Biology subjects

Packheiser, J.

Publications and source records attributed to Packheiser, J..

10 recordsLinked to original sources

bioRxiv2026

Distinct and overlapping correlates of fear acquisition and extinction across different neuroimaging modalities

Interindividual differences in fear acquisition and extinction have been related to variation in specific brain correlates. However, variability in experimental setups complicates the integration of findings. Here, we present a combined fear acquisition (n = 101) and extinction (n = 88) study from which we obtained distinct microstructural, macrostructural, and connectivity brain properties with magnetic resonance imaging in healthy, young participants. The properties included regional brain volume, cortical surface area and thickness, neurite density and orientation dispersion, and nodal efficiency of structural and functional connectivity. Fear responses were quantified as changes in skin conductance. Data from 360 cortical and 16 subcortical brain regions as well as the efficiency of network connections between them were used as independent variables in bootstrapped and cross-validated regularized regression models. Results show that numerous brain regions, spanning the so-called 'fear and extinction network' and extending beyond it, contribute to fear acquisition, to extinction, or dynamically shift between both phases. For several brain regions, data from multiple imaging modalities showed a high degree of concordance for several brain regions. These findings call for further research to examine the potential interplay between brain correlates shaping fear acquisition and extinction, as opposed to studying the imaging modalities in isolation.

neuroscience↗

bioRxiv2025

Heightened Play following Play Observation in the Absence of 22KHz Calls in Juvenile Rats

Emotional contagion, the process leading to emotional state matching between individuals is considered a cornerstone for the proper functioning of social groups, via its contribution to group coordination and cohesion, the ability to learn from others and engage in prosocial behaviors. However, to date, most studies of emotional contagion investigate the transfer of negative emotional states thereby bypassing the neurobiology of positive affect sharing. In this study, we aimed to leverage on the innately rewarding and salient nature of play behaviour, to investigate the potential contagiousness of positive affective states in juvenile rats. Observers that had been moderately socially deprived for varying durations first witnessed highly-playful (Play) or non-playful (Control) demonstrator rats prior to being reunited and given the opportunity to freely interact. Surprisingly, we observed the emission of negatively-valenced 22 kHz calls in a subset of sessions which was also associated with heightened play behavior of the demonstrators. We found that the reunited observers showed an increase in play behavior following observation in the Play condition compared to the Control condition, but only after short social isolation and in sessions without 22 kHz calls. In addition, an overall higher number of positively-valenced 50 kHz calls were emitted in the Play condition, again in sessions without 22 kHz emissions. Despite the limitations of the experimental procedure, our results highlight the complex nature of positive emotional sharing and provide encouraging first indications of using social play observation to study positive emotional contagion. Highlights- Social deprivation positively modulates play behavior and USV emission in reunited juvenile rats - Heightened play is associated with 22 kHz USVs following social deprivation - Heightened play was observed following play observation in the absence of 22 kHz USVs - Play observation was associated with an overall increased number of 50 kHz calls emissions - Play observation as an encouraging approach to study positive emotional contagion in rat

animal behavior and cognition↗

bioRxiv2025

Multi-modal brain properties are associated with interindividual differences in fear acquisition and extinction

Interindividual differences in fear acquisition and extinction have been related to variation in specific brain correlates. However, variability in experimental setups complicates the integration of findings. Here, we present a combined fear acquisition (n = 101) and extinction (n = 88) experiment in which both phenomena were related to brain correlates obtained via functional magnetic resonance imaging in healthy, young participants. Correlates included regional brain volume, cortical surface area and thickness, neurite density and orientation dispersion, structural and functional connectivity. Fear responses were quantified as changes in skin conductance. Data from 376 brain areas and 70,500 network connections were used as independent variables in regularized regression models. Regression models of fear acquisition could be obtained for all modalities but regional brain volume. There were 284 predictors of which 77 appeared in exactly two models and 19 in exactly three. The latter primarily included brain areas from the somatosensory, insular, cingulate, and frontal cortices. Fear extinction yielded regression models based on neurite density, structural connectivity, and functional connectivity with 112 predictors in total. Two predictors, located in the dorsolateral prefrontal cortex, replicated across exactly two regression models (neurite density and structural connectivity). This study is the first to investigate the neural correlates of both fear acquisition and extinction in an explorative, multi-modal fMRI approach. Results show that numerous brain regions contribute to fear conditioning, some of them via more than one correlate. These findings call for further research to examine the potential interplay between brain correlates shaping fear conditioning.

neuroscience↗

bioRxiv2025

Divide and conquer: How avian 'prefrontal' and hippocampal neurons process extinction learning in complementary ways

Context-dependent extinction learning enables organisms to acquire an inhibition of responding to cues that no longer signal reward in specific environmental settings. Both the hippocampus and the prefrontal cortex play key but complementary roles in encoding extinction. To understand what drives the differential contributions of these two structures, we recorded single-unit responses from the pigeon hippocampus (HPC) and the prefrontal nidopallium caudolaterale (NCL), while the animals were engaged in a repeated appetitive ABA extinction learning paradigm. HPC carried more information about experimental phases (acquisition (context A), extinction (context B), and renewal (context A)) than NCL. In addition, hippocampal neurons with mixed selectivity integrated all contextual stimuli and conditioned cues, thereby possibly enabling context integration into phase-dependent extinction events. The mixed selectivity pattern of NCL neurons differed: They encoded all relevant task parameters separately, thereby possibly enabling the weighing and deciding between response alternatives. Repeatedly testing the same animals over many months enabled us to reveal that the activity of NCL neurons increasingly became predictive of the number of responses that animals made during renewal. Thus, NCL neurons possibly assumed a meta-learning ability that enabled a behavioral adaption to the deeper task structure that always followed the sequence of acquisition[->]extinction[->]renewal. Our results make it likely that different processing strategies of hippocampus and prefrontal NCL enable a differential encoding of experimental phase, context, decision-making, and meta-learning during extinction learning.

neuroscience↗

bioRxiv2022

Walk the Plank! Using mobile EEG to investigate emotional lateralization of immersive fear in virtual reality

1.Most studies on emotion processing rely on the presentation of emotional images or films. However, this methodology lacks ecological validity, limiting the extent to which findings can generalize to emotion processing in the wild. More realistic paradigms using Virtual Reality (VR) may be better suited to investigate authentic emotional states and their neuronal correlates. This preregistered study examines the neuronal underpinnings of naturalistic fear, measured using mobile electroencephalography (EEG). Seventy-five healthy participants entered a simulation in which they walked across a virtual plank which extended from the side of a skyscraper - either 80 stories up (the negative condition) or at street level (the neutral condition). Subjective ratings showed that the negative condition induced feelings of fear and presence. Following the VR experience, subjects passively viewed negative and neutral images from the International Affective Picture system (IAPS) outside of VR. We compared frontal alpha asymmetry between the plank and IAPS task and across valence of the conditions. Asymmetry indices (AI) in the plank task revealed greater right-hemispheric lateralization during the negative VR condition, relative to the neutral VR condition and to IAPS viewing. Within the IAPS task, no significant asymmetries were detected, though AIs in the VR task and in the IAPS task were negatively correlated suggesting that stronger right-hemispheric activation in the VR task was associated with stronger left-hemispheric activation during the IAPS task. In summary, our findings indicate that immersive technologies such as VR can advance emotion research by providing more ecologically valid ways to induce emotion.

neuroscience↗

bioRxiv2022

Investigating the mechanistic role of painful self-experience in emotional contagion: an effect of auto-conditioning?

Emotional contagion refers to the transmission of emotions from one conspecific to another. Previous research in rodents has demonstrated that the self-experience of footshocks enhances how much an observer is affected by the emotional state of a conspecific in pain or distress. We hypothesized auditory auto-conditioning to contribute to this enhancement: during the observers own experience of shocks, the animal associates its own audible nocifensive responses, i.e. its pain squeaks, with the negative affective state induced by the shock. When the animal later witnesses a cage mate receive shocks and hears it squeak, the previously strengthened connection between fear and squeaks could be a mechanism eliciting the enhanced fearful response in the observer. As hypothesized, in a first study, we found pre-exposure to shocks to increase freezing and 22 kHz vocalizations associated with distress upon the playback of pain squeaks. Freezing was also increased during the playbacks of phase-scrambled squeaks, but 22 kHz calls were more frequent during the playback of regular squeaks. Core to the notion of auto-conditioning is that the effect of pre-exposure is due to the pairing of a pain-state with hearing ones own pain squeaks. In a second study, we therefore compared the response to squeak playbacks after animals had been pre-exposed to pairings of a CO2 laser with a squeak playback against three control groups that were pre-exposed to the CO2 laser alone, to squeak playbacks alone or to neither of these conditions. We however could not find any differences in freezing or 22 kHz calls among all experimental groups. In summary, we demonstrate the sufficiency of pain squeaks to trigger fear in a way that critically depends on the nature of an animals prior experience and discuss why the pairing of a CO2 laser with pain squeaks cannot substitute footshock pre-exposure.

animal behavior and cognition↗

bioRxiv2021

Working memory performance is tied to stimulus complexity

1.Working memory is the cognitive capability to maintain and process information over short periods. Behavioral and computational studies have shown that visual information is associated with working memory performance. However, the underlying neural correlates remain unknown. To identify how visual information affects working memory performance, we conducted behavioral experiments and single unit recordings in the avian prefrontal analog, the nidopallium caudolaterale (NCL). Complex pictures featuring luminance, spatial and color information, were associated with higher working memory performance compared to uniform gray pictures in conjunction with distinct neural coding patterns. For complex pictures, we found a multiplexed neuronal code displaying visual and value-related features that switched to a representation of the upcoming choice during a delay period. When processing gray stimuli, NCL neurons did not multiplex and exclusively represented the choice already during stimulus presentation and throughout the delay period. The prolonged representation possibly resulted in a decay of the memory trace ultimately leading to a decrease in performance. In conclusion, we found that high stimulus complexity is associated with neuronal multiplexing of the working memory representation possibly allowing a facilitated read-out of the neural code resulting in enhancement of working memory performance.

neuroscience↗

bioRxiv2021

Digital embryos - A novel technical approach to investigate perceptual categorization in pigeons (Columba livia) using machine learning

Pigeons are classic model animals to study perceptual category learning. A theoretical understanding of the cognitive mechanisms of categorization requires a careful consideration of the employed stimulus material. Optimally, stimuli should not consist of real-world objects that might be associated with prior experience. The number of exemplars should be theoretically infinite and easy to produce. In addition, the experimenter should have the freedom to produce 2D- and 3D-versions of the stimuli and, finally, the stimulus set should provide the opportunity to identify the diagnostic elements that the animals use. To this end, we used the approach of "virtual phylogenesis" of "digital embryos" to produce two stimulus sets of objects that meet these criteria. In our experiment pigeons learned to categorize these stimuli in a forced-choice procedure. In addition, we used peck tracking to identify where on the stimulus the animals pecked to signal their choice. Pigeons learned the task and transferred successfully to novel exemplars. Using a k-nearest neighbor classifier, we were able to predict the presented stimulus class based on pecking location indicating that pecks are related to features of interest. We further identified potential strategies of the pigeons through this approach, namely that they were either learning one or two categories to discriminate between stimulus classes. These strategies remained stable during category transfer, but differed between individuals indicating that categorization learning is not limited to a single learning strategy.

animal behavior and cognition↗

bioRxiv2020

Investigating real-life emotions in romantic couples: a mobile EEG study

The neural basis of emotional processing has been largely investigated in constrained spatial environments such as stationary EEGs or fMRI scanners using highly artificial stimuli like standardized pictures depicting emotional scenes. Typically, such standardized experiments have low ecological validity and it remains unclear whether their results reflect neuronal processing in real-life affective situations at all. Critically, emotional situations do not only encompass the perception of emotions, but also behavioral components associated with them. In this study, we aimed to investigate real-life emotions by recording couples in their homes using mobile EEG technology during embracing, kissing and emotional speech. We focused on asymmetries in affective processing as emotions have been demonstrated to be strongly lateralized in the brain. We found higher alpha and beta power asymmetry during kissing and embracing on frontal electrodes during emotional kisses and speech compared to a neutral control condition indicative of stronger left-hemispheric activation. In contrast, we found lower alpha power asymmetry at parieto-occipital electrode sites in the emotional compared to the neutral condition indicative of stronger right-hemispheric activation. Our findings are in line with models of emotional lateralization that postulate a valence-specific processing over frontal cortices and right-hemispheric dominance in emotional processing in parieto-occipital regions. Overall, we could thus support theories of emotional asymmetries which suggest that affective processing is not uniformly lateralized across the brain using a highly ecologically valid paradigm.

neuroscience↗

bioRxiv2020

Complex dynamics of choice during operant extinction and a simple associative learning account

Extinction learning, the process of ceasing an acquired behavior in response to altered reinforcement contingencies, is not only essential for survival in a changing environment, but also plays a fundamental role in the treatment of pathological behaviors. During therapy and other forms of training involving extinction, subjects are typically exposed to several sessions with a similar structure. The effects of this repeated exposure are not well understood. Here, we studied the behavior of pigeons across several sessions of a discrimination learning task in context A, extinction in context B, and a return to context A to test the context-dependent return of the learned responses (ABA renewal). By focusing on individual learning curves across animals, we uncovered a session-dependent variability of behavior: (1) During extinction, pigeons preferred the unrewarded alternative choice in one-third of the sessions, predominantly during the first one. (2) In later sessions, abrupt transitions of behavior at the onset of context B emerged, and (3) the renewal effect decayed as sessions progressed. We show that the observed results can be parsimoniously accounted for by a computational model based only on associative learning between stimuli and actions. Our work thus demonstrates the critical importance of studying the trial-by-trial dynamics of learning in individual sessions, and the power of "simple" associative learning processes.

animal behavior and cognition↗