidence interval: 0.720-0.962). In the ROC analysis, an FD score of <95.5 was chosen as the cutoff value for predicting RD (sensitivity, 0.77; specificity, 0.74).

CONCLUSION

The present study indicated that a lower FD score at preschool age, which was associated with deficits in verbal working memory and attention, is a risk factor for RD at school age among Japanese VLBWI. Further investigation is desired to clarify the cognitive deficits underlying RD in Japanese-speaking preterm children, and to establish appropriate interventions for these children.

A Longitudinal Functional Magnetic Resonance Imaging Study of Working Memory in Patients Following a Transient Ischemic Attack: A Preliminary Study

In this study, we used functional magnetic resonance imaging (fMRI) to investigate longitudinal changes in brain activation during a verbal working memory (VWM) task performed by patients who had experienced a transient ischemic attack (TIA). Twenty-five first-ever TIA patients without visible lesions in conventional MRI and 25 healthy volunteers were enrolled. VWM task-related fMRI was conducted 1 week and 3 months post-TIA. The brain activity evoked by the task and changes over time were assessed. We found that, compared with controls, patients exhibited an increased activation in the bilateral inferior frontal gyrus (IFG), right dorsolateral prefrontal cortex (DLPFC), insula, inferior parietal lobe (IPL), and cerebellum during the task performed 1 week post-TIA. But only the right IFG still exhibited an increased activation at 3 months post-TIA. A direct comparison of fMRI data between 1 week and 3 months post-TIA showed greater activation in the bilateral middle temporal gyrus, right DLPFC, IPL, cerebellum, and left IFG in patients at 1 week post-TIA. We conclude that brain activity patterns induced by a VWM task remain dynamic for a period of time after a TIA, despite the cessation of clinical symptoms. Normalization of the VWM activation pattern may be progressively achieved after transient episodes of ischemia in TIA patients.

Factors that positively or negatively mediate the effects of age on working memory across the adult life span

Working memory abilities significantly decrease with advancing age; hence, the search for factors that may increase or mitigate this decline is critical. Several factors have been identified that influence working memory; however, their effects have been mainly assessed separately and rarely together with other factors in the same sample. We examined 120 variables to search for factors that jointly act as mediators of working memory decay across the adult life span. A sample of 1652 healthy adults was assessed in spatial and verbal working memory domains. Structural equation modeling analyses were conducted to search for potential mediators that intervened between age and working memory. Only 14 and 10 variables reliably mediated spatial and verbal working memory, respectively. Factors from several domains remained in the models, such as individual characteristics, physiological traits, consumption habits, and regular activities. These factors are sufficiently powerful to influence working memory decline when they jointly interact, as in everyday living.

Load matters: neural correlates of verbal working memory in children with autism spectrum disorder

Background

Autism spectrum disorder (ASD) is a pervasive neurodevelopmental disorder characterised by diminished social reciprocity and communication skills and the presence of stereotyped and restricted behaviours. Executive functioning deficits, such as working memory, are associated with core ASD symptoms. Working memory allows for temporary storage and manipulation of information and relies heavily on frontal-parietal networks of the brain. There are few reports on the neural correlates of working memory in youth with ASD. The current study identified the neural systems underlying verbal working memory capacity in youth with and without ASD using functional magnetic resonance imaging (fMRI).

Methods

Fifty-seven youth, 27 with ASD and 30 sex- and age-matched typically developing (TD) controls (9–16 years), completed a one-back letter matching task (LMT) with four levels of difficulty (i.e. cognitive load) while fMRI data were recorded. Linear trend analyses were conducted to examine brain regions that were recruited as a function of increasing cognitive load.

Results

We found similar behavioural performance on the LMT in terms of reaction times, but in the two higher load conditions, the ASD youth had lower accuracy than the TD group. Neural patterns of activations differed significantly between TD and ASD groups. In TD youth, areas classically used for working memory, including the lateral and medial frontal, as well as superior parietal brain regions, increased in activation with increasing task difficulty, while areas related to the default mode network (DMN) showed decreasing activation (i.e., deactivation). The youth with ASD did not appear to use this opposing cognitive processing system; they showed little recruitment of frontal and parietal regions across the load but did show similar modulation of the DMN.

Conclusions

In a working memory task, where the load was manipulated without changing executive demands, TD youth showed increasing recruitment with increasing load of the classic fronto-parietal brain areas and decreasing involvement in default mode regions. In contrast, although they modulated the default mode network, youth with ASD did not show the modulation of increasing brain activation with increasing load, suggesting that they may be unable to manage increasing verbal information. Impaired verbal working memory in ASD would interfere with the youths’ success academically and socially. Thus, determining the nature of atypical neural processing could help establish or monitor working memory interventions for ASD.

Number line estimation and complex mental calculation: Is there a shared cognitive process driving the two tasks?

It is widely accepted that different number-related tasks, including solving simple addition and subtraction, may induce attentional shifts on the so-called mental number line, which represents larger numbers on the right and smaller numbers on the left. Recently, it has been shown that different number-related tasks also employ spatial attention shifts along with general cognitive processes. Here we investigated for the first time whether number line estimation and complex mental arithmetic recruit a common mechanism in healthy adults. Participants' performance in two-digit mental additions and subtractions using visual stimuli was compared with their performance in a mental bisection task using auditory numerical intervals. Results showed significant correlations between participants' performance in number line bisection and that in two-digit mental arithmetic operations, especially in additions, providing a first proof of a shared cognitive mechanism (or multiple shared cognitive mechanisms) between auditory number bisection and complex mental calculation.

Verbal Working Memory as a Longitudinal Mechanism of Vocabulary Problems in Preschoolers with ADHD

Elucidation of early potential risk factors of Attention-Deficit/Hyperactivity Disorder (ADHD) is important to allow for early identification of ADHD and targeted early intervention for children with ADHD. Delayed language skills, particularly poor vocabulary, is an early-developing potential risk factor that is thought to be involved in developmental pathways to ADHD; however, mechanisms explaining the relationship between poor vocabulary skills and ADHD symptoms are unclear and warrant investigation. The present study examines the relationship between poor vocabulary skills and ADHD symptoms by testing cognitive mechanisms, namely verbal working memory (WM), that might account for this link. Participants were 109 young children between the ages of three and six and their primary caregivers. Diagnostic information on ADHD symptoms was available from parents and teachers/daycare providers via standardized rating forms. Vocabulary skills and WM were measured through child performance on laboratory tasks. Mediation analyses found poor verbal working memory significantly partially explained the vocabulary-ADHD association for both parent and teacher-rated ADHD symptoms. Further, effects of verbal WM on the association between poor vocabulary and increased ADHD symptoms largely held at one-year follow-up. Development of early interventions targeting verbal WM may be a promising new direction for early ADHD intervention work.

Visual working memory span in adults with cochlear implants: Some preliminary findings

Objective

Neurocognitive functions, specifically verbal working memory (WM), contribute to speech recognition in postlingual adults with cochlear implants (CIs) and normal-hearing (NH) listener shearing degraded speech. Three hypotheses were tested: (1) WM accuracy as assessed using three visual span measures - digits, objects, and symbols - would correlate with recognition scores for spectrally degraded speech (through a CI or when noise-vocoded); (2) WM accuracy would be best for digit span, intermediate for object span, and lowest for symbol span, due to the increasing cognitive demands across these tasks. Likewise, response times, relating to processing demands, would be shortest for digit span, intermediate for object span, and longest for symbol span; (3) CI users would demonstrate poorer and slower performance than NH peers on WM tasks, as a result of less efficient verbally mediated encoding strategies associated with a period of prolonged auditory deprivation.

Methods

Cross-sectional study of 30 postlingually deaf adults with CIs and 34 NH controls. Participants were tested for sentence recognition in quiet (CI users) or after noise-vocoding (NH peers), along with WM using visual measures of digit span, object span, and symbol span.

Results

Of the three measures of WM, digit span scores alone correlated with sentence recognition for CI users; no correlations were found using these three measures for NH peers. As predicted, WM accuracy (and response times) were best (and fastest) for digit span, intermediate for object span, and worst (and slowest) for symbol span. CI users and NH peers demonstrated equivalent WM accuracy and response time for digit span and object span, and similar response times for symbol span, but contrary to our original predictions, CI users demonstrated better accuracy on symbol span than NH peers.

Conclusions

Verbal WM assessed using visual tasks relates weakly to sentence recognition for degraded speech. CI users performed equivalently to NH peers on most visual tasks of WM, but they outperformed NH peers on symbol span accuracy. This finding deserves further exploration but may suggest that CI users develop alternative or compensatory strategies associated with rapid verbal coding, as a result of their prolonged experience of auditory deprivation.

PFC Activity Pattern During Verbal WM Task in Healthy Male and Female Subjects: A NIRS Study

Near-infrared spectroscopy (NIRS), as a non-invasive optical imaging method, has been widely used in psychology research. Working memory (WM) is an extensively researched psychological concept related to the temporary storage and processing of information. Many neuropsychological studies demonstrate that several brain areas of prefrontal cortex (PFC) are engaged during verbal WM tasks. The gender-based differences in WM remains under dispute. To better understand the active module and gender differences in PFC activity patterns during verbal WM tasks, we investigated the blood oxygenation changes of the PFC in 15 healthy subjects using a homemade multichannel continuous-wave NIRS instrument, while performing a verbal n-back task. We employed traditional activation and novel connectivity analyses simultaneously. Males had a higher level of oxygenation activity and connectivity in PFC than females. Only the results of females revealed a leftward lateralization in the 2-back task.

The Origin of Mathematics and Number Sense in the Cerebellum: with Implications for Finger Counting and Dyscalculia

Background

Mathematicians and scientists have struggled to adequately describe the ultimate foundations 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 not 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 silent 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.

The Monkey game: A computerized verbal working memory task for self-reliant administration in primary school children

In two studies, the psychometric properties of an online self-reliant verbal working memory task (the Monkey game) for primary school children (6–12 years of age) were examined. In Study 1, children (n = 5,203) from 31 primary schools participated. The participants completed computerized verbal and visual–spatial working memory tasks (i.e., the Monkey game and the Lion game) and a paper-and-pencil version of Raven’s Standard Progressive Matrices. Reading comprehension and math achievement test scores were obtained from the schools. First, the internal consistency of the Monkey game was examined. Second, multilevel modeling was used to examine the effects of classroom membership. Multilevel multivariate regression analysis was used to examine the Monkey game’s concurrent relationship with the Lion game and its predictive relationships with reading comprehension and math achievement. Also, age-related differences in performance were examined. In Study 2, the concurrent relationships between the Monkey game and two tester-led computerized working memory tasks were further examined (n = 140). Also, the 1- and 2-year stability of the Monkey game was investigated. The Monkey game showed excellent internal consistency, good concurrent relationships with the other working memory measures, and significant age differences in performance. Performance on the Monkey game was also predictive of subsequent reading comprehension and mathematics performance, even after controlling for individual differences in intelligence. Performance on the Monkey game was influenced by classroom membership. The Monkey game is a reliable and suitable instrument for the online computerized and self-reliant assessment of verbal working memory in primary school children.

Verbal working memory and reading abilities among students with visual impairment

AIM

This study investigated the relationship between working memory (WM) and reading abilities among students with visual impairment (VI). Seventy-five students with VI (visually impairment and blindness), aged 10-15 years old participated in the study, of whom 44 were visually impaired and 31 were blind.

METHODS

The participants' reading ability was assessed with the standardized reading ability battery Test-A (Padeliadu & Antoniou, 2008) and their verbal working memory ability was assessed with the listening recall task from the Working Memory Test Battery for Children (Pickering et al., 2001).

RESULTS-IMPLICATIONS

Data analysis indicated a strong correlation between verbal WM and decoding, reading comprehension and overall reading ability among the participants with VI, while no correlation was found between reading fluency and verbal WM. The present study points out the important role of verbal WM in reading among students who are VI and carries implications for the education of those individuals.

Language facilitates introspection: Verbal mind-wandering has privileged access to consciousness

Introspection and language are the cognitive prides of humankind, but their interactions in healthy cognition remain unclear. Episodes of mind-wandering, where personal thoughts often go unnoticed for some time before being introspected, offer a unique opportunity to study the role of language in introspection. In this paper, we show that inner speech facilitates awareness of mind-wandering. In two experiments, we either interfered with verbal working memory, via articulatory suppression (Exp. 1), or entrained it, via presentation of verbal material (Exp. 2), and measured the resulting awareness of mind-wandering. Articulatory suppression decreased the likelihood to spontaneously notice mind-wandering, whereas verbal material increased retrospective awareness of mind-wandering. In addition, an ecological study using smartphones confirmed that inner speech vividness positively predicted mind-wandering awareness (Exp. 3). Together, these findings support the view that inner speech facilitates introspection of one's thoughts, and therefore provides empirical evidence for a positive relation between language and consciousness.

Predicting the reading skill of Japanese children

OBJECTIVE

To clarify cognitive processes underlining the development of reading in children speaking Japanese as their first language, we examined relationships between performances of cognitive tasks in the preschool period and later reading abilities.

METHODS

Ninety-one normally developing preschoolers (41 girls and 50 boys; 5years 4months to 6years 4months, mean 5years 10months) participated as subjects. We conducted seven cognitive tasks including phonological awareness tasks, naming tasks, and working memory tasks in the preschool period. In terms of reading tasks, the hiragana naming task was administered in the preschool period; the reading times, which is a composite score of the monomoraic syllable reading task, the word and the non-word reading tasks, and the single sentence reading task, was evaluated in first and second grade; and the kanji reading task (naming task) was tested in second grade. Raven's colored progressive matrices and picture vocabulary test revised were also conducted in first grade. Correlation analyses between task scores and stepwise multiple regression analyses were implemented.

RESULTS

Tasks tapping phonological awareness, lexical access, and verbal working memory showed significant correlations with reading tasks. In the multiple regression analyses the performances in the verbal working memory task played a key role in predicting character naming task scores (the hiragana naming task and the kanji reading task) while the digit naming task was an important predictor of reading times. Unexpectedly, the role of phonological (mora) awareness was modest among children speaking Japanese.

CONCLUSION

Cognitive functions including phonological awareness, digit naming, and verbal working memory (especially the latter two) were involved in the development of reading skills of children speaking Japanese.

Dissociation between working memory performance and proactive interference control in post-traumatic stress disorder

Deficits in working memory (WM) and cognitive control processes have been reported in post-traumatic stress disorder (PTSD), in addition to clinical symptoms such as hypervigilance, re-experiencing, and avoidance of trauma reminders. Given the uncontrollable nature of intrusive memories, an important question is whether PTSD is associated with altered control of interference in WM. Some studies also suggest that episodic memory shows a material-specific dissociation in PTSD, with greater impairments in verbal memory and relative sparing of nonverbal memory. It is unclear whether this dissociation applies to WM, as no studies have used identical task parameters across material. Here we tested 29 combat Veterans with PTSD and 29 age-matched control Veterans on a recent probes WM task with words and visual patterns in separate blocks. Participants studied four-item sets, followed by a probe stimulus that had been presented in the previous set (recent probe) or not (nonrecent probe). Participants with PTSD made more errors than controls, and this decrement was similar for verbal and visual stimuli. Proactive interference from items recently presented, but no longer relevant, was not significantly different in the PTSD group and showed no relationship to re-experiencing symptom severity. These results demonstrate that PTSD is not reliably associated with increased intrusions of irrelevant representations into WM when non-emotional stimuli are used. Future studies that use trauma-related material may provide insight into the flashbacks and intrusive thoughts that plague those with PTSD.

Abnormal interactions of verbal- and spatial-memory networks in young people at familial high-risk for schizophrenia

BACKGROUND

Working memory impairment (especially in verbal and spatial domains) is the core neurocognitive impairment in schizophrenia and the familial high-risk (FHR) population. Inconsistent results have been reported in clinical and neuroimaging studies examining the verbal- and spatial-memory deficits in the FHR subjects, due to sample differences and lack of understanding on interactions of the brain regions for processing verbal- and spatial-working memory.

METHODS

Functional MRI data acquired during a verbal- vs. spatial-memory task were included from 51 young adults [26 FHR and 25 controls]. Group comparisons were conducted in brain activation patterns responding to 1) verbal-memory condition (A), 2) spatial-memory condition (B), 3) verbal higher than spatial (A-B), 4) spatial higher than verbal (B-A), 5) conjunction of brain regions that were activated during both A and B (A∧B). Group difference of the laterality index (LI) in inferior frontal lobe for condition A was also assessed.

RESULTS

Compared to controls, the FHR group exhibited significantly decreased brain activity in left inferior frontal during A, and significantly stronger involvement of ACC, PCC, paracentral gyrus for the contrast of A-B. The LI showed a trend of reduced left-higher-than-right pattern for verbal-memory processing in the HR group.

CONCLUSIONS

Our findings suggest that in the entire functional brain network for working-memory processing, verbal information processing associated brain pathways are significantly altered in people at familial high risk for developing schizophrenia. Future studies will need to examine whether these alterations may indicate vulnerability for predicting the onset of Schizophrenia.

Internal modeling of upcoming speech: A causal role of the right posterior cerebellum in non-motor aspects of language production

Some language processing theories propose that, just as for other somatic actions, self-monitoring of language production is achieved through internal modeling. The cerebellum is the proposed center of such internal modeling in motor control, and the right cerebellum has been linked to an increasing number of language functions, including predictive processing during comprehension. Relating these findings, we tested whether the right posterior cerebellum has a causal role for self-monitoring of speech errors. Participants received 1 Hz repetitive transcranial magnetic stimulation during 15 min to lobules Crus I and II in the right hemisphere, and, in counterbalanced orders, to the contralateral area in the left cerebellar hemisphere (control) in order to induce a temporary inactivation of one of these zones. Immediately afterwards, they engaged in a speech production task priming the production of speech errors. Language production was impaired after right compared to left hemisphere stimulation, a finding that provides evidence for a causal role of the cerebellum during language production. We interpreted this role in terms of internal modeling of upcoming speech through a verbal working memory process used to prevent errors.

Increased distractibility in schizotypy: Independent of individual differences in working memory capacity?

Individuals with schizophrenia typically show increased levels of distractibility. This has been attributed to impaired working memory capacity (WMC), since lower WMC is typically associated with higher distractibility, and schizophrenia is typically associated with impoverished WMC. Here, participants performed verbal and spatial serial recall tasks that were accompanied by to-be-ignored speech tokens. For the few trials wherein one speech token was replaced with a different token, impairment was produced to task scores (a deviation effect). Participants subsequently completed a schizotypy questionnaire and a WMC measure. Higher schizotypy scores were associated with lower WMC (as measured with operation span, OSPAN), but WMC and schizotypy scores explained unique variance in relation to the mean magnitude of the deviation effect. These results suggest that schizotypy is associated with heightened domain-general distractibility, but that this is independent of its relationship with WMC.

Modality specificity in the cerebro-cerebellar neurocircuitry during working memory

Previous studies have suggested cerebro-cerebellar circuitry in working memory. The present fMRI study aims to distinguish differential cerebro-cerebellar activation patterns in verbal and visual working memory, and employs a quantitative analysis to deterimine lateralization of the activation patterns observed. Consistent with Chen and Desmond (2005a,b) predictions, verbal working memory activated a cerebro-cerebellar circuitry that comprised left-lateralized language-related brain regions including the inferior frontal and posterior parietal areas, and subcortically, right-lateralized superior (lobule VI) and inferior cerebellar (lobule VIIIA/VIIB) areas. In contrast, a distributed network of bilateral inferior frontal and inferior temporal areas, and bilateral superior (lobule VI) and inferior (lobule VIIB) cerebellar areas, was recruited during visual working memory. Results of the study verified that a distinct cross cerebro-cerebellar circuitry underlies verbal working memory. However, a neural circuitry involving specialized brain areas in bilateral neocortical and bilateral cerebellar hemispheres subserving visual working memory is observed. Findings are discussed in the light of current models of working memory and data from related neuroimaging studies.

HPA axis function predicts development of working memory in boys with FXS

The present study examines verbal working memory over time in boys with fragile X syndrome (FXS) compared to nonverbal mental-age (NVMA) matched, typically developing (TD) boys. Concomitantly, the relationship between cortisol-a physiological marker for stress-and verbal working memory performance over time is examined to understand the role of physiological mechanisms in cognitive development in FXS. Participants were assessed between one and three times over a 2-year time frame using two verbal working memory tests that differ in complexity: memory for words and auditory working memory with salivary cortisol collected at the beginning and end of each assessment. Multilevel modeling results indicate specific deficits over time on the memory for words task in boys with FXS compared to TD controls that is exacerbated by elevated baseline cortisol. Similar increasing rates of growth over time were observed for boys with FXS and TD controls on the more complex auditory working memory task, but only boys with FXS displayed an association of increased baseline cortisol and lower performance. This study highlights the benefit of investigations of how dynamic biological and cognitive factors interact and influence cognitive development over time.

Deficits in Verbal Working Memory among College Students with Attention-Deficit/Hyperactivity Disorder Traits: An Event-related Potential Study

Objective

This study investigated verbal working memory in college students with traits of attention-deficit/hyperactivity disorder (ADHD) using event-related potentials and the 2-back task.

Methods

Based on scores on the Adult ADHD Self-Report Scale and Conners’ Adult ADHD Rating Scale, participants were assigned to the normal control (n=28) or ADHD-trait (n=29) group. The 2-back task, which was administered to evaluate working memory, consists of a congruent condition, under which the current stimulus is the same as the one presented two trials earlier, and an incongruent condition, under which the current stimulus is not the same as the one presented two trials earlier. The numbers 1, 2, 3, and 4 were used as stimuli.

Results

On the 2-back task, the ADHD-trait group committed significantly more errors in response to congruent stimuli and showed a smaller P300 amplitude than did the control group.

Conclusion

These results indicate that college students with ADHD traits have deficits in verbal working memory, possibly due to difficulties in memory updating or attentional allocation.

How the brain attunes to sentence processing: Relating behavior, structure, and function

Unlike other aspects of language comprehension, the ability to process complex sentences develops rather late in life. Brain maturation as well as verbal working memory (vWM) expansion have been discussed as possible reasons. To determine the factors contributing to this functional development, we assessed three aspects in different age-groups (5–6 years, 7–8 years, and adults): first, functional brain activity during the processing of increasingly complex sentences; second, brain structure in language-related ROIs; and third, the behavioral comprehension performance on complex sentences and the performance on an independent vWM test. At the whole-brain level, brain functional data revealed a qualitatively similar neural network in children and adults including the left pars opercularis (PO), the left inferior parietal lobe together with the posterior superior temporal gyrus (IPL/pSTG), the supplementary motor area, and the cerebellum. While functional activation of the language-related ROIs PO and IPL/pSTG predicted sentence comprehension performance for all age-groups, only adults showed a functional selectivity in these brain regions with increased activation for more complex sentences. The attunement of both the PO and IPL/pSTG toward a functional selectivity for complex sentences is predicted by region-specific gray matter reduction while that of the IPL/pSTG is additionally predicted by vWM span. Thus, both structural brain maturation and vWM expansion provide the basis for the emergence of functional selectivity in language-related brain regions leading to more efficient sentence processing during development.

The neurodevelopmental differences of increasing verbal working memory demand in children and adults

Working memory (WM) – temporary storage and manipulation of information in the mind – is a key component of cognitive maturation, and structural brain changes throughout development are associated with refinements in WM. Recent functional neuroimaging studies have shown that there is greater activation in prefrontal and parietal brain regions with increasing age, with adults showing more refined, localized patterns of activations. However, few studies have investigated the neural basis of verbal WM development, as the majority of reports examine visuo-spatial WM.

We used fMRI and a 1-back verbal WM task with six levels of difficulty to examine the neurodevelopmental changes in WM function in 40 participants, twenty-four children (ages 9–15 yr) and sixteen young adults (ages 20–25 yr). Children and adults both demonstrated an opposing system of cognitive processes with increasing cognitive demand, where areas related to WM (frontal and parietal regions) increased in activity, and areas associated with the default mode network decreased in activity. Although there were many similarities in the neural activation patterns associated with increasing verbal WM capacity in children and adults, significant changes in the fMRI responses were seen with age. Adults showed greater load-dependent changes than children in WM in the bilateral superior parietal gyri, inferior frontal and left middle frontal gyri and right cerebellum. Compared to children, adults also showed greater decreasing activation across WM load in the bilateral anterior cingulate, anterior medial prefrontal gyrus, right superior lateral temporal gyrus and left posterior cingulate. These results demonstrate that while children and adults activate similar neural networks in response to verbal WM tasks, the extent to which they rely on these areas in response to increasing cognitive load evolves between childhood and adulthood.

State space modeling of time-varying contemporaneous and lagged relations in connectivity maps

Most connectivity mapping techniques for neuroimaging data assume stationarity (i.e., network parameters are constant across time), but this assumption does not always hold true. The authors provide a description of a new approach for simultaneously detecting time-varying (or dynamic) contemporaneous and lagged relations in brain connectivity maps. Specifically, they use a novel raw data likelihood estimation technique (involving a second-order extended Kalman filter/smoother embedded in a nonlinear optimizer) to determine the variances of the random walks associated with state space model parameters and their autoregressive components. The authors illustrate their approach with simulated and blood oxygen level-dependent functional magnetic resonance imaging data from 30 daily cigarette smokers performing a verbal working memory task, focusing on seven regions of interest (ROIs). Twelve participants had dynamic directed functional connectivity maps: Eleven had one or more time-varying contemporaneous ROI state loadings, and one had a time-varying autoregressive parameter. Compared to smokers without dynamic maps, smokers with dynamic maps performed the task with greater accuracy. Thus, accurate detection of dynamic brain processes is meaningfully related to behavior in a clinical sample.

Brain structural correlates of complex sentence comprehension in children

Prior structural imaging studies found initial evidence for the link between structural gray matter changes and the development of language performance in children. However, previous studies generally only focused on sentence comprehension. Therefore, little is known about the relationship between structural properties of brain regions relevant to sentence processing and more specific cognitive abilities underlying complex sentence comprehension. In this study, whole-brain magnetic resonance images from 59 children between 5 and 8 years were assessed. Scores on a standardized sentence comprehension test determined grammatical proficiency of our participants. A confirmatory factory analysis corroborated a grammar-relevant and a verbal working memory-relevant factor underlying the measured performance. Voxel-based morphometry of gray matter revealed that while children's ability to assign thematic roles is positively correlated with gray matter probability (GMP) in the left inferior temporal gyrus and the left inferior frontal gyrus, verbal working memory-related performance is positively correlated with GMP in the left parietal operculum extending into the posterior superior temporal gyrus. Since these areas are known to be differentially engaged in adults' complex sentence processing, our data suggest a specific correspondence between children's GMP in language-relevant brain regions and differential cognitive abilities that guide their sentence comprehension.