Event-related brain potentials and pupillary responses using a cognitive task in monozygotic twins.
Item
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Title
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Event-related brain potentials and pupillary responses using a cognitive task in monozygotic twins.
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Identifier
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AAI9119629
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identifier
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9119629
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Creator
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Gaudreau, Louise Pauline.
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Contributor
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Adviser: Gad Hakerem
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Date
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1991
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology, Physiological
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Abstract
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This study recorded pupillary and event-related potential (ERP) responses in seven pairs of monozygotic (MZ) twins under two task conditions. The stimuli in both tasks were four possible combinations of a high (2400 Hz) and low (1700 Hz) tone. Task 1 required the subject to guess whether an equiprobable "same" or "different" pair would be presented; the tone pair then presented provided feedback. In Task 2, the guess was "high" or "low" and the exact order of the tones determined four possible outcomes. A "high" guess followed by a high/high pair was a "win confirmed" while a high/low pair resulted in a "win cancelled". The two main objectives were first to determine if MZ twins exhibited a high degree of similarity on their waveforms and second if intertask differences would emerge. The results for the pupil responses showed no task differences in either overall shape, peak dilation or latency of the waveforms. Visual inspection supports a high degree of similarity in the cotwins. The ERP results contrasted the MZ pairs with mean scores for all possible nontwin pairings for each twin in the sample. Naive judges performed considerably above chance (25%) in matching cotwin waveforms (Task 1 50%; Task 2 61%) using a forced choice technique. Larger correlations for twins than nontwins were statistically significant for the whole waveform, first and second half independently. For both groups Task 1 resulted in larger correlations in the waveforms, especially at Cz and Pz. The component amplitudes for {dollar}\rm S\sb1N\sb1{dollar}, {dollar}\rm S\sb1P\sb2{dollar} and {dollar}\rm S\sb2N\sb1{dollar} (S{dollar}\sb1{dollar}/S{dollar}\sb2{dollar} first/second stimulus of pair) were more similar for twins than nontwins while P3 amplitudes were not. Task 1 produced more similar amplitudes in both groups compared to Task 2. The direct amplitude measurements of the 14 twins showed {dollar}\rm S\sb1N\sb1{dollar} and {dollar}\rm S\sb2P\sb3{dollar} to be the largest, as anticipated, yet smaller at Fz. The only latency differences were greater similarity for twins than nontwins for {dollar}\rm S\sb1N\sb1{dollar} and {dollar}\rm S\sb1P\sb2{dollar}. The MZ twins were quite similar in their overall response patterns. The ERP waveforms were more sensitive to task differences with Task 1 showing more overall similarity. A substantial familial contribution was postulated to determine functional processes, as well as, the underlying structural units.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
