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Biomedical subjects

J M Foley

Publications and source records attributed to J M Foley.

At least 55 records · Page 3Linked to original sources
PubMed1985

Visual grating induction.

If a homogeneous illuminated test field is inserted within a sine-wave grating, an opposite phase grating will be perceived in the test field under a wide range of conditions. A cancellation technique was used to measure the magnitude of grating induction. The manner in which the effect depends on eye movements, inducing frequency, test-field height, inducing-field height, inducing amplitude, test-field luminance, and test-field width was determined in four experiments. Mathematical equations that describe these results are presented. It is shown that linear filters whose spatial weighting functions resemble receptive fields of the most common types of visual cell do not produce outputs with the properties of induced gratings. However, linear filters with highly elongated negative end zones and a small positive center produce opposite phase gratings in the test field, and an array of such filters of different sizes can account for several properties of induced gratings. There are other properties of the effect that are highly nonlinear. A second model, which is nonlinear and based on the properties of hypercomplex cells, is suggested that may encompass both the linear and the nonlinear properties of the effect.

Adaptation, Physiological↗
PubMed1981

Spatial bandwidth of channels for slant estimated from complex gratings.

Vertical sinusoidal gratings of slightly differing spatial frequencies presented to each eye lead to the perception of a slanted plane. If a complex pattern is created by presenting two different frequencies to one eye, while the other eye views an increment of one of those frequencies and a decrement of the other, then the stimulus is equivalent to two superimposed vertical planes slanted in opposite directions. Yet the observer generally sees only a single surface at a slant intermediate to the possible extremes. As the relative spatial-frequency content of the two opposing planes is varied, the observed slant is a measure of the strengths of the connecting interactions of the underlying stereomechanisms. From these data the bandwidth of the monocular input channels for the binocular slant mechanism can be estimated and is found to be about two octaves.

Humans↗
PubMed1980

Contrast masking in human vision.

Contrast masking was studied psychophysically. A two-alternative forced-choice procedure was used to measure contrast thresholds for 2.0 cpd sine-wave gratings in the presence of masking sine-wave gratings. Thresholds were measured for 11 masker contrasts spanning three log units, and seven masker frequencies ranging +/- one octave from the signal frequency. Corresponding measurements were made for gratings with horizontal widths of 0.75 degrees (narrow fields) and 6.0 degrees (wide fields). For high contrast maskers at all frequencies, signal thresholds were related to masking contrast by power functions with exponents near 0.6. For a range of low masking contrasts, signal thresholds were reduced by the masker. For the wide fields, high contrast masking tuning functions peaked at the signal frequency, were slightly asymmetric, and had approximately invariant half-maximum frequencies that lie 3/4 octave below and 1 octave above the signal frequency. The corresponding low contrast tuning functions exhibited peak threshold reduction at the signal frequency, with half-minimum frequencies at roughly +/- 0.25 octaves. For the narrow fields, the masking tuning functions were much broader at both low and high masking contrasts. A masking model is presented that encompasses contrast detection, discrimination, and masking phenomena. Central constructs of the model include a linear spatial frequency filter, a nonlinear transducer, and a process of spatial pooling that acts at low contrasts only.

Adult↗
PubMed1979

Free-play behavior of atypical children: an approach to assessment.

Children's free-play behavior and its relationship to IQ and usefulness in assessing severely disturbed children were investigated. The results indicated that (1) the play of 100 normal children scored for quality and time generally yielded significant positive correlations with Binet and WPPSI IQs; (2) the correlations remained the same when verbalizations were deleted from the play protocols; (3) the play scores for 16 severely disturbed boys significantly differentiated two subgroups differing in degree of pathology, showed significant improvement from the pre- to posttreatment periods, and indicated pretreatment scores were significantly and positively correlated with improvement assessed by observer ratings in a 2-year follow-up. Implications for the use of this measure in assessment and the role of play in development were discussed.

Attention↗
PubMed1979

The effects of duration and luminance on binocular depth mixture.

Two stimuli in the same binocular direction, one in front and the other an equal disparity behind a fixation point, are perceived at one depth. This depth is between that corresponding to the two stimulus disparities and varies continuously from one stimulus to the other as a function of the ratio of their luminances. When either duration or absolute luminance is increased, perceived depth changes toward the midpoint of the two disparities.

Adult↗
PubMed1979

Effect of labeling and teacher behavior on children's attitudes.

Seventy-eight fourth-grade subjects from a rural school containing an integrated special-education program viewed one of two videotapes that depicted a child demonstrating various kinds of academic and social behavior. On one tape, the teacher reacted positively to the child's behavior; on the other, negatively. The subjects were told that the child on the tape was either a "normal," mentally retarded, or learning-disabled fourth grader. The subjects were randomly assigned to one of two teacher conditions (positive or negative) and one of three labeling conditions. After viewing the videotape, the subjects filled out a peer-acceptance questionnaire concerning the child on the videotape. Results indicated that across all labeling conditions the subjects rated the child higher on the questionnaire when the child was reacted to positively by the teacher and, further, that the "mentally retarded" label led to significantly higher peer-acceptance ratings than did the "normal" or "learning-disabled" label.

Attitude↗
PubMed1978

Baclofen for spasticity in multiple sclerosis. Double-blind crossover and three-year study.

Baclofen is a safe and effective means for treating spasticity associated with multiple sclerosis. We found no toxic effects on hepatologic, hematopoietic, or renal function, acutely or for over 3 years of follow-up. A statistically significant reduction was noted in frequency of spasms, and clonus, and there was improved range of joint movement, which enabled patients to maintain functional status for prolonged periods. For the more disabled patients, treatment with baclofen gave symptomatic relief of painful spasms and made immobility more tolerable. Optimum effect was achieved when baclofen was administered in the early stages of disease, before major disabilities became permanent.

Activities of Daily Living↗
PubMed1977

Further factor-analytic investigation of the Thorne femininity study.

The responses of 512 undergraduate women to 198 items of the Thorne Femininity Study were factor analyzed in order to isolate the dimensions of femininity represented among the items of this instrument. The procedure used isolated 11 orthogonal factors that accounted for 21.1% of the total variance. Three additional samples of women were tested (total N=222) and compared to the college age samples on the 11 factors. The various samples differed in many systematic and statistically significant ways. Suggestions were made as to the possibility of developing new items to measure some aspects of femininity not represented completely among the items analyzed.

Adolescent↗
PubMed1977

Necrotizing sialometaplasia of the mandible.

A brief review of the literature on necrotizing sialometaplasia has been presented. A patient with necrotizing sialometaplasia of the retromolar pad is reported. This is the first such lesion to be described in an oral site other than the palate. Clinical, histologic, and etiologic aspects of the lesion have veen discussed.

Adult↗
PubMed1977

Effect of distance information and range on two indices of visually perceived distance.

Subjects made verbal reports of the perceived distance of near visual targets and indicated their distances by pointing at them with an unseen hand. The targets were presented under three stimulus conditions: monocular, binocular, and multicue. Two ranges of target distance were studied in separate experiments: 11-39 cm and 21-33 cm. When reciprocals of both response distance and target distance were plotted, all functions were approximately linear. The verbal and manual responses (distance indices) differed greatly, but were found to be related by a constant transform. The range of target distances had no effect on either index. The standard deviation of the manual response was about half that of the verbal response. Stimulus condition had a large effect, with the multicue condition producing the greatest change in indicated distance. and the monocular condition the least. The results are discussed with reference to the definition of perceived distance, and hypothesis concerning the integration of distance information.

Adult↗