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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Psychophysiology 32 (1995), S. 0 
    ISSN: 1469-8986
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: This study assessed whether P300 scalp topography distinguishes subjects with Alzheimer's disease (AD) from controls. Specifically, it was predicted that the AD group would show maximum P300 amplitude over frontal areas and t he largest P300 reduction over parietal and left hemisphere areas. These hypotheses were tested using a standard auditory oddball paradigm to compare 26 AD subjects and 26 controls matched on age, sex, handedness, and education. P300 was measured at frontal, central, parietal, and occipital sites over left and right hemispheres and along the midline. Results revealed that the distribution of P300 was different for the two groups such that the controls manifested a maximum over parietal areas, whereas the AD subjects showed a maximum at frontal sites with the largest reductions in P300 over parietal areas. No hemispheric differences in P300 were found. These results are consistent with the hypothesis that P300 represents the activity of multiple neural generators that are differentially disrupted by the disease process.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Psychophysiology 25 (1988), S. 0 
    ISSN: 1469-8986
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: A recent study by Raine and Venables (1987) reported increased P3 amplitudes in antisocial adolescents, a replicable result indicating enhanced processing of task-relevant events. The present study assesses whether adult psychopaths similarly show enhanced P3 amplitudes; latency of P3 recovery to baseline was also measured to assess Jutai et al.'s (1987) finding of sustained late positivity in psychopaths. EPs were measured at T3, T4, P3, and P4 to targets and nontargets during a continuous performance task in 14 psychopathic and 14 nonpsychopathic top-security prisoners. Psychopaths showed larger P3 amplitudes to targets relative to nontargets at parietal but not temporal sites, and larger P3 recovery times. Psychopaths also scored higher on WAIS subtests sensitive to parietal lobe functioning but not on non-parietal subtests. No laterality effects were uncovered to support a left hemisphere dysfunction theory of psychopathy. It is argued that this evidence for proficient information-processing on parietal-related tasks may underlie clinical reports of enhanced short-term attentional ability in psychopaths.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Psychophysiology 18 (1981), S. 0 
    ISSN: 1469-8986
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: The assumption that cortical augmenting-reducing is independent of stimulus modality was tested by presenting both auditory and visual stimuli to 42 subjects. Cross-modal correlations for P1N1 and N1P2 slope measures were negligible and nonsignificant. They remained insignificant using a measure independent of overall responsivity, after exclusion of “inconsistent” slope values, after equating for relative stimulus intensity, and after data transformations. No evidence was found for overall reducing in the auditory modality, although “paradoxical” reducing was observed over low intensity levels. Slopes derived from this reducing range did not correlate with visual slopes. Visual reducing was not found to be an artifact of selective EP latency jitter or scatter of the data points, but was found to correlate with confidence ratings of peak-trough identification. These results suggest that cortical reducing is modality-specific and is not mediated by a generalized, central inhibitory mechanism but by independent, sensory-specific pathways. Implications were drawn for both the neuroanatomical basis of cortical augmenting-reducing and its application in psychopathology.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1469-8986
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: Although the medial phalanx has been recommended as the preferred site for recording skin conductance activity, a review of articles published in Psychophysiology indicates that a large minority (34%) of studies employ the distal phalanx. Informal observations also suggest that the distal site may be more reactive than the medial site. This study formally tests this observation by recording skin conductance from both medial and distal phalanges. Twenty-four right-handed subjects (12 male, 12 female) were exposed to a series of 10 orienting and defensive stimuli. Electrodes were placed on the fore and middle fingers of each hand, with distal sites used on one hand and medial sites on the other for each subject. Skin conductance amplitudes were 3.5 times larger at distal than medial sites (p〈.002), while skin conductance levels were 2.08 times larger at distal sites (p〈.0005). A significant Site × Stimulus interaction (p〈.025) indicated that the distal site was more sensitive to habituation over trials and to increases in skin conductance amplitudes with increasing stimulus intensity than the medial site. On the basis of these findings it is recommended that distal sites be used in preference to medial sites in the recording of skin conductance activity.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Psychophysiology 27 (1990), S. 0 
    ISSN: 1469-8986
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: Recent event-related potential (ERP) studies indicate that antisocial and psychopathic behavior is in some circumstances characterized by heightened attentional processes. This prospective study assesses whether ERP measures of attention recorded in adolescence are capable of predicting criminality status in adulthood. N1, P300, and contingent negative variation (CNV) were recorded during a CNV paradigm in a representative sample of 101 male schoolchildren at age 15, and related to criminality status at age 24. Criminals-to-be were characterized by larger N1 amplitudes and faster P300 latencies to the warning stimulus. Psychopathic personality within the criminal group was associated with larger N1 and CNV amplitudes. A discriminant function analysis using N1 and P300 measures correctly classified 74% of cases. It is concluded that enhanced early attentional processing may be of etiological significance in the development of criminality and that ERP measures may be of value in the early prediction of criminal behavior.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Psychophysiology 24 (1987), S. 0 
    ISSN: 1469-8986
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: While initial investigations have found significantly lower contingent negative variation (CNV) amplitudes in adult, institutionalised antisocial groups, others have found either no group differences or significantly higher amplitudes. This study attempts to circumvent some methodological and conceptual problems in previous stud its by assessing CNV in a classical forewarned reaction time experiment in two samples of non-institutionalised normal adolescents where behavioral ratings and self-report measures were used to define Antisocial and Pro social groups. A trend toward higher P3 amplitudes to the warning stimulus (SI) observed in a previous study was also investigated by recording evoked potentials to SI. Results indicated no significant group differences in CNV and Nl amplitudes, but a significantly larger P3 amplitude in the Antisocial group in both subject samples. This latter result was viewed as consistent with Jutai and Hare's (1983) finding that psychopathic anti socials have a heightened capacity to attend to events of immediate interest.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1469-8986
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: Little is known about the effects of environmental enrichment on psychophysiological measures of arousal and orienting in humans. This study tests the hypothesis that early educational and health enrichment is associated with long-term increases in psychophysiological orienting and arousal. One hundred children were experimentally assigned to a two-year enriched nursery school intervention at ages 3–5 years and matched at age 3 years on psychophysiological measures, gender, and ethnicity to 100 comparisons who received the normal educational experience. Children were retested 6–8 years later at age 11 years on skin conductance (SC) and electroencephalogram (EEG) measures of arousal and attention during pre- and postexperimental rest periods and during the continuous performance task. Nursery enrichment was associated with increased SC amplitudes, faster SC rise times, faster SC recovery times, and less slow-wave EEG during both rest and CPT conditions. This is believed to be the first study to show that early environmental enrichment is associated with long-term increases in psychophysiological orienting and arousal in humans. Results draw attention to the important influence of the early environment in shaping later psychophysiological functioning.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1469-8986
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: This study assessed whether greater skin conductance activity at the distal versus medial site (Scerbo, Freedman, Raine, Dawson, & Venables, 1992) is attributable to a greater number of active (open) sweat glands at the distal site. The number of sweat glands was measured using the Palmar Sweat Index (PSI). Twenty-four subjects were exposed to 10 auditory stimuli. Electrodes were placed on the fore and middle fingers of each hand, using distal sites on one hand and medial sites on the other. The PSI was measured at the medial and distal phalanges adjacent to the electrode placement sites. The distal site contained more open and total sweat glands. Open gland count had the strongest correlations with skin conductance. Multivariate analyses of covariance revealed that site effects for nonspecific and orienting response frequency and trials to habituation were associated with site differences in open glands. Skin conductance measures and the PSI reveal greater electrodermal activity at the distal site. In addition, the number of open glands may be a useful measure related to electrodermal response frequency when polygraph measurement is unavailable.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Psychophysiology 28 (1991), S. 0 
    ISSN: 1469-8986
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: Although little is known about the neuroanatomical basis of skin conductance orienting in intact normal humans, the limited literature on animals and humans with neurological and clinical disorders implicate prefrontal, temporal/amygdala, and pons brain areas in mediating skin conductance orienting. This study relates area of these structures using magnetic resonance imaging techniques to skin conductance orienting responses in 17 normal humans in order to test hypotheses that larger area of these excitatory structures will be associated with more orienting responses. Left and right hand skin conductance orienting was significantly associated with left and right prefrontal area (r=.44-.60), area of the pons (r=.43-.54), and left but not right temporal/amygdala area (r=.47-.53). No relationships were observed with areas thought to be unrelated to skin conductance activity (cerebellum, nonfrontal cortical area), medial prefrontal cortex, or the third ventricle. This appears to be the first study relating brain structure to skin conductance orienting in intact normal humans. Although preliminary at the present time, these results implicate prefrontal, pons, and temporal/amygdala areas in the mediation of skin conductance orienting in normal humans.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1469-8986
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: Heart rate activity and computed tomographic measures of structural brain abnormalities were evaluated in 32 individuals with a genetic risk for schizophrenia (offspring of schizophrenic mothers). Heart rate activity was assessed in 1962 when the subjects were a mean age of 15.1 years. Diagnostic and computed tomography assessments were conducted in 1980. Compared to individuals with normal third ventricles, individuals with enlarged third ventricles evidenced significantly lower heart rate levels overall and significantly lower heart rate during rest and during the periods preceding conditioning and test for conditioning stimulus trials. These effects were independent of age, psychiatric diagnosis, and abnormalities in other brain regions. Difficulties in interpretaton posed by the index of brain abnormality employed and by the 18-year time interval between the heart rate and computed tomography assessments are discussed. Together with prior evidence of a relationship between third ventricle enlargement and reduced electrodermal responsiveness in the same subjects, these findings provide a preliminary indication that enlargement of the third ventricle may involve damage to diencephalic structures involved in autonomic nervous system activity.
    Type of Medium: Electronic Resource
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