Biology subjects

Kleinschmidt, A.

Publications and source records attributed to Kleinschmidt, A..

3 recordsLinked to original sources

bioRxiv2025

The impact of intrinsic connectome dynamics on perception is context-dependent

1.The behavioral relevance of the static functional connectome is well-established, but the real-time relationship between ongoing connectome dynamics and behavior remains unclear. Because behavior shifts from moment to moment, an important question arises: Are changes in behavioral outcomes linked to fluctuations in task-specific or task-general processes like arousal? Task-specific versus task-general processes should manifest as distinct versus shared connectome patterns that predict moment-to-moment behavioral outcomes across tasks. We analyzed fMRI data from three groups of healthy participants (total N=35), each performing one of three ambiguous perception tasks maximizing behavioral fluctuations: (1) Reporting faces or vase percepts on Rubins figure, (2) detecting near-random motion, or (3) identifying a near-threshold tone. Leveraging long inter-stimulus intervals (>20s), we examined how pre-stimulus connectome states influenced perception on a trial-by-trial basis. Using SVM models, pre-stimulus connectome reliably predicted upcoming post-stimulus perception. Distinct, non-overlapping sets of task-specific connections supported prediction in each task, spanning task-relevant sensory networks as well as higher-order cognitive control networks. Only when predictive connections were aggregated over the well-known intrinsic connectivity networks (ICNs), did we observe partial overlap across tasks. Our findings underscore the functional impact of ongoing connectome dynamics in shaping moment-to-moment behavior, and show that this impact is predominantly context-dependent.

neuroscience↗

bioRxiv2020

Spontaneous network coupling enables efficient task performance without local task-induced activations

Neurobehavioral studies in humans have long concentrated on changes in local activity levels during repetitive executions of a task. Spontaneous neural coupling within extended networks has latterly been found to also influence performance. Here, we intend to uncover the underlying mechanisms and the interaction with task-induced activations. We demonstrate that high performers in visual perception and motor sequence tasks present an absence of classical task-induced activations, but, instead, strong spontaneous network coupling. Activations were thus a compensation mechanism needed only in subjects with lower spontaneous network interactions. This challenges classical models of neural processing and calls for new strategies in attempts to train and enhance performance.

neuroscience↗

bioRxiv2017

Discriminability of numerosity-evoked fMRI activity patterns in human intra-parietal cortex reflects behavioral numerical acuity

Areas of the primate intraparietal cortex have been identified as an important substrate of numerical cognition. In human fMRI studies, activity patterns in these and other areas have allowed researchers to read out the numerosity a subject is viewing, but the relation of such decodable information with behavioral numerical proficiency remains unknown.\n\nHere, we estimated the precision of behavioral numerosity discrimination (internal Weber fraction) in twelve adult subjects based on psychophysical testing in a delayed numerosity comparison task outside the scanner. FMRI data were then recorded during a similar task, to obtain the accuracy with which the same sample numerosities could be read out from evoked brain activity patterns, as a measure of the precision of the neuronal representation. Sample numerosities were decodable in both early visual and intra-parietal cortex with approximately equal accuracy on average. In parietal cortex, smaller numerosities were better discriminated than larger numerosities of the same ratio, paralleling smaller behavioral Weber fractions for smaller numerosities. Furthermore, in parietal but not early visual cortex, fMRI decoding performance was correlated with behavioral number discrimination acuity across subjects (subjects with a more precise behavioral Weber fraction measured prior to scanning showed greater discriminability of fMRI activity patterns in intraparietal cortex, and more specifically, the right LIP region).\n\nThese results suggest a crucial role for intra-parietal cortex in supporting a numerical representation which is explicitly read out for numerical decisions and behavior.

neuroscience↗