Current Search: Evoked potentials Electrophysiology (x)
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- Title
- A NEURAL INHIBITION MODEL OF THE P(300) COMPONENT OF THE AVERAGED EVOKED POTENTIAL.
- Creator
- WILLIAMS, CATHY SUZANNE, Florida Atlantic University
- Abstract/Description
-
Visual and auditory evoked potentials were studied in a selective attention paradigm similar to that of Posner and Boies (1971) wherein a visual letter-matching task was interrupted by auditory probes on selected trials. A neural inhibition model of the P300 component was proposed which generated the hypothesis that the P300 component in response to auditory probes would be greatest in amplitude to probes which occurred between the two to-be-remembered test letters and smaller in amplitude to...
Show moreVisual and auditory evoked potentials were studied in a selective attention paradigm similar to that of Posner and Boies (1971) wherein a visual letter-matching task was interrupted by auditory probes on selected trials. A neural inhibition model of the P300 component was proposed which generated the hypothesis that the P300 component in response to auditory probes would be greatest in amplitude to probes which occurred between the two to-be-remembered test letters and smaller in amplitude to probes which occurred before the presentation of the first test letter. General support for the neural inhibition model was found, however, systematically shifting prestimulus baselines were also observed within these time intervals thereby raising the possibility that the differences in P300 amplitudes were due to nonspecific changes in the general arousal level of the subject. It was also found that instruction-induced differences in response speed affected the amplitude of the evoked potential components in a way which could most parsimoniously be attributed to shifts in general arousal.
Show less - Date Issued
- 1980
- PURL
- http://purl.flvc.org/fcla/dt/14032
- Subject Headings
- Evoked potentials (Electrophysiology), Electroencephalography
- Format
- Document (PDF)
- Title
- THE EFFECTS OF NOVELTY ON THE P-300 COMPONENT OF THE EVENT-RELATED POTENTIAL.
- Creator
- PALMER, ROBERT P., Florida Atlantic University
- Abstract/Description
-
Event-related potentials were studied to explore the effects of novelty, along the dimension of categorizability, on P-300 amplitudes and latency. The effects of spatial and verbal information processing on P-300 amplitude and latency as well as the effects of novelty and processing mode on incidental learning were also studied. No significant P-300 data was demonstrated. A forced choice recognition memory test did show significant differences between the spatial and verbal tasks and between...
Show moreEvent-related potentials were studied to explore the effects of novelty, along the dimension of categorizability, on P-300 amplitudes and latency. The effects of spatial and verbal information processing on P-300 amplitude and latency as well as the effects of novelty and processing mode on incidental learning were also studied. No significant P-300 data was demonstrated. A forced choice recognition memory test did show significant differences between the spatial and verbal tasks and between the three different stimulus types.
Show less - Date Issued
- 1982
- PURL
- http://purl.flvc.org/fcla/dt/14102
- Subject Headings
- Evoked potentials (Electrophysiology)
- Format
- Document (PDF)
- Title
- EVOKED POTENTIAL CORRELATES OF STIMULUS NOVELTY.
- Creator
- JASIUKAITIS, PAUL ALEXANDER, Florida Atlantic University, Nash, Allan J., Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
-
Sokolov's (1963) hypothesis of selective extinction of the orienting response accounts for the phenomenon of dishabituation by a discrepancy between immediate sensory input and a stored template of a habituated stimulus. The "oddball" stimulus procedure often used to elicit the P300 evoked potential waveform bears resemblance to a habituation-dishabituation paradigm. In the present experiment subjects were habituated to a 70 dB tone burst which was then occasionally replaced by 50, 60, 80 or...
Show moreSokolov's (1963) hypothesis of selective extinction of the orienting response accounts for the phenomenon of dishabituation by a discrepancy between immediate sensory input and a stored template of a habituated stimulus. The "oddball" stimulus procedure often used to elicit the P300 evoked potential waveform bears resemblance to a habituation-dishabituation paradigm. In the present experiment subjects were habituated to a 70 dB tone burst which was then occasionally replaced by 50, 60, 80 or 90 dB stimuli. According to a selective extinction model of the P300, equal absolute amounts of stimulus change should evoke equal amplitude waveforms. While the decreased intensity stimuli did evoke a P300, the largest P300s were associated with an intensity increase. The N200 component was seen to be largest with intensity decrease. It is suggested that the N200 is the evoked potential correlate of discrepancy detection which can be obscured by an intensity-driven P300.
Show less - Date Issued
- 1982
- PURL
- http://purl.flvc.org/fcla/dt/14125
- Subject Headings
- Evoked potentials (Electrophysiology)
- Format
- Document (PDF)
- Title
- STIMULUS AND RESPONSE PROBABILITIES: EFFECTS ON THE AMPLITUDE OF P300.
- Creator
- COMPERATORE, CARLOS ARTURO., Florida Atlantic University
- Abstract/Description
-
Evoked potentials elicited by tones of high and low probability of presentation requiring the suppression of a frequent response (counting or not-counting) or its maintenance were studied. Low probability (Novel) tones requiring response (counting) suppression elicited P300 amplitudes of the event-related potential comparable to those elicited by low probability tones (Target) which did not require suppression of an ongoing frequent response. This finding was not in agreement with those...
Show moreEvoked potentials elicited by tones of high and low probability of presentation requiring the suppression of a frequent response (counting or not-counting) or its maintenance were studied. Low probability (Novel) tones requiring response (counting) suppression elicited P300 amplitudes of the event-related potential comparable to those elicited by low probability tones (Target) which did not require suppression of an ongoing frequent response. This finding was not in agreement with those reported in a similar study by Karlin and Martz (1973). It was advanced that situations in which subjects maintain a high level of response readiness enhance the effects of stimulus probability and response probability on P300 amplitude values. In agreement with the current literature, low probability stimuli (Novel and Target) were found to consistently elicit larger P300 amplitudes than high probability (Background) stimuli regardless of response frequency. N100 amplitudes were also larger for low probability tones than for high probability Background tones. These results were attributed to either habituation, attention or a combination of both. P200-N250 peak-to-peak amplitude values were also shown to be larger in response to Target and Novel tones than in response to Background tones.
Show less - Date Issued
- 1982
- PURL
- http://purl.flvc.org/fcla/dt/14126
- Subject Headings
- Evoked potentials (Electrophysiology)
- Format
- Document (PDF)
- Title
- NEURAL CORRELATES OF SIGNAL DETECTION UNDER NON-AROUSAL AND AROUSAL CONDITIONS.
- Creator
- CAEL, WILLIAM WARD, III., Florida Atlantic University
- Abstract/Description
-
A signal detection experiment tested the assumption that the results of Hillyard, Squires, Bauer and Lindsay (1971), who found a significant late positive component (LFC) of the averaged evoked potential only in the hit category, were due to the response set of their Ss and not to any unique associations of the LPC with the hit category as interpreted by them. Phase 1 of the present study was basically a replication of Hillyard's study. In Phase 2 incorrect responses were punished by an...
Show moreA signal detection experiment tested the assumption that the results of Hillyard, Squires, Bauer and Lindsay (1971), who found a significant late positive component (LFC) of the averaged evoked potential only in the hit category, were due to the response set of their Ss and not to any unique associations of the LPC with the hit category as interpreted by them. Phase 1 of the present study was basically a replication of Hillyard's study. In Phase 2 incorrect responses were punished by an unpleasant feedback device designed to place more equal relevance on signal and non-signal trials. Significant LPCs appeared in both signal and non-signal brain waves under both phases indicating that the LPC is not contingent on any particular response category as Hillyard reported, but may instead reflect the relevance of the category to the experimental task as it is perceived by the S.
Show less - Date Issued
- 1973
- PURL
- http://purl.flvc.org/fcla/dt/13605
- Subject Headings
- Evoked potentials (Electrophysiology), Arousal (Physiology)
- Format
- Document (PDF)
- Title
- THE EFFECT OF WORD NOVELTY ON THE P300 COMPONENT OF THE VISUAL EVOKED POTENTIAL IN YOUNG AND ELDERLY ADULTS.
- Creator
- MCDONOUGH, BRUCE EDWARD, Florida Atlantic University
- Abstract/Description
-
Visual evoked potentials were elicited by tachistoscopic presentation of familiar (real words) and novel (pseudowords) verbal stimuli to young and elderly adults. The amplitude and latency of the P300 component did not differ significantly for any of the experimental conditions. Excessive noise in the averaged waveforms, most likely due to eye and motor contaminants, may have been partly responsible for the failure to confirm the hypotheses.
- Date Issued
- 1978
- PURL
- http://purl.flvc.org/fcla/dt/13935
- Subject Headings
- Visual evoked response, Evoked potentials (Electrophysiology)
- Format
- Document (PDF)
- Title
- P100 AND N170 RESPONSES TO RACE: DEVELOPMENT AND RELATIONSHIP WITH CONTACT AND IMPLICIT BIAS.
- Creator
- Fennell, Eli, Anzures, Gizelle, Florida Atlantic University, Department of Psychology, Charles E. Schmidt College of Science
- Abstract/Description
-
Racial bias remains a prevalent issue in society. Clues to the cognitive basis for such biases have been found in EEG studies of the ‘Other Race Effect’ (ORE) in relation to the P100 and N170 event related potentials (ERPs). Previous research in this area has focused on adults, and only one such study has looked at implicit racial biases (He et al., 2009), while only a few have looked at experience with own- and other-race persons (Herzmann et al., 2011; Stahl et al., 2008; Walker et al.,...
Show moreRacial bias remains a prevalent issue in society. Clues to the cognitive basis for such biases have been found in EEG studies of the ‘Other Race Effect’ (ORE) in relation to the P100 and N170 event related potentials (ERPs). Previous research in this area has focused on adults, and only one such study has looked at implicit racial biases (He et al., 2009), while only a few have looked at experience with own- and other-race persons (Herzmann et al., 2011; Stahl et al., 2008; Walker et al., 2008). The present study is the first to examine how race might modulate ERP responses in children, and the first to relate these responses with both implicit racial biases and race contact experience. We examined EEG responses in 5- to 10-year-old children and adults, and whether such responses were associated with implicit racial biases and own- and other-race experience. Results showed that both children and adults displayed larger P100 and N170 responses to other-race faces, greater implicit racial biases related to larger N170 responses to other- than own-race faces, and greater other-race experience related to larger P100 responses to other- than own-race faces. In terms of age differences, we found that compared with adults, children displayed larger and more delayed P100 and N170 responses, and that in children but not in adults, greater experience with own- and other-races were associated with more delayed N170 responses to other- than own-race faces. These findings suggest that age, experience with own- and other-race persons, and implicit racial biases all influence early ERP responses to own- and other-race individuals.
Show less - Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FA00013371
- Subject Headings
- Racism, Evoked potentials (Electrophysiology), Racial bias, Electroencephalography
- Format
- Document (PDF)
- Title
- Alternation of primary task stimulus modality affects event-related brain potentials and secondary task signal detection performance.
- Creator
- Bachanas, Pamela Jane., Florida Atlantic University, Nash, Allan J.
- Abstract/Description
-
The effect of alternating primary task stimulus modality on event-related brain potentials and secondary signal detection performance was examined in a dual-task paradigm. An odd-ball paradigm with alternating pairs of auditory tones and visual lights was employed as the primary counting task. Primary task stimuli were classified by previous trial modality (same vs different), previous trial stimulus type (standard vs deviant), and current trial stimulus type. A signal detection task in which...
Show moreThe effect of alternating primary task stimulus modality on event-related brain potentials and secondary signal detection performance was examined in a dual-task paradigm. An odd-ball paradigm with alternating pairs of auditory tones and visual lights was employed as the primary counting task. Primary task stimuli were classified by previous trial modality (same vs different), previous trial stimulus type (standard vs deviant), and current trial stimulus type. A signal detection task in which an auditory tone followed the primary task stimuli by 120 ms on 50 percent of the trials served as the secondary task. For all but one condition, deviant stimuli produced large P300 and decreased signal detection performance. When a deviant stimulus preceded a deviant in the same modality, however, signal detection performance was better than on standard trials preceded by a deviant. These results were interpreted using a two-parameter model of stimulus probability and subjective value of the stimulus sequence. Also examined were other effects of alternating modality of the primary task stimulus and the sequences defined by the modality and stimulus type of the current and previous trial on the event-related potentials elicited by the primary task stimuli.
Show less - Date Issued
- 1989
- PURL
- http://purl.flvc.org/fcla/dt/14507
- Subject Headings
- Evoked potentials (Electrophysiology), Signal detection (Psychology)
- Format
- Document (PDF)
- Title
- Cognitive deficit in HIV-infected adult women: An event related potentials (P300) study.
- Creator
- Simpkiss, Jaime L., Florida Atlantic University, Nash, Allan J.
- Abstract/Description
-
The P300 (P3) component of the auditory Event-Related Potential (ERP) waveform is a sensitive and clinically useful marker of central nervous system impairment. The amplitude (in muV) and latency (in ms) of the P3 component of the auditory ERP were used in the present study to investigate differences between HIV-asymptomatic, HIV-symptomatic, and HIV-negative control adult (18--35 years old) women under three different task conditions. Results indicated that P3 amplitude measures were...
Show moreThe P300 (P3) component of the auditory Event-Related Potential (ERP) waveform is a sensitive and clinically useful marker of central nervous system impairment. The amplitude (in muV) and latency (in ms) of the P3 component of the auditory ERP were used in the present study to investigate differences between HIV-asymptomatic, HIV-symptomatic, and HIV-negative control adult (18--35 years old) women under three different task conditions. Results indicated that P3 amplitude measures were consistently greater in controls than in the asymptomatic and symptomatic groups for all task conditions and at all electrode locations, suggesting that the available level of attentional resources are reduced similarly in both symptomatics and asymptomatics. P3 latency measures revealed that processing speed by asymptomatics is more similar to controls than it is to symptomatics, indicating that speed of processing is compromised in symptomatics, and possibly, to a lesser degree in asymptomatics.
Show less - Date Issued
- 2001
- PURL
- http://purl.flvc.org/fcla/dt/12731
- Subject Headings
- HIV-positive women, Evoked potentials (Electrophysiology)
- Format
- Document (PDF)
- Title
- Evoked potential correlates of cognitive processing in abstinent alcoholics and cocaine addicts.
- Creator
- Rosko, Judith., Florida Atlantic University
- Abstract/Description
-
The P3 and slow wave measures were examined in a simultaneous oddball task in a clinical population of alcoholics and multiple-drug addicted patients. Standard and Deviant tones and lights were used in a counting task in single modality trials in two separate test sessions and tones and lights were used simultaneously but independently in a counting task in which tones were to be ignored and deviant lights were to be counted. Differences between clinical subjects and control subjects and...
Show moreThe P3 and slow wave measures were examined in a simultaneous oddball task in a clinical population of alcoholics and multiple-drug addicted patients. Standard and Deviant tones and lights were used in a counting task in single modality trials in two separate test sessions and tones and lights were used simultaneously but independently in a counting task in which tones were to be ignored and deviant lights were to be counted. Differences between clinical subjects and control subjects and between test sessions were examined. While there were no significant results between test sessions, there were significant differences between controls and clinical subjects in the P3 component. Amplitude of the P3 was smaller for the clinical subjects in all three conditions and in the bimodal task there was evidence in the P3 EP measure that the clinical group had difficulty ignoring the tones, although there were no significant differences in accuracy of count possibly due to a temporal deficiency on the part of the clinical subjects.
Show less - Date Issued
- 1989
- PURL
- http://purl.flvc.org/fcla/dt/14541
- Subject Headings
- Evoked potentials (Electrophysiology), Drugs--Physiological effect
- Format
- Document (PDF)
- Title
- THE RELATIONSHIP BETWEEN P300 ELICITED DURING A PRIMARY TASK AND PERFORMANCE ON A NEAR-SIMULTANEOUS SECONDARY SIGNAL DETECTION TASK.
- Creator
- PINEDA, JAIME ARMANDO., Florida Atlantic University
- Abstract/Description
-
The relationship between P300 elicited on a primary counting task and performance on a secondary signal detection task was studied in a dual task paradigm where the secondary task followed the primary task by 300 msec. A modified ("count both tones") oddball paradigm, utilizing two auditory tones (Frequent and Rare) was used as the primary counting task to elicit two states characterized by differences in P300 amplitudes. An auditory signal detection task presented on 50 percent of the trials...
Show moreThe relationship between P300 elicited on a primary counting task and performance on a secondary signal detection task was studied in a dual task paradigm where the secondary task followed the primary task by 300 msec. A modified ("count both tones") oddball paradigm, utilizing two auditory tones (Frequent and Rare) was used as the primary counting task to elicit two states characterized by differences in P300 amplitudes. An auditory signal detection task presented on 50 percent of the trials following the primary task tones served as the secondary task. Predictions about performance on the secondary task were based on a neural inhibition model of P300. It was hypothesized that signal detection performance, as measured by detection sensitivity (d') would be less on Rare tone trials than on Frequent tone trials. Results were consistent with the hypothesis and provided support for the neural inhibition model of the P300.
Show less - Date Issued
- 1982
- PURL
- http://purl.flvc.org/fcla/dt/14133
- Subject Headings
- Evoked potentials (Electrophysiology), Signal detection (Psychology)
- Format
- Document (PDF)
- Title
- THE EFFECT OF DUAL-TASK ON THE HUMAN EVOKED POTENTIAL ELICITED ON A PRIMARY TASK AND PERFORMANCE ON A NEAR-SIMULTANEOUS SECONDARY SIGNAL DETECTION TASK.
- Creator
- ODIERNA, LISA ANN., Florida Atlantic University
- Abstract/Description
-
The relationship between P300 elicited on a primary counting task and performance on a secondary signal detection task was examined in a dual-task paradigm in which the secondary task followed the primary task by 120 ms. An odd-ball paradigm, utilizing two auditory tones (Standard and Deviant) was employed as the primary counting task in order to elicit two states characterized by differences in P300 amplitudes. The standard trials were further categorized according to their serial position...
Show moreThe relationship between P300 elicited on a primary counting task and performance on a secondary signal detection task was examined in a dual-task paradigm in which the secondary task followed the primary task by 120 ms. An odd-ball paradigm, utilizing two auditory tones (Standard and Deviant) was employed as the primary counting task in order to elicit two states characterized by differences in P300 amplitudes. The standard trials were further categorized according to their serial position in each series of trials. A signal detection task in which an auditory tone followed the primary task tones on 50 percent of the trials served as the secondary task. The principal hypothesis was that a decrease in sensitivity on secondary signal detection task accompanied Deviant trials in which a P300 was elicited. Results were consistent with the hypothesis and provided support for both neural inhibition and cognitive resource allocation models.
Show less - Date Issued
- 1987
- PURL
- http://purl.flvc.org/fcla/dt/14352
- Subject Headings
- Signal detection (Psychology), Evoked potentials (Electrophysiology)
- Format
- Document (PDF)
- Title
- Effects of information load on auditory event-related potentials (P300) in HIV-infected children.
- Creator
- Gonzales, Julie Ackert, Florida Atlantic University, Nash, Allan J.
- Abstract/Description
-
The P300 component of the auditory event-related potential waveform was investigated in control children and two groups of HIV-infected children (asymptomatic and symptomatic), aged five to seven, under combinations of two interstimulus interval (ISI) rates (1 and 2 sec) and two target probability rates (.2 and.5). No group differences were found under the different combinations of ISI and target probability, for either P3a amplitude and latency, or P3b amplitude and latency. Although the...
Show moreThe P300 component of the auditory event-related potential waveform was investigated in control children and two groups of HIV-infected children (asymptomatic and symptomatic), aged five to seven, under combinations of two interstimulus interval (ISI) rates (1 and 2 sec) and two target probability rates (.2 and.5). No group differences were found under the different combinations of ISI and target probability, for either P3a amplitude and latency, or P3b amplitude and latency. Although the present study was not able to distinguish between-groups by manipulating the target presentation rate, there were several within-group effects on P3a latency that were dependant upon the specific clinical or control group. The general findings for the study were that as the target presentation rates increased, P3a latencies increased.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15434
- Subject Headings
- Auditory evoked response, Evoked potentials (Electrophysiology), AIDS (Disease) in children
- Format
- Document (PDF)
- Title
- The effects of standard and deviant tones on event-related brain potentials and reaction-times to visual stimuli.
- Creator
- Fernandez, Mercedes, Florida Atlantic University, Nash, Allan J.
- Abstract/Description
-
This research investigated whether choice reaction time (RT) measures and the P300 component of the event-related brain potential (ERP) could be employed to index the attentional resources associated with performing two near-simultaneous tasks. Specifically, this study investigated the effects of auditory tones on the ERPs and RTs associated with a visual stimulus when the stimuli in both modalities were presented in close temporal proximity. The hypothesis that the ERPs and RTs elicited by...
Show moreThis research investigated whether choice reaction time (RT) measures and the P300 component of the event-related brain potential (ERP) could be employed to index the attentional resources associated with performing two near-simultaneous tasks. Specifically, this study investigated the effects of auditory tones on the ERPs and RTs associated with a visual stimulus when the stimuli in both modalities were presented in close temporal proximity. The hypothesis that the ERPs and RTs elicited by the deviant visual stimulus would index the processing demands associated with the auditory modality was confirmed. In general, greater P300 amplitude associated with one task indicates diminished P300 and poorer performance on a second task. The results indicate that P300 may be a sensitive indicator of shared processing resources when two tasks are performed near simultaneously.
Show less - Date Issued
- 1995
- PURL
- http://purl.flvc.org/fcla/dt/15122
- Subject Headings
- Selectivity (Psychology), Evoked potentials (Electrophysiology), Visual perception, Signal detection (Psychology)
- Format
- Document (PDF)
- Title
- Neural correlates of human sensorimotor coordination: EEG, MEG, and functional MRI.
- Creator
- Mayville, Justine Meaux, Florida Atlantic University, Charles E. Schmidt College of Science, Center for Complex Systems and Brain Sciences
- Abstract/Description
-
The ability to coordinate rhythmic finger movement with a metronome is constrained by both the target timing relation and the rate of coordination. For slow metronome rates (
Show moreThe ability to coordinate rhythmic finger movement with a metronome is constrained by both the target timing relation and the rate of coordination. For slow metronome rates (<2 Hz), subjects are able to both syncopate (in between successive beats) and synchronize (on each beat) with the metronome. At faster rates, however, syncopation becomes unstable and subjects spontaneously switch to synchronization in order to maintain a 1:1 stimulus/response relationship. No switches are observed if subjects start in synchronization, indicating it is an inherently more stable mode of coordination. Patterns of brain activity associated with transitions from syncopation to synchronization as well as synchronization only were examined as the metronome rate was increased from 1.0 to 2.75 or 3.0 Hz. Significant differences in the power of the coordination frequency component of event-related potentials (EEG) as well as the MEG beta (15--30 Hz) rhythm were observed when brain activity associated with syncopation was compared to that accompanying synchronization. These differences were focused over left central and centro-parietal areas and the direction of difference in both cases suggests that syncopation is associated with stronger activation of contralateral sensorimotor cortex. Similar results were found when subjects only imagined performing each mode of coordination at an increasing rate, indicating that differences in signal power at least partially reflect neural processes associated with motor planning and preparation independent of overt execution. Consistent with these findings, functional MRI revealed syncopation to be accompanied by significantly more activity in a wide array of cortical (e.g., premotor, prefrontal) and subcortical (basal ganglia, cerebellum) areas known to play a role in motor planning and/or timing of behavior. Whereas the neuromagnetic auditory response decreased as function of coordination rate, the motor evoked response remained approximately constant. This was true both when subjects syncopated and synchronized but may reflect changes in auditory-motor integration near movement rates that induce transitions in the former case. A control experiment examined only self-paced movement and showed a second neuromagnetic motor 'readiness' response that was strongly attenuated for rates above 1.0 Hz. This may signify a decreased need for the planning of motor behavior at faster rhythmic rates.
Show less - Date Issued
- 2000
- PURL
- http://purl.flvc.org/fcla/dt/12658
- Subject Headings
- Biology, Neuroscience, Brain -- Electric properties, Brain -- Localization of functions, Evoked potentials (Electrophysiology)
- Format
- Document (PDF)
- Title
- Auditory event-related potentials (P300) in the assessment of cognition in HIV infected children.
- Creator
- Starratt, Gerene K., Florida Atlantic University, Nash, Allan J.
- Abstract/Description
-
The P300 component of the auditory event-related potential waveform was investigated in two groups of HIV positive children (symptomatic and asymptomatic) who were compared to HIV negative relatives. Results demonstrated the expected increased latencies of the P3b component in the symptomatic group, but no P3a latency differences. Amplitude measures of P3a and P3b showed no group differences. However, the symptomatic children had relatively larger P3a amplitudes whereas the asymptomatic...
Show moreThe P300 component of the auditory event-related potential waveform was investigated in two groups of HIV positive children (symptomatic and asymptomatic) who were compared to HIV negative relatives. Results demonstrated the expected increased latencies of the P3b component in the symptomatic group, but no P3a latency differences. Amplitude measures of P3a and P3b showed no group differences. However, the symptomatic children had relatively larger P3a amplitudes whereas the asymptomatic children had a larger P3b. Difference measures (P3b minus P3a) revealed a significant difference across groups. Discussion focuses on three interrelated issues: (1) the cognitive mechanisms which could account for the current findings, (2) the relevance of a symptomatic/asymptomatic distinction and a P3a/P3b distinction for the purposes of clinical research, and (3) the clinical implications of these findings.
Show less - Date Issued
- 1996
- PURL
- http://purl.flvc.org/fcla/dt/15306
- Subject Headings
- Evoked potentials (Electrophysiology), Auditory evoked response, Perception in children--Testing, Cognition in children--Testing, Psychological tests for children, AIDS (Disease) in children
- Format
- Document (PDF)
- Title
- The effect of age on processing family, famous and novel faces: An fMRI study.
- Creator
- Jones, Lana Casey, Florida Atlantic University, Tuller, Betty, Charles E. Schmidt College of Science, Department of Psychology
- Abstract/Description
-
Facial recognition memory is a specialized system in the human brain, with an effect of familiarity playing a role in the brain activations involved. Previous studies examining the familiar face processing system have used college-aged subjects. However, memory disorders, like those associated with Alzheimer's disease, typically affect adults over sixty. In an attempt to reveal possible differences between young and older adults', two different age groups were subjected to fMRI analysis while...
Show moreFacial recognition memory is a specialized system in the human brain, with an effect of familiarity playing a role in the brain activations involved. Previous studies examining the familiar face processing system have used college-aged subjects. However, memory disorders, like those associated with Alzheimer's disease, typically affect adults over sixty. In an attempt to reveal possible differences between young and older adults', two different age groups were subjected to fMRI analysis while viewing face images with varying familiarity (family, famous and novel). The result showed a significant difference in activations for various cortical areas including the precuneus, cingulate cortex, and fusiform gyrus. Among the differences, an overall trend of greater activation in the left hemisphere for younger subjects compared to the older group was revealed. The results have implications for the study of memory disorders afflicting older adults, like Alzheimer's disease.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fcla/dt/13358
- Subject Headings
- Brain--Magnetic resonance imaging, Evoked potentials (Electrophysiology), Memory, Cognition--Age factors, Aging--Psychological aspects, Memory disorders in old age
- Format
- Document (PDF)