Biomedical subjects

L A Buck

Publications and source records attributed to L A Buck.

8 recordsLinked to original sources

PubMed1998

Sustained visual-spatial attention produces costs and benefits in response time and evoked neural activity.

This study investigated the simple reaction time (RT) and event-related potential (ERP) correlates of biasing attention towards a location in the visual field. RTs and ERPs were recorded to stimuli flashed randomly and with equal probability to the left and right visual hemifields in the three blocked, covert attention conditions: (i) attention divided equally to left and right hemifield locations; (ii) attention biased towards the left location; or (iii) attention biased towards the right location. Attention was biased towards left or right by instructions to the subjects, and responses were required to all stimuli. Relative to the divided attention condition, RTs were significantly faster for targets occurring where more attention was allocated (benefits), and slower to targets where less attention was allocated (costs). The early P1 (100-140 msec) component over the lateral occipital scalp regions showed attentional benefits. There were no amplitude modulations of the occipital N1 (125-180 msec) component with attention. Between 200 and 500 msec latency, a late positive deflection (LPD) showed both attentional costs and benefits. The behavioral findings show that when sufficiently induced to bias attention, human observers demonstrate RT benefits as well as costs. The corresponding P1 benefits suggest that the RT benefits of spatial attention may arise as the result of modulations of visual information processing in the extrastriate visual cortex.

Adolescent↗

PubMed1996

Early progressive mobilization of patients with left ventricular assist devices is safe and optimizes recovery before heart transplantation.

BACKGROUND: As early perioperative survival with left ventricular assist device support improves, additional emphasis must be placed on patient rehabilitation. Especially as mean left ventricular assist device support times exceed 100 days, it is essential for health professionals to mobilize patients to prevent the incidence of the deleterious effects of bedrest. The timing of optimal functional performance and the safety of rehabilitation has not been described. METHODS: We retrospectively studied patients surviving left ventricular assist device implantation (34 of 41 patients; 27 men, 7 women; age 51 +/- 11 years). Physical therapy consisted of progressive mobilization leading to treadmill exercise or cycling. All patients exercised in the "pump on full" mode with flows >or= 3.0 L/min. RESULTS: Twenty of thirty-four patients initiated ambulation at 7 to 10 days with independent ambulation by 14 days in 55% of the group. Treadmill exercise was tolerated by 82% of the patients, begun at postoperative day 21 by eighteen patients. The greatest improvement in exercise performance was seen by 6 to 8 weeks (20 to 30 minutes at 3.17 +/- 0.79 metabolic equivalents). Maximal functional capacity achieved was influenced by medical complications. A total of 1878 treatment sessions lasting 1390 hours was performed. Only four minor incidents occurred representing 2.9 incidents/1000 patient hours; all involved a transient decrease in pump flow. None of these events resulted in an increase in morbidity or mortality. CONCLUSIONS: Progressive mobilization in patients with left ventricular assist device is safe. Patients return to independence in activities of daily living and tolerate prolonged workloads of up to 5 metabolic equivalents. There is rapid improvement in functional capacity until 6 weeks after operation. Delay in transplantation until this time may optimize postoperative recovery.

Activities of Daily Living↗

PubMed1977

Creative potential in schizophrenia.

The purpose of this paper is to demonstrate the presence of creative potential in a group of hospitalized persons who have been categorized as schizophrenic. Previous work (Buck and Kramer, 1973, 1974) has made it obvious that considerable poetic skill exists in this group of people. While creative potential was apparent in large numbers of those we have worked with, it is unnecessary to claim that our present data represent all (or even a majority) of the hospital population. However, we are concerned with providing a more balanced perspective on the ego strength and creativity which are retained in people who are labeled schizophrenic-even those considered to be regressed. In the following selections, we will attempt to demonstrate, first, an openness to fantasy and an access to primary-process thought which is molded by sufficient technical skill to warrant being labeled poetry, and second, an active, reconstructive capacity which includes a clear intention of communicating with an audience. The technical skill and the reconstructive capacity are critical in substantiating the retention of ego strength necessary for the mobilization of secondary-process cognition. We are interested, therefore, in exploring poetry written with clarity, intelligibility, and cohesiveness, where the visual can be translated into the verbal, where the effort is directed toward communication rather than sorcery, and where sponteneity replacesstereotypy. In the case of originality of style-that is, artistic license-these distinctions may not always be clear; but where questions arise, the artist's ability to justify his own intentions becomes critical.

Cognition↗

PubMed1976