Influence of the interstimulus interval on temporal processing and learning: testing the state-dependent network model

Abstract

The ability to determine the interval and duration of sensory events is fundamental to most forms of sensory processing, including speech and music perception. Recent experimental data support the notion that different mechanisms underlie temporal processing in the subsecond and suprasecond range. Here, we examine the predictions of one class of subsecond timing models: state-dependent networks. We establish that the interval between the comparison and the test interval, interstimulus interval (ISI ), in a two-interval forced-choice discrimination task, alters the accuracy of interval discrimination but not the point of subjective equality-i.e. while timing was impaired, subjective time contraction or expansion was not observed. We also examined whether the deficit in temporal processing produced by short ISIs can be reduced by learning, and determined the generalization patterns. These results show that training subjects on a task using a short or long ISI produces dramatically different generalization patterns, suggesting different forms of perceptual learning are being engaged. Together, our results are consistent with the notion that timing in the range of hundreds of milliseconds is local as opposed to centralized, and that rapid stimulus presentation rates impair temporal discrimination. This interference is, however, decreased if the stimuli are presented to different sensory channels.

Reminder and 2AFC tasks provide similar estimates of the difference limen: A reanalysis of data from Lapid, Ulrich, and Rammsayer (2008) and a discussion of Ulrich and Vorberg (2009)

“…It has indeed been shown that, with comparison and standard stimuli identical in all other respects, tooshort intertrial intervals (ITIs) or interstimulus intervals (ISIs) produce a shift of the PSE away from the POE that is eliminated only when ITI and ISI have appropriate durations (Alcalá-Quintana & García-Pérez, 2009). This effect appears to be caused by a temporary sensory impairment reflecting that the processing network has not had time to reset back to baseline conditions during the ISI or the ITI (Buonomano et al, 2009). It should also be noted that the problem cannot be eliminated with ITIs and ISIs that are too long, because memory issues may come into play to produce the same net effect (Wickelgren, 1969).…”

“…This outcome is a natural consequence of the well-known fact that, when data are not unreasonably scarce, the true parameters can always be accurately recovered when the generating and fitted models match-that is, when the target function whose parameters are estimated coincides with the function that actually generated the data. The reason that It should be noted that the DL for stimulus duration has been documented to be in the 5%-10% range for standard durations in the 150-1,500 msec range, whether in the visual, auditory, or tactile sensory modalities, and whether observers are trained or untrained (Westheimer, 1999; see also Buonomano, Bramen, & Khodadadifar, 2009). Thus, for the 500-msec standard duration in the experiments of Lapid et al, DLs would be expected to be in the 25-to 50-msec range.…”

Can ‘Theory of Everything’ Be Global Theory of Consciousness? Ontology and Psychodynamics of I-observer.

“…Another equivalent description of the stream in temporal presentation is a chain of IWorld states, ( ) = { (0), (0 + ), … } Where (0) is the initial I-World state, and is some minimal interval between two states. To date the lower boundary of temporal discrimination is detected experimentally within ~ 100 − 750 (Buonomano 2009). In other words, while the mental states ( ) are assumed to be instant, the mental acts take just the interval to prepare these states.…”

Self, Time, and Reality in Quantum Stream of Consciousness

“…To date, neurophysiology estimates a minimal interval between two immediate acts about 100 -750 ms (Buonomano et al, 2009).…”

“…Although, 'the ability to determine the interval and duration of sensory events is fundamental to most forms of sensory processing, including speech and music perception' (Buonomano et al 2009), in introspecting on time, P can find none other than a new mental act but not a quantum itself. Its short-term memory holds only the order of the events (mental acts) in a small interval Δt but not time between them.…”