Modeling body state-dependent multisensory integration

The brain often integrates multisensory sources of information in a way that is close to the optimal according to Bayesian principles. Since sensory modalities are grounded in different, body-relative frames of reference, multisensory integration requires accurate transformations of information. We have shown experimentally, for example, that a rotating tactile stimulus on the palm of the right hand can influence the judgment of ambiguously rotating visual displays. Most significantly, this influence depended on the palm orientation: when facing upwards, a clockwise rotation on the palm yielded a clockwise visual judgment bias; when facing downwards, the same clockwise rotation yielded a counterclockwise bias. Thus, tactile rotation cues biased visual rotation judgment in a head-centered reference frame. Recently, we have generated a modular, multimodal arm model that is able to mimic aspects of such experiments. The model co-represents the state of an arm in several modalities, including a proprioceptive, joint angle modality as well as head-centered orientation and location modalities. Each modality represents each limb or joint separately. Sensory information from the different modalities is exchanged via local forward and inverse kinematic mappings. Also, re-afferent sensory feedback is anticipated and integrated via Kalman filtering. Information across modalities is integrated probabilistically via Bayesian-based plausibility estimates, continuously maintaining a consistent global arm state estimation. This architecture is thus able to model the described effect of posture-dependent motion cue integration: tactile and proprioceptive sensory information may yield top-down biases on visual processing. Equally, such information may influence top-down visual attention, expecting particular arm-dependent motion patterns. Current research implements such effects on visual processing and attention.     

Goal-relevant events need not be rare to boost memory for concurrent images

In the attentional boost effect, memory for images presented at the same time as unrelated targets (e.g., an orange square) is enhanced relative to images presented at the same time as distractors (e.g., a blue square). One difficulty in understanding the nature of this enhancement is that, in most experiments demonstrating the attentional boost effect, targets have been less common than distractors. As a result, the memory enhancement associated with target detection may have been driven by differences in the relative frequencies of targets and distractors. In four experiments, participants encoded images into memory at the same time that they monitored a second, unrelated stimulus stream for targets. In some conditions, targets were as common as distractors (1:1 ratio); in others, targets were rare (1:6 ratio). The attentional boost effect was present when the target and distractor frequencies were equated, ruling out oddball and distinctiveness effects as explanations. These effects were observed when targets required a buttonpress and when they were covertly counted. Memory enhancements were not observed for images presented at the same time as rare distractor stimuli. We concluded that selectively attending to events that require an overt or covert response enhances the processing of concurrent information.     

Neural control of voluntary eye closure: a case study and an fMRI investigation of blinking and winking

The current paper describes a rare case of a patient who suffered from unilateral apraxia of eye closure as a result of a bilateral stroke. Interestingly, the patient's ability to voluntarily close both eyelids (i.e. blinking) was not affected, indicating that different neural mechanisms control each type of eye closure. The stroke caused damage to a large part of the right frontal cortex, including the motor cortex, pre-motor cortex and the frontal eye field (FEF). The lesion in the left hemisphere was restricted to the FEF. In order to further study the neural mechanisms of eye closure, we conducted an fMRI study in a group of neurological healthy subjects. We found that all areas of the oculomotor cortex were activated by both left and right winking, including the FEF, supplementary eye field (SEF), and posterior parietal cortex (PPC). Blinking activated FEF and SEF, but not PPC. Both FEF and PPC were significantly more active during winking than blinking. Together, these results provide evidence for a critical role of the FEF in voluntary unilateral eye closure.     

Hesitancy to Return to the Pre-pandemic Routine

Journal of Rational-Emotive & Cognitive-Behavior Therapy - The goal of the present study was to explore COVID-19 related hesitancy, which represents the inability of people to return to...     

Behavior analysis of cigarette smoking

Patterns of cigarette smoking, treated as series of discrete events in time, were investigated with a variety of quantitative techniques designed to characterize individual subject smoking series and to illuminate the relationship between cigarette smoking and environmental events. Data were collected from a total of 35 subjects who were either participants in residential laboratory studies or in a smoking cessation program. Cigarette smoking events were found to be fairly irregularly distributed with respect to time within individual subject series. However, strong dependencies were found between the occurrence in time of individual acts of cigarette smoking and coffee drinking. In addition, the distribution and frequency of smoking events throughout one-hour activity sequences were found to be dependent upon the nature of the activity, and the temporal scheduling of activities was found to affect several quantitative indices of smoking patterns.     

Retention of orienting reaction habituation in patients with postmeningoencephalitic epilepsy

A polygraphic study on habituation of the somatic, autonomic, and EEG components of the orienting reaction elicited by a repetitive auditory stimulus during successive (weekly) sessions was performed in 29 patients with postmeningoencephalic epilepsy (PME) and in 116 control subjects. The study evidenced significant retention disturbances of orienting reaction habituation (i.e., of learning), the “saving” of stimulation, achieved from one session to another to obtain the habituation criterion, being lesser in PME patients than in control subjects. The severity of habituation retention disturbances depended on seizure frequency, electroclinical form, and history, as well as on features of EEG tracings.