A model of empty duration perception

An attempt to construct a general theory of duration perception is presented. First, four experiments are reported in which the supplement hypothesis, on the relation between two or three empty durations, was examined: the subjective duration of a subjectively empty time interval is directly proportional to its physical duration plus a constant of approximately 80 ms. This hypothesis could be applied to the ratio judgments of auditorily marked empty durations between 40 and 600 ms given serially. It could also explain the discrepancies between musically notated rhythms and the corresponding physical performed rhythms in very simple rhythm patterns consisting of three tones. Next, three earlier experiments on discriminations of empty durations marked by sound bursts were also reanalyzed. Within the range 40-600 ms, the absolute just noticeable difference of an empty duration was almost directly proportional to the standard duration plus a constant of about 80 ms. If the supplement hypothesis is accepted, this means that the relative just noticeable difference of the subjective duration was constant. Finally, the processing time hypothesis is presented: subjective duration is directly proportional to the physical time required to process the given empty duration. This processing is considered to begin with the detection of the first marker, and to end approximately 80 ms after the detection of the second marker.     

Further evidence for the summation of latent inhibition and overshadowing in rats’ conditioned taste aversion

Repeated exposures to a target taste (X) attenuated subsequent development of rats’ conditioned aversion to X (latent inhibition effect). Presentation of another taste (A) after X in conditioning (serial X-A compound conditioning) also attenuated conditioned X aversion compared with conditioning without A (overshadowing). Furthermore, the latent inhibition and overshadowing effects summed to show the least conditioned aversion in the rats given both the target preexposures and the serial X-A compound conditioning treatment. These results question the validity of the comparator hypothesis as an explanation for Pavlovian conditioning of rats’ conditioned taste aversion.     

Support for Returning to Work for a Patient of Social Behavior Disorder with Impaired Self-awareness

Social behavioral disorders and impaired self-awareness, which are sequelae of brain injuries, have negative effects on interpersonal relationships and employment. In this study, we performed a long-term client-centered approach to help the patient diagnosed with a social behavior disorder and impaired self-awareness return to work. Cognitive rehabilitation, cognitive-behavioral treatment, and positive behavioral support were provided while assessing the self-awareness using the Japanese version of the Self-Regulation Skills Interview. This patient exemplifies the importance of establishing methods for self-monitoring and rebuilding a positive self-identity while considering the complexities of self-awareness when helping patients with impaired self-awareness. The patient took the initiative in managing problematic behaviors due to social behavior disorder, and as a result, was able to achieve stable self-awareness. The strategies described in this patient can be used in the future to treat patients with social behavior disorder due to inadequate self-awareness. In order to practice a client-centered approach while assessing the patient's level of self-awareness, it is important to build a trusting relationship over a long period. To assess the level of self-awareness, existing interviews, questionnaires, and work to express one's mental and physical state as seen by the patient may be effective.

     

Subjectively divided tone components in the gap transfer illusion

When a long glide with a short temporal gap in its middle crosses with a continuous short glide at the temporal midpoint of both glides, the gap is perceived in the short glide instead of in the long glide. In the present article, we tested possible explanations for this "gap transfer illusion" by obtaining points of subjective equality of the pitches and durations of the two short tones that are subjectively divided by the gap. The results of two experiments showed that neither an explanation in terms ofenvelope patterns nor explanations in terms of combinationtones or acoustic beats could account for the perception of the short tones in the gap transfer illusion. Rather, the results were compatible with the idea that the illusory tones were formed by the perceptual integration of onsets and offsets of acoustically different sounds. Implications for the perceptual construction of auditory events are discussed.     

Failure of Retrospective Inference in Rats' Taste Aversion

Three experiments explored the possibility of retrospective inference in the rat. Experiment 1 revealed that poisoning of an element of a taste compound after single compound poisoning enhanced aversion to the other element, and that presentation of an element without poison after the compound poisoning reduced aversion to the other element. These results were opposite to those predicted by retrospective inference. Experiment 2 eliminated some confounding variables and examined the effect of element poisoning after compound poisoning. The result again was opposite to what the retrospective view predicts. The results, however, accorded with the idea that within-compound learning was established during compound presentation, and subsequent poisoning or nonpoisoning of one element affected response to the other element via the within-compound learning. In Experiment 3, the possibility of within-compound learning was reduced by using sequential presentation of tastes, but there was no indication of retrospective inference even under this condition.     

The perceptual integration of auditory stimulus edges: an illusory short tone in stimulus patterns consisting of two partly overlapping glides

Two partly overlapping frequency glides can be perceived as consisting of a long pitch trajectory accompanied by a short tone in the temporal middle. It was found that the appearance of this middle tone could not be related to peripheral processes concerned with spectral splatter or combination tones that could have emerged during the overlap of the glides. Furthermore, it was found that the middle tone was perceived even when components of the 2 glides were separated by more than an equivalent rectangular bandwidth at any time during the overlap. The appearance of the middle tone indicates that auditory events can result from the perceptual integration of component parts-that is, stimulus edges-of acoustically different sounds.     

Facilitation of Sodium Aversion Learning in Sodium-Deprived Rats

Two experiments with rats explored the effects of sodium deprivation induced by furosemide injections upon acquisition of taste aversion to sodium chloride (NaCl). In Experiment 1, rats under either sodium deprivation or a balanced nutrition condition were given access to a limited amount of NaCl solution prior to poisoning. When all rats were tested under sodium repletion, the previously sodium-deprived rats consumed less NaCl than did the nondeprived rats. This finding was replicated in Experiment 2A in which ingestion of a compound solution of NaCl and hydrochloric acid (HCl) was followed by poisoning. Consumption of HCl, however, showed the opposite pattern: the sodium-deprived rats drank more HCl than did the nondeprived rats, a result that was replicated in Experiment 2B. These results suggest that sodium deprivation strengthens the salience of NaCl, thereby facilitating acquisition of aversion to this taste and strongly overshadowing that to a simultaneously presented taste.     

Changes in somatosensory evoked potentials and Hoffmann reflexes during fast isometric contraction of foot plantarflexor in humans

In the present study, the extent to which the early component of somatosensory evoked potentials (SEPs) and the Hoffmann (H-) reflex induced by stimulation of the posterior tibial nerve are altered during the ascending and descending phases of fast plantarflexion was investigated. SEPSs and H-reflex of the soleus following tibial nerve stimulation were examined during fast plantarfiexion when performed by nine normal subjects. The analyses focused on differences in amplitude modulation of the P30-P40 component of SEP and the H-reflex between the ascending and descending phases of full-wave rectified and averaged soleus electromyographic (EMG) activity. The H-reflex amplitude was significantly increased and decreased during the ascending and descending phases more than under resting control conditions, respectively. The reduction of SEP amplitude was 49% for the ascending phase and 83% for the descending phases with respect to the resting situation. Modulation of SEP during the ascending and descending phases was robustly retained even during ischemic nerve blockade of large diameter afferent fibers. These findings suggest that the transmission of afferent inputs from muscle spindles to motoneurons and to the somatosensory cortex during fast isometric contraction of the plantar flexor is regulated in a time-dependent fashion by descending commands.