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1.
Neurosci Biobehav Rev ; 156: 105489, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38040075

RESUMEN

Neural degeneration is a hallmark of healthy aging and can be associated with specific cognitive impairments. However, neural degeneration per se is not matched by unremitting declines in cognitive abilities. Instead, middle-aged and older adults typically maintain surprisingly high levels of cognitive functioning, suggesting that the human brain can adapt to structural degeneration by neural compensation. Here, we summarize prevailing theories and recent empirical studies on neural compensation with a focus on often neglected contributing factors, such as lifestyle, metabolism and neural plasticity. We suggest that these factors moderate the relationship between structural integrity and neural compensation, maintaining psychological well-being and behavioral functioning. Finally, we discuss that a breakdown in neural compensation may pose a tipping point that distinguishes the trajectories of healthy vs pathological aging, but conjoint support from psychology and cognitive neuroscience for this alluring view is still scarce. Therefore, future experiments that target the concomitant processes of neural compensation and associated behavior will foster a comprehensive understanding of both healthy and pathological aging.


Asunto(s)
Disfunción Cognitiva , Neurociencia Cognitiva , Persona de Mediana Edad , Humanos , Anciano , Envejecimiento/psicología , Encéfalo , Cognición
2.
Brain Commun ; 5(5): fcad262, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37901036

RESUMEN

Recent models of Alzheimer's disease suggest the nucleus basalis of Meynert (NbM) as an early origin of structural degeneration followed by the entorhinal cortex (EC). However, the functional properties of NbM and EC regarding amyloid-ß and hyperphosphorylated tau remain unclear. We analysed resting-state functional fMRI data with CSF assays from the Alzheimer's Disease Neuroimaging Initiative (n = 71) at baseline and 2 years later. At baseline, local activity, as quantified by fractional amplitude of low-frequency fluctuations, differentiated between normal and abnormal CSF groups in the NbM but not EC. Further, NbM activity linearly decreased as a function of CSF ratio, resembling the disease status. Finally, NbM activity predicted the annual percentage signal change in EC, but not the reverse, independent from CSF ratio. Our findings give novel insights into the pathogenesis of Alzheimer's disease by showing that local activity in NbM is affected by proteinopathology and predicts functional degeneration within the EC.

3.
Neurosci Biobehav Rev ; 154: 105393, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37717861

RESUMEN

Recent models of Alzheimer's disease (AD) suggest that neuropathological changes of the medial temporal lobe, especially entorhinal cortex, are preceded by degenerations of the cholinergic Nucleus basalis of Meynert (NbM). Evidence from imaging studies in humans, however, is limited. Therefore, we performed an activation-likelihood estimation meta-analysis on whole brain voxel-based morphometry (VBM) MRI data from 54 experiments and 2581 subjects in total. It revealed, compared to healthy older controls, reduced gray matter in the bilateral NbM in AD, but only limited evidence for such an effect in patients with mild cognitive impairment (MCI), which typically precedes AD. Both patient groups showed less gray matter in the amygdala and hippocampus, with hints towards more pronounced amygdala effects in AD. We discuss our findings in the context of studies that highlight the importance of the cholinergic basal forebrain in learning and memory throughout the lifespan, and conclude that they are partly compatible with pathological staging models suggesting initial and pronounced structural degenerations within the NbM in the progression of AD.


Asunto(s)
Enfermedad de Alzheimer , Disfunción Cognitiva , Humanos , Enfermedad de Alzheimer/diagnóstico por imagen , Enfermedad de Alzheimer/patología , Núcleo Basal de Meynert/diagnóstico por imagen , Núcleo Basal de Meynert/patología , Disfunción Cognitiva/diagnóstico por imagen , Disfunción Cognitiva/patología , Imagen por Resonancia Magnética/métodos , Corteza Entorrinal , Colinérgicos
4.
NPJ Sci Learn ; 8(1): 28, 2023 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-37587116

RESUMEN

Social rewards and punishments are strong motivators. Since experimental work has focused on young adults using simplistic feedback, the effects of more naturalistic stimuli on motivation, evaluative learning, and socio-emotional processing with advanced age remain unclear. Therefore, we compared the effects of static (photos) vs dynamic (videos) social feedback in a social incentive delay (SID) task in young (18-35 years) and older adults (50-84 years) with neutral, positive, and negative feedback, on response times (RTs), and assessed the emotional valence of feedback cues and feedback videos. We found that anticipating positive and negative social feedback accelerated RTs regardless of age and without additional effects of video feedback. Furthermore, the results suggest a valence transfer from positive feedback videos to predictive cues in both groups (i.e., evaluative learning). Finally, older adults reported less pronounced negative affect for negative feedback videos, indicating age differences in socio-emotional processing. As such, our findings foster our understanding of the underlying cognitive and emotional aspects involved in the processing of social rewards and punishments.

5.
Hum Brain Mapp ; 44(13): 4667-4678, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37376724

RESUMEN

Novelty can promote subsequent long-term memory via the mesolimbic system, including the medial temporal lobe and midbrain structures. Importantly, these and other brain regions typically degenerate during healthy aging, which suggests a reduced impact of novelty on learning. However, evidence in favor of such a hypothesis is scarce. Thus, we used functional MRI in combination with an established paradigm in healthy young (19-32 years, n = 30) and older (51-81 years, n = 32) humans. During encoding, colored cues predicted the subsequent presentation of either a novel or previously familiarized image (75% cue validity), and approximately 24 h later, recognition memory for novel images was tested. Behaviorally, expected novel images, as compared to unexpected novel images, were better recognized in young and, to a lesser degree, older subjects. At the neural level, familiar cues activated memory related areas, especially the medial temporal lobe, whereas novelty cues activated the angular gyrus and inferior parietal lobe, which may reflect enhanced attentional processing. During outcome processing, expected novel images activated the medial temporal lobe, angular gyrus and inferior parietal lobe. Importantly, a similar activation pattern was observed for subsequently recognized novel items, which helps to explain the behavioral effect of novelty on long-term memory. Finally, age-effects were pronounced for successfully recognized novel images with relatively stronger activations in attention-related brain regions in older adults; younger adults, on the other hand, showed stronger hippocampal activation. Together, expectancy promotes memory formation for novel items via neural activity in medial temporal lobe structures and this effect appears to be reduced with age.


Asunto(s)
Reconocimiento en Psicología , Lóbulo Temporal , Humanos , Anciano , Reconocimiento en Psicología/fisiología , Lóbulo Temporal/diagnóstico por imagen , Lóbulo Temporal/fisiología , Memoria a Largo Plazo/fisiología , Hipocampo/fisiología , Imagen por Resonancia Magnética/métodos , Mapeo Encefálico/métodos
6.
bioRxiv ; 2023 Mar 28.
Artículo en Inglés | MEDLINE | ID: mdl-37034733

RESUMEN

BACKGROUND AND OBJECTIVES: Recent models of Alzheimer's Disease (AD) suggest the nucleus basalis of Meynert (NbM) as the origin of structural degeneration followed by the entorhinal cortex (EC). However, the functional properties of NbM and EC regarding amyloid-ß and hyperphosphorylated tau remain unclear. METHODS: We analyzed resting-state (rs)fMRI data with CSF assays from the Alzheimer's Disease Neuroimaging Initiative (ADNI, n=71) at baseline and two years later. RESULTS: At baseline, local activity, as quantified by fractional amplitude of low-frequency fluctuations (fALFF), differentiated between normal and abnormal CSF groups in the NbM but not EC. Further, NbM activity linearly decreased as a function of CSF ratio, resembling the disease status. Finally, NbM activity predicted the annual percentage signal change in EC, but not the reverse, independent from CSF ratio. DISCUSSION: Our findings give novel insights into the pathogenesis of AD by showing that local activity in NbM is affected by proteinopathology and predicts functional degeneration within the EC.

7.
Neuroimage ; 274: 120131, 2023 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-37094625

RESUMEN

The mesolimbic system and basal forebrain (BF) are implicated in processing rewards and punishment, but their interplay and functional properties of subregions with respect to future social outcomes remain unclear. Therefore, this study investigated regional responses and interregional functional connectivity of the lateral (l), medial (m), and ventral (v) Substantia Nigra (SN), Nucleus Accumbens (NAcc), Nucleus basalis of Meynert (NBM), and Medial Septum/Diagonal Band (MS/DB) during reward and punishment anticipation in a social incentive delay task with neutral, positive, and negative feedback using high-resolution fMRI (1.5mm3). Neuroimaging data (n = 36 healthy humans) of the anticipation phase was analyzed using mass-univariate, functional connectivity, and multivariate-pattern analysis. As expected, participants responded faster when anticipating positive and negative compared to neutral social feedback. At the neural level, anticipating social information engaged valence-related and valence-unrelated functional connectivity patterns involving the BF and mesolimbic areas. Precisely, valence-related connectivity between the lSN and NBM was associated with anticipating neutral social feedback, while connectivity between the vSN and NBM was associated with anticipating positive social feedback. A more complex pattern was observed for anticipating negative social feedback, including connectivity between the lSN and MS/DB, lSN and NAcc, as well as mSN and NAcc. To conclude,  functional connectivity patterns of the BF and mesolimbic areas signal the anticipation of social feedback depending on their emotional valence. As such, our findings give novel insights into the underlying neural processes of social information processing.


Asunto(s)
Prosencéfalo Basal , Humanos , Prosencéfalo Basal/diagnóstico por imagen , Retroalimentación , Núcleo Accumbens/diagnóstico por imagen , Sustancia Negra , Mapeo Encefálico , Recompensa , Imagen por Resonancia Magnética/métodos
8.
Neuroimage ; 273: 120114, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37080120

RESUMEN

Schemas, or internal representation models of the environment, are thought to be central in organising our everyday life behaviour by giving stability and predictiveness to the structure of the world. However, when an element from an unfolding event mismatches the schema-derived expectations, the coherent narrative is interrupted and an update to the current event model representation is required. Here, we asked whether the perceived incongruence of an item from an unfolding event and its impact on memory relied on the disruption of neural stability patterns preceded by the neural reactivation of the memory representations of the just-encoded event. Our study includes data from two different experiments whereby human participants (N = 33, 26 females and N = 18, 16 females, respectively) encoded images of objects preceded by trial-unique sequences of events depicting daily routine. We found that neural stability patterns gradually increased throughout the ongoing exposure to a schema-consistent episode, which was corroborated by the re-analysis of data from two other experiments, and that the brain stability pattern was interrupted when the encoding of an object of the event was incongruent with the ongoing schema. We found that the decrease in neural stability for low-congruence items was seen at ∼1000 ms from object encoding onset and that it was preceded by an enhanced N400 ERP and an increased degree of neural reactivation of the just-encoded episode. Current results offer new insights into the neural mechanisms and their temporal orchestration that are engaged during online encoding of schema-consistent episodic narratives and the detection of incongruencies.


Asunto(s)
Electroencefalografía , Memoria Episódica , Humanos , Masculino , Femenino , Electroencefalografía/métodos , Potenciales Evocados/fisiología , Encéfalo/fisiología , Mapeo Encefálico , Recuerdo Mental/fisiología , Imagen por Resonancia Magnética
9.
Front Psychiatry ; 13: 909442, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36245884

RESUMEN

Episodic memory impairments beyond the traumatic event might be a characteristic hallmark of post-traumatic stress disorder (PTSD). Although several studies support such a claim, empirical findings are inconsistent. Therefore, we performed a random-effects meta-analysis including data from a total of 47 studies and 3,062 subjects. As main finding, we can show that PTSD patients show episodic memory deficits compared to all controls. This effect was significantly stronger for PTSD vs. non-traumatized healthy controls as compared to PTSD vs. traumatized controls without PTSD. Finally, episodic memory impairments in PTSD were most pronounced in verbal memory tests as compared to non-verbal memory tests. Our results provide new evidence that PTSD is characterized by impaired episodic long-term memory beyond the traumatic event, and these deficits are particularly pronounced in verbal memory. We will discuss our findings in the context of physiological, psychological and trauma related memory models. From a broader perspective, our findings may have implications for the treatment of PTSD by suggesting that the assessment and, if necessary, training of memory deficits could be included as part of diagnostics and psychotherapeutic treatment.

10.
Front Neurol ; 13: 852725, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35928127

RESUMEN

Introduction: It is well-known that, in Parkinson's disease (PD), executive function (EF) and motor deficits lead to reduced walking performance. As previous studies investigated mainly patients during the compensated phases of the disease, the aim of this study was to investigate the above associations in acutely hospitalized patients with PD. Methods: A total of seventy-four acutely hospitalized patients with PD were assessed with the delta Trail Making Test (ΔTMT, TMT-B minus TMT-A) and the Movement Disorder Society-revised version of the motor part of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS III). Walking performance was assessed with wearable sensors under single (ST; fast and normal pace) and dual-task (DT; walking and checking boxes as the motor secondary task and walking and subtracting seven consecutively from a given three-digit number as the cognitive secondary task) conditions over 20 m. Multiple linear regression and Bayes factor BF10 were performed for each walking parameter and their dual-task costs while walking (DTC) as dependent variables and also included ΔTMT, MDS-UPDRS III, age, and gender. Results: Under ST, significant negative effects of the use of a walking aid and MDS-UPDRS III on gait speed and at a fast pace on the number of steps were observed. Moreover, depending on the pace, the use of a walking aid, age, and gender affected step time variability. Under walking-cognitive DT, a resolved variance of 23% was observed in the overall model for step time variability DTC, driven mainly by age (ß = 0.26, p = 0.09). Under DT, no other significant effects could be observed. ΔTMT showed no significant associations with any of the walking conditions. Discussion: The results of this study suggest that, in acutely hospitalized patients with PD, reduced walking performance is mainly explained by the use of a walking aid, motor symptoms, age, and gender, and EF deficits surprisingly do not seem to play a significant role. However, these patients with PD should avoid walking-cognitive DT situations, as under this condition, especially step time variability, a parameter associated with the risk of falling in PD worsens.

11.
Cereb Cortex Commun ; 3(1): tgac009, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35372838

RESUMEN

Retrieval practice improves retention of information in long-term memory more than restudy, but the underlying neural mechanisms of this "retrieval practice effect" (RPE) remain poorly understood. Therefore, we investigated the behavioral and neural differences between previously retrieved versus restudied items at final retrieval. Thirty younger (20-30 years old) and twenty-five older (50+ years old) adults learned familiar and new picture stimuli either through retrieval or restudy. At final recognition, hemodynamic activity was measured using functional magnetic resonance imaging (fMRI). Behaviorally, younger and older adults showed similar benefits of retrieval practice, with higher recollection, but unchanged familiarity rates. In a univariate analysis of the fMRI data, activation in medial prefrontal cortex and left temporal regions correlated with an individual's amount of behavioral benefit from retrieval practice, irrespective of age. Compatible with this observation, in a multivariate representational similarity analysis (RSA), retrieval practice led to an increase in pattern similarity for retested items in a priori defined regions of interest, including the medial temporal lobe, as well as prefrontal and parietal cortex. Our findings demonstrate that retrieval practice leads to enhanced long-term memories in younger and older adults alike, and this effect may be driven by fast consolidation processes.

12.
Front Psychol ; 13: 817929, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35310276

RESUMEN

Our ability to rapidly distinguish new from already stored (old) information is important for behavior and decision making, but the underlying processes remain unclear. Here, we tested the hypothesis that contextual cues lead to a preselection of information and, therefore, faster recognition. Specifically, on the basis of previous modeling work, we hypothesized that recognition time depends on the amount of relevant content stored in long-term memory, i.e., set size, and we explored possible age-related changes of this relationship in older humans. In our paradigm, subjects learned by heart four different word lists (24, 48, 72, and 96 words) written in different colors (green, red, orange, and blue). On the day of testing, a color cue (e.g., green) indicated with a probability of 50% that a subsequent word might be from the corresponding list or from a list of new words. The old/new status of the word had to be distinguished via button press. As a main finding, we can show in a sample of n = 49 subjects, including 26 younger and 23 older humans, that response times increased linearly and logarithmically as a function of set size in both age groups. Conversely, corrected hit rates decreased as a function of set size with no statistically significant differences between both age groups. As such, our findings provide empirical evidence that contextual information can lead to a preselection of relevant information stored in long-term memory to promote efficient recognition, possibly by cyclical top-down and bottom-up processing.

13.
Ann N Y Acad Sci ; 1511(1): 228-243, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35188272

RESUMEN

Novelty anticipation activates the mesolimbic system and promotes subsequent long-term memory in younger adults. Importantly, mesolimbic structures typically degenerate with age, which might reduce positive effects of novelty anticipation. Here, we used electroencephalography in combination with an established paradigm in healthy young (19-33 years old, n = 28) and older (53-84, n = 27) humans. Colored cues predicted the subsequent presentation of either a novel or previously familiarized image (75% cue validity). On the subsequent day, recognition memory for the novel images was tested. Behaviorally, novelty anticipation improved recollection-based but not familiarity-based recognition memory in both groups, and this effect was more pronounced in older subjects. Furthermore, novelty and familiarity cues increased theta (4-8 Hz) and decreased alpha/beta power (9-20 Hz); at outcome, expected novel and familiar images both increased beta power (13-25 Hz). Finally, a subsequent memory effect for expected novel images was associated with increases in beta power independent of age. Together, novelty anticipation drives hippocampus-dependent long-term recognition memory across the life span, and this effect appears to be related to neural beta oscillations.


Asunto(s)
Encéfalo/fisiología , Sistema Límbico/fisiología , Memoria a Largo Plazo/fisiología , Recuerdo Mental/fisiología , Reconocimiento en Psicología , Adulto , Anciano , Anciano de 80 o más Años , Mapeo Encefálico/métodos , Señales (Psicología) , Electroencefalografía , Humanos , Persona de Mediana Edad , Reconocimiento en Psicología/fisiología , Adulto Joven
14.
Front Aging Neurosci ; 14: 1070093, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36620765

RESUMEN

Introduction: Links between cognition and walking performance in patients with Parkinson's disease (PD), which both decline with disease progression, are well known. There is lack of knowledge regarding the predictive value of cognition for changes in walking performance after individualized therapy. The aim of this study is to identify relevant predictive cognitive and affective parameters, measurable in daily clinical routines, for change in quantitative walking performance after early geriatric rehabilitation. Methods: Forty-seven acutely hospitalized patients with advanced PD were assessed at baseline (T1) and at the end (T2) of a 2-week early rehabilitative geriatric complex treatment (ERGCT). Global cognitive performance (Montreal Cognitive Assessment, MoCA), EF and divided attention (Trail Making Test B minus A, delta TMT), depressive symptoms, and fear of falling were assessed at T1. Change in walking performance was determined by the difference in quantitative walking parameters extracted from a sensor-based movement analysis over 20 m straight walking in single (ST, fast and normal pace) and dual task (DT, with secondary cognitive, respectively, motor task) conditions between T1 and T2. Bayesian regression (using Bayes Factor BF10) and multiple linear regression models were used to determine the association of non-motor characteristics for change in walking performance. Results: Under ST, there was moderate evidence (BF10 = 7.8, respectively, BF10 = 4.4) that lower performance in the ∆TMT at baseline is associated with lower reduction of step time asymmetry after treatment (R 2 adj = 0.26, p ≤ 0.008, respectively, R 2 adj = 0.18, p ≤ 0.009). Under DT walking-cognitive, there was strong evidence (BF10 = 29.9, respectively, BF10 = 27.9) that lower performance in the ∆TMT is associated with more reduced stride time and double limb support (R 2 adj = 0.62, p ≤ 0.002, respectively, R 2 adj = 0.51, p ≤ 0.009). There was moderate evidence (BF10 = 5.1) that a higher MoCA total score was associated with increased gait speed after treatment (R 2 adj = 0.30, p ≤ 0.02). Discussion: Our results indicate that the effect of ERGT on change in walking performance is limited for patients with deficits in EF and divided attention. However, these patients also seem to walk more cautiously after treatment in walking situations with additional cognitive demand. Therefore, future development of individualized treatment algorithms is required, which address individual needs of these vulnerable patients.

15.
Neuroimage ; 245: 118696, 2021 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-34732325

RESUMEN

Anticipating social and non-social incentives recruits shared brain structures and promotes behavior. However, little is known about possible age-related behavioral changes, and how the human substantia nigra (SN) signals positive and negative social information. Therefore, we recorded intracranial electroencephalography (iEEG) from the SN of Parkinson's Disease (PD) patients (n = 12, intraoperative, OFF medication) in combination with a social incentive delay task including photos of neutral, positive or negative human gestures and mimics as feedback. We also tested a group of non-operated PD patients (n = 24, ON and OFF medication), and a sample of healthy young (n = 51) and older (n = 52) adults with behavioral readouts only. Behaviorally, the anticipation of both positive and negative social feedback equally accelerated response times in contrast to neutral social feedback in healthy young and older adults. Although this effect was not significant in the group of operated PD patients - most likely due to the small sample size - iEEG recordings in their SN showed a significant increase in alpha-beta power (9-20 Hz) from 300 to 600 ms after cue onset again for both positive and negative cues. Finally, in non-operated PD patients, the behavioral effect was not modulated by medication status (ON vs OFF medication) suggesting that other processes than dopaminergic neuromodulation play a role in driving invigoration by social incentives. Together, our findings provide novel and direct evidence for a role of the SN in processing positive and negative social information via specific oscillatory mechanisms in the alpha-beta range, and they suggest that anticipating social value in simple cue-outcome associations is intact in healthy aging and PD.


Asunto(s)
Mapeo Encefálico/métodos , Cognición/fisiología , Imagen por Resonancia Magnética , Motivación/fisiología , Recompensa , Sustancia Negra/diagnóstico por imagen , Sustancia Negra/fisiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Electroencefalografía , Femenino , Humanos , Longevidad , Masculino , Persona de Mediana Edad
16.
Front Aging Neurosci ; 13: 683908, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34594212

RESUMEN

Learning novel information can be promoted if it is congruent with already stored knowledge. This so-called semantic congruence effect has been broadly studied in healthy young adults with a focus on neural encoding mechanisms. However, the impacts on retrieval, and possible impairments during healthy aging, which is typically associated with changes in declarative long-term memory, remain unclear. To investigate these issues, we used a previously established paradigm in healthy young and older humans with a focus on the neural activity at a final retrieval stage as measured with electroencephalography (EEG). In both age groups, semantic congruence at encoding enhanced subsequent long-term recognition memory of words. Compatible with this observation, semantic congruence led to differences in event-related potentials (ERPs) at retrieval, and this effect was not modulated by age. Specifically, congruence modulated old/new ERPs at a fronto-central (Fz) and left parietal (P3) electrode in a late (400-600 ms) time window, which has previously been associated with recognition memory processes. Importantly, ERPs to old items also correlated with the positive effect of semantic congruence on long-term memory independent of age. Together, our findings suggest that semantic congruence drives subsequent recognition memory across the lifespan through changes in neural retrieval processes.

17.
Neuroimage ; 244: 118563, 2021 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-34537382

RESUMEN

The medial temporal lobe drives semantic congruence dependent memory formation. However, the exact roles of hippocampal subfields and surrounding brain regions remain unclear. Here, we used an established paradigm and high-resolution functional magnetic resonance imaging of the medial temporal lobe together with cytoarchitectonic probability estimates in healthy humans. Behaviorally, robust congruence effects emerged in young and older adults, indicating that schema dependent learning is unimpaired during healthy aging. Within the medial temporal lobe, semantic congruence was associated with hemodynamic activity in the subiculum, CA1, CA3 and dentate gyrus, as well as the entorhinal cortex and laterobasal amygdala. Importantly, a subsequent memory analysis showed increased activity for later remembered vs. later forgotten congruent items specifically within CA3, and this subfield showed enhanced functional connectivity to the laterobasal amygdala. As such, our findings extend current models on schema dependent learning by pinpointing the functional properties of subregions within the medial temporal lobe.


Asunto(s)
Amígdala del Cerebelo/diagnóstico por imagen , Región CA3 Hipocampal/diagnóstico por imagen , Memoria a Largo Plazo/fisiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Corteza Entorrinal/diagnóstico por imagen , Femenino , Hipocampo/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Lóbulo Temporal/diagnóstico por imagen , Adulto Joven
18.
Sci Rep ; 11(1): 9438, 2021 05 03.
Artículo en Inglés | MEDLINE | ID: mdl-33941809

RESUMEN

Age-related cognitive decline has been linked to alterations of the dopaminergic system and its subcortical trajectories. Recent work suggests a critical role of iron accumulation within the basal ganglia (BG) in verbal memory performance, and increased iron levels have been related to demyelination. However, the specificity of age-related iron increases with respect to cognitive functions remains unclear. Therefore, we investigated the interplay of age, cognitive performance, and structural integrity of the BG. In total, 79 healthy older participants underwent a broad cognitive assessment (fluid and crystallized intelligence, verbal and numeric memory, processing speed, executive functions) and structural MRI. As expected, performance in most cognitive tests had a negative relationship with age. Moreover, BG grey matter volume and magnetization transfer (MT, indicative of myelin) decreased, and R2* (indicative of iron) increased with age. Importantly, R2* and demyelination negatively correlated with verbal memory and executive functions. Within the SN/VTA, age correlated negatively with MT, but there was no clear evidence in favor of a relationship between behavior and R2* or MT. Our results suggest that age-related increases in iron and demyelination within the BG, which are part of a fronto-striatal network, not only impact on verbal memory but also executive functions.


Asunto(s)
Ganglios Basales/patología , Disfunción Cognitiva/patología , Enfermedades Desmielinizantes/patología , Función Ejecutiva/fisiología , Hierro/metabolismo , Memoria/fisiología , Anciano , Anciano de 80 o más Años , Envejecimiento , Cognición/fisiología , Femenino , Sustancia Gris/fisiología , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas
19.
Front Behav Neurosci ; 14: 539725, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33328916

RESUMEN

In humans, monetary reward can promote behavioral performance including response times, accuracy, and subsequent recognition memory. Recent studies have shown that the dopaminergic system plays an essential role here, but the link to interindividual differences remains unclear. To further investigate this issue, we focused on previously described polymorphisms of genes affecting dopaminergic neurotransmission: DAT1 40 base pair (bp), DAT1 30 bp, DRD4 48 bp, and cannabinoid receptor type 1 (CNR1). Specifically, 669 healthy humans participated in a delayed recognition memory paradigm on two consecutive days. On the first day, male vs. female faces served as cues predicting an immediate monetary reward upon correct button presses. Subsequently, participants performed a remember/know recognition memory task on the same day and 1 day later. As predicted, reward increased accuracy and accelerated response times, which were modulated by DAT 30 bp. However, reward did not promote subsequent recognition memory performance and there was no interaction with any genotype tested here. Importantly, there were differential effects of genotype on declarative long-term memory independent of reward: (a) DAT1 40 bp was linked to the quality of memory with a more pronounced difference between recollection and familiarity in the heterozygous and homozygous 10-R as compared to homozygous 9-R; (b) DAT1 30 bp was linked to memory decay, which was most pronounced in homozygous 4-R; (c) DRD4 48 bp was linked to overall recognition memory with higher performance in the short allele group; and (d) CNR1 was linked to overall memory with reduced performance in the homozygous short group. These findings give new insights into how polymorphisms, which are related to dopaminergic neuromodulation, differentially affect long-term recognition memory performance.

20.
Sci Rep ; 10(1): 9116, 2020 06 04.
Artículo en Inglés | MEDLINE | ID: mdl-32499519

RESUMEN

Long-term memory can improve when incoming information is congruent with known semantic information. This so-called congruence effect has widely been shown in younger adults, but age-related changes and neural mechanisms remain unclear. Here, congruence improved recognition memory in younger and older adults (i.e. congruence effect), with only weak evidence for age-related decline in one behavioral study. In an EEG study, however, no significant behavioral differences in the congruence effect could be observed between age-groups. In line with this observation, electroencephalography data show that, in both groups, congruence led to widespread differences in Event-Related Potentials (ERPs), starting at around 400 ms after stimulus onset, and theta, alpha and beta oscillations (4-20 Hz). Importantly, these congruence-related ERPs were associated to increases in memory performance for congruent items, in both age groups. Finally, the described ERPs and neural oscillations in the theta-alpha range (5-13 Hz) were less pronounced in the elderly despite a preserved congruence effect. Together, semantic congruence increases long-term memory across the lifespan, and, at the neural level, this could be linked to neural oscillations in the theta, alpha and beta range, as well as ERPs that were previously associated with semantic processing.


Asunto(s)
Potenciales Evocados/fisiología , Memoria a Largo Plazo , Adulto , Factores de Edad , Anciano , Encéfalo/fisiología , Análisis por Conglomerados , Electroencefalografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estimulación Luminosa , Semántica , Adulto Joven
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