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Biomedical subjects

M McCloskey

Publications and source records attributed to M McCloskey.

At least 19 recordsLinked to original sources
PubMed2000

Attention-referenced visual representations: evidence from impaired visual localization.

Spatial representations in the visual system were probed in 4 experiments involving A. H., a woman with a developmental deficit in localizing visual stimuli. Previous research (M. McCloskey et al., 1995) has shown that A. H.'s localization errors take the form of reflections across a central vertical or horizontal axis (e.g., a stimulus 30 degrees to her left localized to a position 30 degrees to her right). The present experiments demonstrate that A. H.'s errors vary systematically as a function of where her attention is focused, independent of how her eyes, head, or body are oriented, or what potential reference points are present in the visual field. These results suggest that the normal visual system constructs attention-referenced spatial representations, in which the focus of attention defines the origin of a spatial coordinate system. A more general implication is that some of the brain's spatial representations take the form of coordinate systems.

Adult↗
PubMed2000

The industry manipulation attitudes of smokers and nonsmokers.

A cross-sectional random sample was obtained of Florida youth between the ages of 12-17. Data were collected through a telephone survey after obtaining parent and child consent. Industry manipulation attitudes of three groups (self-identified nonsmokers who did not use cigarettes in the past 30 days, self-identified nonsmokers who used cigarettes in the past 30 days, and self-identified smokers who used cigarettes in the past 30 days) were compared. Constraints resulting from the method of data collection resulted in a conservative estimate of the strength of the association between industry manipulation attitudes and smoking behavior.

Adolescent↗
PubMed2000

Clinical features associated with a delayed diagnosis of cystic fibrosis.

BACKGROUND: The majority of patients with cystic fibrosis (CF) are diagnosed in the first decade of life. In a small number of patients, the diagnosis is not made until later. OBJECTIVE: In this study, the clinical and genetic features of patients diagnosed after the age of 10 were examined. METHODS: All living patients in Northern Ireland diagnosed prior to 1983, when neonatal screening was introduced, were studied. A total of 103 patients were identified of whom 18 were diagnosed after the age of 10. The relationships between late diagnosis and clinical presentation, sputum microbiology, pancreatic sufficiency, nutritional status, genotype and distance from the regional CF centres was determined by multiple regression analysis. RESULTS: All 18 late-diagnosed patients had a sweat (chloride >70 mmol/l). Late diagnosis was significantly related to carriage of the R117H mutation (r(2) = 0.45) and pancreatic sufficiency (r(2) = 0.37). There was a weak relationship with pulmonary function (r(2) = 0.09). CONCLUSIONS: In Northern Ireland, late diagnosis in mainly associated with pancreatic function and carriage of the R117H mutation.

Adolescent↗
PubMed1999

Sedation guidance.

Explore the source record for details and available documents.

Anesthesia, Dental↗
PubMed1996

CT of pancreatic gas gangrene.

A case of gas gangrene complicating acute pancreatitis is presented. The presence of gas within the pancreatic bed is very suggestive of infection with gas forming organisms in the right clinical setting.

Acute Disease↗
PubMed1996

Near-field confocal optical spectroscopy (NCOS): subdiffraction optical resolution for biological systems.

Optical resolution is limited by diffraction. However, in near-field microscopes sample illumination is provided through a subwavelength aperture to increase optical resolution. In this study we have evaluated the usefulness of this technique for living biological systems and report two significant improvements in this form of microscopy to enhance optical resolution for biological studies. We report a unique feedback method, photon-density feedback, which is used to monitor the registration of a near-field illumination probe with living cell membranes. In this method, the fluorescence intensity of a uniformly distributed fluorochrome is monitored while the sample is moved in the z-axis towards the probe. Upon contact between the cell membrane and the near-field probe a maximum intensity is detected. A problem with near-field microscopy is that enhanced optical resolution is only achieved within the near-field of the illuminating aperture. Thick biological specimens also fluoresce in the far-field reducing optical resolution. To reduce this problem we incorporated a confocal pinhole together with the near-field probe to enhance the resolution of this form of near-field microscopy. Finally, we demonstrate that near-field confocal optical spectroscopy does not impair physiological properties of neurons, astrocytes or mast cells, indicating that this high-resolution optical methodology will permit a new approach to the study of molecular distribution and action within living specimens.

Aniline Compounds↗
PubMed1995

Representing and using numerical information.

Issues of mental representation are central to cognitive psychology and indeed to psychology in general. This article synthesizes recent theoretical and empirical research concerning cognitive representations in one specific domain, that of numbers. First, several forms of cognitive numerical representation are defined, and the roles the various forms may play in numerical processing are considered. Then, two current representational issues that have generated some controversy are examined: In what form are arithmetic table facts (e.g., 4 x 7 = 28) stored in memory, and what forms of representation are involved in converting numerals from one form to another (as in reading 604 aloud as "six hundred four")? In the course of the discussion the major current theories of numerical cognition are described, with emphasis on how they differ in their assumptions about numerical representations and how these differences are reflected in the positions taken on various specific issues.

Cognition↗
PubMed1992

Cognitive mechanisms in numerical processing: evidence from acquired dyscalculia.

This article discusses cognitive neuropsychological research on acquired dyscalculia (i.e., impaired numerical processing resulting from brain damage), surveying issues of current interest, and illustrating the ways in which analyses of acquired deficits can contribute to an understanding of normal processing. I first review the logic whereby inferences concerning normal cognition are drawn from patterns of impaired performance. I then consider research exploring the general functional architecture of the cognitive numerical processing mechanisms, and finally turn to studies aimed at probing the internal structure and functioning of individual processing components.

Brain Damage, Chronic↗
PubMed1992

The organization of arithmetic facts in memory: evidence from a brain-damaged patient.

We report a single case study of a brain-damaged patient with impaired arithmetic performance. Three principal findings are presented: First, in a task involving production of answers to simple arithmetic problems, the patient's performance was far better for subtraction than for addition or multiplication. Second, in all arithmetic operations performance was generally much better for problems potentially solvable by rule (e.g., 5 + 0) than for problems requiring retrieval of specific facts (e.g., 5 + 3). Third, the dissociation between subtraction and the other arithmetic operations obtained in the production task was not observed in a verification task. The implications of these findings for claims concerning the organization of stored arithmetic facts are discussed.

Aged↗
PubMed1991

Facts, rules, and procedures in normal calculation: evidence from multiple single-patient studies of impaired arithmetic fact retrieval.

This article presents results from multiple single-case studies of brain-damaged patients with impairments in retrieval of arithmetic facts (i.e., "table" facts such as 8 x 7 = 56). The results provide a basis for exploring the types of knowledge implicated in simple arithmetic performance, the internal representations for the various knowledge types, the processes operating upon these representations, and the ways in which the representations or processes may be disrupted by brain damage.

Adult↗
PubMed1991

Theory-based assessment of acquired dyscalculia.

This article describes a theory-based approach to assessment of acquired dyscalculia. A model of the normal cognitive number-processing/calculation system is presented, and methods are discussed for characterizing number-processing/calculation deficits in terms of functional damage to the mechanisms specified in the model.

Adult↗
PubMed1991

Cognitive representations and processes in arithmetic: inferences from the performance of brain-damaged subjects.

In this article, we present data from two brain-damaged patients with calculation impairments in support of claims about the cognitive mechanisms underlying simple arithmetic performance. We first present a model of the functional architecture of the cognitive calculation system based on previous research. We then elaborate this architecture through detailed examination of the patterns of spared and impaired performance of the two patients. From the patients' performance we make the following theoretical claims: that some arithmetic facts are stored in the form of individual fact representations (e.g., 9 x 4 = 36), whereas other facts are stored in the form of a general rule (e.g., 0 x N = 0); that arithmetic fact retrieval is mediated by abstract internal representations that are independent of the form in which problems are presented or responses are given; that arithmetic facts and calculation procedures are functionally independent; and that calculation algorithms may include special-case procedures that function to increase the speed or efficiency of problem solving. We conclude with a discussion of several more general issues relevant to the reported research.

Brain Damage, Chronic↗
PubMed1991

Models of arithmetic fact retrieval: an evaluation in light of findings from normal and brain-damaged subjects.

Retrieval of basic arithmetic facts is a central aspect of almost any arithmetic performance. Furthermore, the arithmetic facts provide an opportunity to study memory processes in the context of a naturally occurring but circumscribed set of facts. This article examines current models of arithmetic fact retrieval in light of previously reported data from normal subjects, as well as the results from brain-damaged patients reported by Sokol, McCloskey, Cohen, and Aliminosa (1991) in the preceding article. The discussion serves to delineate the strengths and limitations of the models and, more generally, to identify important theoretical and empirical issues in the study of arithmetic fact retrieval.

Brain Damage, Chronic↗