Predicting executive functioning from brain networks: modality specificity and age effects.

Healthy aging is associated with structural and functional network changes in the brain, which have been linked to deterioration in executive functioning (EF), while their neural implementation at the individual level remains unclear. As the biomarker potential of individual resting-state functional connectivity (RSFC) patterns has been questioned, we investigated to what degree individual EF abilities can be predicted from the gray-matter volume (GMV), regional homogeneity, fractional amplitude of low-frequency fluctuations (fALFF), and RSFC within EF-related, perceptuo-motor, and whole-brain networks in young and old adults. We examined whether the differences in out-of-sample prediction accuracy were modality-specific and depended on age or task-demand levels. Both uni- and multivariate analysis frameworks revealed overall low prediction accuracies and moderate-to-weak brain-behavior associations (R2 < 0.07, r < 0.28), further challenging the idea of finding meaningful markers for individual EF performance with the metrics used. Regional GMV, well linked to overall atrophy, carried the strongest information about individual EF differences in older adults, whereas fALFF, measuring functional variability, did so for younger adults. Our study calls for future research analyzing more global properties of the brain, different task-states and applying adaptive behavioral testing to result in sensitive predictors for young and older adults, respectively.

Brain functional characterization of response-code conflict in dual-tasking and its modulation by age.

Crosstalk between conflicting response codes contributes to interference in dual-tasking, an effect exacerbated in advanced age. Here, we investigated (i) brain activity correlates of such response-code conflicts, (ii) activity modulations by individual dual-task performance and related cognitive abilities, (iii) task-modulated connectivity within the task network, and (iv) age-related differences in all these aspects. Young and older adults underwent fMRI while responding to the pitch of tones through spatially mapped speeded button presses with one or two hands concurrently. Using opposing stimulus-response mappings between hands, we induced conflict between simultaneously activated response codes. These response-code conflicts elicited activation in key regions of the multiple-demand network. While thalamic and parietal areas of the conflict-related network were modulated by attentional, working-memory and task-switching abilities, efficient conflict resolution in dual-tasking mainly relied on increasing supplementary motor activity. Older adults showed non-compensatory hyperactivity in left superior frontal gyrus, and higher right premotor activity was modulated by working-memory capacity. Finally, connectivity between premotor or parietal seed regions and the conflict-sensitive network was neither conflict-specific nor age-sensitive. Overall, resolving dual-task response-code conflict recruited substantial parts of the multiple-demand network, whose activity and coupling, however, were only little affected by individual differences in task performance or age.

Response-code conflict in dual-task interference and its modulation by age.

Difficulties in performing two tasks at once can arise from several sources and usually increase in advanced age. Tasks with concurrent bimodal (e.g., manual and oculomotor) responding to single stimuli consistently revealed crosstalk between conflicting response codes as a relevant source. However, how this finding translates to unimodal (i.e., manual only) response settings and how it is affected by age remains open. To address this issue, we had young and older adults respond to high- or low-pitched tones with one (single task) or both hands concurrently (dual task). Responses were either compatible or incompatible with the pitch. When responses with the same level of compatibility were combined in dual-task conditions, their response codes were congruent to each other, whereas combining a compatible and an incompatible response created mutually incongruent (i.e., conflicting) response codes, potentially inducing detrimental crosstalk. Across age groups, dual-task costs indeed were overall highest with response-code incongruency. In these trials, compatible responses exhibited higher costs than incompatible ones, even after removing trials with strongly synchronized responses. This underadditive cost asymmetry argues against mutual crosstalk as the sole source of interference and corroborates notions of strategic prioritization of limited processing capacity based on mapping-selection difficulty. As expected, the effects of incongruent response codes were found to be especially deleterious in older adults, supporting assumptions of age-related deficits in multiple-action control at the level of task-shielding. Overall, our results suggest that aging is linked to higher response confusability and less efficient flexibility for capacity sharing in dual-task settings.

Estudio de traducción y validez del Sistema de Codificación Etológica para Entrevistas ECSI (Ethological Coding System for Interviews) / Study of the application and validation of the Ethological Coding System for Interviews (ECSI)

Antecedentes El diagnóstico psicoterapéutico se fundamenta en exploraciones verbales y/o pruebas psicológicas. En contraste, a menudo se descuida la relevancia de la comunicación no-verbal. El objetivo del presente artículo es aportar una herramienta para medir y evaluar conductas no-verbales en entrevistas clínicas, basado en el Ethological Coding System for Interviews (ECSI), desarrollado por Troisi (1999), el cual se tradujo y validó en español. Un etograma es un catálogo de conductas o patrones conductuales, operacionalizados y agrupados en categorías, como afiliación, evasión, asertividad, relajación, entre otras. Método Estudio 1. El etograma ECSI fue traducido al español. Tres observadores "ciegos" registraron las frecuencias de los patrones conductuales del paciente. Los registros se realizaron en intervalos de 15 segundos durante los primeros y últimos 10 minutos de la entrevista clínica. Se obtuvo una validez interobservador de r=0.989, p<0.001. Estudio 2. Con base en el primer estudio se consideró pertinente agregar patrones conductuales, así como reacomodar y redefinir las categorías propuestas. Los tres observadores realizaron el mismo procedimiento que en el estudio 1 con una segunda videograbación. Además de las frecuencias de las conductas observadas, se midió la duración de la conducta. Se obtuvo una validez interobservadores de r=0.993, p<0.001. Resultados y discusión Se probó que el ECSI es una herramienta confiable y válida para examinar la conducta no-verbal de pacientes durante entrevistas. Se espera que el ECSI se pueda incluir al proceso diagnóstico durante las sesiones psicoterapéuticas.

Background Psychotherapeutic diagnosis is largely based on verbal explorations and/or psychological tests. In contrast, the relevance of non-verbal communication is often disregarded. Here, we aim to provide a tool to measure and assess non-verbal behavior in clinical interviews, based on the Ethological Coding System for Interviews (ECSI), developed by Troisi (1999), which was translated and validated in Spanish. An ethogram is a catalogue of behaviours or patterns of behaviour, which are operationalized and grouped in categories such as affiliation, flight, assertiveness, relaxation and so forth. Method Study 1. The ECSI was translated into Spanish. Three "blind" observers registered the frequencies of the behavioral patterns of the patient. The recordings were made in 15 seconds intervals during the first and the last 10 minutes of a clinical interview. An inter-observer reliability of r=0.989, p<0.001 was obtained. Study 2. Based on the first study, it was considered pertinent to add behavioral patterns, as well as rearranging and redefining the proposed categories. The three "blind" observers performed the same task as in study 1 with a second video-recording. Aside from the frequency of the observed behaviours, the duration of the behavior was measured. An inter-observer reliability of r=0.993, p<0.001 was obtained. Results and discussion The ECSI has proven a reliable and valid tool for the examination of patients' nonverbal behaviour during interviews. It is hoped that the ECSI can be added to the diagnostic process during psychotherapeutic sessions.