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Biomedical subjects

J Polich

Publications and source records attributed to J Polich.

At least 91 records · Page 5Linked to original sources
PubMed1994

Meta-analysis of P300 amplitude from males at risk for alcoholism.

The P3(00) event-related brain potential (ERP) is used to study the development of alcoholism by comparing males who have a positive family history of alcoholism with control Ss who have no such familial history. Meta-analysis indicated that overall, smaller P3 amplitudes were obtained from males with family histories of alcoholism compared to controls. Moderator analysis indicated that paradigms using difficult visual tasks yielded the most reliable effects. Furthermore, no differences in outcomes were obtained among studies that recruited positive family history Ss exclusively from among individuals whose father had received treatment for alcoholism as compared with other studies. These findings are discussed in the context of using ERPs as an evaluative tool in the study of psychopathology.

Adolescent↗
PubMed1994

Olfactory-evoked potentials: assessment of young and elderly, and comparison to psychophysical threshold.

Olfactory-evoked potentials (OEPs) were recorded monopolarly at the Fz, Cz and Pz electrode sites in young adults and elderly subjects with an amyl acetate stimulus presented olfactometrically. Psychophysical odor thresholds for amyl acetate were determined using a two-alternative, forced-choice detection procedure. These demonstrated a decreased odor detection sensitivity in the elderly relative to tye young subjects. In accordance with the threshold findings, elderly subjects produced significantly smaller N1 and P2 amplitudes, and a trend towards longer latencies than younger subjects. Moreover, odor threshold was found to correlate with amplitude magnitude. The OEP findings, which are discussed in the context of previous OEP studies, offer promise as an objective, non-invasive measure of sensory function in both clinical and non-clinical settings.

Adult↗
PubMed1993

P300 from amnesic patients with bilateral hippocampal lesions.

P3(00) event-related brain potentials (ERPs) were recorded using auditory and visual stimuli from 5 amnesic patients with confirmed (n = 4) or suspected (n = 1) bilateral damage to the hippocampal formation without skull defects. Four normal control subjects were matched to each amnesic patient with respect to age, sex, education, and IQ subtest scores (n = 20 total controls). All 5 amnesic patients exhibited ERPs, and no reliable differences in P3 amplitude or latency could be detected between the patients and the control subjects in either modality. The findings indicate that the hippocampal formation does not contribute significantly to the scalp-recorded P3 from auditory and visual target stimuli, a conclusion also supported by additional recent findings from studies of patients with extensive bilateral medial temporal lobe damage studies. The significance of the P3 component for cognitive processing is discussed.

Acoustic Stimulation↗
PubMed1993

P300, habituation, and response mode.

The P3(00) event-related brain potential (ERP) was elicited with an auditory discrimination paradigm under two response task conditions in which the probability of the target tone was always 0.20. Subjects either counted the occurrence of each target tone or pressed a button to the target in different conditions. No response was made to the standard tone. Consecutive blocks of trials were obtained to assess habituation of P3 amplitude. The count task demonstrated less habituation than the button-press task, with a strong interaction obtained between response mode and trial block for all electrode sites. The findings suggest that habituation of P3 amplitude is sensitive to the amount of attentional resources allocated to the processing of a target stimulus, with more resources required for a count task compared to fewer needed for a button-press response.

Adult↗
PubMed1993

Behavioral management of chronic pain and excess disability: long-term follow-up of an outpatient program.

OBJECTIVE: To assess the overall efficiency of an outpatient behavioral rehabilitation program for excess disability and chronic pain and to describe the program staff, treatment components and outcomes in sufficient detail to facilitate comparison with similar programs. DESIGN: Eight-year follow-up study of patients referred and treated. SETTING: Outpatient primary care and multispecialty group medical practice. PATIENTS: 354 of 421 unselected patients referred for the behavioral management of excess disability, who completed the treatment program and participated in follow-up. INTERVENTIONS: 15-20 sessions of physical and occupational therapy, 5-10 sessions of biofeedback, and one or two family sessions all based upon behavioral techniques described by Fordyce and by Roberts. MAIN OUTCOME MEASURES: Questionnaires, including analog scales, administered before treatment and at 1, 6, 12, and 24 months posttreatment. RESULTS: Patients (n = 67) who dropped out did not differ systematically from those who participated (n = 354). The treatment program resulted in a marked and enduring reduction of pain, and a statistically and clinically significant improvement in patients' ability to function at work and in the home. Patients overwhelmingly endorsed the program. CONCLUSIONS: A brief, inexpensive, outpatient behavioral rehabilitation program for chronic pain and excess disability can achieve a clinically significant and lasting reduction of pain and improvement in function at work and at home.

Adolescent↗
PubMed1992

Comparison of infant and adult P300 from auditory stimuli.

Event-related brain potentials (ERPs) using auditory stimuli were recorded from 5- to 10-month-old infants and normal young adults with a passive tone sequence paradigm. A P3 (P300) component was obtained which demonstrated the same central-parietal maximum scalp distribution for both subject groups. P3 amplitude was smaller and its peak latency longer for infants compared to those of the adults across all electrode sites. P3 measures remained stable across stimulus trials indicating that ERP habituation was not occurring. Evaluation of individual subjects suggests that the P3 can be elicited from infants with auditory stimuli in a manner similar to that from adults and may serve as a useful index for the assessment of cognitive function in infants.

Acoustic Stimulation↗
PubMed1992

P300 in multiple sclerosis: a preliminary report.

The P300 component of the event-related brain potential (ERP) elicited with auditory stimuli and pattern-shift visual evoked potentials (VEPs) was obtained from 16 patients with multiple sclerosis (MS) and 16 matched control subjects. P300 latency was significantly longer and component amplitude relatively depressed in the MS patients compared to control subjects. The P100 potential of the VEP also was delayed for both full-field and half-field stimulus conditions in the patients compared to control subjects. The findings suggest that the P300 ERP may reflect the cognitive decline associated with MS.

Adult↗
PubMed1992

P300, probability, and introverted/extroverted personality types.

Extreme introverted and extroverted subject groups (n = 24 each) containing equal numbers of male and females were assessed with the P300 (P3) component of the event-related potential (ERP). A two-tone auditory discrimination task in which the probability of the target stimulus varied systematically in different conditions (.20, .40, .60, .80) was used to elicit the ERPs. The P3 amplitude demonstrated a significant interaction between personality type, probability, and subject gender and was generally smaller for introverts than for extroverts. Female subjects tended to have larger overall P3 components than male subjects. P3 latency was not affected by the personality variable. The results support previous findings for ERP differences between introverts and extroverts and suggest that personality type differentially influences target stimulus probability effects. The findings are discussed in terms of individual differences in cortical activity on P3 amplitude and personality measures.

Adult↗
PubMed1992

P300, food consumption, and memory performance.

The effects of food intake on the P300 (P3) component of the event-related brain potential (ERP) were assessed in two studies. Experiment 1 compared 24 subjects who had not eaten within 6 hours of testing with 24 subjects who had consumed food within 3 hours of testing. P3 target stimulus amplitude was reduced significantly for the subjects who had not eaten relative to those who had eaten, whereas peak P3 latency was only moderately affected by the recency of food consumption over task conditions. In Experiment 2, P3 measurements, memory performance in a word recall task, and blood glucose levels were obtained from 24 subjects at three different times: 1) after a 14-hour fast, 2) 5 min after consuming lunch, and 3) 30 min after consuming lunch. P3 target stimulus amplitude increased initially after food intake and decreased slightly at the third measurement time, while peak P3 latency became somewhat shorter immediately after food intake but then returned to baseline. Recall for recently presented items mimicked the P3 amplitude changes, whereas blood glucose levels increased monotonically across food conditions. The results from both studies suggest that: 1) target stimulus P3 amplitude is affected by the recency of food intake; 2) food-related P3 amplitude changes appear related to memory function; and 3) subjects should eat within several hours before ERPs are acquired to ensure that P3 component measurements reflect values indicative of normal bodily functioning.

Acoustic Stimulation↗
PubMed1992

P300 and individual differences: morning/evening activity preference, food, and time-of-day.

To determine how individual differences stemming from activity preference, previous food intake, and time-of-day affect the P300 or P3 event-related brain potential (ERP), subject groups who varied orthogonally on these factors were compared using a simple auditory discrimination task to elicit the ERPs. Amplitude of the P3 component for morning-preferring subjects who had eaten recently was relatively large for both the morning and evening measurement time groups. P3 amplitude for the morning-preferring subjects who had not eaten recently was large for those measured in the morning and relatively small for those subjects measured in the evening. For evening-preferring subjects who had eaten recently, P3 amplitude was again relatively large for both the morning and evening measurement time groups. Evening-preferring subjects who had not eaten recently produced very small P3 components for those measured in the morning compared to the large components produced by those subjects measured in the evening. P3 latency tended to be longer for all subjects who had not eaten recently compared to those who had. The results suggest that the P3 component is sensitive to physiological and psychological changes originating from individual differences related to bodily state, which perhaps stems from individual differences in arousal level.

Adolescent↗
PubMed1991

The effects of hemispheric differences on feature perturbations.

Hemispheric differences for feature perturbations were investigated in two experiments. Stimulus displays consisting of five small squares arranged in a single row were presented tachistoscopically, with the subject instructed to state in which square a horizontal tick mark was located. Ticks could occur in any of the three middle squares, with half of the ticks presented on the inside and half presented on the outside of the square in relation to the fovea. Experiment 1 presented each array of five squares to the right or left of fixation at one of three distances from the fovea. Experiment 2 manipulated the distance between the squares and kept foveal distance constant. In each experiment, fewer errors were made when stimuli were presented to the left visual field/right hemisphere than when they were presented to the right visual field/left hemisphere, when ticks migrated toward the fovea. Experiment 1 found that increasing the distance from the fovea increased the error rate, but did not change the hemispheric differences. Experiment 2 found that increasing the distance between the squares did not change hemispheric effects reliably. The data imply that hemispheric differences for perceptual processing begin very early during sensory analysis.

Adult↗
PubMed1991

P300 from auditory and somatosensory stimuli: probability and inter-stimulus interval.

The P300 (P3) event-related brain potential (ERP) was elicited with auditory and somatosensory stimuli using an easy discrimination task in two experiments. Experiment 1 manipulated target stimulus probability (0.20 vs. 0.80). Experiment 2 manipulated inter-stimulus interval (2 s vs. 6 s) for both stimulus modalities in different conditions while keeping target probability constant. Probability and inter-stimulus interval had similar effects for auditory and somatosensory stimuli, with lower probability and longer inter-stimulus intervals producing larger P3 amplitudes. No statistically reliable differences in scalp distribution between modalities were obtained, with both modalities producing maximal amplitudes at Pz. The results suggest that auditory and somatosensory stimuli when used in a relatively easy discrimination task yield the same overall P3 values.

Acoustic Stimulation↗
PubMed1991

P300 and introverted/extraverted personality types.

The P300 component of the event-related potential elicited with a two-tone auditory discrimination task and two-trial block replication procedure was obtained from 16 introverted and 16 extraverted undergraduate students. P300 demonstrated no overall significant effects for either the personality variable or the block variable. However, P300 amplitude to the target stimuli declined significantly between Block 1 and Block 2 for the extraverted subjects, but did not change across trial blocks for the introverted group. Female subjects tended to have larger P3 amplitudes than male subjects, but this factor did not interact with either the personality variable or the trial block variable. The results suggest that P3 amplitude habituates more rapidly for extraverts than for introverts.

Adult↗
PubMed1990

Hemispheric differences in visual search of simple line arrays.

The effects of perceptual organization on hemispheric visual-information processing were assessed with stimulus arrays composed of short lines arranged in columns. A visual-search task was employed in which subjects judged whether all the lines were vertical (same) or whether a single horizontal line was present (different). Stimulus-display organization was manipulated in two experiments by variation of line density, linear organization, and array size. In general, left-visual-field/right-hemisphere presentations demonstrated more rapid and accurate responses when the display was perceived as a whole. Right-visual-field/left-hemisphere superiorities were observed when the display organization coerced assessment of individual array elements because the physical qualities of the stimulus did not effect a gestalt whole. Response times increased somewhat with increases in array size, although these effects interacted with other stimulus variables. Error rates tended to follow the reaction-time patterns. The results suggest that laterality differences in visual search are governed by stimulus properties which contribute to, or inhibit, the perception of a display as a gestalt. The implications of these findings for theoretical interpretations of hemispheric specialization are discussed.

Adult↗
PubMed1990

Hemispheric local/global processing revisited.

Hemispheric differences for local and global processing were assessed with square and rectangular stimulus shapes which contained either squares or rectangles within them. Experiment 1 manipulated the overall size and area of the stimulus items, while experiment 2 kept stimulus area constant and manipulated the number of shapes inside the stimulus. In different conditions subjects judged whether the inside shapes (local processing) or whether the outside shapes (global processing) were squares or rectangles. Reaction time measures revealed that hemispheric differences were unrelated to the local or global processing requirements as well as the spatial frequency of the stimulus texture. A left hemisphere advantage generally was obtained across stimulus and processing conditions, with the pattern of task effects dependent on the specific stimuli employed. The results suggest that the overall stimulus shape rather than processing mode or specific spatial frequency is a primary determinant of hemispheric differences for visual information.

Adult↗
PubMed1990

Probability and inter-stimulus interval effects on the P300 from auditory stimuli.

The relationship between target stimulus probability and inter-stimulus interval (ISI) on the P300 (P3) component of the event-related potential was assessed in two experiments. An auditory discrimination paradigm was employed wherein subjects indicated with a finger tap response the occurrence of a randomly presented 2000 Hz target tone embedded in a series of 1000 Hz tones. Experiment 1 presented stimuli with target probabilities of 0.10, 0.30, and 0.50 at ISIs of 1.5 or 3.0 s and produced P3 amplitudes which decreased with increases in target probability and were smaller at the shorter compared to the longer ISI. Experiment 2 presented stimuli with target probabilities of either 0.20, 0.50, or 0.80 at ISIs of 4.0 and 10.0 s and produced P3 amplitudes which were unaffected by either variable. P3 latency demonstrated relatively few changes in either experiment. When taken together with previous findings, the results suggest that inter-stimulus interval affects P3 amplitude by determining the amount of processing resources available during ERP generation.

Acoustic Stimulation↗