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The predictive coding theory of allostatic-interoceptive load states that brain networks mediating autonomic regulation and interoceptive-exteroceptive balance regulate the internal milieu to anticipate future needs and environmental demands. These functions seem to be distinctly compromised in behavioral variant frontotemporal dementia (bvFTD), including alterations of the allostatic-interoceptive network (AIN). Here, we hypothesize that bvFTD is typified by an allostatic-interoceptive overload.We assessed resting-state heartbeat evoked potential (rsHEP) modulation as well as its behavioral and multimodal neuroimaging correlates in patients with bvFTD relative to healthy control subjects and patients with Alzheimer's disease (N = 94). We measured 1) resting-state electroencephalography (to assess the rsHEP, prompted by visceral inputs and modulated by internal body sensing), 2) associations between rsHEP and its neural generators (source location), 3) cognitive disturbances (cognitive state, executive functions, facial emotion recognition), 4) brain atrophy, and 5) resting-state functional magnetic resonance imaging functional connectivity (AIN vs. control networks).Relative to healthy control subjects and patients with Alzheimer's disease, patients with bvFTD presented more negative rsHEP amplitudes with sources in critical hubs of the AIN (insula, amygdala, somatosensory cortex, hippocampus, anterior cingulate cortex). This exacerbated rsHEP modulation selectively predicted the patients' cognitive profile (including cognitive decline, executive dysfunction, and emotional impairments). In addition, increased rsHEP modulation in bvFTD was associated with decreased brain volume and connectivity of the AIN. Machine learning results confirmed AIN specificity in predicting the bvFTD group.Altogether, these results suggest that bvFTD may be characterized by an allostatic-interoceptive overload manifested in ongoing electrophysiological markers, brain atrophy, functional networks, and cognition.

Background: In the COVID-19 pandemic, older adults from vulnerable ethnoracial groups are at high risk of infection, hospitalization, and death. We aimed to explore the pandemic's impact on the well-being and cognition of older adults living in the United States (US), Argentina, Chile, Mexico, and Peru. Methods: 1,608 (646 White, 852 Latino, 77 Black, 33 Asian; 72% female) individuals from the US and four Latin American countries aged ≥ 55 years completed an online survey regarding well-being and cognition during the pandemic between May and September 2020. Outcome variables (pandemic impact, discrimination, loneliness, purpose of life, subjective cognitive concerns) were compared across four US ethnoracial groups and older adults living in Argentina, Chile, Mexico, and Peru. Findings: Mean age for all participants was 66.7 (SD = 7.7) years and mean education was 15.4 (SD = 2.7) years. Compared to Whites, Latinos living in the US reported greater economic impact (p

The cascade model of cognitive control, mostly relying on functional neuroimaging studies, stipulates that the lateral frontal cortex (LFC) is organized as a cascade of executive processes involving three levels of cognitive control, implemented in distinct LFC areas from the premotor to the anterior prefrontal regions. The present experiment tested this model in patients with LFC lesions and studied the hierarchy of executive functions along the caudo-rostral axis, i.e. the respective roles of the different LFC areas in the control of behavior. Voxel-based lesion-symptom mapping and region of interest group analyses were conducted in 32 patients with focal LFC lesions who performed cognitive tasks assessing the cascade model. We first showed that three different LFC areas along the caudo-rostral axis subserved three distinct control levels, whose integrity is necessary for adaptive behavior. Second, we found that prefrontal cognitive control has an asymmetric organization: higher control processes involving more anterior prefrontal regions rely on the integrity of lower control processes in more posterior regions, while lower control processes can operate irrespective of the integrity of higher control processes. Altogether, these findings support a caudo-rostral cascade of executive processes from premotor to anterior prefrontal regions.

Background: The prevalence of cognitive impairment (CI) will double in the next 20 years, making early detection a key priority. Objectives: Validation of a 5-minute CI screening test. Methods: Adults aged 60 years and older were recruited from memory clinics and the community at large in the Santiago, Chile metropolitan area. Based on clinical examination they were categorised as No CI (NCI), Mild CI (MCI) and dementia sufferers (DS). We measured the validity of a new test, MEFO, evaluating memory (5 points), phonetic verbal fluency (2 points) and orientation (6 points) by comparing its results with those from the MMSE. Results: We evaluated 214 subjects, comprising 49 with dementia, 47 with MCI, and 118 with no CI. The MEFO differentiated between all 3 groups whereas the MMSE did not discriminate between the MCI and NCI groups. The area under the ROC curve (AUC) for the MEFO distinguishing NCI subjects from dementia sufferers was 0.97; for NCI vs CI (dementia + MCI), 0.89; and for NCI vs MCI, 0.80. On the MMSE these values were 0.95, 0.84, and 0.73, respectively. A cut-off score of 6/7 on the MEFO identified dementia sufferers with a sensitivity of 86% and a specificity of 96%. A cut-off score of 8/9 distinguished CI from NCI subjects with a sensitivity of 83% and a specificity of 75%. Conclusions: The MEFO is a valid and reliable test for discriminating between dementia and CI sufferers and subjects with no CI. Its validity is similar to that of the MMSE under these conditions, but it is more effective for identifying subjects with MCI and its administration time is shorter. Resumen: Antecedentes: En los próximos 20 años se duplicará la cantidad de personas con deterioro cognitivo (DC) apremiando su pronta detección. Objetivos: Validar una prueba de cribado de DC aplicable en < de 5 minutos. Métodos: Adultos ≥60 años reclutados desde la comunidad y clínicas de memoria de la zona urbana de Santiago de Chile fueron clasificados clínicamente en: Dementes, DC leve (DCL) y Sin DC (SDC). Se evaluó la validez de un nuevo test: MEFO, consistente en la evaluación de: Memoria (5 puntos), Fluidez Fonética (2 puntos) y Orientación (6 puntos) contrastado con los resultados del MMSE. Resultados: Se evaluaron 214 personas: 49 con demencia, 47 con DCL y 118 SDC. El MEFO diferenció a los 3 grupos clínicos entre sí, mientras que el MMSE no permitió discriminar DCL de SDC. El área bajo la curva ROC en el MEFO para diferenciar los grupos SDC versus: i: Demencia fue = 0,97; ii: DC (dementes + DCL)fue = 0,89; y iii: DCL fue = 0,80; siendo estos valores para el MMSE de 0,95, 0,84, y 0,73, respectivamente. Un punto de corte (PC) del MEFO = 6/7 distinguió a las personas con demencia con una sensibilidad (S) = 86% y especificidad (E) = 96%; y un PC = 8/9 distinguió a aquellos con DC con una: S = 83% y E = 75%. Conclusiones: El MEFO resultó una prueba confiable y válida para diferenciar a personas con demencia y DC, similar al MMSE en éstos casos, pero con mayor utilidad para distinguir a los pacientes con DCL y de menor duración de aplicación. Keywords: Cognitive impairment screening, Chile, Dementia, Spanish, Palabras clave: Cribado de deterioro cognitivo, Chile, Demencias, Español

To investigate the role of the prefrontal cortex in conscious monitoring, we used an experimental paradigm generating a conflict between the action planned and the sensory-motor feedback. We analyzed the acquisition of explicit knowledge of the strategy for resolving the conflict and its influence on motor adaptation. Twenty patients with frontal lobe lesions and 18 controls had to trace a sagittal line with a stylus on a graphics tablet. A mirror on which the traced line, processed by a computer, was projected hid the hand. A mask limited visual feedback to the last third of the trajectory. Without informing the subjects, the line traced was modified by introducing a bias of 24 degrees to the right. To succeed in the task, subjects had to modify their motor program and to deviate their trajectory in the opposite direction. Conscious elaboration of the strategy was evaluated by the number of trials needed to explicitly report the required deviation. Three groups of patients were distinguished: (1). with normal explicit strategy; (2). with delayed explicit strategy, and (3). without explicit strategy at the last trial. They significantly differed by the severity of the dysexecutive syndrome, particularly of environmental adherence. Motor adaptation was evaluated by the area between the line traced and the ideal line to compensate for the deviation. In patients with normal elaboration of the strategy, motor control was similar to that of controls, but it was severely disturbed in the other two groups. These results suggest the involvement of the prefrontal cortex in conscious motor monitoring.

Immanuel Kant, one of the most brilliant minds of the XVIII century and of western philosophy, suffered from dementia in his late years. Based on the analysis of testimonies of his close friends, in this report we describe his neurological disorder which, after 8 years of evolution, led to his death. His cognitive decline was strongly associated with a parasomnia compatible with a severe rapid eye movement (REM) behavior disorder (RBD) and dementia with Lewy bodies.

The desriptive statistics, limitation, strenghts especially in primaty care units be discussed. Results: The database was initiated in May 2007 and covers almost all of Sweden. There were 50 000 patients registered during 2007– 2014. The role of primary care units increased in that time and helped for diagnosis of new cases. Conclusion: SveDem provides knowledge about current dementia care in Sweden and serves as a framework for ensuring the quality of diagnostics, treatment and care across the country. The special role of primary care in dementia work up is important.