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<p> The binary choice Fast Guess Model of Ollman and Yellott was generalized to a multiple choice model and six subjects were run in a choice reaction time task to test the model. Stimulus set sizes of two, four and six were used and response accuracy and speed motivation was manipulated through specific instructions which were changed from trial to trial. Three different motivational instructions were used. In all cases, subjects were to respond with maximum accuracy but were also told on each trial to either disregard the duration of their response, respond within 440 milliseconds or respond within 300 milliseconds.</p> <p> The generalized Fast Guess Model was rejected because response time parameters of the SCR state were found to change across response accuracy-speed motivation instructions and across stimulus set sizes. Implications of these results for other classes of models were also discussed.</p> / Thesis / Doctor of Philosophy (PhD)

Mobility is essential for the independent lifestyle. However, as the US population ages, challenges to mobility start to arise, among them just the aging itself which leads to decreased postural stability, falls and the second most common neurodegenerative disease, that is Parkinson’s disease (PD). We decided to investigate step initiation as it is crucial to mobility: walking is not possible without the first step. Step initiation is impaired in PD. However, the impact of PD on the neural mechanisms of step initiation when some of the step parameters are unpredictable remains unexplored. Cortical preparation for step initiation can be assessed by beta event-related desynchronization (ERD) derived from electroencephalography (EEG) recordings. We hypothesized that subjects with PD would exhibit less cortical modulation between conditions of forward step initiation with and without prior knowledge of limb choice. Further, we hypothesized that decreased cortical modulation in PD would associate with a higher impairment of motor performance. Results identified that the group with PD exhibited decreased beta ERD amplitudes that were similar regardless of condition, whereas control subjects modulated beta ERD amplitudes between conditions, particularly in early stages of pre-movement processing in areas overlying sensory cortex. Subjects with PD presented with delayed and reduced postural preparation with increased step target error across both conditions and exhibited a greater incidence of multiple anticipatory postural adjustments (APAs) in the predictable relative to the unpredictable condition. Delayed postural preparation significantly correlated with lower amplitudes of beta ERD. We concluded that diminished early pre-movement processing over sensory cortex was concomitant with poor pre-selection of the stepping limb in predictable conditions and that a generally diminished amplitude of cortical pre-movement processing relates to delayed step initiation in people with PD. Furthermore, impaired mobility accompanies healthy aging, but there is a need for deeper understanding of how aging changes central control of motor behavior. Using previous study’s method, we compared cortical preparation for step initiation using beta ERD in young and older healthy subjects performing forward steps with and without prior knowledge of limb choice. Our results show that older subjects exhibited increased beta ERD amplitudes before the step regardless of whether they were informed of limb choice or not. Moreover, older subjects exhibited early increases in beta ERD in the “sensory” cluster of electrodes, but only when full limb-choice information was available. Behaviorally, the older subjects also exhibited shortened and increased anticipatory postural adjustments which led to earlier step initiation and similar swing-foot velocities but was also accompanied by greater target step placement errors and decreased postural stability. For the older group, condition-related increases in beta ERD amplitudes and stability correlated with condition-related prolongation of APA durations. We conclude that older subjects exhibited a spectrum across two strategies: (1) a “fast” strategy associated with decreased neural preparation that trades shortened step preparation and higher swing-foot velocity for target step errors and lowered postural stability; and (2) an “accurate” strategy associated with greater neural preparation, longer step-preparation time, and higher stability during step execution. In conclusion, this thesis provides more support for beta ERD as a useful tool for studying cortical preparation non-invasively. We have also established the importance of the signals recorded by “sensory” clusters: in subjects with PD the absence of beta ERD similar to the control group was associated with impaired motor behavior even when conditions were predictable. Similarly, a part of the older group seemed to pre-potentiate its cortex lying beneath the cluster of “sensory” electrodes which was associated with more safe and accurate steps. Further investigations should focus on the importance of sensorimotor integration and its’ changes due to PD or healthy aging and beta ERD may be an excellent tool for this task.

Objetivo Desenvolver um teste psicofísico apoiado em tecnologia móvel em que o desempenho do participante possa revelar à influência da ingestão de álcool pelas alterações cognitivas e motoras produzidas por essa droga. Método Foram 3 protocolos experimentais preliminares. Protocolo experimental 1: Um total de 11 participantes (6 homens e 5 mulheres, de 30 a 53 anos) executaram um teste de tempo de reação go-no-go a três estímulos (semáforo verde:go, semáforo vermelho: no-go, semáforo amarelo: no-go e um estímulo preparatório: semáforo apagado). Protocolo experimental 2: Um total de 13 participantes (mulheres, de 18 a 37 anos) executaram 3 testes: a) Teste de tempo de reação escolha a três estímulos (semáforo verde, semáforo vermelho, semáforo amarelo) e um estímulo preparatório (semáforo apagado). b) Teste de memória em que a tarefa era a de pressionar um botão informando se a imagem que aparecia na tela era nova e outro botão caso a imagem fosse repetida. c) Teste de associação em que a tarefa era a de associar figuras a um número seguindo uma tabela de comparação. Protocolo experimental 3: Um total de 8 participantes (5 homens e 2 mulheres, de 22 a 42 anos) executaram os mesmos testes aplicados no protocolo experimental 2 com apenas uma diferença em uma das tarefas do teste de tempo de reação escolha. A análise de dados privilegiou a análise dos tempos de reação e o índice de acertos. Resultados Protocolo experimental 1 Os testes pareados, tanto para os tempos de reação (t(5)=0,199, p=0,850), quanto para a quantidade de erros (t(5)=0,675, p=0,529), não apontaram nenhuma diferença significativa entre as condições sem e com álcool. Resultados Protocolo experimental 2 As ANOVAs-MR dos tempos de reação e do número de erros do teste de reação escolha não revelaram diferenças significativas para a condição (F(2,36)=1,175, p=0.315, hp 2 =0.32 e F(2,36)=1.944, p=0.165, respectivamente), para cor de semáforo (F(2,36)=0.289, p>0.5, hp 2 =0.16) e tampouco para interação condição x cor de semáforo (F(2,36)=0,355, p=0.840, hp 2 =0.19). No teste de memória, as ANOVAs-MR não revelaram nenhuma 6 diferença significativa para a condição dos tempos de reação (F(2,36)=0,693, p>0,05, n2 =0,05). No teste de associação uma ANOVA-MR revelou uma diferença significativa nos tempos de reação F(2,36)=4,924, p=0,016, n2=0,291), porém nenhuma diferença foi encontrada para erros absolutos (F(2,36)=0,255, p>0,5, n2=0,090) e erros absolutos (F(2,36)=0,255, p>0.5, n=0,02) para a condição sem álcool e com álcool acima de 0.06 %BAC. Resultados Protocolo experimental 3 No teste de tempo de reação escolha não houve indícios de diferenças significantes para as condições com e sem álcool. Os níveis descritivos encontrados no teste Kruskall-Walis foram 0,309, 0,222 e 0,323 para percentual de acerto, tempo médio de reação verde e vermelho, respectivamente. No teste de memória nenhuma das variáveis de tempo de reação (média, maior e menor) apresentou indícios estatisticamente significantes (p-valores 0,633 0,975 e 0,431, respectivamente), tampouco o padrão e indices descritivos (p=0,238) para a média de acertos e o número de acertos. No teste de associação a variável tempo de resposta apresentou evidências estatisticamente significantes de que os grupos não apresentaram valores médios e medianos iguais entre si (p<0,001), houve evidências de que o grupo de 0 a 0,1 %BAC e maior de 0,1 %BAC eram diferentes entre si (p=0,003). Discussão Parece promissor a realização do teste de associação com um aumento da carga cognitiva afim de poder verificar diferenças mesmo quando o indivíduo consumir pequenas doses de álcool. Considerações Finais Os resultados expostos acima dão margem a otimismo e abrem um amplo horizonte de perspectivas em situações ecológicas da vida real, e não mais nas situações tradicionais e artificiais de laboratório, estendendo o ambiente de experimentação e viabilizando a coleta de grandes conjuntos de dados / Objective To Develop a psychophysical test supported by mobile technology in which the performance of the participant could reveal the influence of alcohol intake by cognitive and motor changes produced by this drug. Method There were 3 preliminary experiments. Experiment 1: A total of 11 participants (6 males and 5 females, 30-53 years) performed a go-no-go reaction time test to three stimuli (green traffic light: go, red trafic light: no-go, yellow trafic light: no-go and a preparatory stimulus: black trafic light). Experiment 2: A total of 13 participants (women, 18-37 years) performed three tests: a) A choice reaction time test to three stimuli (green trafic light, red trafic light, yellow trafic light) and a preparatory stimulus (black trafic light). b) A memory test where the task was to press a button stating that the image that was displayed on the screen was new and another button stating that the image was repeated. c) An association test where the task was to associate figures to a number, following a comparison chart. Experiment 3: A total of 8 participants (5 men and 2 women, 22 to 42 years) performed the same tests applied in experiment number 2 with only one difference in a task of the choice reaction time test. Data analysis focused on standart deviations and coefficients of variation. Results Experiment 1 A paired test for both, reaction times (t (5) = 0.199, p = 0.850) and for the number of errors (t (5) = 0.675, p = 0.529) did not show any significant difference between the conditions with and without alcohol. Results Experiment 2 In the choice reaction time test the ANOVAs 2-MR reaction times and the number of reaction errors revealed no significant differences in both conditions (F (2,36) = 1.175, p = 0.315, HP2 and F = 12:32 (2, 36) = 1.944, p = 0.165, respectively) for color signal (F (2,36) = 0.289, p> 0.5, HP2 = 0:16) and also for condition x color signal (F (2,36) = 0.355, p = 0.840, hp2 = 12:19). In the memory test, the ANOVAs-MR showed no significant differences of the reaction time in all conditions (F (2,36) = 0.693, p> 0.05, n2 = 0.05). In the association test ANOVA-MR revealed a significant difference in 8 reaction times F (2,36) = 4.924, p = 0.016, n 2 = 0.291), but no difference was found for absolute errors (F (2,36) = 0.255, p> 0.5, n2 = 0.090) and absolute errors (F (2,36) = 0.255, p> 0.5, n = 0.02) for the alcohol and alcohol above condition 0.06% BAC. Results Experiment 3 In the choice reaction time test there were no significant evidence of a difference between their position values for the condition with and without alcohol. Descriptive levels found in the Kruskal-Wallis test were 0.309, 0.222 and 0.323 for percentage of correct answers, average reaction time of green and red, respectively. In the memory test, none of the reaction time variables (average, highest and lowest) showed statistically significant evidence (p-value 0.633 0.975 and 0.431, respectively), p-value standard (p = 0.238) for the mean score and the number of hits. In the association test the time variable response presented significant statistically evidence that the groups didnt have mean values equal to each other (p <0.001) there were evidence that the group 0 to 0.1% BAC, and the group larger than 0,1% BAC were different from each other (p = 0.003.) Discussion It sounds promising do to more research with the association test with an increase of the cognitive challange in order to verify differences even when the individual takes use of small doses of alcohol. Conlusion The results presented above give rise to optimism and open up a wide horizon of perspectives on ecological situations of real life, and not just in the traditional and artificial situations of the laboratory, extending the experimentation environment and enabling the collection of large data sets

Objetivo Desenvolver um teste psicofísico apoiado em tecnologia móvel em que o desempenho do participante possa revelar à influência da ingestão de álcool pelas alterações cognitivas e motoras produzidas por essa droga. Método Foram 3 protocolos experimentais preliminares. Protocolo experimental 1: Um total de 11 participantes (6 homens e 5 mulheres, de 30 a 53 anos) executaram um teste de tempo de reação go-no-go a três estímulos (semáforo verde:go, semáforo vermelho: no-go, semáforo amarelo: no-go e um estímulo preparatório: semáforo apagado). Protocolo experimental 2: Um total de 13 participantes (mulheres, de 18 a 37 anos) executaram 3 testes: a) Teste de tempo de reação escolha a três estímulos (semáforo verde, semáforo vermelho, semáforo amarelo) e um estímulo preparatório (semáforo apagado). b) Teste de memória em que a tarefa era a de pressionar um botão informando se a imagem que aparecia na tela era nova e outro botão caso a imagem fosse repetida. c) Teste de associação em que a tarefa era a de associar figuras a um número seguindo uma tabela de comparação. Protocolo experimental 3: Um total de 8 participantes (5 homens e 2 mulheres, de 22 a 42 anos) executaram os mesmos testes aplicados no protocolo experimental 2 com apenas uma diferença em uma das tarefas do teste de tempo de reação escolha. A análise de dados privilegiou a análise dos tempos de reação e o índice de acertos. Resultados Protocolo experimental 1 Os testes pareados, tanto para os tempos de reação (t(5)=0,199, p=0,850), quanto para a quantidade de erros (t(5)=0,675, p=0,529), não apontaram nenhuma diferença significativa entre as condições sem e com álcool. Resultados Protocolo experimental 2 As ANOVAs-MR dos tempos de reação e do número de erros do teste de reação escolha não revelaram diferenças significativas para a condição (F(2,36)=1,175, p=0.315, hp 2 =0.32 e F(2,36)=1.944, p=0.165, respectivamente), para cor de semáforo (F(2,36)=0.289, p>0.5, hp 2 =0.16) e tampouco para interação condição x cor de semáforo (F(2,36)=0,355, p=0.840, hp 2 =0.19). No teste de memória, as ANOVAs-MR não revelaram nenhuma 6 diferença significativa para a condição dos tempos de reação (F(2,36)=0,693, p>0,05, n2 =0,05). No teste de associação uma ANOVA-MR revelou uma diferença significativa nos tempos de reação F(2,36)=4,924, p=0,016, n2=0,291), porém nenhuma diferença foi encontrada para erros absolutos (F(2,36)=0,255, p>0,5, n2=0,090) e erros absolutos (F(2,36)=0,255, p>0.5, n=0,02) para a condição sem álcool e com álcool acima de 0.06 %BAC. Resultados Protocolo experimental 3 No teste de tempo de reação escolha não houve indícios de diferenças significantes para as condições com e sem álcool. Os níveis descritivos encontrados no teste Kruskall-Walis foram 0,309, 0,222 e 0,323 para percentual de acerto, tempo médio de reação verde e vermelho, respectivamente. No teste de memória nenhuma das variáveis de tempo de reação (média, maior e menor) apresentou indícios estatisticamente significantes (p-valores 0,633 0,975 e 0,431, respectivamente), tampouco o padrão e indices descritivos (p=0,238) para a média de acertos e o número de acertos. No teste de associação a variável tempo de resposta apresentou evidências estatisticamente significantes de que os grupos não apresentaram valores médios e medianos iguais entre si (p<0,001), houve evidências de que o grupo de 0 a 0,1 %BAC e maior de 0,1 %BAC eram diferentes entre si (p=0,003). Discussão Parece promissor a realização do teste de associação com um aumento da carga cognitiva afim de poder verificar diferenças mesmo quando o indivíduo consumir pequenas doses de álcool. Considerações Finais Os resultados expostos acima dão margem a otimismo e abrem um amplo horizonte de perspectivas em situações ecológicas da vida real, e não mais nas situações tradicionais e artificiais de laboratório, estendendo o ambiente de experimentação e viabilizando a coleta de grandes conjuntos de dados / Objective To Develop a psychophysical test supported by mobile technology in which the performance of the participant could reveal the influence of alcohol intake by cognitive and motor changes produced by this drug. Method There were 3 preliminary experiments. Experiment 1: A total of 11 participants (6 males and 5 females, 30-53 years) performed a go-no-go reaction time test to three stimuli (green traffic light: go, red trafic light: no-go, yellow trafic light: no-go and a preparatory stimulus: black trafic light). Experiment 2: A total of 13 participants (women, 18-37 years) performed three tests: a) A choice reaction time test to three stimuli (green trafic light, red trafic light, yellow trafic light) and a preparatory stimulus (black trafic light). b) A memory test where the task was to press a button stating that the image that was displayed on the screen was new and another button stating that the image was repeated. c) An association test where the task was to associate figures to a number, following a comparison chart. Experiment 3: A total of 8 participants (5 men and 2 women, 22 to 42 years) performed the same tests applied in experiment number 2 with only one difference in a task of the choice reaction time test. Data analysis focused on standart deviations and coefficients of variation. Results Experiment 1 A paired test for both, reaction times (t (5) = 0.199, p = 0.850) and for the number of errors (t (5) = 0.675, p = 0.529) did not show any significant difference between the conditions with and without alcohol. Results Experiment 2 In the choice reaction time test the ANOVAs 2-MR reaction times and the number of reaction errors revealed no significant differences in both conditions (F (2,36) = 1.175, p = 0.315, HP2 and F = 12:32 (2, 36) = 1.944, p = 0.165, respectively) for color signal (F (2,36) = 0.289, p> 0.5, HP2 = 0:16) and also for condition x color signal (F (2,36) = 0.355, p = 0.840, hp2 = 12:19). In the memory test, the ANOVAs-MR showed no significant differences of the reaction time in all conditions (F (2,36) = 0.693, p> 0.05, n2 = 0.05). In the association test ANOVA-MR revealed a significant difference in 8 reaction times F (2,36) = 4.924, p = 0.016, n 2 = 0.291), but no difference was found for absolute errors (F (2,36) = 0.255, p> 0.5, n2 = 0.090) and absolute errors (F (2,36) = 0.255, p> 0.5, n = 0.02) for the alcohol and alcohol above condition 0.06% BAC. Results Experiment 3 In the choice reaction time test there were no significant evidence of a difference between their position values for the condition with and without alcohol. Descriptive levels found in the Kruskal-Wallis test were 0.309, 0.222 and 0.323 for percentage of correct answers, average reaction time of green and red, respectively. In the memory test, none of the reaction time variables (average, highest and lowest) showed statistically significant evidence (p-value 0.633 0.975 and 0.431, respectively), p-value standard (p = 0.238) for the mean score and the number of hits. In the association test the time variable response presented significant statistically evidence that the groups didnt have mean values equal to each other (p <0.001) there were evidence that the group 0 to 0.1% BAC, and the group larger than 0,1% BAC were different from each other (p = 0.003.) Discussion It sounds promising do to more research with the association test with an increase of the cognitive challange in order to verify differences even when the individual takes use of small doses of alcohol. Conlusion The results presented above give rise to optimism and open up a wide horizon of perspectives on ecological situations of real life, and not just in the traditional and artificial situations of the laboratory, extending the experimentation environment and enabling the collection of large data sets