Predicting the future: from implicit learning to consolidation

Sequence learning can be differentiated according to phases (rapid and slower), modalities (perceptual and motor), and whether or not it is conscious (implicit and explicit). Implicit sequence learning occurs when information is acquired from an environment of complex stimuli without conscious access either to what was learned or to the fact that learning occurred. In everyday life, this learning mechanism is crucial for adapting to the environment and for predicting events unconsciously. Implicit sequence learning underlies not only motor, but also cognitive and social skills; it is therefore an important aspect of life from infancy to old age. Moreover, this kind of learning does not occur only during practice, in the so-called online periods, but also between practice periods, during the so-called offline periods. The process that occurs during the offline periods is referred to as consolidation, which denotes the stabilization of a memory trace after the initial acquisition; this can result in increased resistance to interference or even improvement in performance following an offline period. Understanding the multiple aspects and influencing factors of consolidation can help us to reveal the nature of memory and changes in brain plasticity. Our review focuses on how consolidation varies with factors such as awareness, the length of offline periods, the type of information to be learned, and the age of participants. We highlight that consolidation is not a single process; instead, there are multiple mechanisms in the offline period, which are differently influenced by these factors

Implicit sequence learning and working memory: correlated or complicated?

The relationship between implicit/incidental sequence learning and working memory motivated a series of research because it is plausible that higher working memory capacity opens a “larger window” to a sequence, allowing thereby the sequence learning process to be easier. Although the majority of studies found no relationship between implicit sequence learning and working memory capacity, in the past few years several studies have tried to demonstrate the shared or partly shared brain networks underlying these two systems. In order to help the interpretation of these and future results, in this mini-review we suggest the following factors to be taken into consideration before testing the relationship between sequence learning and working memory: 1) the explicitness of the sequence; 2) the method of measuring working memory capacity; 3) online and offline stages of sequence learning; and 4) general skill- and sequence-specific learning

Age-dependent and coordinated shift in performance between implicit and explicit skill learning

It has been reported recently that while general sequence learning across ages conforms to the typical inverted-U shape pattern, with best performance in early adulthood, surprisingly, the basic ability of picking up in an implicit manner triplets that occur with high vs. low probability in the sequence is best before 12 years of age and it significantly weakens afterwards. Based on these findings, it has been hypothesized that the cognitively controlled processes coming online at around 12 are useful for more targeted explicit learning at the cost of becoming relatively less sensitive to raw probabilities of events. To test this hypothesis, we collected data in a sequence learning task using probabilistic sequences in five age groups from 11 to 39 years of age (N=288), replicating the original implicit learning paradigm in an explicit task setting where subjects were guided to find repeating sequences. We found that in contrast to the implicit results, performance with the high- vs. low-probability triplets was at the same level in all age groups when subjects sought patterns in the sequence explicitly. Importantly, measurements of explicit knowledge about the identity of the sequences revealed a significant increase in ability to explicitly access the true sequences exactly around the age where the earlier study found the significant drop in ability to learn implicitly raw probabilities. These findings support the conjecture that the gradually increasing involvement of more complex internal models optimizes our skill learning abilities by compensating for the performance loss due to down-weighting the raw probabilities of the sensory input, while expanding our ability to acquire more sophisticated skills

A Montreal Kognitív Felmérés (MoCa) magyar nyelvű adaptálása egészséges, enyhe kognitív zavarban és demenciában szenvedő idős személyek körében

Az enyhe kognitív zavar (Mild Cognitive Impairment – MCI) az egészséges kognitív öregedés és a demencia közé helyezhetô állapot, melynek korai szûrése kulcsfontosságú, hiszen az esetek 10–15%-a egy éven belül komoly kognitív hanyatlásnak indul. Hazánkban mind a demencia, mind az enyhe kognitív zavar szûrésére a Mini- Mentál Teszt a legelterjedtebb mérôeljárás, amelyet sok kritika ér az érzékenységét illetôen. A Montreal Kognitív Felmérés (Montreal Cognitive Assessment – MoCA) ezt a hiányosságot igyekszik kiküszöbölni, hiszen kifejezetten az enyhe kognitív zavar detektálására készült. Vizsgálatunkban a MoCA magyar nyelvre fordított változatából származó eredményeket mutatjuk be. A depresszió kiszûrésére Beck Depresszió Kérdôívet (BDI) használtunk. A MoCA teszten az MCI-s és az egészséges személyek közti választóvonal 24 pont; a MoCA nagyobb érzékenységet mutatott az enyhe kognitív zavarra, mint a MMSE, valamint belsô konzisztenciája is erôsebb volt. A specificitás hasonló volt a két teszt esetében. A BDI teszten elért pontszámok egyik kognitív teszt eredményeivel sem álltak szignifikáns kapcsolatban. Eredményeink arra utalnak, hogy a MoCA teszt hasznos kiegészítôje lehet a demenciaszûrésnek

Is there more room to improve? The lifespan trajectory of procedural learning and its relationship to the between-and within-group differences in average response times

Characterizing the developmental trajectories of cognitive functions such as learning, memory and decision making across the lifespan faces fundamental challenges. Cognitive functions typically encompass several processes that can be differentially affected by age. Methodological issues also arise when comparisons are made across age groups that differ in basic performance measures, such as in average response times (RTs). Here we focus on procedural learning – a fundamental cognitive function that underlies the acquisition of cognitive, social, and motor skills – and demonstrate how disentangling subprocesses of learning and controlling for differences in average RTs can reveal different developmental trajectories across the human lifespan. Two hundred-seventy participants aged between 7 and 85 years performed a probabilistic sequence learning task that enabled us to separately measure two processes of procedural learning, namely general skill learning and statistical learning. Using raw RT measures, in between-group comparisons, we found a U-shaped trajectory with children and older adults exhibiting greater general skill learning compared to adolescents and younger adults. However, when we controlled for differences in average RTs (either by using ratio scores or focusing on a subsample of participants with similar average speed), only children (but not older adults) demonstrated superior general skill learning consistently across analyses. Testing the relationship between average RTs and general skill learning within age groups shed light on further age-related differences, suggesting that general skill learning measures are more affected by average speed in some age groups. Consistent with previous studies of learning probabilistic regularities, statistical learning showed a gradual decline across the lifespan, and learning performance seemed to be independent of average speed, regardless of the age group. Overall, our results suggest that children are superior learners in various aspects of procedural learning, including both general skill and statistical learning. Our study also highlights the importance to test, and control for, the effect of average speed on other RT measures of cognitive functions, which can fundamentally affect the interpretation of group differences in developmental, aging and clinical psychology and neuroscience studies

Az öregedés hatása az implicit készségek konszolidációjára

Az implicit tanulás nem csak online, gyakorlás közben történik, hanem offline is, a gyakorlások közötti fázisokban (konszolidáció). Az implicit tanulás offline változása egyre többet kutatott téma, azonban az öregedés hatása e területen még nem teljesen feltárt. Kutatásunkban fiatal és idős személyek implicit tanulását mértük az ASRT feladattal (J.H. Howard Jr. & Howard, 1997), ami lehetővé teszi az általános motoros és a szekvencia-specifikus tanulás külön elemzését. A vizsgálat során két adatfelvétel volt, 12 órás késleltetéssel, mely vagy tartalmazott alvást vagy nem. Az eredmények azt mutatják, hogy az általános motoros készségben a fiatal és az idős személyeknél is van offline teljesítményjavulás, de az utóbbi csoportban kisebb mértékű, mint a fiataloknál. A szekvencia-specifikus tudás megszilárdult az offline periódusban, de nem mutatkozott teljesítményjavulás egyik csoportban sem. Alvásfüggő konszolidációt nem találtunk sem az általános motoros, sem a szekvencia-specifikus tanulás esetében. The consolidation of implicit skills is a topic of increasing interest for researchers, but there were only a few studies that investigated the effects of aging in this regard. We measured implicit learning with the ASRT task in younger and older adults before and after a 12h interval. This interval contained sleep (night group) or it did not contain sleep (day group). We analyzed the consolidation of general motor skill and sequence-specific learning separately. The results showed offline improvement in general motor skill learning in both the younger and the elder group, however, the effect was lower in the elder group than in the younger group. The sequence specific knowledge did not change between the sessions, thus there was no offline improvement neither in the younger, nor in the older groups. Sleep dependent consolidation happened neither in general motor skill, nor in sequence-specific skill

Different levels of statistical learning-hidden potentials of sequence learning tasks

In this paper, we reexamined the typical analysis methods of a visuomotor sequence learning task, namely the ASRT task (J. H. Howard & Howard, 1997). We pointed out that the current analysis of data could be improved by paying more attention to pre-existing biases (i.e. by eliminating artifacts by using new filters) and by introducing a new data grouping that is more in line with the task’s inherent statistical structure. These suggestions result in more types of learning scores that can be quantified and also in purer measures. Importantly, the filtering method proposed in this paper also results in higher individual variability, possibly indicating that it had been masked previously with the usual methods. The implications of our findings relate to other sequence learning tasks as well, and opens up opportunities to study different types of implicit learning phenomena

Hallási mondatterjedelem teszt : a Listening Span teszt magyar nyelvű verziójának alapjai

A verbális munkamemória feladata a „beszédalapú" információk tárolása és frissítése. Ennek az egyik legtöbbet használt mérőeljárása a listening span teszt. Mivel az angol nyelvű változat sztenderd értékei nem érvényesek a magyar lakosságra, ezért elkészítettük a teszt magyar nyelvű verzióját, a hallási mondatterjedelem tesztet. A sztenderdizálási folyamat első lépéseként megvizsgáltuk kapcsolatát más munkamemória feladatokkal: az olvasási terjedelem teszttel, a számterjedelem teszttel, a fordított számterjedelem teszttel és az álszó ismétlési teszttel. Vizsgálatunkban korrelációt találtunk mind a négy mérőeljárással, legmagasabbat az olvasási terjedelem teszttel, amely megfelel elvárásainknak, mivel az angol nyelvű változatokban is ez a két teszt korrelált a legjobban egymással. További célkitűzéseink közt szerepel a teszt felvétele különböző korcsoportokban, a sztenderd értékek meghatározása céljából. Az általunk kidolgozott hallási mondatterjedelem teszt jól alkalmazható lesz mind az egészséges, mind a patológiás kognitív működés vizsgálatára. One of the most frequently used tasks for measuring complex verbal working memory capacity is the listening span test. Our research group developed the Hungarian version of this test. The purpose of this study was to make a comparison among reading span test, digit span test, the backward digit span test and the non-word repetition test. In our study the highest correlation was found between the listening span and the reading span test. The English versions of these tests show the same pattern. After the standardization procedure this test will be a useful method for mapping working memory capacity in Hungarian language

How can the depressed mind extract and remember predictive relationships of the environment? evidence from implicit probabilistic sequence learning

A growing body of evidence suggests that emotion and cognition are fundamentally intertwined; impairments in explicit, more effortful and attention-dependent cognitive functions have widely been observed in negative mood. Here we aimed to test how negative mood affects implicit cognition that is less susceptible to motivational and attentional factors associated with negative mood. Therefore, we examined implicit learning and retention of predictive relationships in patients with major depressive episode (MDE). Additionally, we directly compared subgroups of patients with major depressive disorder (MDD) vs. bipolar disorder (BD) in order to gain a deeper understanding of how implicit cognition is affected by these conditions. Implicit probabilistic sequence learning was measured by the Alternating Serial Reaction Time Task. The acquired knowledge was retested after a 24-hour delay period. Consistent with the frontostriatal deficits frequently reported in depression, we found weaker learning in patients with MDE, with a more pronounced deficit in patients with MDD compared to BD. After the 24-hour delay, MDE patients (both subgroups) showed forgetting, while the controls retained the previously acquired knowledge. These results cannot be explained by alterations in motivation, attention and reward processing but suggest more profound impairments of implicit learning and retention of predictive relationships among neutral stimuli in depression. To the best of our knowledge, this is the first study investigating retention of implicitly acquired sequential knowledge and reporting deficits in this domain in MDE. Our findings not only contribute to a better understanding of the complex interplay between affect and cognition but can also help improve screening, diagnosis and treatment protocols of depression