Explicit processing of verbal and spatial features during letter-location binding modulates oscillatory activity of a fronto-parietal network.

The present study investigated the binding of verbal and spatial features in immediate memory. In a recent study, we demonstrated incidental and asymmetrical letter-location binding effects when participants attended to letter features (but not when they attended to location features) that were associated with greater oscillatory activity over prefrontal and posterior regions during the retention period. We were interested to investigate whether the patterns of brain activity associated with the incidental binding of letters and locations observed when only the verbal feature is attended differ from those reflecting the binding resulting from the controlled/explicit processing of both verbal and spatial features. To achieve this, neural activity was recorded using magnetoencephalography (MEG) while participants performed two working memory tasks. Both tasks were identical in terms of their perceptual characteristics and only differed with respect to the task instructions. One of the tasks required participants to process both letters and locations. In the other, participants were instructed to memorize only the letters, regardless of their location. Time–frequency representation of MEG data based on the wavelet transform of the signals was calculated on a single trial basis during the maintenance period of both tasks. Critically, despite equivalent behavioural binding effects in both tasks, single and dual feature encoding relied on different neuroanatomical and neural oscillatory correlates. We propose that enhanced activation of an anterior–posterior dorsal network observed in the task requiring the processing of both features reflects the necessity for allocating greater resources to intentionally process verbal and spatial features in this task

Active Forgetting: Adaptation of Memory by Prefrontal Control.

Over the past century, psychologists have discussed whether forgetting might arise from active mechanisms that promote memory loss to achieve various functions, such as minimizing errors, facilitating learning, or regulating one's emotional state. The past decade has witnessed a great expansion in knowledge about the brain mechanisms underlying active forgetting in its varying forms. A core discovery concerns the role of the prefrontal cortex in exerting top-down control over mnemonic activity in the hippocampus and other brain structures, often via inhibitory control. New findings reveal that such processes not only induce forgetting of specific memories but also can suppress the operation of mnemonic processes more broadly, triggering windows of anterograde and retrograde amnesia in healthy people. Recent work extends active forgetting to nonhuman animals, presaging the development of a multilevel mechanistic account that spans the cognitive, systems, network, and even cellular levels. This work reveals how organisms adapt their memories to their cognitive and emotional goals and has implications for understanding vulnerability to psychiatric disorders

Forgetting of Emotional Information Is Hard: An fMRI Study of Directed Forgetting

Strong evidence suggests that memory for emotional information is much better than for neutral one. Thus, one may expect that forgetting of emotional information is difficult and requires considerable effort. The aim of this item-method directed forgetting functional magnetic resonance imaging study was to investigate this hypothesis both at behavioral and neural levels. Directed forgetting effects were observed for both neutral and emotionally negative International Affective Picture System images. Moreover, recognition rate of negative to-be-forgotten images was higher than in case of neutral ones. In the study phase, intention to forget and successful forgetting of emotionally negative images were associated with widespread activations extending from the anterior to posterior regions mainly in the right hemisphere, whereas in the case of neutral images, they were associated with just one cluster of activation in the right lingual gyrus. Therefore, forgetting of emotional information seems to be a demanding process that strongly activates a distributed neural network in the right hemisphere. In the test phase, in turn, successfully forgotten images—either neutral or emotionally negative—were associated with virtually no activation, even at the lowered P value threshold. These results suggest that intentional inhibition during encoding may be an efficient strategy to cope with emotionally negative memorie

Fostering advances to neuropsychological assessment based on the Research Domain Criteria: The bridge between cognitive functioning and physiology

Objectives: The current review aimed to explore the advances in neuropsychological assessment in light of a recent research framework designed to improve our knowledge on mental health – the Research Domain Criteria (RDoC). Methods: RDoC proposals on neuropsychological tests were reviewed across the RDoC cognitive systems domain. The focus is on the physiological unit of analysis and the potential applications are illustrated given the functional relevance of RDoC constructs to psychopathological and neurological conditions. Results: The advances in neuropsychology anchored in RDoC are not observable in terms of innovative paradigms, but rather in the neurobiological correlates that may be obtained from the classical neuropsychological tasks. The behavior unit of analysis may be integrated with physiological outcomes while mapping distinct cognitive constructs simultaneously. Conclusions: Under the aegis of RDoC, the integration of multiple levels of analysis allows to obtain a more detailed and complete neuropsychological characterization with high potential to be translated into better intervention strategies.info:eu-repo/semantics/publishedVersio

Mirroring Intentional Forgetting in a Shared-Goal Learning Situation

Background: Intentional forgetting refers to the surprising phenomenon that we can forget previously successfully encoded memories if we are instructed to do so. Here, we show that participants cannot only intentionally forget episodic memories but they can also mirror the ‘‘forgetting performance’ ’ of an observed model. Methodology/Principal Findings: In four experiments a participant observed a model who took part in a memory experiment. In Experiment 1 and 2 observers saw a movie about the experiment, whereas in Experiment 3 and 4 the observers and the models took part together in a real laboratory experiment. The observed memory experiment was a directed forgetting experiment where the models learned two lists of items and were instructed either to forget or to remember the first list. In Experiment 1 and 3 observers were instructed to simply observe the experiment (‘‘simple observation’ ’ instruction). In Experiment 2 and 4, observers received instructions aimed to induce the same learning goal for the observers and the models (‘‘observation with goal-sharing’ ’ instruction). A directed forgetting effect (the reliably lower recall of to-be-forgotten items) emerged only when models received the ‘‘observation with goal-sharing’ ’ instruction (P,.001 in Experiment 2, and P,.05 in Experiment 4), and it was absent when observers received the ‘‘simple observation’’ instruction (P..1 in Experiment 1 and 3). Conclusion: If people observe another person with the same intention to learn, and see that this person is instructed t

Improving episodic memory: frontal-midline theta neurofeedback training increases source memory performance

Cognitive and neurofeedback training (NFT) studies have demonstrated that training-induced alterations of frontal-midline (FM) theta activity (4-8 Hz) transfer to cognitive control processes. Given that FM theta oscillations are assumed to provide top-down control for episodic memory retrieval, especially for source retrieval, that is, accurate recollection of contextual details of prior episodes, the present study investigated whether FM theta NFT transfers to memory control processes. It was assessed (1) whether FM theta NFT improves source retrieval and modulates its underlying EEG characteristics and (2) whether this transfer extends over two posttests. Over seven NFT sessions, thetraining group who trained individual FM theta activity showed greater FM theta increase than an active control group who trained randomly chosen frequency bands. The training group showed better source retrieval in a posttraining session performed 13 days after NFT and their performance increasesfrom pre- to both posttraining sessions were predicted by NFT theta increases. Thus, training-induced enhancement of memory control processes seems to protect newly formed memories from proactive interference of previously learned information. EEG analyses revealed that during pretest both groups showed source memory specific theta activity at frontal and parietal sites. Surprisingly, training-induced improvements in source retrieval tended to be accompanied by less prestimulus FM theta activity, which was predicted by NFT theta change for the training but not the control group, suggesting a more efficient use of memory control processes after training. The present findings provide unique evidence for the enhancement of memory control processes by FM theta NFT

Learning under uncertainty in the young and older human brain: Common and distinct mechanisms of different attentional and intentional systems

The human brain is able to infer the probability of future events by combining information of past observations with current sensory input. Naturally, we are surrounded by more stimuli than we can pay attention to, so selection of relevant input is crucial. The present thesis aimed at identifying common and distinct neural correlates engaged in predictive processing in spatial attention (selection of attended locations) and motor intention (selection of prepared motor responses). Secondly, age-related influences on probabilistic inference in spatial-attention, feature-based attention (selection of attended color) and motor intention, and the impact of task difficulty were considered. Orienting attention during goal-directed behavior can be supported by visual cues, whereas reorienting to unexpected events following misguiding information is linked to behavioral costs and updating of predictions. These processes can be investigated with a cueing paradigm in which differences in reaction time (RT) between valid and invalidly cued trials increase with higher cue validity (%CV) (Posner, 1980). Bayesian models can describe the experience-dependent learning effects of inferring %CV, following novel events (Vossel et al., 2014c; Vossel, Mathys, Stephan & Friston, 2015). The principle aim of the first experiment was to identify and compare the neural correlates involved in inferring probabilities in the spatial attentional and motor intentional domain. Cues indicated either the possible location or prepared the motor response associated with the target. Instead of a fixed probability context, participants were exposed to a volatile environment, in which the validity of the cue information changed unpredictably over time. Combining functional magnetic resonance imaging (fMRI) data with behavioral estimates derived from a Bayesian learning model (Mathys, Daunizeau, Friston & Stephan, 2011) unveiled domain-specific predictability-dependent responses within the right temporoparietal junction (TPJ) for spatial attention and the left angular gyrus (ANG) and anterior cingulate (ACC) in the motor intention task. The blood oxygen level dependent (BOLD) amplitude particularly increased in accord with violations of cue predictability in high cue validity contexts (i.e. when invalid trials were least expected). Valid trials however, induced no (TPJ and ANG) or decreased modulation (ACC). A further aim was to examine possible commonalities in the neural signatures of predictability-dependent processing. Connectivity analysis uncovered common coupling of all three seed regions involved in predictability-dependent processing with the right anterior hippocampus. Since cognitive functions undergo substantial changes in healthy ageing, a second behavioral study was conducted to test whether age differentially influences probabilistic inference in different attentional subsystems, and how task difficulty impacts on learning performance. Thus, following up on the first experiment, similar tasks and the same computational model was used to assess updating behavior in healthy aging. Older and younger adults performed two separate experiments with different difficulty levels. Each experiment included three versions of a cueing task, entailing predictive spatial- (i.e. location), feature- (i.e. color of target) and motor intention cues (i.e. prepare response). Results of the easier version demonstrated a preserved ability of older adults to generate predictions and profit from all cue types. Interestingly, increased task demand uncovered a reduced ability to use motor intention cues to update predictions in older compared to younger adults. In conclusion, the results provide evidence for a segregated functional anatomy of probabilistic inference in spatial attention and motor intention. Nonetheless a common connectivity profile with the hippocampus also points at commonalities. Finally age seems to differentially impact the efficiency of learning behavior in the motor intention system, supporting the notion of independence of the attentional- and intentional subsystems