TYMES: A high-level language for process control and data manipulation in the behavior laboratory

This paper describes outlines of the TYMES software system designed and developed to control complicated experiments in the behavior laboratory. A versatile programming language is adopted to perform a wide range of real-time data manipulations and interactive controls based on a PDP-11 small computer.     

Temperature dependence of the low-cycle fatigue behaviour of a Cu-SiO2 bicrystal with a [011], 18° twist boundary

The temperature dependence of the low-cycle fatigue behaviour of a Cu bicrystal containing dispersed SiO₂ particles and having a [011], 18° twist boundary has been studied. Failure occurred at shorter times with increasing temperature and stress amplitude. Crack nucleation took place at the particles' surfaces on the grain boundary where slip lines intersected. The crack tended to propagate along primary slip lines and this tendency became stronger as the temperature was increased.     

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.     

Effect of static visual acuity on dynamic visual acuity: a pilot study

The aim of this pilot study was to evaluate whether dynamic visual acuity changes with or without refractive correction. 42 healthy enrolled subjects with normal vision were divided into two age-matched groups. In Group A, dynamic visual acuity was measured first with the refractive error fully corrected and then without. In Group B, dynamic visual acuity measurements were taken in the reverse order of that performed by Group A. The measurements were binocularly performed five times using free-head viewing after dynamic visual acuity values were stable. Significant changes in dynamic visual acuity (static visual acuity 20/20 vs 12/20) were observed in both Group A (171.6 +/- 36.0 deg./sec. vs 151.8 +/- 39.6 deg./sec., Wilcoxon test, p < .001) and Group B (169.8 +/- 30.0 deg./sec. vs 151.2 +/- 36.0 deg./sec., Wilcoxon test, p < .001). The interaction was significant (F1.20 = 8.12, p = .009). These results indicated that refractive correction affected dynamic visual acuity.     

Human group choice: discrete-trial and free-operant tests of the ideal free distribution

Ideal free distribution theory predicts that foragers will form groups proportional in number to the resources available in alternative resource sites or patches, a phenomenon termed habitat matching. Three experiments tested this prediction with college students in discrete-trial simulations and a free-operant simulation. Sensitivity to differences in programmed reinforcement rates was quantified by using the sensitivity parameter of the generalized matching law (s). The first experiment, replicating prior published experiments, produced a greater degree of undermatching for the initial choice (s = 0.59) compared to final choices (s = 0.86). The second experiment, which extended prior findings by allowing only one choice per trial, produced comparable undermatching (s = 0.82). The third experiment used free-operant procedures more typical of laboratory studies of habitat matching with other species and produced the most undermatching (s = 0.71). The results of these experiments replicated previous results with human groups, supported predictions of the ideal free distribution, and suggested that undermatching represents a systematic deviation from the ideal free distribution. These results are consistent with a melioration account of individual behavior as the basis for group choice.     

Photoinduced volume changes related to photoinduced anisotropy in chalcogenide glasses

We report metastable photoinduced volume expansion (hyperexpansion) of up to 10 µm in height and several millimetres in diameter for the chalcogenide glass As 2 S 3 . This is an order of magnitude larger than reported to date in any material, including chalcogenide glasses. We suggest a model for the effect and propose that its origin is similar to the origin of photoinduced anisotropy in glassy chalcogenides proposed earlier. The model is based on the anisotropic chemical bonding found in most chalcogenide glasses; the anisotropy arises from the fact that chalcogen atoms exhibit both strong covalent bonding and weak van der Waals bonding. The origin of the photoinduced volume changes (expansion and contraction) is in a thermally induced diffusion, or athermal tunnelling, of photoexcited chalcogen atoms, with possible subsequent sublimation from the sample surface. The primary role of hyperpolarizable van der Waals bonds is supported by the absence of photoinduced volume changes in the chalcogenide glass Ga 1.4 La 0.6 S 3, in which chalcogen atoms do not bond via van der Waals bonds.     

Analysis of five cases with neurogenic stuttering following brain injury in the basal ganglia

This study examined stuttering patterns in five patients with basal ganglia injury. None of the patients had a history of developmental stuttering. Four patients were right-handed; one patient was ambidextrous. Stuttering tests administered to patients assessed sentence repetition, reading aloud, explanations of a comic strip, and conversation. Accessory behaviors such as facial grimaces, associated movements of the limbs, and avoidance behaviors were observed. The results of this study differ from those of previous studies of neurogenic stuttering in several respects: (1) blocks were frequently observed. (2) Adaptation was observed. (3) Almost all stuttering occurred at the initiation of words. (4) Across patients, stuttering frequency did not vary in a consistent manner with speaking task. New speech characteristics for neurogenic stuttering without aphasia following injury to the basal ganglia are described.Educational objectives: After reading this text, the reader will be able to: (1) provide characteristics of neurogenic stuttering after the basal ganglia in patients without aphasia; (2) discuss the difference of the features and characteristics of stuttering between previously reported patients and present patients.     

Influence of motoric encoding on forgetting function of memory for action sentences in patients with Alzheimer's disease

This study assessed whether verbal encoding and motoric encoding have different effects on the forgetting function for action sentences of patients with Alzheimer's disease. Subjects were 13 healthy elderly adults and 10 patients diagnosed with Alzheimer's disease. Three tasks were used: verbal tasks, subject-performed tasks, observed tasks. On the verbal tasks, subjects only heard the action sentences as read to them. On the subject-performed tasks, subjects heard, then performed each action sentence. On the observed tasks, subjects heard the action sentences read while observing the object mentioned in each action sentence. After presentation of each task, subjects conducted immediate and 30-min. delayed recall tests, and then a recognition test. Analysis indicated recall performance for subject-performed tasks was significantly better than that for verbal tasks and observed tasks at both immediate and delayed recall in each group. On the recognition test, carrying out the action had no effect, but for both groups recognition was enhanced by observing the object. Elderly adults performed significantly better than patients on all tasks of recall and recognition. However, the results indicate that patients with Alzheimer's disease can use multimodal resources from motoric encoding even if time passes.     

Effect of pupil size on dynamic visual acuity

This study was conducted to assess the effect of pupil size on dynamic visual acuity (DVA). 60 young healthy men (M = 28.1 yr., SD = 3.9) with normal vision were divided into three age-matched groups by pupil size: dilated (n=20), unchanged (n=20), and constricted (n=20). DVA was measured binocularly with freehead viewing before and at 30 min. after each drop was instilled. Each of the three groups got a different amount. The sizes of the constricted, unchanged, and dilated pupils were 2.8 mm (SD = 0.5), 4.1 mm (SD = 0.3), and 7.8 mm (SD = 0.5), respectively. The pupil size x DVA interaction was significant (F(2,114)= 6.07). DVA in the constricted pupil decreased, but that in the dilated pupil increased (paired t test). DVA in the unchanged pupil did not change significantly (paired t test). Pupil size is possibly one of the factors which may affect DVA measurement.