Quantifying temporal ventriloquism in audiovisual synchrony perception

The integration of visual and auditory inputs in the human brain works properly only if the components are perceived in close temporal proximity. In the present study, we quantified cross-modal interactions in the human brain for audiovisual stimuli with temporal asynchronies, using a paradigm from rhythm perception. In this method, participants had to align the temporal position of a target in a rhythmic sequence of four markers. In the first experiment, target and markers consisted of a visual flash or an auditory noise burst, and all four combinations of target and marker modalities were tested. In the same-modality conditions, no temporal biases and a high precision of the adjusted temporal position of the target were observed. In the different-modality conditions, we found a systematic temporal bias of 25–30 ms. In the second part of the first and in a second experiment, we tested conditions in which audiovisual markers with different stimulus onset asynchronies (SOAs) between the two components and a visual target were used to quantify temporal ventriloquism. The adjusted target positions varied by up to about 50 ms and depended in a systematic way on the SOA and its proximity to the point of subjective synchrony. These data allowed testing different quantitative models. The most satisfying model, based on work by Maij, Brenner, and Smeets (Journal of Neurophysiology 102, 490–495, 2009), linked temporal ventriloquism and the percept of synchrony and was capable of adequately describing the results from the present study, as well as those of some earlier experiments.     

Electromagnetic tracking of motion in the proximity of computer generated graphical stimuli: A tutorial

Electromagnetic motion-tracking systems have the advantage of capturing the tempo-spatial kinematics of movements independently of the visibility of the sensors. However, they are limited in that they cannot be used in the proximity of electromagnetic field sources, such as computer monitors. This prevents exploiting the tracking potential of the sensor system together with that of computer-generated visual stimulation. Here we present a solution for presenting computer-generated visual stimulation that does not distort the electromagnetic field required for precise motion tracking, by means of a back projection medium. In one experiment, we verify that cathode ray tube monitors, as well as thin-film-transistor monitors, distort electro-magnetic sensor signals even at a distance of 18 cm. Our back projection medium, by contrast, leads to no distortion of the motion-tracking signals even when the sensor is touching the medium. This novel solution permits combining the advantages of electromagnetic motion tracking with computer-generated visual stimulation.     

On the relation between spontaneous perspective taking and other visuospatial processes

Common processes and representations engaged by visuospatial tasks were investigated by looking at four frequently used visuospatial research paradigms, the aim being to contribute to a better understanding of which specific processes are addressed in the different paradigms compared. In particular, the relation between spontaneous and instructed perspective taking, as well as mental rotation of body-part/non-body-part objects, was investigated. To this end, participants watched animations that have been shown to lead to spontaneous perspective taking. While they were watching these animations, participants were asked to explicitly adopt another perspective (Experiment 1), perform a mental object rotation task that involved a non-body-part object (Experiment 2), or perform a mental rotation of a body-part object (Experiment 3). Patterns of interference between the tasks, reflected in the reaction time patterns, showed that spontaneous and instructed perspective taking rely on similar representational elements to encode orientation. By contrast, no such overlap was found between spontaneous perspective taking and the rotation of non-body-part objects. Also, no overlap in orientation representation was evident with mental body-part rotations. Instead of an overlap in orientation representations, the results suggest that spontaneous perspective taking and the mental rotation of body parts rely on similar—presumably, motor—processes. These findings support the view that motor processes are involved in perspective taking and mental rotation of body parts.     

Contextual learning of multiple target locations in visual search

In visual search, detection of a target is faster when a layout of nontarget items is repeatedly encountered, suggesting that contextual invariances can guide attention. Moreover, contextual cueing can also adapt to environmental changes. For instance, when the target undergoes a predictable (i.e., learnable) location change, then contextual cueing remains effective even after the change, suggesting that a learned context is “remapped” and adjusted to novel requirements. Here, we explored the stability of contextual remapping: Four experiments demonstrated that target location changes are only effectively remapped when both the initial and the future target positions remain predictable across the entire experiment. Otherwise, contextual remapping fails. In sum, this pattern of results suggests that multiple, predictable target locations can be associated with a given repeated context, allowing the flexible adaptation of previously learned contingencies to novel task demands.     

Automatic priming for translation- and scale-invariant representations of object shape

A series of visual search experiments explored whether early visual processes are sensitive to the overall shape of objects. Previous work (Wolfe & Bennett, 1997) has suggested that information concerning overall shape is not coded in early vision. However, in Experiment 1, we demonstrate that these previous findings are explicable in terms of non-target heterogeneity rather than an absence of shape information in early vision. In Experiments 2 and 3, we demonstrate that shape similarity, rather than individual contour similarity, can determine search efficiency. In Experiments 4 and 5, we show that manipulating the contrast polarity of contours and defining shape using texture significantly impeded search for an odd-one-out shape. The implications of these results for shape processing in early vision are discussed.     

Effects of stimulus synchrony on mechanisms of perceptual organization

When neurons adopt a synchronized, oscillatory response to stimulus Gestalten, the phase of those oscillations almost always varies relative to stimulus activity. This has been taken to indicate that form-coding mechanisms are synchronized by internal timing mechanisms, and/or may be sensitive to stimulus activity only via motion detectors. This proposal is problematic for interpreting recent demonstrations of the effects of stimulus synchrony particularly when stimuli are stationary. Here we offer an account of stimulus-driven synchronization supported by evidence that segmentation by stimulus synchrony can be relatively insensitive to explicit motion signals. The argument is made that qualitative similarities between the effects of phase-independent and phase-locked oscillations in the EEG, the effects of phase synchronization at the cellular level and evidence for phase-enhanced stimulus grouping should be considered as functionally equivalent. This argument emphasizes the flexibility of temporal synchrony as a code for perceptual organization.     

The scenic function of the ego and its role in symptom and character formation1

The author argues that the scenic function of the ego permits the situationally appropriate representation of an unconscious, infantile configuration – that is, of a relatively stable, personality‐based drive scene having the same status as latent dream thoughts. The products of conflict elaboration (symptoms, etc.) are manifested in different ways in accordance with the conditions of the relevant situation. The contents of the drive scene are created by the psychical apparatus on the basis of infantile perceptions and are revealed in screen memories. The capacity for situationally appropriate representation is apparently bound up with the mobile drive, including its narcissistic transformations. Desexualization (in the sense of neutralization) renders scenic elaboration impossible. The drive derivatives withdrawn from the scenic configuration contribute to ego organization and the formation of character traits, which no longer vary according to the situation, but can only be modified by a change in personality structure itself. It is as yet unclear whether a process of resexualization can make them amenable once more to analytic work. The form of narcissistic libido that can assume a scenic configuration is closely related to primary narcissism. Its manifestations, which may likewise emerge in situation‐dependent symptom formations, appear accessible to analysis.     

CB1 cannabinoid receptors modulate kinase and phosphatase activity during extinction of conditioned fear in mice

Cannabinoid receptors type 1 (CB1) play a central role in both short-term and long-term extinction of auditory-cued fear memory. The molecular mechanisms underlying this function remain to be clarified. Several studies indicated extracellular signal-regulated kinases (ERKs), the phosphatidylinositol 3-kinase with its downstream effector AKT, and the phosphatase calcineurin as potential molecular substrates of extinction behavior. To test the involvement of these kinase and phosphatase activities in CB1-dependent extinction of conditioned fear behavior, conditioned CB1-deficient mice (CB1(-/-)) and wild-type littermates (CB1(+/+)) were sacrificed 30 min after recall of fear memory, and activation of ERKs, AKT, and calcineurin was examined by Western blot analysis in different brain regions. As compared with CB1(+/+), the nonreinforced tone presentation 24 h after auditory-cued fear conditioning led to lower levels of phosphorylated ERKs and/or calcineurin in the basolateral amygdala complex, ventromedial prefrontal cortex, dorsal hippocampus, and ventral hippocampus of CB1(-/-). In contrast, higher levels of phosphorylated p44 ERK and calcineurin were observed in the central nucleus of the amygdala of CB1(-/-). Phosphorylation of AKT was more pronounced in the basolateral amygdala complex and the dorsal hippocampus of CB1(-/-). We propose that the endogenous cannabinoid system modulates extinction of aversive memories, at least in part via regulation of the activity of kinases and phosphatases in a brain structure-dependent manner.     

Internalization of the therapeutic process: differences between borderline and neurotic patients

Intersession process in psychotherapy refers to the thoughts, memories, and feelings about each other and about their therapy sessions that participants experience during the intervals between sessions. This study compared the intersession process experienced by patients who had been diagnosed with severe borderline personality disorders (BPD) with others who had not. A total of 76 patients with neurotic disturbances and 20 patients with BPD were treated in a therapeutic day clinic and completed the Intersession Experience Questionnaire (IEQ) before sessions of individual psychotherapy and the Session Questionnaire (Stundenbogen) after those sessions. Comparison of the two groups on these measures of intersession process and postsession outcome showed markedly different patterns in patients' evaluations and internalizations of in-session therapeutic experiences: most prominently, that BPD patients internalize therapy sessions with much more negative and contradictory emotions.