Images in neuroscience. Cognition. Memory, 1: episodic memory retrieval.
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Biomedical subjects
Publications and source records attributed to D Barch.
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We describe the development of a new system for categorizing thought disorder. In the development phase (Study 1), we examined the degree to which speech samples and definitions of thought disorder subtypes taken from: (1) the Scale for the Assessment of Thought, Language, and Communication (TLC); (2) the Thought Disorder Index (TDI); and (3) the Assessment of Bizarre-Idiosyncratic Thinking (BIT), reflected disturbances in form versus disturbances in content. Ratings were provided by naive judges, experienced clinicians, and linguistic experts. The results contributed to the development of a new system dividing thought disorder into disturbances in (1) fluency, (2) discourse coherence, (3) content, and (4) social convention. In the validation phase (Study 2), 21 schizophrenic and 19 manic subjects were interviewed, interpreted proverbs, and responded to Rorschach cards. Subjects' speech was rated using the TLC, TDI, and BIT. We also measured hallucinations, delusions, and digit span performance. The results of Study 2 provided evidence supporting the validity of our new categorization system.
We examined whether two negative symptoms, alogia and affective flattening, were more strongly associated with dysfunction of certain brain regions than with others in a sample of 27 schizophrenic subjects. Neuropsychological tests were used to measure the integrity of functioning of different brain regions. Functioning of left and right frontal regions was assessed by word fluency and design fluency, respectively, and functioning of the left temporo-hippocampal region was assessed by Hebb's digit-sequences recall test. Measures of alogia and affective flattening were obtained using the Scale for the Assessment of Negative Symptoms. The results indicated that more severe levels of these negative symptoms were associated with poorer performance on the fluency tests. These relationships were fairly specific as indicated in two ways: (1) only certain neuropsychological measures were associated with negative symptoms; and (2) poor performance on fluency tests was not associated with all psychiatric symptoms. In addition, affective flattening, but not alogia, appeared to be associated with lateralized dysfunction.
We explored the relationships between information processing and language in order to further the understanding of language disturbances in psychiatric patients. To assess the impact of reduced processing capacity on language, 50 undergraduates completed an interview concurrent with a category monitoring task and a control interview without a concurrent task. Syntactic complexity, verbosity, and pause patterns were all disrupted by a reduction in processing capacity. In addition, individual differences in syntactic complexity and information processing were significantly associated, even after accounting for verbal intelligence. We discuss the relevance of the results for understanding language disturbances in psychopathology and hypothesize that a reduction in processing capacity may underlie the decreased syntactic complexity, decreased verbal output, and increased pause length found in schizophrenia.
Hepatic cellular retinol-binding protein (cRBP) levels were measured from the livers of four groups of Sprague-Dawley rats after three weeks of dietary treatment. The experimental group (n = 8) received a zinc-deficient (2.3 mg/kg dry powder) liquid diet ad libitum. A pair-fed control group (n = 8) received the same amount of liquid diet with supplemental zinc (60 mg/kg dry powder). Another control group (n = 8) received liquid diet ad libitum with supplemental zinc (60 mg/kg powder). A third control group (n = 7) received a pellet diet which also contained the same amount of zinc as the other control groups (60 mg/kg). Hepatic cRBP was reduced by more than 50% in the experimental group as compared to each of three control groups. It appears that zinc may be an essential element for the intra-cellular transport of vitamin A, in addition to its well-established role in the intercellular transport of vitamin A.
A versatile, qualitative, agarose gel immunoprecipitation (IP) test for the detection of fecal occult hemoglobin (Hb) was developed to provide a more accurate method for the detection of occult blood in stool. This test allowed detection of 0.2 mg human hemoglobin/g of stool after a 2-h incubation. In addition, a specimen application device which can accommodate a variety of specimens was developed for this test. A study of 252 clinical stool specimens revealed a close correlation in the results obtained at three separate laboratories. The IP test identified blood in 11 out of 24 specimens collected from patients with colorectal carcinoma as compared to 4 of 24 specimens positive with a guaiac-based Hemoccult II test. The simplicity of immunoprecipitation coupled with the high sensitivity and specificity of this technique suggests that this new test would be a very useful and effective means with which to screen for occult blood in stool.