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S Sutton

Publications and source records attributed to S Sutton.

121 records · Page 7Linked to original sources
PubMed1967

Information delivery and the sensory evoked potential.

The waveform of evoked responses recorded from human scalp is not determined solely by the physical eliciting stimulus, but also varies as a function of the effective information provided by the stimulus. There is a positive component whose latency is determined by the point in time at which ambiguity is reduced, and whose shape and amplitude are influenced by whether it is the presence or absence of an external event which delivers the information.

Auditory Perception↗
PubMed1967

Effects of visual form on the evoked response.

The average visual evoked potentials elicited from relaxed human subjects are different for a blank visual field and one containing a geometric form, are different for different geometric forms of equal area, are similar for versions of the same geometric fortn of unequal area, and are different for two printed words equated for total letter area. These findings suggest that the waveform of evoked responses is not determined solely by the set of peripheral receptors which is stimulated, but it also reflects the perceptual content of the stimulus.

Brain↗
PubMed1965

Evoked-potential correlates of stimulus uncertainty.

The average evoked-potential waveforms to sound and light stimuli recorded from scalp in awake human subjects show differences as a function of the subject's degree of uncertainty with respect to the sensory modality of the stimulus to be presented. Differences are also found in the evoked potential as a function of whether or not the sensorymodality of the stimulus was anticipated correctly. The major waveform alteration is in the amplitude of a positive-going component which reaches peak amplitude at about 300 milliseconds.

Electroencephalography↗
PubMedDate not supplied

Activin A, corticotropin-releasing factor and prostaglandin F2 alpha increase immunoreactive oxytocin release from cultured human placental cells.

The aim of the present study was to investigate the presence of the immunoreactive oxytocin in human placental extracts and putative factors regulating the release of immunoreactive oxytocin from cultured human placental cells. Fresh placental tissue was collected from pregnant women at term and dissected of membranes (n = 5). Presence of immunoreactive oxytocin in trophoblast tissue was evaluated by a specific radio-immunoassay after acidic extraction and high-pressure liquid chromatography. In a second set of experiments, primary cultures of placental cells were performed and, 48-72 h after dissociation, the effect of arginine vasopressin, corticotropin-releasing factor, neuropeptide Y, activin A, inhibin A, noradrenaline or prostaglandins on immunoreactive oxytocin level in culture medium was investigated. The presence of immunoreactive oxytocin was shown in the acidic extract of trophoblast at term, and in the culture medium of human placental cells, and it was identical to the native peptide. The addition of corticotropin-releasing factor or arginine vasopressin, but not of neuropeptide Y, increased the release of immunoreactive oxytocin three- to fourfold from placental cells, with a dose-dependent effect (P < 0.01). A significantly increased release of immunoreactive oxytocin was shown in presence of noradrenaline (P < 0.01), which was reversed by prazosin, an antagonist of alpha-adrenergic receptors. Recombinant human activin A (P < 0.01), but not inhibin A, stimulated the release of immunoreactive oxytocin three- to fourfold from placental cells. Prostaglandin F2 alpha was a potent secretagogue of immunoreactive oxytocin, whereas a partial or no effect was observed when prostaglandin E2 or prostaglandin I2 was added. Thus, the present findings showed that human placenta contains immunoreactive oxytocin, and that its release from cultured placental cells is regulated by neurohormones, growth factors or prostaglandins.

Activins↗
PubMedDate not supplied

Elderly nonrespondents to a mail survey: a telephone follow-up.

The most frequently used method to request and collect health-related information has been the mail questionnaire. While self-administered surveys offer a relatively low-cost and convenient method for collecting health data, they have been unpopular among researchers because of concerns about low response rates and nonresponse bias. This study examines differences in demographic and health characteristics between mail survey respondents and nonrespondents who were subsequently interviewed by telephone. Subjects for this study had at least one health care encounter in 1990 from a Medicare-waiver program. The telephone survey was conducted approximately two months after the last wave of a three-wave mailing survey of this urban elderly population. No significant differences were found between telephone and mail respondents for demographic, socioeconomic, quality of life, or perceived oral health characteristics. However, mail respondents were more likely to be dentate and report better perceived general health than were the telephone respondents.

Aged↗