Event-Related Potentials Reveal Altered Executive Control Activity in Healthy Elderly With Subjective Memory Complaints

Several studies reported that healthy elderly with subjective memory complaints (SMC) evolve to Alzheimer’s disease (AD) more frequently than elderly without subjective memory decline. In the present study, we investigated event-related potentials (ERPs) associated to executive control processes taking place during the performance of a Simon task with two irrelevant dimensions (stimulus position and direction pointed by an arrow) in healthy elderly divided in low and high SMC (LSMC, HSMC) groups. P300 was studied as a correlate of working memory. Medial frontal negativity (MFN) was studied as a correlate of conflict monitoring. Whereas the LSMC group showed interference from the stimulus position, participants with HSMC showed interference from both irrelevant dimensions. P300 latency was longer and P300 amplitude was lower when the stimulus position was incompatible with the required response but differences between both groups were not observed. MFN was not modulated in the LSMC group; however, the HSMC group showed larger MFN when the stimulus position and/or the direction pointed by the arrow were incompatible with the required response. These results suggest that participants with HSMC deployed greater conflict monitoring activity to maintain the performance when the target stimulus contained conflictive spatial informationThis study was financially supported by funds from the Spanish Government: Ministerio de Economía y Competitividad (PSI2014-55316-C3-3-R; PSI2017-89389-C2-2-R), with FEDER Funds; the Galician Government: Consellería de Cultura, Educación e Ordenación Universitaria; Axudas para a Consolidación e Estruturación de Unidades de Investigación Competitivas do Sistema Universitario de Galicia: GRC (GI-1807-USC); Ref: ED431-2017/27, with FEDER funds; Juan de la Cierva-Incorporación postdoctoral grantsS

Cognitive control activity is modulated by the magnitude of interference and pre-activation of monitoring mechanisms

The Simon task is used to study interference from irrelevant spatial information. Interference is manifested by longer reaction times when the required response –based on non-spatial features- is spatially incompatible with stimulus position. Interference is greater when incompatible trials are preceded by compatible trials (compatible-incompatible sequence) than when they are preceded by incompatible trials (incompatible-incompatible sequence). However, the relationships between spatial attention, interference and cognitive control have not been investigated. In the present study, we distinguished three experimental conditions according to sequential effects: same mappings (SM, compatible-compatible/incompatible-incompatible sequences: low interference), opposite mappings (OM, compatible-incompatible/incompatible-compatible sequences: high interference) and unrelated mappings (UM, central-compatible/central-incompatible sequences: intermediate interference). The negativity central contralateral (N2cc, a correlate of prevention of spatial response tendencies) was larger in OM than in SM, indicating greater cognitive control for greater interference. Furthermore, N2cc was larger in UM than in SM/OM, indicating lower neural efficiency for suppressing spatial tendencies of the response after central trials. Attentional processes (negativity posterior contralateral) were also delayed in UM relative to SM/OM, suggesting attentional facilitation by similar sets of attentional shifts in successive trials. Overall, the present findings showed that cognitive control is modulated by the magnitude of interference and pre-activation of monitoring mechanismshis study was funded by the Spanish Government (Ministerio de Economía y Competitividad: PSI2014-55316-C3-3-R), the Galician Government (Consellería de Cultura, Educación e Ordenación Universitaria, Axudas para a consolidación e Estruturación de unidades de investigación competitivas do SUG: GPC2014/047, with FEDER funds and by European Commission (Marie Skłodowska Curie Actions, Individual Fellowships: Grant Reference NIBSAD-655423)S

Inhibition deficit in the spatial tendency of the response in multiple-domain amnestic mild cognitive impairment. An event-related potential study

Longitudinal studies have shown that a high percentage of people with amnestic mild cognitive impairment (MCI) develop Alzheimer’s disease (AD). Prodromal AD is known to involve deficits in executive control processes. In the present study, we examined such deficits by recording EEG in 13 single-domain amnestic MCI (sdaMCI), 12 multiple-domain amnestic MCI (mdaMCI) and 18 healthy elderly (control group, CG) participants while they performed a Simon task. The Simon task demands deployment of executive processes because participants have to respond to non-spatial features of a lateralized stimulus and inhibit the more automatic spatial tendency of the response. We specifically focused on the negativity central contralateral (N2cc), an event-related potential (ERP) component related to brain activity that prevents the cross-talk between direction of spatial attention and manual response preparation. The reaction time (RT) was not significantly different among the three groups of participants. The percentage of errors (PE) was higher in mdaMCI than in CG and sdaMCI participants. In addition, N2cc latency was delayed in mdaMCI (i.e., delayed implementation of mechanisms for controlling the spatial tendency of the response). The N2cc latency clearly distinguished among mdaMCI and CG/sdaMCI participants (area under curve: 0.91). Longer N2cc was therefore associated with executive control deficits, which suggests that N2cc latency is a correlate of mdaMCIThis study was funded by the Spanish Government: Ministerio de Economía y Competitividad (PSI2010-22224-C03-03); and by the Galician Government: Consellería de Economía e Industria (10 PXIB 211070 PR), and Consellería de Cultura, Educación e Ordenación Universitaria (Axudas de Apoio á etapa inicial de formación posdoutoral 2011-2015 (Plan I2C); Axudas para a Consolidación e Estruturación de unidades de investigación competitivas do sistema universitario de Galicia. Ref: CN 2012/033; with FEDER funds)S

Denominando caras: una revisión e integración multidisciplinar

Naming faces is a common area of study from a wide range of perspectives in social sciences, including cognitive psychology and several branches of cognitive neuroscience. This paper provides a comprehensive review of the cognitive models that have been proposed to explain the diverse aspects of face naming, taking into account face processing and language production models. In addition, a review of the neuroscientific data from event-related potential studies (when) and functional neuroimaging studies (where) is presented. Thus, an integrated view of the cognitive models and the data relating the different processes involved in naming faces to the brain activity is providedLa denominación de caras es un área de interés para diversas perspectivas en ciencias sociales, incluyendo la psicología cognitiva y diversas ramas de neurociencia cognitiva. Este artículo proporciona una revisión de los modelos cognitivos que han sido propuestos para explicar los diversos aspectos de la denominación de caras. Además, se presenta una revisión de los datos neurocientíficos de potenciales evocados (cuándo) y de estudios de neuroimagen funcional (dónde). Así, se presenta una visión integrada de los modelos cognitivos y los datos relacionando los distintos procesos implicados en la denominación de caras y la actividad cerebralThis work was financially supported by the Spanish Ministerios: Educación y Ciencia and Ciencia e Innovación (SEF2007-67964-C02-02), and the Galician Consellería de Innovación e Industria (PGIDIT07PXIB211018PR)S

Secuencia de actividad cerebral relacionada con la denominación de caras y el fenómeno de la punta de la lengua

Active brain areas and their temporal sequence of activation during the successful retrieval and naming of famous faces (KNOW) and during the tip-of-the-tongue (TOT) state were studied by means of low resolution electromagnetic tomographic analysis (LORETA) applied to event-related potentials. The results provide evidence that adequate activation of a neural network during the fi rst 500 ms following presentation of the photograph —mainly involving the posterior temporal region, the insula, lateral and medial prefrontal areas and the medial temporal lobe— is associated with successful retrieval of lexical-phonological information about the person’s name. Signifi cant differences between conditions were observed in the 538-698-ms interval; specifi cally there was greater activation of the anterior cingulate gyrus (ACC) towards the supplementary motor area (SMA) in the KNOW than in the TOT condition, possibly in relation to the motor response and as a consequence of the successful retrieval of lexical-phonological information about the personLas áreas cerebrales más activas y su secuencia de activación durante el recuerdo y la denominación exitosa de caras (Condición SI) y durante el fenómeno de la punta de la lengua (Condición PDL) fueron estimadas a partir de potenciales evocados mediante tomografías electromagnéticas de baja resolución (LORETA). Los resultados muestran evidencia de que una adecuada activación de una red neural (estando principalmente implicadas áreas temporales posteriores, insula, áreas prefrontales mediales y laterales, y áreas temporales mediales) durante los primeros 500 ms después de la presentación de la cara está relacionada con la recuperación exitosa de información léxico-fonológica sobre el nombre de la persona. Además se obtuvieron diferencias significativas entre ambas condiciones en el intervalo 538-698 ms; concretamente, el giro cingulado anterior y el área motora suplementaria mostraron una mayor activación en la Condición SI que en la Condición PDL, posiblemente relacionada con la respuesta motora y como consecuencia de la recuperación exitosa de la información léxico-fonológica sobre la personaThis work was financially supported by the Spanish Ministerio de Educación y Ciencia (SEF2007-67964-C02-02), and Galician Consellería de Innovación e Industria (PGIDIT07PXIB211018PR)S

Electrophysiological Correlates of Amnestic Mild Cognitive Impairment in a Simon Task

Amnestic mild cognitive impairment (aMCI) represents a prodromal stage of Alzheimer`s disease (AD), especially when additional cognitive domains are affected (Petersen et al., 2009). Thus, single-domain amnestic MCI (sdaMCI) and multipledomain-amnestic MCI (mdaMCI) biomarkers are important for enabling early interventions to help slow down progression of the disease. Recording event-related potentials (ERPs) is a non-invasive and inexpensive measure of brain activity associated with cognitive processes, and it is of interest from a clinical point of view. The ERP technique may also be useful for obtaining early sdaMCI and mdaMCI biomarkers because ERPs are sensitive to impairment in processes that are not manifested at behavioral or clinical levels. In the present study, EEG activity was recorded in 25 healthy participants and 30 amnestic MCI patients (17 sdaMCI and 13 mdaMCI) while they performed a Simon task. The ERPs associated with visuospatial (N2 posterior-contralateral – N2pc -) and motor (lateralized readiness potential – LRP –) processes were examined. The N2pc amplitude was smaller in participants with mdaMCI than in healthy participants, which indicated a decline in the correlates of allocation of attentional resources to the target stimulus. In addition, N2pc amplitude proved to be a moderately good biomarker of mdaMCI subtype (0.77 sensitivity, 0.76 specificity). However, the LRP amplitude was smaller in the two MCI groups (sdaMCI and mdaMCI) than in healthy participants, revealing a reduction in the motor resources available to execute the response in sdaMCI and mdaMCI patients. Furthermore, the LRP amplitude proved to be a valid biomarker (0.80 sensitivity, 0.92 specificity) of both amnestic MCI subtypesThis study was financially supported by funds from the Spanish Government: Ministerios de Educación (Beca FPU AP2007-04362) and Economía y Competitividad (PSI2010-22224-C03-03), and from the Galician Government: Consellería de Economía e Industria (10 PXIB 211070 PR), and Consellería de Educación e Ordenación Universitaria (Axudas para a Consolidación e Estruturación de unidades de investigación competitivas do sistema universitario de Galicia. Modalidade: Grupos con potencial de crecemento. Ref: CN 2012/033). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscriptS

Age-related effects on event-related brain potentials in a congruence/incongruence judgment color-word Stroop task

We examined the event-related brain potentials elicited by color-word stimuli in a Stroop task in which healthy participants (young and old) had to judge whether the meaning and the color of the stimulus were congruent or incongruent. The Stroop effect occurred in both age groups, with longer reaction times in the older group than in the young group for both types of stimuli, but no difference in the number of errors made by either group. Although the N2 and P3b latencies were longer in the older than in the younger group, there were no differences between groups in the latencies of earlier event-related potential components, and therefore the age-related processing slowing is not generalized. The frontal P150 amplitude was larger, and the parietal P3b amplitude was smaller, in the older than in the younger group. Furthermore, the P3b amplitude was maximal at frontal locations in older participants and at parietal locations in young participants. The age-related increase in perceptual resources and the posterior-to-anterior shift in older adults support adaptive reorganization of the neural networks involved in the processing of this Stroop-type taskThis study was financially supported by funds from the Spanish Government: Ministerio de Economía y Competitividad (PSI2010-22224-C03-03); and by the Galician Government: Consellería de Economía e Industria (10 PXIB 211070 PR), and Consellería de Cultura, Educación e Ordenación Universitaria (Axudas para a Consolidación e Estruturación de unidades de investigación competitivas do sistema universitario de Galicia. Ref: CN 2012/033; with FEDER funds)S

Neural correlates of unpredictable Stop and non-Stop cues in overt and imagined execution

The ability to inhibit incorrect behaviors is crucial for survival. In real contexts, cues that require stopping usually appear intermixed with indications to continue the ongoing action. However, in the classical Stop-signal task (SST), the unpredictable stimuli are always signals that require inhibition. To understand the neural mechanisms activated by low-probability nonstop cues, we recorded the electroencephalography from 23 young volunteers while they performed a modified SST where the unpredictable stimuli could be either Stop or confirmatory Go signals (CGo). To isolate the influence of motor output, the SST was performed during overt and covert execution. We found that, paradoxically, CGo stimuli activated motor inhibition processes, and evoked patterns of brain activity similar to those obtained after Stop signals (N2/P3 event-related potentials and midfrontal theta power increase), though in lesser magnitude. These patterns were also observed during the imagined performance. Finally, applying machine learning procedures, we found that the brain activity evoked after CGo versus Stop signals can be classified above chance during both, overt and imagined execution. Our results provide evidence that unpredictable signals cause motor inhibition even when they require to continue an ongoing actionThis work was supported by funding from the Galician Government (Consellería de Cultura, Educación e Ordenación Universitaria; Axudas para a consolidación e Estruturación de unidades de investigación competitivas do Sistema universitario de Galicia; grant number Ref:: ED431C 2021/04.); and from Fundação para a Ciência e a Tecnologia––Scientific Employment Stimulus (CEECIND/02639/2017 to A.G.V.)S

Affective picture modulation: Valence, arousal, attention allocation and motivational significance

The present study analyses the modulatory effects of affective pictures in the early posterior negativity (EPN), the late positive potential (LPP) and the human startle response on both the peripheral (eye blink EMG) and central neurophysiological levels (Probe P3), during passive affective pictures viewing. The affective pictures categories were balanced in terms of valence (pleasant; unpleasant) and arousal (high; low). The data shows that EPN may be sensitive to specific stimulus characteristics (affective relevant pictures versus neutral pictures) associated with early stages of attentional processing. In later stages, the heightened attentional resource allocation aswell as themotivated significance of the affective stimuliwas found to elicit enhancedamplitudes of slow wave processes thought to be related to enhanced encoding, namely LPP,. Although pleasant low arousing pictureswere effective in engaging the resources involved in the slowwave processes, the highly arousing affective stimuli (pleasant and unpleasant) were found to produce the largest enhancement of the LPP, suggesting that high arousing stimulimay are associatedwith increasedmotivational significance. Additionally the response to high arousing stimulimay be suggestive of increasedmotivational attention, given the heightened attentional allocation, as expressed in the P3 probe, especially for the pleasant pictures. The hedonic valencemay then serve as amediator of the attentional inhibition to the affective priming, potentiating or inhibiting a shift towards defensive activation, as measured by the startle reflex.Portuguese Foundation for Science and Technology with individual grants (SFRH/BD/41484/2007 and SFRH/BD/64355/2009) and by the Spanish Xunta de Galicia – with FEDER funds – (DOG 233 — Resolution date: 2009 November 18t

Abnormal processing of emotional prosody in Williams syndrome: an event-related potentials study

Williams syndrome (WS), a neurodevelopmental genetic disorder due to a microdeletion in chromosome 7, is described as displaying an intriguing socio-cognitive phenotype. Deficits in prosody production and comprehension have been consistently reported in behavioral studies. It remains, however, to be clarified the neurobiological processes underlying prosody processing in WS. This study aimed at characterizing the electrophysiological response to neutral, happy, and angry prosody in WS, and examining if this response was dependent on the semantic content of the utterance. A group of 12 participants (5 female and 7male), diagnosed with WS, with age range between 9 and 31 years, was compared with a group of typically developing participants, individually matched for chronological age, gender and laterality. After inspection of EEG artifacts, data from 9 participants with WS and 10 controls were included in ERP analyses. Participants were presented with neutral, positive and negative sentences, in two conditions: (1) with intelligible semantic and syntactic information; (2) with unintelligible semantic and syntactic information (‘pure prosody’ condition). They were asked to decide which emotion was underlying the auditory sentence. Atypical event-related potentials (ERP) components were related with prosodic processing (N100, P200, N300) in WS. In particular, reduced N100 was observed for prosody sentences with semantic content; more positive P200 for sentences with semantic content, in particular for happy and angry intonations; and reduced N300 for both types of sentence conditions. These findings suggest abnormalities in early auditory processing, indicating a bottomup contribution to the impairment in emotional prosody processing and comprehension. Also, at least for N100 and P200, they suggest the top-down contributions of semantic processes in the sensory processing of speech. This study showed, for the first time, that abnormalities in ERP measures of early auditory processing in WS are also present during the processing of emotional vocal information. This may represent a physiological signature of underlying impaired on-line language and socio-emotional processing.This work was supported by a Doctoral Grant (SFRH/BD/35882/2007) awarded to APP, as well as by the grant PIC/IC/83290/2007Fundação para a Ciência e a Tecnologia (FCT