Donald J. O'Boyle

Chapter 11 On the human neuropsychology of timing of simple, repetitive movements

Publisher Summary This chapter is concerned almost exclusively with research, which is conducted within the general conceptual framework of cognitive or information-processing psychology. This approach to the study of timing of repetitive movements, which was given quantitative and theoretical impetus by the seminal work of Michon involved, in large part, the use of auto- and cross-covariance functions to capture the sequential structure of statistical dependencies between successive response intervals and between response intervals and other salient events (e.g., extrinsic timing cues). The form of the observed statistical dependencies is seen to provide clues about the nature of the underlying processes, and constitutes a statistical description of the temporal characteristics of performance, which are to be explained by any model within which hypothesized processes are instantiated. The neuropsychological work conducted suggests unequivocally that the normal control of explicit timing of repetitive movements and the explicit temporal representations underlying important aspects of normal temporal perception are dependent upon the functional integrity of the cerebellum and of the basal ganglia.

Effect of click trains on duration estimates by people with Parkinson's disease.

Patients with a diagnosis of Parkinsons disease and age- and IQ-matched controls estimated the duration of short 500-Hz tones (325–1,225 ms), on trials where the tone was either preceded by 3 s of 5-Hz clicks, or presented without clicks. The click manipulation had been shown in earlier studies with student participants to make verbal estimates longer. Patients were tested both on and off their dopaminergic medication, and controls were also tested in two sessions. Verbal estimates were markedly and significantly longer on trials with clicks than on those without clicks for both the patients and the controls, but there were no significant performance differences between patients or controls, nor between the on and off medication sessions in the patients. The study shows that a manipulation of subjective time, which has had small but consistent effects in student participants, also affects timing in patients and adds to a growing body of evidence that timing in patients with Parkinsons disease may in many cases have the same characteristics as those of neurologically intact control groups.

Effects of alcohol, at two times of day, on EEG-derived indices of physiological arousal.

Effects of alcohol consumption (0.8 ml/kg) on sleep propensity, spectral characteristics of the EEG and self-rated activation in 16 young male subjects, were investigated during sessions at each of two times of day (08.00 and 16.00). Within-session, time-related changes in the pattern of stage-1 sleep occurrence, and of spectral power in different EEG bands indicated that, irrespective of time of day, physiological arousal increased as estimated blood alcohol concentration (BAC) was rising, and decreased as BAC was falling. Subjective activation was reduced by alcohol during both phases of the BAC curve. A pattern of reduced stage-1 sleep occurrence, higher absolute high alpha power and higher ratings of activation suggested that, irrespective of alcohol condition, physiological and subjective arousal was higher during sessions starting at 16.00 than during those starting at 08.00. There were no significant interactions between alcohol and time of day in respect of any dependent variable. However, the degree to which effects reflecting circadian variation may have been masked by effects of limited sleep restriction prior to morning sessions remains unclear. Subjects reported having slept on only 23.5% of occasions when sleep was scored. Comparison of patterns of statistically significant changes in absolute and relative power in different bands indicated that the two indices do not provide exactly equivalent information about changes in the EEG.

Effects of alcohol on the sleep-stage structure of a nap in the afternoon

The effects of the ingestion of 0.8 ml/kg alcohol on the sleep-stage structure of nap sleep were compared with those of a non-alcoholic drink in 8 young male subjects napping between 14.00 h and 15.00 h. During nights immediately preceding experimental sessions, time to bed and time in bed (hence, sleep duration) were controlled. While not affecting total nap sleep duration, alcohol significantly increased time in stage 4 sleep, primarily at the expense of time in stage 2.

Characterising perceptual latency: Commentary on Jaśkowski

Publisher Summary This chapter discusses characterizing perceptual latency. The ordering of relative magnitudes of perceptual latencies in A and V modalities derived in this way from the experiments mentioned above (i.e., V > A) is consistent with that derived in SRT studies and in the majority of published studies in the temporal order judgment (TOJ) literature. Given that different component processes involved in tracking are, to varying degree, shared or independent of those involved in SRT and TOJ tasks, use of this third task seems potentially promising in characterizing more rigorously exactly what the concept of perceptual latency entails and in understanding the source of both intra-modal and inter-modal inconsistencies between estimates derived from SRT and TOJ tasks. Second, the so-called “modality dissociation” clearly requires further study. As is made clear in this chapter, most previous studies have involved examination of the effects, on SRT and TOJ, of changes in stimulus-characteristics within a single (visual) modality.