PubMed Health⌕ Search

Biomedical subjects

B J Anthony

Publications and source records attributed to B J Anthony.

6 recordsLinked to original sources
PubMed1991

Analysis of the elements of attention: a neuropsychological approach.

A model for conceptualizing the components or elements of attention is presented. The model substitutes for the diffuse and global concept of "attention" a group of four processes and links them to a putative system of cerebral structures. Data in support of the model are presented; they are derived from neuropsychological test scores obtained from two samples, the first consisting of 203 adult neuropsychiatric patients and normal control subjects, and the second, an epidemiologically-based sample of 435 elementary school children. Principal components analyses of test scores from these two populations yielded similar results: a set of independent elements of attention that are assayed by different tests. This work presents a heuristic for clinical research in which the measurement of attention is essential.

Adult↗
PubMed1989

Prestimulation effects on blink and cardiac reflexes of 15-month human infants.

Reduction of reflex startle by brief changes in prestimulation is a robust phenomenon in adults of several species. Although the phenomenon does not require structures above midbrain, it has a long and uneven developmental course. This study of human infants assessed prestimulus effects at 15 months, within a period which has failed, in past work, to show the usual inhibitory modulation. Magnitude and onset latency of the startle blink and concurrent changes in heart rate were measured under four conditions: 2 single-stimulus conditions, 25-msec, 84-dB, 1000-Hz tone or 50-msec, 109-dB white noise; 2 paired-stimulus conditions, noise bursts preceded by tone at lead times of 125 msec or 225 msec. Compared to noise-alone, paired conditions elicited insignificant increases in blink size, significant shortening of blink onset latency, and significant attenuation of heart rate responses. The findings add to growing evidence of a dissociation between modulating effects on blink magnitude and latency and of a dissociation between modulating effects on somatic and autonomic reflexes.

Arousal↗
PubMed1987

Stimulus duration as an age-dependent factor in reflex blinking.

Alternative hypotheses of differential development of auditory and visual systems versus temporal-processing systems were tested to explain prior adult-infant differences in reflex blink latency. The present study removed a confound between stimulus modality and duration, present in prior work, and determined whether age interacted with modality or with duration when they were varied orthogonally. Reflexes were elicited from human adults and infants under 4 stimulus conditions: flash and click, delivered singly and in trains. Age interacted only with duration to affect latency and elicitation probability, reflex characteristics which depend on adequate triggering by a transient change at onset. In contrast, age did not interact with duration to affect peak amplitude which presumably depends on temporal integration. Findings are compatible with the hypothesis that processes or structures, specialized for differentiation of transient stimulus change, mature at a different rate than those specialized for integration of stimulus energy over time.

Acoustic Stimulation↗
PubMed1985

Blink reflex modification by selective attention: evidence for the modulation of 'automatic' processing.

Probe stimuli which elicit activity reflexly provide a means of assessing 'top-down' effects of attentional manipulations while minimizing the perhaps insolvable problem of determining whether effects are due to post-perceptual selection or to changes in the input pathway. Parallel experiments on adults and infants presented acoustic and visual probes unpredictably while subjects attended to acoustic and visual foregrounds: Attention was indexed by heart rate deceleration. When probe and foreground modality matched, probe-elicited reflex blinks were significantly facilitated in magnitude (infants) or latency (adults) relative to reflexes elicited when probe and foreground modality mismatched. Further, facilitation was greater when modality-matching probes were presented over foregrounds judged a priori to be more 'interesting' than 'dull' foregrounds. Because acoustic and visual blink reflexes have a common efferent path, modulating effects must have occurred earlier, in modality-specific paths. As such, the results suggest that attention can influence 'automatic' sensory-perceptual analysis.

Adolescent↗
PubMed1983

Evidence for sensory-selective set in young infants.

The existence of low-level filtering of sensory input is a point of debate among cognitive theorists. This present study suggests that filtering by modality exists at levels low enough to modulate the brainstem blink reflex and that it is evident as early as the 16th week of life. During foreground listening or looking conditions, blinks elicited by acoustic or visual probes were larger when probe and foreground modality matched than when they mismatched. "Interesting" foregrounds, by comparison with "dull" ones, intensified the modality-selective effect.

Attention↗