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Cognitive Reserve (CR) is considered a protective factor during the aging process. However, although CR is a multifactorial construct, it has been operationalized in a unitary way (years of formal education or IQ). In the present study, a validated measure to categorize CR holistically (Cognitive Reserve Index Questionnaire) was used to evaluate the resting-state functional connectivity in 77 cognitively unimpaired participants aged 50 years and over with high and low CR, and matched brain global atrophy levels. The connectivity of networks linked to attentional (Dorsal Attention Network -DAN-) and executive (Frontal-Parietal Control Network -FPCN-) processes were evaluated by the combination of Independent Component Analysis and seed-based approaches, since these networks have been proposed as candidates to underlie the protective effect of CR in the aging context. Participants with high CR showed an increase of the connectivity in the FPCN and a decrease in the DAN with respect to the low CR group, correlating with neuropsychological scores and supporting that high CR is related to a better neurocognitive preservation during aging This study was supported by grants from the Spanish Government, Ministerio de Ciencia e Innovación (PSI2017-89389-C2-R; PID2020-114521RB-C21/C22); the Galician Government (Xunta de Galicia), Axudas para a Consolidación e Estruturación de Unidades de Investigación Competitivas do Sistema Universitario de Galicia: GRC (GI-1807-USC); Ref: ED431-2017/27; ED431C-2021/04; all with ERDF/FEDER fund SI

Introduction: This study aimed to evaluate, in adults with mild cognitive impairment (MCI), the brain atrophy that may distinguish between three AT(N) biomarker-based profiles, and to determine its clinical value. Methods: Structural MRI (sMRI) was employed to evaluate the volume and cortical thickness differences in MCI patients with different AT(N) profiles, namely, A−T−(N)−: normal AD biomarkers; A+T−(N)−: AD pathologic change; and A+T+(N)+: prodromal AD. Sensitivity and specificity of these changes were also estimated. Results: An initial atrophy in medial temporal lobe (MTL) areas was found in the A+T−(N)− and A+T+(N)+ groups, spreading toward the parietal and frontal regions in A+T+(N)+ patients. These structural changes allowed distinguishing AT(N) profiles within the AD continuum; however, the profiles and their pattern of neurodegeneration were unsuccessful to determine the current clinical status. Conclusion: sMRI is useful in the determination of the specific brain structural changes of AT(N) profiles along the AD continuum, allowing differentiation between MCI adults with or without pathological AD biomarkers This study was supported by grants from the Spanish Government, Ministerio de Ciencia e Innovación (PSI2017- 89389-C2-R and PID2020-114521RB-C21/C22); the Galician Government, Axudas para a Consolidación e Estruturación de Unidades de Investigación Competitivas do Sistema Universitario de Galicia: GRC (GI-1807- USC); Refs: ED431-2017/27 and ED431C-2021/04; all with ERDF/FEDER funds SI

Alzheimer’s Disease (AD) has become a major health issue in recent decades, and there is now growing interest in amnestic mild cognitive impairment (aMCI), an intermediate stage between healthy aging and dementia, usually AD. Event-related brain potential (ERP) studies have sometimes failed to detect differences between aMCI and control participants in the Go-P3 (or P3b, related to target classification processes in a variety of tasks) and NoGo-P3 (related to response inhibition processes, mainly in Go/NoGo tasks) ERP components. The aim of the present study was to evaluate whether the age factor, which is not usually taken into account in ERP studies, modulates group differences in these components. With this aim, we divided two groups of volunteer participants, 34 subjects with aMCI (51–87 years) and 31 controls (52–86 years), into two age subgroups: 69 years or less and 70 years or more. We recorded brain activity while the participants performed a distraction-attention auditory-visual (AV) task. Task performance was poorer in the older than in the younger group, and aMCI participants produced fewer correct responses than the matched controls; but no interactions of the age and group factors on performance were found. On the other hand, Go-P3 and NoGo-N2 latencies were longer in aMCI participants than in controls only in the younger subgroup. Thus, the younger aMCI participants categorized the Go stimuli in working memory and processed the NoGo stimuli (which required response inhibition) slower than the corresponding controls. Finally, the combination of the number of hits, Go-P3 latency and NoGo-N2 latency yielded acceptable sensitivity and specificity scores (0.70 and 0.92, respectively) as regards distinguishing aMCI participants aged 69 years or less from the age-matched controls. The findings indicate age should be taken into account in the search for aMCI biomarkers This study was supported by grants 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 SI

In the present study we used the event-related brain potentials (ERP) technique and eLORETA (exact low-resolution electromagnetic tomography) method in order to characterize and compare the performance and the spatiotemporal pattern of the brain electrical activity related to the immediate episodic retrieval of information (words) that is being learned relative to delayed episodic retrieval twenty-minutes later. For this purpose, 16 young participants carried out an old/new word recognition task with source memory (word colour). The task included an immediate memory phase (with three study-test blocks) followed (20 min later) by a delayed memory phase with one test block. The behavioural data showed progressive learning and consolidation of the information (old words) during the immediate memory phase. The ERP data to correctly identified old words for which the colour was subsequently recollected (H/H) compared to the correctly rejected new words (CR) showed: (1) a significant more positive-going potential in the 500–675 ms post-stimulus interval (parietal old/new effect, related to recollection), and (2) a more negative-going potential in the 950–1850 ms interval (LPN effect, related to retrieval and post-retrieval processes). The eLORETA data also revealed that the successful recognition of old words (and probably retrieval of their colour) was accompanied by activation of (1) left medial temporal (parahippocampal gyrus) and parietal regions involved in the recollection in both memory phases, and (2) prefrontal regions and the superior temporal gyrus (in the immediate and delayed memory phases respectively) involved in monitoring, evaluating and maintaining the retrieval products. These findings indicate that episodic memory retrieval depends on a network involving medial temporal lobe and frontal, parietal and temporal neocortical structures. That network was involved in immediate and delayed memory retrieval and during the course of memory consolidation, with greater activation of some nodes (mobilization of more processing resources) for the delayed respect to the immediate retrieval condition This study was supported by grants from the Spanish Government, Ministerio de Ciencia e Innovación (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 SI

The present fMRI study aimed to characterize the performance and the brain activity changes related to episodic memory retrieval in adults with single domain aMCI (sdaMCI), relative to cognitively unimpaired adults. Participants performed an old/new recognition memory task with words while BOLD signal was acquired. The sdaMCI group showed lower hits (correct recognition of old words), lower ability to discriminate old and new words, higher errors and longer reaction times for hits. This group also displayed brain hypoactivation in left precuneus and the left midcingulate cortex during the successful recognition of old words. These changes in brain activity suggest the presence of neural dysregulations in brain regions involved during successful episodic memory retrieval. Moreover, hypoactivation in these brain areas discriminated both groups with moderate sensitivity and specificity values, suggesting that it might constitute a potential neurocognitive biomarker of sdaMCI This study was supported by grants from the Spanish Government, Ministerio de Economía y Competitividad (PSI2014–55316-C3–3-R; PSI2017–89389-C2–2-R; PID2020–114521RB-C21/C22); and the Galician Government, Axudas para a Consolidación e Estruturación de Unidades de Investigación Competitivas do Sistema Universitario de Galicia: GRC (GI-1807-USC. Ref: ED431–2017/27; ED431C-2021/04. All with ERDF/FEDER funds SI

Early identification of amnestic mild cognitive impairment (aMCI) subtypes is important for early diagnosis and prognosis of Alzheimer’s disease. Healthy, single-domain (sdaMCI) and multiple-domain aMCI (mdaMCI) participants performed an auditory-visual distraction-attention task. Event-related brain potentials (ERPs) were recorded while the participants performed the task to evaluate Go/NoGo N2 and P3 ERP components. The results showed the expected behavioral and cognitive decline in mdaMCI participants relative to controls (fewer hits, longer reaction times [RTs], slightly smaller Go-N2 and NoGo-N2 amplitudes), while sdaMCI participants showed some decline (slightly longer RTs, smaller Go- and NoGo-N2 amplitudes) along with some unexpected results (a late positive slow wave, PSW) and good levels of execution. In addition, some of these parameters proved to be useful markers. Thus, the number of hits was the best marker for diagnosing mdaMCI participants (distinguishing them from controls, from sdaMCI participants, and from both groups together), while the PSW amplitude was the best marker for diagnosing sdaMCI participants (distinguishing them from controls, and from control & mdaMCI participants).

The event-related potential (ERP) technique has been shown to be useful for evaluating changes in brain electrical activity associated with different cognitive processes, particularly in Alzheimer’s disease (AD). Longitudinal studies have shown that a high proportion of people with amnestic mild cognitive impairment (aMCI) go on to develop AD. aMCI is divided into two subtypes according to the presence of memory impairment only (single-domain aMCI: sdaMCI) or impairment of memory and other cognitive domains (multi-domain aMCI: mdaMCI). The main aim of this study was to examine the effects of sdaMCI and mdaMCI on the P3a ERP component associated with the involuntary orientation of attention toward unattended infrequent novel auditory stimuli. Participants performed an auditory-visual distraction-attention task, in which they were asked to ignore the auditory stimuli (standard, deviant, and novel) and to attend to the visual stimuli (responding to some of them: Go stimuli). P3a was identified in the Novel minus Standard difference waveforms, and reaction times (RTs) and hits (in response to Go stimuli) were also analyzed. Participants were classified into three groups: Control, 20 adults (mean age (M): 65.8 years); sdaMCI, 19 adults (M: 67 years); and mdaMCI, 11 adults (M: 71 years). In all groups, the RTs were significantly longer when Go stimuli were preceded by novel (relative to standard) auditory stimuli, suggesting a distraction effect triggered by novel stimuli; mdaMCI participants made significantly fewer hits than control and sdaMCI participants. P3a comprised two consecutive phases in all groups: early-P3a (e-P3a), which may reflect the orienting response toward the irrelevant stimuli, and late-P3a (l-P3a), which may be a correlate of subsequent evaluation of these stimuli. The e-P3a amplitude was significantly larger in mdaMCI than in sdaMCI participants, and the l-P3a amplitude was significantly larger in mdaMCI than in sdaMCI and Control participants, indicating greater involuntary capture of attention to unattended novel auditory stimuli and allocation of more attentional resources for the subsequent evaluation of these stimuli in mdaMCI participants. The e-P3a and l-P3a components showed moderate to high sensitivity and specificity for distinguishing between groups, suggesting that both may represent optimal neurocognitive markers for differentiating aMCI subtypes This study was supported by grants from the Spanish Government (Ministerio de Economía y Competitividad) (PSI2014-55316-C3-3-R) and 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: GRC; ED431-2017/27), with FEDER funds SI

The aim of this study was to evaluate the effects of aging and attentional capture provoked by novel auditory stimuli on behavior (reaction time [RT], hits) and on response-related brain potentials (preRFP, CRN, postRFP, parietalRP) to target visual stimuli. Twenty-two young, 27 middle-aged, and 24 old adults performed an auditory-visual distraction-attention task. The RTs and latencies of preRFP, postRFP and parietalRT were longer in old and middle-aged than in young participants, reflecting the well-established age-related slowing of processing and performance. The inter-peak latencies (P3b-preRFP, preRFP-parietalRP, parietalRP-postRFP) were also longer in old and middle-aged than in young participants, further indicating an age-related tendency to increased predominance of serial (rather than parallel) processing of information, and that preRFP, CRN, postRFP, and parietalRP represent different cognitive processes from those indexed by the stimulus-related P3b. Finally, a distraction effect in performance (all three groups) and in postRFP latency (only middle-aged group) was also observed.

BACKGROUND: The findings of previous studies, in which event-related potentials (ERPs) related to stimulus evaluation were measured, do not fully explain the behavioral decline observed in amnestic mild cognitive impairment (aMCI; prodromal stage of Alzheimer’s Disease). OBJECTIVES: Motor ERPs were evaluated in this study with the aim of discovering complementary explanations and identifying aMCI biomarkers. DESIGN: Cross-sectional study. SETTING: Santiago de Compostela, Galicia, Spain. PARTICIPANTS: Nineteen healthy control (52-81 years old), 21 single-domain aMCI (sdaMCI; 51-87 years old) and 12 multi-domain aMCI (mdaMCI, 62-85 years old) adults. MEASUREMENTS: Reaction times (RTs), percentage of hits, and stimulus-locked and response-locked lateralized readiness potentials (sLRP and rLRP, indexes of response selection and preparation) were evaluated. RESULTS: mdaMCI participants showed longer RTs than control adults and less hits than control and sdaMCI participants. In addition, the mdaMCI group showed lower sLRP amplitudes than the control participants, and the sdaMCI group showed longer sLRP peak latencies. CONCLUSIONS: Control and sdaMCI groups did not differ in relation to RTs or hits, although sLRP peak latencies (sensitivity and specificity >.73) were longer in the sdaMCI group, which may be a sign of compensatory mechanisms or early indication of a decline in motor control. RTs were longer and sLRP amplitudes were smaller in the mdaMCI than in the Control group, and mdaMCI scored fewer hits than control and sdaMCI participants, indicating behavioral and neurocognitive deficits. The combination of hits and RTs discriminated mdaMCI from control adults (sensitivity and specificity >.82); and the combination of sLRP peak latency and hits discriminated mdaMCI from sdaMCI adults (sensitivity=1.00, specificity=.88).

Although many studies have demonstrated decline in attention and executive function (especially in inhibitory control) in healthy aging and Alzheimer's disease (AD), similar studies concerning mild cognitive impairment (MCI) are scarce. In the present study, we evaluated how the cognitive decline associated with amnestic MCI (aMCI) affects these processes, analyzing the N2 and P3 components of event-related potentials (ERPs) during the response (Go) and inhibition of response (NoGo) to different stimuli. ERPs were analyzed in 63 healthy and 30 aMCI adults (aged 50 to 87 years) during performance of a Go/NoGo auditory-visual attention-distraction task. aMCI adults showed poorer execution (longer response times and fewer correct responses) and smaller Go-N2 and NoGo-N2 amplitudes than control adults, whereas P3 amplitudes and N2 and P3 latencies did not differ between the groups. These results show that aMCI is associated with decline in executive function and stimuli evaluation in working memory. © 2014-IOS Press.

The main aim of this study was to examine the effects of aging on event-related brain potentials (ERPs) associated with the automatic detection of unattended infrequent deviant and novel auditory stimuli (Mismatch Negativity, MMN) and with the orienting to these stimuli (P3a component), as well as the effects on ERPs associated with reorienting to relevant visual stimuli (Reorienting Negativity, RON). Participants were divided into three age groups: (1) Young: 21–29 years old; (2) Middle-aged: 51–64 years old; and (3) Old: 65–84 years old. They performed an auditory-visual distraction-attention task in which they were asked to attend to visual stimuli (Go, NoGo) and to ignore auditory stimuli (S: standard, D: deviant, N: novel). Reaction times (RTs) to Go visual stimuli were longer in old and middle-aged than in young participants. In addition, in all three age groups, longer RTs were found when Go visual stimuli were preceded by novel relative to deviant and standard auditory stimuli, indicating a distraction effect provoked by novel stimuli. ERP components were identified in the Novel minus Standard (N-S) and Deviant minus Standard (D-S) difference waveforms. In the N-S condition, MMN latency was significantly longer in middle-aged and old participants than in young participants, indicating a slowing of automatic detection of changes. The following results were observed in both difference waveforms: (1) the P3a component comprised two consecutive phases in all three age groups—an early-P3a (e-P3a) that may reflect the orienting response toward the irrelevant stimulation and a late-P3a (l-P3a) that may be a correlate of subsequent evaluation of the infrequent unexpected novel or deviant stimuli; (2) the e-P3a, l-P3a, and RON latencies were significantly longer in the Middle-aged and Old groups than in the Young group, indicating delay in the orienting response to and the subsequent evaluation of unattended auditory stimuli, and in the reorienting of attention to relevant (Go) visual stimuli, respectively; and (3) a significantly smaller e-P3a amplitude in Middle-aged and Old groups, indicating a deficit in the orienting response to irrelevant novel and deviant auditory stimuli This work was financially supported by funds from the Spanish Government: Ministerio de Economía y Competitividad (PSI2014-55316-C3-3-R); and 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 (GPC2014/047), with FEDER funds SI

A famous-face naming task was used to establish the electrophysiological characterization of the tip-of-the-tongue (TOT) state, successful naming (K), and nonrecognition (DK). The differences in the direct event-related potentials (ERPs) and in the lateralized readiness potential between those categories were studied. The ERP correlates of recognition and access to semantic and lexical information were similar between K and TOT, but showed amplitude differences with respect to DK. A delayed onset of the response selection was obtained in TOT in comparison with K, suggesting an insufficient activation of phonological information from 360ms onwards. The continuous search for the name and the conflict monitoring in TOT led to differences in ERP amplitudes between TOT and the other categories from 750ms onwards as well as to a delayed onset of response preparation, indicating a continuous engagement of processing resources. © 2012 Society for Psychophysiological Research.

In the present study a face naming reaction time task was employed in order to evaluate the effect of age on performance and on movement related cortical potentials (MRCPs). In addition, the effect of three response categories with different cognitive demands (DON'T KNOW–don't know the name–, KNOW–correct naming– and TOT—tip-of the-tongue state) on performance and on MRCPs in a sample of older adults was evaluated. The same MRCPs found in a previous study in a sample of young adults were identified in older adults. The results indicated that older participants were generally slower at providing responses than young adults, and that both age groups showed longer reaction time in TOT than in DON'T KNOW and KNOW categories. The first component of readiness potential (1st-RP) showed larger amplitude and longer duration in older than in young adults, especially in the TOT category, which would explain the generally slower responses provided by older participants. In addition, in older adults, the 1st-RP was larger in TOT than in the DON'T KNOW category, but a slope reduction and stabilization were observed in TOT from the more demanding stages of stimulus processing. These results may reflect a lengthening in the preparation period in the TOT category, which probably explains the behavioural slowing in this category. The data of the present study suggest differences in the allocation of processing resources between groups, indicating that the sensoriomotor performance should be compromised more in older than in young adults in tasks with high cognitive load.

The tip-of-the-tongue state (TOT) in face naming is a transient state of difficulty in access to a person's name along with the conviction that the name is known. The aim of the present study was to characterize the spatio-temporal course of brain activation in the successful naming and TOT states, by means of magnetoencephalography, during a face-naming task. Following famous face presentations, subjects indicated whether they knew the name, did not know the name, or experienced a TOT state. Next they produced the name aloud, if they could, although they did not indicate whether they retrieved any other information about the person. The TOT state was characterized by lower activation than for successful retrieval, in the 310-520 ms poststimulus interval, localized to left temporal and frontal areas, bilateral parahippocampal gyrus, and right fusiform gyrus, which may underlie the genesis of TOT. Greater activation was also found in the 740-820 ms interval, localized to bilateral occipital, left temporal, and right frontal and parietal areas, corresponding with the unfruitful search for the name after the TOT state was produced. These results showed the differential brain dynamics underlying searching for the name of a known individual according to whether the search was successful or subjectively rated as just short of success.

The aim of the present study was evaluate the movement-related cortical potentials (MRCPs) associated with manual and speech movements during a face naming task carried out by the same participants as in a previous study, in order to: 1) determine whether the slowing down of the reaction time observed in the tip-of-the-tongue (TOT) state was caused by motor processes; 2) compare the MRCPs among the three response categories (tip-of-the-tongue, successful retrieval and not knowing the name); and 3) determine whether the MRCPs modulated the differences in amplitude of the late negative wave among response categories. The first component of readiness potential, the negative slope, the motor potential and the reafferent potential associated with the manual response, and two components associated with the verbal responses—the speech-related motor potential and the speech-related reafferent potential—were identified. The slowing down of reaction time observed in the TOT category may be due to a temporal interruption in the motor programming of the responses due to the TOT state. The longer latency in speech-related components in the KNOW with respect to the TOT category can be attributed to the greater cognitive demands involved in the retrieval of proper names in the former category. The brain activity associated with the preparation and execution of the responses had a differential modulatory effect on the amplitude of the LNW component, which may partially explain the differences between the categories observed in the previous study by Diaz et al. [Diaz, F., Lindin, M., Galdo-Alvarez, S., Facal, D., Juncos-Rabadan, O., 2007. An event-related potentials study of face identification and naming: the tip-of-the-tongue state. Psychophysiology 44, 50–68].

An evaluation was made of whether stimulus intensity affects changes of P300 amplitude in response to repeated presentation of the target stimulus in a standard auditory oddball task. P300 latency values were also evaluated. Three samples were selected, one for each intensity used: 65, 85 and 105 dB SPL (sound pressure level). Five hundred tones (5 subblocks, 100 tones each) were presented. P300 amplitude (1) increased from Fz to Pz, (2) was larger at 105 than 65 or 85 dB SPL, (3) increased from the first to second subblock and decreased from the second subblock onwards at the three intensities, replicating our previous findings at 85 dB SPL and demonstrating a consistent phenomenon, and (4) at 105 dB SPL, the decrease was less pronounced, which we attribute to the more intense stimuli capturing the attention in a sustained manner during the task and interfering with the possible automation of the context-updating process.

Introduction Naming is the result of complex cognitive processes, as it involves remembering the verbal label associated with an object, action, place, animal, or person. Naming requires retrieval of a label and its spoken or written production. However, although we know the names of many people, animals, or things, in the course of daily life, the naming of known names can fail momentarily. A universal experience is the annoying feeling of wanting to say a word and not being able to, while being completely sure that we know it, that we have recalled it in the past, and that we are on the verge of retrieving it. This experience is, of course, the “tip-of-the-tongue state” (TOT). One of the main features of the phenomenon lies in the temporary inability to access information that is undoubtedly registered in the memory stores of the person who presents a TOT. Understanding how this phenomenon occurs, therefore, may be helpful to understand how the mechanisms of accessing information stored in memory take place. We also think that TOTs can aid our understanding of memory retrieval disorders.

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 task This 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) SI

This work was financially supported by funds from the Spanish Ministerio de Economía y Competitividad (PSI2010-22224-C03-03), and from the Galician Government: Consellería de Industria e Innovación (PGIDIT07PXIB211018PR, 10PXIB 211070 PR); and Consellería de Educación e Ordenación Universitaria (Ref: CN 2012/033) The main aim of the present study was to assess whether aging modulates the effects of involuntary capture of attention by novel stimuli on performance, and on event-related potentials (ERPs) associated with target processing (N2b and P3b) and subsequent response processes (stimulus-locked Lateralized Readiness Potential -sLRP- and response-locked Lateralized Readiness Potential -rLRP-). An auditory-visual distraction-attention task was performed by 77 healthy participants, divided into three age groups (Young: 21–29, Middle-aged: 51–64, Old: 65–84 years old). Participants were asked to attend to visual stimuli and to ignore auditory stimuli. Aging was associated with slowed reaction times, target stimulus processing in working memory (WM, longer N2b and P3b latencies) and selection and preparation of the motor response (longer sLRP and earlier rLRP onset latencies). In the novel relative to the standard condition we observed, in the three age groups: (1) a distraction effect, reflected in a slowing of reaction times, of stimuli categorization in WM (longer P3b latency), and of motor response selection (longer sLRP onset latency); (2) a facilitation effect on response preparation (later rLRP onset latency), and (3) an increase in arousal (larger amplitudes of all ERPs evaluated, except for N2b amplitude in the Old group). A distraction effect on the stimulus evaluation processes (longer N2b latency) were also observed, but only in middle-aged and old participants, indicating that the attentional capture slows the stimulus evaluation in WM from early ages (from 50 years onwards, without differences between middle-age and older adults), but not in young adults SI

The authors thank the participants and their relatives. They also thank S. Galdo, A. Buján, J. Cespón, D. Pinal, M. Ramos, C. Libisch, and S. Cid for help in the sample selection, electroencephalographic recordings and ERP processing It has been suggested that changes in some event-related potential (ERP) parameters associated with controlled processing of stimuli could be used as biomarkers of amnestic mild cognitive impairment (aMCI). However, data regarding the suitability of ERP components associated with automatic and involuntary processing of stimuli for this purpose are not conclusive. In the present study, we studied the Mismatch Negativity (MMN) component, a correlate of the automatic detection of changes in the acoustic environment, in healthy adults and adults with aMCI (age range: 50-87 years). An auditory-visual attention-distraction task, in two evaluations separated by an interval of between 18 and 24 months, was used. In both evaluations, the MMN amplitude was significantly smaller in the aMCI adults than in the control adults. In the first evaluation, such differences were observed for the subgroup of adults between 50 and 64 years of age, but not for the subgroup of 65 years and over. In the aMCI adults, the MMN amplitude was significantly smaller in the second evaluation than in the first evaluation, but no significant changes were observed in the control adult group. The MMN amplitude was found to be a sensitive and specific biomarker of aMCI, in both the first and second evaluation This work was financially supported by funds from the Spanish Ministerio Economía y Competitividad (PSI2010-22224-C03-03), and from the Galician Government: Consellería de Industria e Innovación/Economía e Industria (PGIDIT07PXIB211018PR, 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 crecimento. Ref: CN 2012/033) SI

A famous-face naming task was used to establish the electrophysiological characterization of the tip-of-the-tongue (TOT) state, successful naming (K), and nonrecognition (DK). The differences in the direct event-related potentials (ERPs) and in the lateralized readiness potential between those categories were studied. The ERP correlates of recognition and access to semantic and lexical information were similar between K and TOT, but showed amplitude differences with respect to DK. A delayed onset of the response selection was obtained in TOT in comparison with K, suggesting an insufficient activation of phonological information from 360 ms onwards. The continuous search for the name and the conflict monitoring in TOT led to differences in ERP amplitudes between TOT and the other categories from 750 ms onwards as well as to a delayed onset of response preparation, indicating a continuous engagement of processing resources.

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 first 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. Significant differences between conditions were observed in the 538-698-ms interval; specifically 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 person.

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 provided.

This study was carried out to investigate the ERP correlates (some of which were characterized in a previous study) of the "tip-of-the-tongue" (TOT) state, in a face naming task, and to determine how dissociation of the manual and verbal responses (delaying the verbal response 2s from the stimulus onset) affects the Late Negative Wave (LNW). The results showed: 1) new ERP correlates of the TOT state, as the latency of both the Early P3 and N450 components was significantly longer in TOT than in successful naming, reflecting slower access in TOT, from the 300 ms post-stimulus, to information about the famous people, and 2) no differences in the amplitude of LNW among response categories, which suggests that the LNW amplitude is modulated by the brain activity associated with the verbal response.

Studies that have attempted to determine the effects of aging on the brain neural sources of memory retrieval have reported two contrasting age effects: under-recruitment and over-recruitment of several prefrontal areas. However, the causes for these effects are still a matter of debate. In order to study the underlying factors that cause the effects, we compared brain activation in young and older adults, in a successful word retrieval condition, and a failed word retrieval condition: the tip-of-the-tongue state. For this, we used the event-related potentials technique and neural source estimation with low-resolution tomographies. The results showed that the older adults did not display under-recruitment in any brain area in comparison with the young adults. However, they displayed additional prefrontal activation that varied depending on the processing stage and the condition, which supports the hypothesis of selective over-recruitment in older adults.

Event-Related Potentials (ERPs) elicited by congruent and incongruent colour-word stimuli of a Stroop paradigm, in a task in which participants were required to judge the congruence/incongruence of the two dimensions of the stimuli, were recorded in order to study the timing of the semantic conflict. The reaction time to colour-word incongruent stimuli was significantly longer than the reaction time to congruent stimuli (the Stroop effect). A temporal Principal Components Analysis was applied to the data to identify the ERP components. Three positive components were identified in the 300-600 ms interval in response to the congruent and incongruent stimuli: First P3, P3b and PSW. The factor scores corresponding to the First P3 and P3b components were significantly smaller for the incongruent stimuli than for the congruent stimuli. No differences between stimuli were observed in the factor scores corresponding to the PSW or in the ERP latencies. We conclude that the temporal locus of the semantic conflict, which intervenes in generating the Stroop effect, may occur within the time interval in which the First P3 and P3b components are identified, i.e. at approximately 300-450 ms post-stimulus. We suggest that the semantic conflict delays the start of the response selection process, which explains the longer reaction time to incongruent stimuli.

This study examined the effects of aging on the ERP components associated with the different processing stages in a face naming task. Two hundred photographs were presented to 13 young and 10 elderly adults, who had to press a button and then to say the name aloud (KNOW condition), or “Can’t remember” if they were experiencing a tip-of-the-tongue state (TOT condition). Young adults showed larger ERP amplitudes in KNOW than in TOT in the 550–750 and 1550–2000 ms intervals, but the older adults did not show any such differences. The older adults showed a specific lengthening in ERP latencies from 250 ms onwards, and smaller mean amplitudes in the 550–750 ms interval in the KNOW category and in the 750–1000 ms interval in both categories, and a wider and more frontalized scalp topographical distribution of the ERP amplitudes than the young adults. The results may indicate activation of compensatory mechanisms in elderly adults.

With the aim of identifying event-related potential (ERP) correlates of the tip-of-the-tongue (TOT) state, we employed a task involving identification and naming of the faces of famous people with three response categories: KNOW (correct naming), DON'T KNOW (name not known), and TOT. Before 450 ms, no differences are observed between TOT and KNOW conditions in ERPs related to face processing and recognition. The smaller mean amplitude in TOT than in KNOW responses over the 550-750-ms interval and the N-TOT difference wave are correlates of the onset of the TOT state, probably reflecting a division of processing resources and low activation of the lexical-phonological route. The smaller amplitude of a late negative wave (between 1350 and 1550 ms) in TOT than in DON'T KNOW responses, and the P-TOT difference wave, seem to indicate that an important amount of processing resources is engaged in resolving the TOT. Copyright © 2006 Society for Psychophysiological Research.

This study evaluated whether P300 amplitude declines in response to repeated presentation of the target in a standard auditory oddball task; to what extent the decrease is affected by the number of targets presented, interrupted by an interblock interval (IBI, 3 min) and consistent. We also aimed to identify factors inducing P300 amplitude decrease and its psychological significance. Two blocks of 500 tonnes (each divided into five subblocks of 100 tones) were presented. First block: P300 amplitude was smaller in the first subblock than in the second, which we attribute to processing resources during the first subblock being divided between the task of identifying the target and the process of estimating subjective probability. Amplitude decreased from the second subblock onwards. The interblock interval was sufficient for amplitude to return to pre-decrease levels. The intrablock decline was replicated in the second block. The decline in P300 amplitude might to reflect a progressive automation of the context-updating operations.