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PubMed1995

Spatial and temporal factors determine auditory-visual interactions in human saccadic eye movements.

In this paper, we show that human saccadic eye movements toward a visual target are generated with a reduced latency when this target is spatially and temporally aligned with an irrelevant auditory nontarget. This effect gradually disappears if the temporal and/or spatial alignment of the visual and auditory stimuli are changed. When subjects are able to accurately localize the auditory stimulus in two dimensions, the spatial dependence of the reduction in latency depends on the actual radial distance between the auditory and the visual stimulus. If, however, only the azimuth of the sound source can be determined by the subjects, the horizontal target separation determines the strength of the interaction. Neither saccade accuracy nor saccade kinematics were affected in these paradigms. We propose that, in addition to an aspecific warning signal, the reduction of saccadic latency is due to interactions that take place at a multimodal stage of saccade programming, where the perceived positions of visual and auditory stimuli are represented in a common frame of reference. This hypothesis is in agreement with our finding that the saccades often are initially directed to the average position of the visual and the auditory target, provided that their spatial separation is not too large. Striking similarities with electrophysiological findings on multisensory interactions in the deep layers of the midbrain superior colliculus are discussed.

Adult↗
PubMed1995

Spatiotemporal boundaries of linear vection.

Thresholds for the perception of linear vection were measured. These thresholds allowed us to define the spatiotemporal contrast surface sensitivity and the spatiotemporal domain of the perception of rectilinear vection (a visually induced self-motion in a straight line). Moreover, a Weber's law was found, such that a mean relative differential threshold in angular velocity of about 41% is necessary to perceive curvilinear vection. This visually induced self-motion corresponds to the sensation of moving in a curved path. It is proposed that curvilinear vection is induced when the apparent velocity difference is detectable. The spatiotemporal domain of perception of rectilinear vection and its spatiotemporal contrast surface sensitivity are centered on low spatial frequencies. Concurrently, the values which correspond to the relative differential thresholds of curvilinear vection are low spatial frequencies. Accordingly, the peripheral ambient visual system seems to be involved in perceiving linear vection. It is argued further that the central ambient system might also be involved in the processing of linear vection.

Contrast Sensitivity↗
PubMed1991

Some structural determinants of melody recall.

Sophisticated musicians were asked to recall, using musical notation, a set of unfamiliar folk tunes that varied in rhythmic structure and referents of tonality. The results showed that memory was facilitated by tonic triad members marking phrase endings, but only when their presence was highlighted by a corresponding pattern of temporal accents. Conversely, recall significantly declined when tonal information was either absent or obscured by rhythmic structure. Error analyses further revealed that the retention of overall pitch contour and information at phrase ending points varied as a function of these manipulations. The results are discussed in terms of a framework that links the acts of perceiving and remembering to a common attentional scheme.

Adult↗
PubMed1993

Perceptual organization of auditory temporal patterns in European starlings (Sturnus vulgaris).

The perception of continuously repeating auditory patterns by European starlings was explored in seven experiments. In Experiment 1, 4 starlings learned to discriminate between two continuously repeating, eight-element, auditory patterns. Each eight-element pattern was constructed from different temporal organizations of two elements differing in timbre. In Experiments 2-7, the repeating patterns were transformed in ways designed to identify the starlings' perceptual organization of the patterns. In Experiment 2, the starlings identified patterns beginning with novel starting points. In Experiment 3, discrimination performance was adversely affected by reorganizing the elements in the patterns. In Experiments 4 and 5, the pattern elements were altered. In Experiment 4, the patterns were constructed from two novel elements. In Experiment 5, the temporal location of the two pattern elements was reversed. The transformations of the patterns in Experiments 4 and 5 affected discrimination performance for some, but not all, of the starlings. In Experiments 6 and 7, replacing either of the two elements with silent intervals had no effect on discrimination performance. The results of these experiments identify basic grouping principles that starlings use when they perceive auditory patterns.

Animals↗
PubMed1996

Perceptual normalization for speaking rate: effects of temporal distance.

A series of studies was undertaken to examine how rate normalization in speech perception would be influenced by the similarity, duration, and phonotactics of phonemes that were adjacent or distal from the initial, target phoneme. The duration of the adjacent (following) phoneme always had an effect on perception of the initial target. Neither phonotactics nor acoustic similarity seemed to have any influence on this rate normalization effect. However, effects of the duration of the nonadjacent (distal) phoneme were only found when that phoneme was temporally close to the target. These results suggest that there is a temporal window over which rate normalization occurs. In most cases, only the adjacent phoneme or adjacent two phonemes will fall within this window and thus influence perception of a phoneme distinction.

Adult↗
PubMed1986

[The diminution of spatial effects upon duration estimation with focused attention].

The purpose of this study is to investigate the influence of spatial attributes of stimuli upon the estimation of duration time. Using magnitude estimation method, three tasks were imposed on seven undergraduate students. C (control) task was to estimate the duration of a static small circle, MF (moving-free) task was that of a moving pattern of randomly located luminous spots, both with free regard, and MX (moving-fixed) task was that of the small circle superimposed on the moving pattern, with focused attention. In the MF task, there was found a velocity effect, i.e. the higher the velocity was, the larger was the estimated duration. In the MX task, the velocity effect was also found but in a small amount. The estimated durations in the C task were larger than those for the lowest velocity conditions in the other two tasks. These results were discussed in terms of two hypothetical cognitive processing systems in prospective time estimation.

Adult↗
PubMed1988

[How do we remember when and where?].

The short-term retention of temporal order and that of spatial position were compared using six types of materials. They were three types of letters: (a) Hiragana (phonetically one syllable), (b) Kanji-1 (one syllable), (c) Kanji-2 (two syllables, and three types of non-verbal materials: (d) two-digit numeral, (e) musical note, (f) non-sense figure. Eight stimuli of each type were presented visually to 40 female subjects. It was shown that the performance changed with the types of materials in both retention tasks and that for some materials the retention of temporal order was better than that of spatial position, and for others, vice versa. In the temporal tasks, Hiragana attained the highest score, Kanji-1 the second and Kanji-2 the third. In contrast, the scores were reversed in the spatial tasks. The results suggested that the number of syllables was one of the important factors in temporal memory, though not necessarily in spatial one. The effect of other more subtle factors on retention such as visual tracking of temporal order and imprinting of visual image on the position of presentation was discussed.

Female↗
PubMed1975

Female work capacity during the menstrual cycle: physiological and psychological reactions.

Changes in physical and mental work capacity during the menstrual cycle were studied in 12 healthy woemen with severe menstrual distress. Physiological and psychological tests were performed before, during, and after menstruation. Heart rate, pulmonary ventilation, oxygen uptake, blood lactate concentration, and perceived exertion were measured during work on a bicycle ergometer ar two submaximal work loads corresponding to 40 and 70 %, respectively, of individual maximal oxygen uptake. Mental work capacity was studied with the aid of performance tests of psychological functions such as attention, short-term memory, perceptual speed, perception of time, and reaction time. No change in heart rate or oxygen uptake could be observed over the three phases of the menstrual cycle. However, pulmonary ventilation during work varied significantly. It was highest in the menstrual phase. At the same heart rate exercise on the bicycle ergometer was perceived as more exerting in the menstrual phase than in either the premenstrual or postmenstrual phase. Among the performance tests significant results were obtained only in a test of reaction time, which was slightly impaired during the menstrual phase. The results of the performance tests do not however support the assumption that menstruation affects a woman's mental work capacity.

Adult↗
PubMed1999

[Specific disorders in the language development: neurobiological basis].

Studies of twins, familial aggregates and particular phenotypic conditions have shown an inherited basis for some dysphasias or specific developmental language impairments (SLI). This predisposition is usually multifactorial but the analysis of some families allows to postulate an autosomal dominant transmission of deficits in specific modular aspects of linguistic competences. Moreover, neuroimaging studies have shown modifications of normal volumetric interhemispheric asymmetries, and in group of SLI with receptive prominent disorder coexist epileptiform activity in wakefulness and non-REM sleep EEG; in some of these cases, antiepileptic drugs, specially steroids, can significantly ameliorate the language processing. As many patients with SLI have a difficulty for discrimination of subtle temporal indices, a hypothesis can also be made of a dysfunction in various subcortical structures (thalamus, basal ganglia, cerebellum) modulating the cerebral cortex in phonological processing.

Aphasia↗
PubMedDate not supplied

Spatial and temporal organization of episodic and semantic processes revealed by event-related potentials to unfamiliar faces.

This study investigated whether the semantic and episodic processes underlying the old/new effect can be dissociated by analyzing the spatial and temporal characteristics of event-related potentials (ERPs) evoked by unfamiliar face stimuli during direct and indirect memory tests. The ERP old/new effects obtained included three components. First, the classical posterior component, present in both tasks, which was thus interpreted as reflecting changes in the automatic activation of semantic representation. Second, an earlier frontal component, present in the direct test only, which was seen a consequence of the building of a contextual representation of presented items formed of a conjunction of elements stored in semantic memory. Third, a late right-temporal component, in the direct test, which was related to the integration of this conjunction into a unitized representation of the presented stimuli.

Adult↗