FIGURE 2 - available via license: Creative Commons Attribution 4.0 International
Content may be subject to copyright.
| Heatmap of motion tracking data of study 1 using every fifth recorded data point during the exploration phase (N 30). Areas with lighter colors depict areas with greater activity. The center area is defined as transition zone, thus excluded from analyses.
Source publication
The Elevated Plus-Maze (EPM) is a well-established apparatus to measure anxiety in rodents, i.e., animals exhibiting an increased relative time spent in the closed vs. the open arms are considered anxious. To examine whether such anxiety-modulated behaviors are conserved in humans, we re-translated this paradigm to a human setting using virtual rea...
Context in source publication
Context 1
... of the motion tracking data revealed that participants spent overall more time on the open (M 151.52, SD 58.96) compared to the closed (M 60.54, SD 33.39) arms, t (29) 6.36, p < 0.001, d 1.14 (see Figure 2). On average, subjects walked a total of 191.72 m (SD 44.85) throughout the exploration phase and 51.89 (SD 27.57) and 99.05 (SD 44.77) meters on the closed and open arms, respectively. ...
Similar publications
Feedforward modeling, the creation of one’s own behaviour that is potentially achievable in the future, can support motor performance and learning. While this has been shown for sequences of motor actions, it remains to be tested whether feedforward modelling is beneficial for single complex motor actions. Using an immersive, state-of-the-art, low-...
Citations
... This allows for the comprehensive characterization of emotional states on a cognitive-verbal, physiological-humoral, and motor-behavioral level (Fox 2008). Furthermore, the use of virtual environments facilitates translational work (Fig. 2b), such that certain experimental protocols, which are traditionally used in animals, can now be easily recreated in VR to allow for a more direct comparison between animal and human research (e.g., Biedermann et al. 2017;Madeira et al. 2021). ...
... (a) Participants can be located within a CAVE and by means of a gamepad they can freely move within a virtual environment including, for example, a tower inducing fear of height (Gromer et al. 2018). (b) Protocols of animal studies can be easily translated to VR settings as demonstrated with the elevated plus maze (EPM; Biedermann et al. 2017;Madeira et al. 2021). (c) The realism of the virtual environments can be manipulated in order to induce a stronger sense of presence (Gromer et al. 2019) VR tricks our minds to believe in a world that does not exist. ...
Emotions are frequently considered as the driving force of behavior, and psychopathology is often characterized by aberrant emotional responding. Emotional states are reflected on a cognitive-verbal, physiological-humoral, and motor-behavioral level but to date, human research lacks an experimental protocol for a comprehensive and ecologically valid characterization of such emotional states. Virtual reality (VR) might help to overcome this situation by allowing researchers to study mental processes and behavior in highly controlled but reality-like laboratory settings. In this chapter, we first elucidate the role of presence and immersion as requirements for eliciting emotional states in a virtual environment and discuss different VR methods for emotion induction. We then consider the organization of emotional states on a valence continuum (i.e., from negative to positive) and on this basis discuss the use of VR to study threat processing and avoidance as well as reward processing and approach behavior. Although the potential of VR has not been fully realized in laboratory and clinical settings yet, this technological tool can open up new avenues to better understand the neurobiological mechanisms of emotional responding in healthy and pathological conditions.KeywordsApproachAvoidanceEmotionsPresenceVirtual reality
Anxiety research is one of the major psychological research domains and looks back on decades of research activity. Traditionally, novel theories and approaches are tested utilizing animal models. One way to study inherent anxiety in rodents is the elevated plus-maze (EPM). The EPM is a plus-shaped platform with two closed, i.e., walled, arms and two open unwalled arms. If given the opportunity to freely explore the apparatus, rodents instinctively avoid the open arms to protect themselves from predators. Hence, they spent less time on open and more time on closed arms, which is behaviorally associated with general anxiety. In the course of the pharmacological validation, it was found that this exploratory pattern can be reversed by anxiolytic substances, e.g., benzodiazepines, or potentiated by anxiogenics. One of the significant advantages of the EPM is that no prior training session is required in contrast to conditioning studies, thus allowing to observe natural behavior. Therefore, together with the economic and uncomplicated setup, the EPM has become a standard preclinical rodent anxiety test over the decades. In order to validate these rodent anxiety tests, there have recently been attempts to retranslate them to humans. A paramount of cross-species validation is not only the simple transferability of these animal tests but also the observation of anxiety behaviors that are evolutionarily conserved across species. Accordingly, it could be possible to conclude various factors associated with the etiology and maintenance of anxiety disorders in humans. So far, convincing translations of the EPM to humans are still lacking. For that reason, the primary aim of this dissertation is to retranslate the EPM throughout three studies and to evaluate cross-species validity critically. Secondly, the undertaken studies are set out to observe ambulatory activity equivalent to rodent EPM behavior, i.e., open arm avoidance. Thirdly, the undertaken studies aimed to assess the extent to which trait anxiety influences human exploratory activity on the platform to associate it with the assumption that rodent EPM-behavior is a reflection of general anxiety. Finally, virtual reality (VR) was the method of choice to maintain the economic advantage and adjust the EPM size to humans. Study 1 (N = 30) was set up to directly transfer the rodent EPM regarding test design and experimental procedure using a Computer Automatic Virtual Environment (CAVE). The results revealed that humans unlike rodents display a general open arms approach during free exploration. However, open arm avoidance was associated with high trait anxiety and acrophobia (fear of height), which was initially assessed as a control variable due to the virtual platform height. Regression analyses and subjective anxiety ratings hinted at a more significant influence of acrophobia on open arm avoidance. In addition, it was assumed that the open arms approach might have resulted from claustrophobic tendencies experienced in the closed arms due to the high walls. Study 2 (N = 61) sought to differentiate the influence of trait anxiety and acrophobia and adapt the virtual EPM to humans. Therefore, parts of the platform held a semi-transparent grid-floor texture, and the wall height on the closed arms was reduced to standard handrail level. Moreover, participants were priorly screened to exclude clinically significant levels of acrophobia, claustrophobia, and agoraphobia. The data on general exploratory activity showed no arm preference. Regression analyses confirmed that acrophobia is related to open arm avoidance, corroborating the finding of Study 1. Surprisingly, for trait anxiety, the result of Study 1 could not be replicated. Instead, for trait anxiety, no significant effect was found indicating that predominantly fear of heights shapes human EPM behavior even on a subclinical stage. In Study 3 (N = 57), the EPM was embedded into a city setting to 1) create a more natural human environment and 2) eliminate height. Furthermore, a head-mounted display was utilized for VR presentation, and arousal ratings were introduced. Participants were screened for high and low levels of trait anxiety and agoraphobia, and claustrophobia. Replicating the findings of Study 2, no difference in open and closed arm activity was observed, and no effect was found in relationship with trait anxiety. The data on anxiety ratings and claustrophobia suggest a positive correlation indicating that in this city EPM, claustrophobic tendencies might play a role in closed arm avoidance. In summary, this thesis added valuable insights into the retranslation of a well-established standard anxiety test used in rodents. However, it also majorly challenges current findings on the cross-species validity of the EPM. Various explanatory models for the results are critically discussed and associated with clinical implications concerning future research.
This work is concerned with the modelling and control of the state of presence of a user in a virtual reality system (VRS). The manner how the state of a user interacting with the VRS is measured by some of its physiological signals is discussed. Based on the user-VRS interaction, a novel feedback control schema to manipulate the user state is proposed. In this, the error between the required and the actual user behavior is used by a controller to select the appropriate stimulus that must be executed by the VRS core scenario to reduce the error. The schema includes the modelling of the presence state by a discrete event strategy based on Petri Nets. Based on the obtained model, the control strategy to select the appropriate stimuli is devised. Finally, some real experiments with a VRS prototype are carried out to show the effectiveness of the proposal.
