Biology subjects

König, P.

Publications and source records attributed to König, P..

3 recordsLinked to original sources

bioRxiv2018

The social situation affects how we process feedback about our actions

Humans achieve their goals in joint action tasks either by cooperation or competition. In the present study, we investigated the neural processes underpinning error and monetary rewards processing in such cooperative and competitive situations. We used electroencephalography (EEG) and analyzed event-related potentials (ERPs) triggered by feedback in both social situations. 26 dyads performed a joint four-alternative forced choice (4AFC) visual task either cooperatively or competitively. At the end of each trial, participants received performance feedback about their individual and joint errors and accompanying monetary rewards. Furthermore, the outcome, i.e. resulting positive, negative or neutral rewards, was dependent on the pay-off matrix, defining the social situation either as cooperative or competitive. We used linear mixed effects models to analyze the feedback-related-negativity (FRN) and used the Thresholdfree cluster enhancement (TFCE) method to explore activations of all electrodes and times. We found main effects of the outcome and social situation at mid-line frontal electrodes. The FRN was more negative for losses than wins in both social situations. However, the FRN amplitudes differed between social situations. Moreover, we compared monetary with neutral outcomes in both social situations. Our exploratory TFCE analysis revealed that processing of feedback differs between cooperative and competitive situations at right temporo-parietal electrodes where the cooperative situation elicited more positive amplitudes. Further, the differences induced by the social situations were stronger in participants with higher scores on a perspective taking test. In sum, our results replicate previous studies about the FRN and extend them by comparing neurophysiological responses to positive and negative outcomes in a task that simultaneously engages two participants in competitive and cooperative situations.

neuroscience↗

bioRxiv2017

Deep Sequencing Reveals Transient Segregation of T Cell Repertoires in Splenic T Cell Zones During an Immune Response

Immunological differences between hosts, such as diverse T-cell receptor (TCR) repertoires, are widely credited for reducing the risk of pathogen spread and adaptation in a population. Within-host immunological diversity might likewise be important for robust pathogen control, but to what extent naive TCR repertoires differ across different locations in the same host is unclear. T-cell zones (TCZs) in secondary lymphoid organs provide secluded micro-environmental niches. By harboring distinct TCRs, such niches could enhance within-host immunological diversity. On the other hand, rapid T cell migration is expected to dilute such diversity. Here, we combined tissue micro-dissection and deep sequencing of the TCR {beta} chain to examine the extent to which TCR repertoires differ between TCZs in murine spleens. In the absence of antigen, we found little evidence for differences between different TCZs of the same spleen. Yet, three days after immunization with sheep red blood cells, we observed a >10-fold rise in the number of clones that appeared to localize to individual zones. Remarkably, these differences largely disappeared at 4 days after immunization, when hallmarks of an ongoing immune response were still observed. These data suggest that in the absence of antigen, any repertoire differences observed between TCZs of the same host can largely be attributed to random clone distribution. Upon antigen challenge, segregated TCR compartments appear and disappear within days. Such \"transient mosaic\" dynamics could be an important barrier for pathogen adaptation and spread during an immune response.

immunology↗

bioRxiv2017

Entorhinal cortex receptive fields are modulated by spatial attention, even without movement.

Grid cells have been identified in the entorhinal cortex in a variety of species and allow for the precise decoding of position in space (1-7). Along with potentially playing an important role in navigation, grid cells have recently been hypothesized to make a general contribution to mental operations, including remembering the past and thinking about the future (8,9). A prerequisite for this hypothesis is that grid cell activity does not critically depend on physical movement. Directed attention, which contributes to virtually all mental operations and can be separated from physical movement provides a good test case to investigate this hypothesis. Overt attention in the form of fixational eye movements leads to grid-like firing fields in the monkey entorhinal cortex (3). Here we show that movement of covert attention, without any physical movement, also elicits spatial receptive fields with a triangular tiling of the space. In monkeys trained to maintain central fixation while covertly attending to a stimulus moving in the periphery we identified a significant population (20/141, 14% neurons at a FDR<5%) of entorhinal cells with spatially structured receptive fields. Further, we were able to identify a population of neurons that were labeled as grid cells on an individual basis. This contrast with our recordings obtained in the hippocampus, where grid-like representations were not observed. Our results provide compelling evidence that neurons in macaque entorhinal cortex do not rely on physical movement. Notably, these results support the notion that grid cells may be capable of serving a variety of different cognitive functions and suggest that grid cells are a versatile component of many neural algorithms.

neuroscience↗