The Serial Reaction Time Task (SRTT) was designed to measure motor sequence learning and is widely used in many fields in cognitive science and neuroscience. However, the common performance measures derived from SRTT—reaction time (RT) difference scores—may not provide valid measures of sequence learning. This is because RT-difference scores may be subject to floor effects and otherwise not sufficiently reflective of learning. A ratio RT measure might minimize floor effects. Furthermore, measures derived from predictive accuracy may provide a better assessment of sequence learning. Accordingly, we developed a Predictive Sequence Learning Task (PSLT) in which performance can be assessed via both RT and predictive accuracy. We compared performance of N = 99 adults on SRTT and PSLT in a within-subjects design and also measured fluid abilities. The RT-difference scores on both tasks were generally not related to fluid abilities, replicating previous findings. In contrast, a ratio RT measure on SRTT and PSLT and accuracy measures on PSLT were related to fluid abilities. The accuracy measures also indicated an age-related decline in performance on PSLT. The current patterns of results were thus inconsistent across different measures on the same tasks, and we demonstrate that this discrepancy is potentially due to floor effects on the RT difference scores. This may limit the potential of SRTT to measure sequence learning and we argue that PSLT accuracy measures could provide a more accurate reflection of learning ability.
Performing sequences of movements is a ubiquitous skill that involves dopamine transmission. However, it is unclear which components of the dopamine system contribute to which aspects of motor sequence learning. Here we used a genetic approach to investigate the relationship between different components of the dopamine system and specific aspects of sequence learning in humans. In particular, we investigated variations in genes that code for the catechol-O-methyltransferase (COMT) enzyme, the dopamine transporter (DAT) and dopamine D1 and D2 receptors (DRD1 and DRD2). COMT and the DAT regulate dopamine availability in the prefrontal cortex and the striatum, respectively, two key regions recruited during learning, whereas dopamine D1 and D2 receptors are thought to be involved in long-term potentiation and depression, respectively. We show that polymorphisms in the COMT, DRD1 and DRD2 genes differentially affect behavioral performance on a sequence learning task in 161 Caucasian participants. The DRD1 polymorphism predicted the ability to learn new sequences, the DRD2 polymorphism predicted the ability to perform a previously learnt sequence after performing interfering random movements, whereas the COMT polymorphism predicted the ability to switch flexibly between two sequences. We used computer simulations to explore potential mechanisms underlying these effects, which revealed that the DRD1 and DRD2 effects are possibly related to neuroplasticity. Our prediction-error algorithm estimated faster rates of connection strengthening in genotype groups with presumably higher D1 receptor densities, and faster rates of connection weakening in genotype groups with presumably higher D2 receptor densities. Consistent with current dopamine theories, these simulations suggest that D1-mediated neuroplasticity contributes to learning to select appropriate actions, whereas D2-mediated neuroplasticity is involved in learning to inhibit incorrect action plans. However, the learning algorithm did not account for the COMT effect, suggesting that prefrontal dopamine availability might affect sequence switching via other, non-learning, mechanisms. These findings provide insight into the function of the dopamine system, which is relevant to the development of treatments for disorders such as Parkinson's disease. Our results suggest that treatments targeting dopamine D1 receptors may improve learning of novel sequences, whereas those targeting dopamine D2 receptors may improve the ability to initiate previously learned sequences of movements.
Sexuality, relationships, and intimacy are integral parts of many peoples’ lives, not negated by mental distress and illness. Yet typically, these needs are not addressed adequately in mental health settings. In‐depth interviews were conducted with mental health clinicians with an aim of exploring their perceptions and understandings of sexuality and sexual concerns within mental health settings. Participants were 22 mental health nurses, psychologists, and psychiatrists working with people across a range of settings in four Australian cities. Sexuality or aspects of this were often not addressed in clinical practice, and this was common across participants’ accounts. A critical thematic analysis was conducted to explore how participants made sense of or explained this silence in relation to sexuality. Two key themes were ‘Sexuality is hard to talk about’ and ‘Sexuality is a “peripheral issue”’. In positioning sexuality as a peripheral issue, participants drew on three key explanations (sub‐themes): that sexuality rarely ‘comes up’, that it is not pragmatic to address sexuality, and that addressing sexuality is not part of participants’ roles or skill sets. A third theme captured the contrasting perception that ‘Sexuality could be better addressed’ in mental health settings. This analysis indicates that, beyond anticipated embarrassment, mental health clinicians from three disciplines account for omissions of sexuality from clinical practice in similar ways. Moreover, these accounts serve to peripheralize sexuality in mental health settings. We consider these results within the context of espoused holistic and recovery‐oriented principles in mental health settings.
The Serial Reaction Time Task (SRTT) is thought to assess implicit learning, which seems to be preserved with age. However, the reaction time (RT) measures employed on implicit-like tasks might be too unreliable to detect individual differences. We investigated whether RT-based measures mask age effects by comparing the performance of 43 younger and 35 older adults on SRTT and an explicit-like Predictive Sequence Learning Task (PSLT). RT-based measures (difference scores and a ratio) were collected for both tasks, and accuracy was additionally measured for PSLT. We also measured fluid abilities. The RT-difference scores indicated preserved SRTT and PSLT performance with age and did not correlate with fluid abilities, while ratio RT and the accuracy-based measures indicated age-related decline and correlated with fluid abilities. Therefore, RT-difference scores might mask individual differences, which compromises the interpretation of previous studies using SRTT.
Qualitative story completion (QSC) is an innovative research method that offers researchers a range of unique opportunities for generating and analysing data. Participants are asked to write a ‘story’ in response to a hypothetical ‘story stem’, often in the third-person and involving fictional characters, rather than reporting on their direct experiences. QSC is being developed and increasingly taken up by researchers working across a range of fields; but it has been little used in health research, especially in the fields of nursing, health services research, medicine, and allied health. This means that health researchers have few examples to draw on when considering what QSC can offer them and how to rigorously design, conduct, and report a QSC study within health-related fields. We aim to address this gap and contribute to existing QSC literature by promoting increased use of QSC by health researchers and supporting them to produce rigorous QSC research. We outline three case examples illustrating how we have used QSC to conduct multidisciplinary health research relevant to nursing, medicine and nutrition. Drawing on these case examples, we reflect on challenges that we encountered, describe decision-making processes, and offer recommendations for conducting rigorous health research using QSC.
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