The neurobiology of semantic memory

Mining complexes can contain multiple mines operating simultaneously along with multiple processing streams, stockpiles and products. Stochastic optimization methods developed to date generate only local optimal solutions in the sense that they do not consider the entire mining complex. This paper presents an extension of a multi-stage method used for generating long-term risk-based mine production schedules, to operations with multiple rock types and processing streams. The developed method uses a simulated annealing based algorithm during the optimization stage, seeking to minimize deviations from production targets for waste and different ore processing streams. The proposed approach is applied at Escondida Norte copper deposit, Chile, in which sulphide, oxide, mixed and waste materials are present with milling, bio-leaching and acid-leaching being the available processing streams. The stochastic schedule generates expected deviations from mill and waste production targets smaller than 5%, which avoid indirect costs associated to idle capacities. A schedule generated conventionally exhibits expected deviations of the order of 20%.

A heuristic approach to stochastic cutoff grade optimization for open pit mining complexes with multiple processing streams

This study investigates the relationship between semantic memory and social cognition in schizophrenia. The sample included 50 individuals with schizophrenia (mean age 42.54, SD 9.98; 14 women, 36 men) and 30 controls (mean age 42.06, SD 12.50; 6 women, 24 men). Semantic memory was assessed using verbal fluency and the Camel and Cactus Test, while social cognition was evaluated through the Face Test and the Hinting Task. The schizophrenia group showed significantly lower performance in both semantic memory (semantic fluency: t(78) = 7.77, p < 0.007, δ = 1.79; Camel and Cactus Test: t(78) = 5.37, p < 0.007, δ = 1.26) and social cognition (Face Test: t(78) = 5.94, p < 0.007, δ = 1.34; Hinting Task: t(78) = 7.79, p < 0.007, δ = 1.79). Strong correlations were observed between the Camel and Cactus Test and social cognition measures (Face Test: r = 0.63, p < 0.005; Hinting Task: r = 0.54, p < 0.005). Regression analyses indicated that the Camel and Cactus Test significantly predicted social cognition performance independent of symptomatology, explaining 53% of the variance in the Face Test and 54% in the Hinting Task. This study provides new insights into the cognitive underpinnings of schizophrenia, emphasizing the need for further research to explore these relationships and their implications for cognitive models and therapeutic interventions.

Time Course of fMRI-Activation in Language and Spatial Networks during Sentence Comprehension

Music and speech are often cited as characteristically human forms of communication. Both share the features of hierarchical structure, complex sound systems, and sensorimotor sequencing demands, and both are used to convey and influence emotions, among other functions [1]. Both music and speech also prominently use acoustical frequency modulations, perceived as variations in pitch, as part of their communicative repertoire. Given these similarities, and the fact that pitch perception and production involve the same peripheral transduction system (cochlea) and the same production mechanism (vocal tract), it might be natural to assume that pitch processing in speech and music would also depend on the same underlying cognitive and neural mechanisms. In this essay we argue that the processing of pitch information differs significantly for speech and music; specifically, we suggest that there are two pitch-related processing systems, one for more coarse-grained, approximate analysis and one for more fine-grained accurate representation, and that the latter is unique to music. More broadly, this dissociation offers clues about the interface between sensory and motor systems, and highlights the idea that multiple processing streams are a ubiquitous feature of neuro-cognitive architectures.

This study examined the effects of anodal transcranial direct current stimulation (a-tDCS) on sentence and word comprehension in healthy adults. Healthy adult participants, aged between 19 and 30 years, received either a-tDCS over the left inferior frontal gyrus (n=18) or sham stimulation (n=18). Participants completed sentence comprehension and word comprehension tasks before and during stimulation. Accuracy and reaction times (RTs) were recorded as participants completed both tasks. a-tDCS was found to significantly decrease RT on the sentence comprehension task compared to baseline. There was no change in RT following sham stimulation. a-tDCS was not found to have a significant effect on accuracy. Also, a-tDCS did not affect accuracy or RTs on the word comprehension task. The study provides evidence that non-invasive anodal electrical stimulation can modulate sentence comprehension in healthy adults, at least compared to their baseline performance. (JINS, 2019, 25, 331-335).

The present paper argues for a model of language production and comprehension in which a MIC-component interacts with working memory, episodic memory, and semantic memory as resources for the meta-informative processing of new and old information. This component is also interconnected with the grammatical encoding system which produces “surface” structures. Focused attention plays a decisive functional role in this system as it directs the processes which transform intentions into messages. Although MIC theory is essentially a linguistic theory it offers itself to direct mapping with notions from cognitive and clinical neuropsychology. Levelt (1989) dedicates pioneering work to the attention resources, the focus of the message and the macro-planning of the information in the early stages of speech production, however, his model remains vague with respect to the formal status of the cognitive systems involved. MIC theory complemented by findings from cognitive neuropsychology can fill these gaps. Despite ample evidence for the relative independence of the different memory systems (e.g. double dissociations between episodic and semantic memory; particular vulnerability of episodic memory in medial temporal lobe impairment and diseases such as Alzheimer’s), recent research accentuates the interaction between these systems in building up generic “semantic” knowledge from autobiographical experience and vice versa facilitating the retrieval of information from episodic memory by contributing generic information from semantic memory. Input of information into the MIC-component from episodic memory is more likely to be attributed “new status” than inputs from semantic memory, although attention processes can redirect the meta-informative status of that information at any time depending on outcomes from ToM (Theory of Mind), which is attributed an active role in this model. ToM is the capacity of humans to understand mental states of others including the ability to judge the contents of their respective memory systems. In verbal interaction estimates of the communication partners’ memory systems’ contents form an input to the MIC component of the speaker who selects CAs. This ability is seen in early childhood and understood as a key factor in Tomasello’s (2000) social-pragmatic theory of word learning and language acquisition. The model proposed here will be further scrutinized by examining cognitive communication disorders caused by lesions of the right hemisphere, which will be explained as disruptions of the interaction of the modules described in the MIC based model.

Background The clinical diagnosis of Huntington’s disease (HD) is based on motor symptoms, although these can be preceded by cognitive changes. However, it is still difficult to predict the clinical onset of HD based on neuropsychological tests. Increasingly, social cognition impairments have been found in HD patients. In recent studies, social cognition has been put forward as possible predictor of the clinical diagnosis in premanifest HD patients. Aims The aim of the present study was to assess whether impairments in social cognition might be a more sensitive predictor of the onset of the disease than non-social cognitive impairments. Therefore we wanted to assess whether impairments in social cognition preceded deterioration of general cognitive functions in premanifest gene carriers and whether social cognition was related to non-social cognition measures in a group of premanifest and manifest HD patients. Methods/Techniques A cohort of 14 premanifest gene carriers of HD and 40 manifest HD patients were assessed on psychomotor speed, executive functioning, verbal and categorical fluency and emotion recognition. Results/outcome In the premanifest stage, patients did not have lower scores on emotion recognition as compared to general cognitive tasks. In the manifest group and combined group correlations were found between social and non-social cognition tasks, but this was not found in the premanifest group. Conclusions Overall, disease progression seems to affect both social and non-social cognition equally. Based on the present study social cognition is unlikely to be indicative in the premanifest stage for conversion to the manifest stage of HD.

Background: Social cognition involves a complex set of mental abilities related to perceiving, processing, interpreting, and responding to social cues. These skills enable people to behave appropriately in various social settings. Social cognition includes essential skills such as recognising facial expressions, understanding others’ perspectives (theory of mind), social reasoning, moral judgment, and decision-making. Objective: This study aims to investigate how different elements of cognition may influence the social cognition of patients with dementia, specifically those with AD and FTD. Methods: We included two groups of participants: 1) FTD (n=19, 11M/8F; mean age=63.7±9.8 years; mean schooling=11.7±5.4; Disease Duration:4.1±2.4; MMSE=23.0±6.2); and 2) AD (n=25; 9M/16F; mean age=69.8±10.4 years; mean schooling=9.2±5.6; Disease Duration:6.31±5.1; MMSE=22.1±4.0). All participants underwent a comprehensive cognitive assessment using the following tests: Craft Story 21, The Beson Complex Figure Test, Digit Span test, Semantic Verbal Fluency, Trail Making Test, The Multilingual Naming Test (MINT) and Phonemic Verbal Fluency (P and M). The neuropsychiatric symptoms were evaluated using the Neuropsychiatric Inventory (NPI). Social cognition was assessed with Mini-Sea (Faux-Pas and Ekman test). Results: Patients with FTD performed statistically better than the AD group in cognitive tests assessing immediate memory, visuoconstructive function, processing speed, and executive functions. When assessing the cognition elements that could affect the social cognition of patients with dementia, it was found that both patients with FTD and those with AD showed a positive correlation between social cognition and various cognitive functions. These included working memory and attention (Digit Span test), semantic memory (MINT test), and language skills (animal category fluency and phonemic verbal fluency). Additionally, both groups of dementia patients displayed a negative relationship between social cognition and the time it took to complete the Trail Making Test, which is linked to processing speed and executive functions. On the other hand, when evaluating the differences between both groups, it was possible to identify that the social cognition of patients with AD, unlike patients with FTD, showed a positive correlation with visuoconstructive functions (Beson Complex Figure) and a stronger correlation with language (not only animal category but also vegetable category fluency). Additionally, it is worth noting the negative correlation between the neuropsychiatric symptom agitation (NPI) and social cognition in the AD group. Conclusion: The study highlights the complex relationship between cognitive functions and social cognition in patients with dementia, emphasising the need to consider specific cognitive profiles and neuropsychiatric symptoms when assessing social cognition for tailored interventions and support strategies.

Manual gestures and speech form a single integrated system during native language comprehension. However, it remains unclear whether this hold for second language (L2) comprehension, more specifically for simultaneous interpreting (SI), which involves comprehension in one language and simultaneous production in another. In a combined mismatch and priming paradigm, we presented Swedish speakers fluent in L2 English with multimodal stimuli in which speech was congruent or incongruent with a gesture. A picture prime was displayed before the stimuli. Participants had to decide whether the video was related to the prime, focusing either on the auditory or the visual information. Participants performed the task either during passive viewing or during SI into their L1 Swedish (order counterbalanced). Incongruent stimuli yielded longer reaction times than congruent stimuli, during both viewing and interpreting. Visual and audio targets were processed equally easily in both activities. However, in both activities incongruent speech was more disruptive for gesture processing than incongruent gesture was for speech processing. Thus, the data only partly supports the expected mutual and obligatory interaction of gesture and speech in L2 comprehension. Interestingly, there were no differences between activities suggesting that the language comprehension component in SI shares features with other (L2) comprehension tasks.

Social cognition and neurocognition as independent domains in psychosis

The Apolipoprotein epsilon 4 (APOE ε4) genetic variant is notoriously linked to enhanced risk of developing Alzheimer's Disease (AD). Several studies have examined how this allele could influence cognitive functioning in healthy adults, and whether ε4 carriers show a subtle cognitive decline that would indicate preclinical AD pathology. Research has predominantly focused on episodic memory, where ε4 carriers are usually impaired, while semantic memory functioning has received less attention. To evaluate current evidence on the influence of APOE ε4 on semantic memory, we systematically reviewed the research literature assessing semantic memory in non-clinical adult populations according to the PRISMA guidelines. We reviewed 17 studies that revealed high heterogeneity in how semantic memory is conceptualised and assessed. When tested via standard neuropsychological tests (i.e., category fluency, naming, language comprehension, and general knowledge), ε4 carriers did not significantly differ from non-carriers. Instead, ε4 carriers showed lower performance than non-carriers when assessed via more complex semantic memory tasks (i.e., longer category fluency tasks, autobiographical memory tasks, measures of semantic clustering). The impact of APOE ε4 on semantic memory thus appears to be restricted to these more complex tasks, which could constitute a better match to episodic memory tasks for which APOE effects are typically observed, though a mediating role of executive functions should also be considered. Future research investigating autobiographical memory retrieval in ε4 carriers could provide a more sensitive and ecologically valid assessment of semantic memory and would help disentangle personal and general forms of semantic memory.

Although much is known about the relationship between neuropsychiatric problems and the severity of cognitive impairments, relatively little is known about the association with specific cognitive impairments. The aim of this study was to determine whether specific cognitive impairments are predictive of neuropsychiatric problems. One hundred twenty-six patients were evaluated every 6 months for 2 years. In particular, a low level of language expression was related to higher levels of overall neuropsychiatric problems and to psychosis. Impairment of abstract reasoning was related to psychosis and aberrant motor behavior.

The present article aims to compare the performance in students with Attention Deficit Disorder to those who do not present it, in tasks of reading comprehension and text production carried out by students attending the fourth grade of primary education. This quantitative, non-experimental comparative study aims to provide evidence regarding the way in which this condition limits the learning outcomes in the tasks of comprehension and production of texts, language, and communication. One the main findings of this research was that students with attention deficit disorder showed lower reading comprehension performance than their peers who do not presented this diagnosis. This same tendency was observed in the results of the texts production tasks. This implies that the disorder affecting the attention in students with it interferes in the process of language learning. This generates challenges and new questions for those who do research in this topic; and for the case of teachers, it presents new challenges when planning the teaching in order to adapt it to the specific requirements of these students in the area of language.

Encyclopedia of human behavior