Biology subjects

Ridderinkhof, K. R.

Publications and source records attributed to Ridderinkhof, K. R..

6 recordsLinked to original sources

bioRxiv2024

The timing of preceding tactile inputs modulates cortical processing

Sensory experiences in the real world cut across timescales from milliseconds to seconds. Emerging evidence suggests that somatosensory processing is sensitive to the temporal structure of the stimuli in the sub-second scale, yet only a few select ranges within this scale have been studied. To process real-world information, the integration of tactile inputs must occur over a much broader temporal range. To address temporal integration across timescales, we recorded scalp EEG signals from somatosensory cortex in response to a train of tactile pulses presented to the fingertips with varying inter-stimulus intervals (ISI) spanning 100 to 10,000 ms. To capture a rich variety of influences of the temporal structure on the cortical signals, we used a multi-dimensional event-related potential where the stimulations are separated according to the next interval structure. We tracked cortical tactile processing through its early (<75 ms), intermediate (75 to 150 ms) and late stages (150 to 300 ms). We find that the early and late stages of cortical activity were similarly dominated by the preceding ISI; EEG signals were suppressed with ISIs < 500 ms and enhanced with longer ISIs, with this effect persisting even when ISIs were approximately 8 seconds. The intermediate stage of cortical activity was sensitive to both the previous and the penultimate ISIs. Our findings suggest that the specific somatosensory cortical networks integrate temporal structure across timescales to enable complex sensory experiences.

neuroscience↗

bioRxiv2024

Age-related behavioral resilience in smartphone touchscreen interaction dynamics

We experience a life that is full of ups and downs. The ability to bounce back after adverse life events such as the loss of a loved one or serious illness declines with age, and such isolated events can even trigger accelerated aging. How humans respond to common day-to-day perturbations is less clear. Here, we infer the aging status from smartphone behavior by using a decision tree regression model trained to accurately estimate the chronological age based on the dynamics of touchscreen interactions. Individuals (N = 280, 21 to 83 years of age) expressed smartphone behavior that appeared younger on certain days and older on other days through the observation period that lasted up to [~]4 years. We captured the essence of these fluctuations by leveraging the mathematical concept of critical transitions and tipping points in complex systems. In most individuals, we find one or more alternative stable aging states separated by tipping points. The older the individual, the lower the resilience to forces that push the behavior across the tipping point into an older state. Traditional accounts of aging based on sparse longitudinal data spanning decades suggest a gradual behavioral decline with age. Taken together with our current results, we propose that the gradual age-related changes are interleaved with more complex dynamics at shorter timescales where the same individual may navigate distinct behavioral aging states from one day to the next. Real-world behavioral data modeled as a complex system can transform how we view and study aging.

animal behavior and cognition↗

bioRxiv2021

Effects of tDCS on the attentional blink revisited: A statistical evaluation of a replication attempt

The attentional blink (AB) phenomenon reveals a bottleneck of human information processing: the second of two targets is often missed when they are presented in rapid succession among distractors. In our previous work, we showed that the size of the AB can be changed by applying transcranial direct current stimulation (tDCS) over the left dorsolateral prefrontal cortex (lDLPFC) (London & Slagter, Journal of Cognitive Neuroscience, 33, 756-68, 2021). Although AB size at the group level remained unchanged, the effects of anodal and cathodal tDCS were negatively correlated: if a given individuals AB size decreased from baseline during anodal tDCS, their AB size would increase during cathodal tDCS, and vice versa. Here, we attempted to replicate this finding. We found no group effects of tDCS, as in the original study, but we no longer found a significant negative correlation. We present a series of statistical measures of replication success, all of which confirm that both studies are not in agreement. First, the correlation here is significantly smaller than a conservative estimate of the original correlation. Second, the difference between the correlations is greater than expected due to sampling error, and our data are more consistent with a zero-effect than with the original estimate. Finally, the overall effect when combining both studies is small and not significant. Our findings thus indicate that the effects of lDPLFC-tDCS on the AB are less substantial than observed in our initial study. Although this should be quite a common scenario, null findings can be difficult to interpret and are still under-represented in the brain stimulation and cognitive neuroscience literatures. An important auxiliary goal of this paper is therefore to provide a tutorial for other researchers, to maximize the evidential value from null findings.

neuroscience↗

bioRxiv2018

Creative Minds Are Out of Control: Mid Frontal Theta and Creative Thinking

Creativity is considered to be the driving force behind innovation and progress, yet the mechanisms supporting creative thought remain elusive. In the current study, we investigated whether fluctuations in top-down control are related to creative thinking. Here, participants performed a caption this task in which they had to provide an original and apt caption to accompany a presented picture, while EEG signals were recorded. To assess changing levels of top-down control, we made use of the strong relationship between mid frontal oscillatory activity in the theta range (4-7 HZ) and top-down control. Results demonstrate that specifically during the process of optimization and implementation of creative solutions, lower levels of mid frontal theta resulted in higher levels of creativity. In addition, increased creativity related to enhanced functional connectivity between occipital and mid frontal cortex. Together, our findings indicate that creativity benefits from a top-down induced shift towards an internally-oriented state during idea optimization and evaluation.

animal behavior and cognition↗

bioRxiv2018

No evidence that frontal eye field tDCS affects latency or accuracy of prosaccades

Transcranial direct current stimulation (tDCS) may be used to directly affect neural activity from outside of the skull. However, its exact physiological mechanisms remain elusive, particularly when applied to new brain areas. The frontal eye field (FEF) has rarely been targeted with tDCS, even though it plays a crucial role in control of overt and covert spatial attention. Here we investigate whether tDCS over the FEF can affect the latency and accuracy of saccadic eye movements. 26 participants performed a prosaccade task in which they made eye movements to a sudden-onset eccentric visual target (lateral saccades). After each lateral saccade, they made an eye movement back to the center (center saccades). The task was administered before, during and after anodal or cathodal tDCS over the FEF, in a randomized, double-blind, within-subject design. One previous study (Kanai et al., 2012) found that anodal tDCS over the FEF decreased the latency of saccades contralateral to the stimulated hemisphere. We did not find the same effect: neither anodal nor cathodal tDCS influenced the latency of lateral saccades. tDCS also did not affect accuracy of lateral saccades (saccade endpoint deviation and saccade endpoint variability). For center saccades, we found some differences between the anodal and cathodal sessions, but these were not consistent across analyses (latency, endpoint variability), or were already present before tDCS onset (endpoint deviation). We tried to improve on the design of Kanai et al. (2012) in several ways, including the tDCS duration and electrode montage, which could explain the discrepant results. Our findings add to a growing number of null results, which have sparked concerns that tDCS outcomes are highly variable. Future studies should aim to establish the boundary conditions for frontal eye field tDCS to be effective, in addition to increasing sample size and adding additional controls such as a sham condition. At present, we conclude that it is unclear whether eye movements or other aspects of spatial attention can be affected through tDCS of the frontal eye fields.

neuroscience↗

bioRxiv2017

Cross-task contributions of fronto-basal ganglia circuitry in response inhibition and conflict-induced slowing

Why are we so slow in choosing the lesser of two evils? We considered whether such slowing relates to uncertainty about the value of these options, which arises from the tendency to avoid them during learning, and whether such slowing relates to fronto-subthalamic inhibitory control mechanisms. 49 participants performed a reinforcement-learning task and a stop-signal task while fMRI was recorded. A reinforcement-learning model was used to quantify learning strategies. Individual differences in lose-lose slowing related to information uncertainty due to sampling, and independently, to less efficient response inhibition in the stop-signal task. Neuroimaging analysis revealed an analogous dissociation: subthalamic nucleus (STN) BOLD activity related to variability in stopping latencies, whereas weaker fronto-subthalamic connectivity related to slowing and information sampling. Across tasks, fast inhibitors increased STN activity for successfully cancelled responses in the stop task, but decreased activity for lose-lose choices. These data support the notion that fronto-STN communication implements a rapid but transient brake on response execution, and that slowing due to decision uncertainty could result from an inefficient release of this \"hold your horses\" mechanism.

neuroscience↗