Timing processes: an outline of behavioural and neural indices not systematically considered in timing models.

This paper deals with two questions: what are the main characteristics of timing performance, and how do current timing models account for them? An outline of the most significant behavioural and neural indices of time processing is presented, with particular emphasis on the effects of activation and attention, and on data drawn from an important electrophysiological indice, the Contingent Negative Variation (CNV). A sample of influent timing models is then considered, ranged in two categories depending on whether they provide a representation of the time elapsing online between the limits of a target interval or a representation of the interval limits. The authors support the concept of online "pulse accumulation" as various types of cumulative mechanisms have been described at both neural and behavioural levels.

Contrasting effects of interference and of breaks in interval timing.

When a break is introduced during an interval to be timed, the interval is perceived shorter as break location is delayed. This is interpreted as a result of attention sharing between timing and monitoring the source of the break signal. Similar effects and interpretations are found in another context involving interfering tasks.

Overproduction timing errors in expert dancers.

The authors investigated how expert dancers achieve accurate timing under various conditions. They designed the conditions to interfere with the dancers' attention to time and to test the explanation of the interference effect provided in the attentional model of time processing. Participants were 17 expert contemporary dancers who performed a freely chosen duration while walking and executing a bilateral cyclic arm movement over a given distance.

The supplementary motor area in motor and perceptual time processing: fMRI studies.

The neural bases of timing mechanisms in the second-to-minute range are currently investigated using multidisciplinary approaches. This paper documents the involvement of the supplementary motor area (SMA) in the encoding of target durations by reporting convergent fMRI data from motor and perceptual timing tasks. Event-related fMRI was used in two temporal procedures, involving (1) the production of an accurate interval as compared to an accurate force, and (2) a dual-task of time and colour discrimination with parametric manipulation of the level of attention attributed to each parameter.

Timing functions of the supplementary motor area: an event-related fMRI study.

Two previous studies in which we recorded slow brain potential shifts over the scalp revealed performance-dependent effects that sustained one prominent model of timing mechanisms. These effects seemed to be derived from the supplementary motor area (SMA). Event-related functional magnetic resonance imagery (fMRI) was used to check this hypothesis.

Functional anatomy of the attentional modulation of time estimation.

Attention modulates our subjective perception of time. The less we attend to an event's duration, the shorter it seems to last. Attention to time or color stimulus attributes was modulated parametrically in an event-related functional magnetic resonance imaging study.

The CNV peak: an index of decision making and temporal memory.

A slow brain potential change, the contingent negative variation (CNV), was recorded in a temporal generalization schedule. The task was to judge the duration of a signal (1.250 to 3.

Expectancy, controlled attention and automatic attention in prospective temporal judgments.

Two experiments indicate that prospective judgments of a temporal target are influenced by nontarget temporal features. The basic task was to reproduce a target interval marked by visual events. In addition, visual or auditory interfering events were delivered.

Time processing reflected by EEG surface Laplacians.

We previously described significant relationships between amplitude variations in slow brain potentials and timed between-press intervals (2.5 s). We suggested that these variations are neural traces of timing mechanisms.