| 1. |
- Forsman, Lea J, et al.
(författare)
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Differences in regional brain volume related to the extraversion–introversion dimension : a voxel based morphometry study
- 2012
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Ingår i: Neuroscience research. - : Elsevier. - 0168-0102 .- 1872-8111. ; 72:1, s. 59-67
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Tidskriftsartikel (refereegranskat)abstract
- Extraverted individuals are sociable, behaviorally active, and happy. We report data from a voxel based morphometry study investigating, for the first time, if regional volume in gray and white matter brain regions is related to extraversion. For both gray and white matter, all correlations between extraversion and regional brain volume were negative, i.e. the regions were larger in introverts. Gray matter correlations were found in regions that included the right prefrontal cortex and the cortex around the right temporo–parietal junction – regions that are known to be involved in behavioral inhibition, introspection, and social-emotional processing, e.g. evaluation of social stimuli and reasoning about the mental states of others. White matter correlations extended from the brainstem to widespread cortical regions, and were largely due to global effects, i.e. a larger total white matter volume in introverts. We speculate that these white matter findings may reflect differences in ascending modulatory projections affecting cortical regions involved in behavioral regulation.
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| 2. |
- Forsman, Lea J., et al.
(författare)
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Neuroticism is correlated with drift in serial time interval production
- 2009
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Ingår i: Personality and Individual Differences. - : Elsevier. - 0191-8869 .- 1873-3549. ; 47:3, s. 229-232
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Tidskriftsartikel (refereegranskat)abstract
- Low neuroticism and high intelligence are both related to lower intertrial variability in reaction time tasks. However, intelligence and neuroticism are weakly related traits, which suggests that they may be related to different sources of timing variability. The relation between intelligence and timing variability has recently been investigated using isochronous serial interval production (ISIP). This is a simple, automatic timing task where participants first synchronize movements with an isochronous sound sequence and then continue with self-paced production of a sequence of intervals with the same inter-onset interval (IOI). For all IOIs, local interval-to-interval variability correlated strongest with intelligence. The purpose of the present study was to test whether neuroticism, in contrast, is related to the non-local component of ISIP variability, i.e. drift or gradual changes in response IOI. We found a significant correlation of r = 0.42 between drift and neuroticism, thereby confirming the hypothesis. We suggest that this finding reflects that individuals high on neuroticism have more frequent slips in top–down cognitive control mechanisms. These cognitive failures may in turn interfere with the processing of previously produced intervals in short-term memory, which gives an unstable IOI in the ISIP task, i.e. drift.
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| 3. |
- Holm, Linus, et al.
(författare)
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Executive control and working memory are involved in sub-second repetitive motor timing
- 2017
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Ingår i: Experimental Brain Research. - : Springer Science and Business Media LLC. - 0014-4819 .- 1432-1106. ; 235:3, s. 787-798
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Tidskriftsartikel (refereegranskat)abstract
- The nature of the relationship between timing and cognition remains poorly understood. Cognitive control is known to be involved in discrete timing tasks involving durations above 1 s, but has not yet been demonstrated for repetitive motor timing below 1 s. We examined the latter in two continuation tapping experiments, by varying the cognitive load in a concurrent task. In Experiment 1, participants repeated a fixed three finger sequence (low executive load) or a pseudorandom sequence (high load) with either 524-, 733-, 1024- or 1431-ms inter-onset intervals (IOIs). High load increased timing variability for 524 and 733-ms IOIs but not for the longer IOIs. Experiment 2 attempted to replicate this finding for a concurrent memory task. Participants retained three letters (low working memory load) or seven letters (high load) while producing intervals (524- and 733-ms IOIs) with a drum stick. High load increased timing variability for both IOIs. Taken together, the experiments demonstrate that cognitive control processes influence sub-second repetitive motor timing.
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| 4. |
- Holm, Linus, 1978-, et al.
(författare)
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Intelligence and temporal accuracy of behaviour : unique and shared associations with reaction time and motor timing
- 2011
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Ingår i: Experimental Brain Research. - : Springer. - 0014-4819 .- 1432-1106. ; 214:2, s. 175-183
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Tidskriftsartikel (refereegranskat)abstract
- Intelligence is associated with accuracy in a wide range of timing tasks. One source of such associations is likely to be individual differences in top-down control, e.g. sustained attention, that influence performance in both temporal tasks and other cognitively controlled behaviors. In addition, we have studied relations between intelligence and a simple rhythmic motor task, isochronous serial interval production (ISIP), and found a substantial component of that relation, which is independent of fluctuations in top-down control. The main purpose of the present study was to investigate whether such bottom-up mechanisms are involved also in the relation between intelligence and reaction time (RT) tasks. We thus investigated if common variance between the ISIP and RT tasks underlies their respective associations with intelligence. 112 participants performed a simple RT task, a choice RT task and the ISIP task. Intelligence was assessed with the Raven SPM Plus. The analysed timing variables included mean and variability in the RT tasks and two variance components in the ISIP task. As predicted, RT and ISIP variables were associated with intelligence. The timing variables were positively intercorrelated and a principal component analysis revealed a substantial first principal component that was strongly related to all timing variables, and positively correlated with intelligence. Furthermore, a commonality analysis demonstrated that the relations between intelligence and the timing variables involved a commonality between the timing variables as well as unique contributions from choice RT and ISIP. We discuss possible implications of these findings, and argue that they support our main hypothesis, i.e. that relations between intelligence and RT tasks have a bottom-up component.
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| 5. |
- Holm, Linus, et al.
(författare)
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Motor and Executive Control in Repetitive Timing of Brief Intervals
- 2013
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Ingår i: Journal of Experimental Psychology. - : American Psychological Association (APA). - 0096-1523 .- 1939-1277. ; 39:2, s. 365-380
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the causal role of executive control functions in the production of brief time intervals by means of a concurrent task paradigm. To isolate the influence of executive functions on timing from motor coordination effects, we dissociated executive load from the number of effectors used in the dual task situation. In 3 experiments, participants produced isochronous intervals ranging from 524 to 2,000 ms with either the left or the right hand. The concurrent task consisted of the production of either a pseudorandom (high cognitive load) or a simple repeated (low cognitive load) spatial sequence of key presses, while also maintaining a regular temporal sequence. This task was performed with either a single hand (unimanual) or with both hands simultaneously (bimanual). Interference in terms of increased timing variability caused by the concurrent task was observed only in the bimanual condition. We verified that motor coordination in bimanual tasks alone could not account for the interference. Timing interference only appeared when (a) more than 1 effector was involved and (b) there were simultaneous task demands that recruited executive functions. Task interference was not seen if only 1 of these 2 conditions was met. Thus, our results suggest that executive functions are not directly involved in motor timing, but can indirectly affect timing performance when they are required to schedule complex motor coordination.
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| 6. |
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| 7. |
- Karampela, Olympia, 1983-
(författare)
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Exploring models of time processing : effects of training and modality, and the relationship with cognition in rhythmic motor tasks
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Timing can be defined as the ability to perceive temporal sequences and regulate timed behaviors. As in other animals, our ability to make accurate time estimations is crucial in order to accomplish several activities. Organisms can process time over a wide range of durations ranging from microseconds to days. In the middle of these extremes is the hundreds of milliseconds to seconds range which is important for many everyday behaviors, such as walking, speaking and dancing. Yet, how this is managed remains poorly understood. Some central issues with regard time processing in this particular time range are whether timing is governed by one, or by several different mechanisms, possibly invoked by different effectors used to perform the timing task, as well as, if cognitive capacities are also involved in rhythmic motor timing.This thesis includes three studies. Study I investigated the effects of short- term practice on a motor timing task. Analyses of the timing variability indicated that a substantial amount of learning occurred in the first hour of practice and declined afterwards, exhibiting no trend for further decrease across the remaining 60 or 210 minutes. This effect was similar across effector, amount of feedback, and interval duration. Our results suggested that training effects influenced mainly motor precision and raised the question of whether motor timing training influenced also cognitive capacities.Study II investigated the relationship between motor timing and cognition. Specifically, participants had to train a sensorimotor synchronization task (SMS) over several days, and the question was whether this training would improve cognitive performance. A near transfer effect was found between the sensorimotor synchronization task and the sustained attention task, indicating that sustained attention is involved in motor timing.Study III compared the timing variability between the eyes and the hands, as a function of four different intervals, in order to examine whether these systems are temporally controlled by the same or different mechanism(s). The results showed several positive correlations in variability, between the eye and the finger movements, which, however, were significant only for the longer intervals. In addition, they were differences in variability between the eye and the hand, for the different interval durations.In general, the pattern of results from these studies suggested that voluntary motor timing is managed by overlapping distributed mechanisms and that these mechanisms are related to systems that manage cognitive processes, such as attention. The results partially explain the well-known relationships between cognitive ability and timing.
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| 8. |
- Madison, Guy, et al.
(författare)
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Common genetic influences on intelligence and auditory simple reaction time in a large Swedish sample
- 2016
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Ingår i: Intelligence. - : Elsevier. - 0160-2896 .- 1873-7935. ; 59, s. 157-162
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Tidskriftsartikel (refereegranskat)abstract
- Intelligence and cognitive ability have long been associated with chronometric performance measures, such as reaction time (RT), but few studies have investigated auditory RT in this context. The nature of this relationship is important for understanding the etiology and structure of intelligence. Here, we present a bivariate twin analysis of simple auditory RT and psychometric intelligence (measured by the Wiener Matrizen Test). The sample consisted of 1,816 complete twin pairs and 4623 singletons enrolled in the Swedish Twin Registry, who performed the tests online. The heritabilities were 0.54 and 0.21 for intelligence and RT, respectively, and the phenotypic correlation was −0.17, 47% of which was explained by common genetic variance. These results are comparable to those found for visual RT and for other cognitive tests, and add RT in the auditory modality to the small literature on common genetic influences across intelligence and other cognitive and chronometric variables.
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| 9. |
- Madison, Guy, et al.
(författare)
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Common genetic influences onintelligence and simple reaction time
- 2014
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Konferensbidrag (refereegranskat)abstract
- Introduction: Psychometric intelligence (IQ) is correlated with a range of timing performance measures, including simple and choice reaction time (RT) mean and variability, temporal discrimination accuracy and reproduction tasks [1,2,3]. We have proposed that this relation may include bottom-up mechanisms, in the sense that basic neural properties may influence both temporal accuracy and cognitive processes, rather than a top-down relation in which cognitively superior strategies facilitate timing performance [3,4,5,6]. IQ, RT, and most other timing measures have been found to be moderately heritable. The extent of possible common genetic influence on IQ and timing tasks, as well as specific (non-overlapping) genetic influences, may be informative regarding functional relationships. However, most twin studies of this kind have considered choice RT [reviewed in 7] rather than simple RT [8,9]. In particular has no study addressed IQ and auditory RT, which is shorter than visual RT and also more suitable for on-line administration. Here, we investigate common genetic influence on IQ and simple auditory RT (SART) in a large genetically informative sample.Method: Data were collected via an on-line survey from 11,543 Swedish twins, recruited through the Swedish Twin Registry. Intelligence was measured with the Wiener Matrizen(WMT, α= .81) matrix reasoning test [10]. Simple auditory reaction time (SART, α= .86) was measured by pressing the space bar on a computer as fast as possible after hearing a cowbell sound, presented after random intervals 2.5-4.0 s. Individual SART was computed as the median of 25 runs. The finalsample consisted of 893 complete MZ and 924 complete DZ pairs and 4,623 single twins without a participating co-twin who had a score for at least one of the variables (N = 8,257, age M 40.1, SD 7.9, R 27-54). Singletons were included for estimation of means and variances. The classical twin designwas applied to estimate genetic and environmental influences on the covariance between the traits. Analyses were conducted in Mxwhich takes the relatedness of the sample into account. First a bivariate sex-limitation model was fitted to allow the estimates to quantitatively differ between the sexes.However, estimates could be equated between the sexes (see figure with final model).Results and conclusions: Possible dominant genetic effects were not significant and an ACE model was therefore fitted. Twin correlations for SART and IQ are shown in the table above. The bivariate ACE Choleskydecomposition (see figure) suggested that both additive genetic and non-shared environmental effects significantly contribute to the covariance between the traits.The phenotypic correlation between the two traits was smaller (-0.17, CI: -.20; -.15) than the ~.3-.5 found for laboratory data,and is therefore likely due to lower reliability associated with on-line testing. The h2estimate for SART (.21) was comparable to one previous estimate of visual SRT h2of .22 [8] and smaller than two previous h2’s of .48 [9] and .52 [10]. Hence, the present study extends previous ones by much larger N’s. Furthermore, this is the first study to establish these estimates for auditory RT. The results may have implications for assessing the usefulness of SRT as a proxy for IQ when psychometric intelligence scoresare problematic, for example because of secular changes in test-taking performance and re-norming in response to the Flynn-Lynn effect [e.g. 12].
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| 10. |
- Madison, Guy, 1961-, et al.
(författare)
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Correlations between intelligence and components of serial timing variability
- 2009
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Ingår i: Intelligence. - : Elsevier BV. - 0160-2896 .- 1873-7935. ; 37, s. 68-75
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Tidskriftsartikel (refereegranskat)abstract
- Psychometric intelligence correlates with reaction time in elementary cognitive tasks, as well as with performance in time discrimination and judgment tasks. It has remained unclear, however, to what extent these correlations are due to top–down mechanisms, such as attention, and bottom–up mechanisms, i.e. basic neural properties that influence both temporal accuracy and cognitive processes. Here, we assessed correlations between intelligence (Raven SPM Plus) and performance in isochronous serial interval production, a simple, automatic timing task where participants first make movements in synchrony with an isochronous sequence of sounds and then continue with self-paced production to produce a sequence of intervals with the same inter-onset interval (IOI). The target IOI varied across trials. A number of different measures of timing variability were considered, all negatively correlated with intelligence. Across all stimulus IOIs, local interval-to-interval variability correlated more strongly with intelligence than drift, i.e. gradual changes in response IOI. The strongest correlations with intelligence were found for IOIs between 400 and 900 ms, rather than above 1 s, which is typically considered a lower limit for cognitive timing. Furthermore, poor trials, i.e. trials arguably most affected by lapses in attention, did not predict intelligence better than the most accurate trials. We discuss these results in relation to the human timing literature, and argue that they support a bottom–up model of the relation between temporal variability of neural activity and intelligence.
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