Timing, sequencing, and executive control in repetitive movement production

The authors demonstrate that the timing and sequencing of target durations require low-level timing and executive control. Sixteen young (M-sub(age) = 19 years) and 16 older (M-sub(age) = 70 years) adults participated in 2 experiments. In Experiment 1, individual mean-variance functions for low-level timing (isochronous tapping) and the sequencing of multiple targets (rhythm production) revealed (a) a dissociation of low-level timing and sequencing in both age groups, (b) negligible age differences for low-level timing, and (c) large age differences for sequencing. Experiment 2 supported the distinction between low-level timing and executive functions: Selection against a dominant rhythm and switching between rhythms impaired performances in both age groups and induced pronounced perseveration of the dominant pattern in older adults.     

Iatrogenic damage to the nervous system]

A survey is given of the most important findings in respect of iatrogenic damage to the nervous system on the basis of published reports and the author's own findings, taking special account of lumbar puncture and suboccipital puncture, myelography, contrast-medium encephalography, ventriculography and cerebral angiography. The possibility of damage such as the danger of embolism in diagnostic and therapeutic vascular puncture is referred to. Among the lesions caused in the course of therapy, the side-effects of treatment with drugs, effects of radiation, effects resulting from anesthesia, sequelae of neural therapy and of manual manipulations, sequelae of operations, and postvaccinal encephalopathies are discussed. The necessity of systematic morphological examinations for exact assessment of ioatrogenic lesions is stressed. Iatrogenic damage due to neglect of diagnostic and therapeutic measures is also considered.     

Independent feature processing in the visual system

Summary A recognition experiment with a set of simple visual patterns was performed. The patterns were composed of three binary features: Lines, angles and curve segments. The pattern sets differed with respect to the distance between components and the symmetry of the arrangement. The empirical confusion matrices were analysed assuming two different models: A model assuming independent feature analysis and a model that assumes that one of the features is analysed independently of the other two. The main result was that quite a large distance between features was necessary to achieve independent processing of the features. Moreover, in the asymmetric pattern set the predictions of the independence model were better than in the symmetric pattern set.     

Stimulus information and processing time in pitch perception

Summary The assumption of Massaro, that the preperceptual auditory image is processed at the same rate as the stimulus information, was tested for pitch recognition, using a recognition masking paradigm. The data clearly show that the preperceptual image is processed with a much lower rate.