Stability of visceral behavior in the awake rat during rest.

Brady and colleagues have championed the importance of careful delineation and control of a subject's behavioral state. In this paper we develop the concept of visceral behavior from a physiological perspective. Sprague-Dawley rats were instrumented to record arterial blood pressure, renal sympathetic nerve activity, and respiration. The rats were restrained in a conical cloth sock. Rats that were well adapted to the sock restraint showed a regular respiratory pattern and consistent pressure recordings; they rested quietly in the sock and moved only occasionally to adjust their position. Fourier analysis of blood pressure and nerve activity showed a concentration of power below 1 Hz. The coherence between the two signals was strong (0.83 +/- 0.03) at 0.42 Hz. Conversely, during their initial adjustment to the sock restraint, the rats tended to show large fluctuations in blood pressure associated with episodic apneic breathing; 1 animal displayed this pattern of visceral behavior throughout most of the experiment. Despite this instability in pressure, the rats' overt behavior was stable: They rested quietly in the sock with only occasional position shifts. Spectral analysis and coherence computations showed large shifts in the distribution of power and frequency range over which arterial pressure and sympathetic activity were tightly coupled. These data are consistent with the view that an animal's circulatory adjustments, as well as adjustments in other aspects of its physiological state, constitute an important aspect of behavior, and that this behavior can influence the interpretation of biobehavioral data.     

Where Have All the Children Gone? Movement from Child to Adult Mental Health Systems

The mental health histories of the 448 children 15 and 16 years of age who were admitted to state-operated children's psychiatric inpatient services in New York during 1982 were reviewed for the 11 year period through April 1993, Thirty-three percent were served as adults (after age 18) in the state-operated adult civil mental health system; 42% of these individuals were still receiving services at the end of the period. 113 of the 146 individuals served as adults were served only in the civil system. Thirteen percent of the cohort received some of their mental health services as adults in the state-operated adult forensic mental health system due to criminal law involvement. This includes nine percent who received mental health services while they were inmates in state prisons. Twenty four of the 57 forensic clients received services as adults only in the forensic system. Diagnostic, demographic, and service history characteristics of the groups were compared to foster an early understanding of policy and programmatic issues related to movement from the child mental health system to the adult system. Baseline (1982) information was used to identify predictors of later service utilization.     

Baroreflex responses to the stress of severe hemorrhage in the rat.

In two groups of anesthetized (sodium pentobarbital), mature Sprague-Dawley rats, 1) aged 2 years and weighing 300-400 grams, 2) aged 6 months weighing 200-300 grams, baroreflex-induced circulatory responses to pressor (graded doses phenylephrine) and depressor (graded doses nitroglycerine) agents were compared to those occurring during progressive hemorrhage in the same animals. Graded withdrawals of blood from the femoral artery elicited progressive hypotension accompanied by bradycardia rather than expected tachycardia. Graded doses of phenylephrine (2.5 ug to 40 ug bolus, via femoral vein) regularly induced elevations in arterial blood pressure with associated reflex bradycardia. Similarly graded doses of nitroglycerine induced a marked decline in arterial blood pressure, without expected tachycardia. As hypotension became more severe (during hemorrhage), atrioventricular conduction slowed and A-V block developed, resulting in statistically greater slowing in ventricular than in atrial excitation and contractile cycles. Heart failure during hemorrhage in the rat is characterized sequentially by severe bradycardia, depressed atrial contractile force, impaired conduction and A-V block, terminating in ventricular, atrial, and finally, in pacemaker failure. Baroreceptor reflexes were blunted or even absent in both young and old animals during induced hypotension.     

Filling gaps: Decision principles and structure in sentence comprehension

The correct grammatical characterization of sentences containing filler-gap dependencies is a topic of considerable theoretical interest in linguistics. In some grammatical frameworks, these dependencies are representef in terms of conditions on the permissible indexing of structures (or alternative structure evaluation conditions) which a representation must adhere to in order to be well-formed. In other frameworks, constraints on permissible filler-gap dependencies are simply inherent in the set of phrase structure rules contained in the grammar of a language.The processing of sentences with multiple (potential) filler-gap dependencies was investigated in two experiments. The first experiment provided evidence for three claims. First, the human sentence processor abides by a strategy of assigning the most recent potential filler to a gap. Hence, ‘recent filler’ sentences where this assignment proves to be correct takes less time to comprehend than ‘distant filler’ sentences where this decision turns out to be incorrect. Second, the recent filler strategy is itself just a special case of a more general strategy of assigning the most salient potential filler to a gap. Third, unambiguous sentences in which a filler-gap assignment is disambiguated by ‘control’ information specified by individual verbs gives rise to the same recent filler errors as ambiguous sentences. This suggests that tentative filler-gap assignments are made by the processor before all of the relevant constraints on permissible filler-gap dependencies are consulted by the processor.The second experiment tested an alternative hypothesis that the more complex ‘distant filler’ sentences took longer to comprehend in the first experiment only because these sentences often contained verbs which license two adjacent gaps. The experiment showed that there was a significant recent filler effect in sentences that did not contain adjacent gaps and that this effect did not interact with verb class.The finding that the processor delays use of verb-control information is extremely surprising. It may be explained by the fact that this information is only relevant to one type of gap (‘equi-gaps’) and what type of gap the processor is dealing with often can not be determined unambiguously at the time when it initially encounters a gap in its left-to-right processing of a sentence.If our interpretation of these findings is correct, they argue for a considerable amount of structure in the sentence comprehension system. Further, they favor a view of sentence processing in which processing operations involving constraints on the permissible indexing (or evaluation) of structures lag behind the processor's structure building operations. Hence, the results favor those grammatical theories which preserve this distinction over grammatical theories which provide a uniform characterization of all syntactic well-formedness conditions.     

Do developmental changes in digit span result from acquisition strategies?

This study tested the theoretical proposition that the developmental increase in memory span results from a corresponding increase in the use of grouping strategies. With slow presentation, experimenter-provided grouping eliminated the span differences between sixth graders and adults but, while grouping helped first graders more than adults, a sizable difference in digit span remained. With fast presentation, grouping increased the adults' performance more than the childrens'. Another finding was that both groups of children had greater digit spans with fast presentation than with slow. For adults, the reverse was true.     

The dimensions of tonal experience: A nonmetric multidimensional scaling approach

Subjects were required in each trial to directly compare two pairs of tones and indicate which pair of tones had the greater subjective difference or dissimilarity. Eleven tones differing in both intensity and frequency were employed. Subjects made binary comparisons among the 55 tone pairs which can be formed from the set of 11 tones. These paired comparisons of tonal intervals were used to determine a two-dimensional Euclidean representation for tonal experience. Loudness and pitch appeared as orthogonal dimensions in this representation. However, a 45-deg rotation of loudness and pitch axes produced axes which could be identified as volume and density. This relationship suggested that volume and density were simple functions of pitch and loudness. Volume and density predictions based on this two-dimensional representation were shown to provide a good account of the data from three experiments on volume and density.     

Outcome in short-term group psychotherapy

This study examines the effectiveness of planned dynamic short-term group psychotherapy in a health maintenance organization setting. The groups, conducted by experienced short-term psychodynamically trained therapists, focused on common life-stage issues. A pretest/posttest design was employed; group participants completed a battery of self-report measures before, after, and 4–6 months after treatment. Group participants made statistically (and clinically) significant positive changes on the majority of change measures. They saw themselves as improved on target problems, became far less symptomatic, and reported considerable growth in interpersonal functioning.     

The effect of memory load on negative priming: An individual differences investigation

The effect of a verbal (Experiment 1) and a nonverbal (Experiment 2) memory load on negative priming was investigated by employing a concurrent memory task with a letter naming task. Across both experiments, negative priming was reliable only under conditions of zero memory load, suggesting that the processes that contribute to negative priming are resource demanding and dependent on a domain-free resource pool. Individual differences in negative priming were observed, such that high working memory capacity subjects showed reliable negative priming whereas low working memory capacity subjects did not. The results suggest that the negative priming effect results from allocation of controlled attention and that individual differences in working memory capacity correspond to the ability to efficiently handle irrelevant information.     

Attitudes of African Americans Toward Participation in Medical Research

The underrepresentation of African Americans in medical research is problematic for several reasons, including disparities in health outcomes, differences in metabolism of pharmacological agents, and accurate assessment of health needs and costs. This paper investigates factors contributing to African Americans' lower likelihood of consenting to participation in medical research. In Study 1, three focus groups were conducted to assess concerns about research participation and to generate further hypotheses for questionnaire development. Study 2 presented a hypothetical clinical trial and collected questionnaire data on attitudes about participation. Both studies revealed a greater likelihood to mistrust the medical establishment among African American students. However, suspicion did not contribute to a decreased likelihood of participation. Several recommendations are offered regarding the recruitment of African Americans in research.