-
[show abstract]
[hide abstract]
ABSTRACT: Emotionally negative stimuli serve as a mechanism of biological preparedness to enhance attention. We hypothesized that emotionally negative stimuli would also serve as motivational priming to increase attention resources for subsequent stimuli. To that end, we tested 11 participants in a dual sensory modality task, wherein emotionally negative pictures were contrasted with emotionally neutral pictures and each picture was followed 600 ms later by a tone in an auditory oddball paradigm. Each trial began with a picture displayed for 200 ms; half of the trials began with an emotionally negative picture and half of the trials began with an emotionally neutral picture; 600 ms following picture presentation, the participants heard either an oddball tone or a standard tone. At the end of each trial (picture followed by tone), the participants categorized, with a button press, the picture and tone combination. As expected, and consistent with previous studies, we found an enhanced visual late positive potential (latency range=300-700 ms) to the negative picture stimuli. We further found that compared to neutral pictures, negative pictures resulted in early attention and orienting effects to subsequent tones (measured through an enhanced N1 and N2) and sustained attention effects only to the subsequent oddball tones (measured through late processing negativity, latency range=400-700 ms). Number pad responses to both the picture and tone category showed the shortest response latencies and greatest percentage of correct picture-tone categorization on the negative picture followed by oddball tone trials. Consistent with previous work on natural selective attention, our results support the idea that emotional stimuli can alter attention resource allocation. This finding has broad implications for human attention and performance as it specifically shows the conditions in which an emotionally negative stimulus can result in extended stimulus evaluation.
International journal of psychophysiology: official journal of the International Organization of Psychophysiology 01/2012; 83(1):36-44. · 3.05 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The onset and time-course of HIV-associated cognitive deficits are not well established. The present experiment compared physiological and neurometric assessments of cognitive decline in HIV-asymptomatic, HIV-symptomatic, and HIV-negative control adult women. The P3 component of standard auditory, event-related electrical potentials of the brain (ERP) and standard neurometric (pencil and paper) test scores were recorded. The P3 ERP measures differentiated both of the clinical HIV groups from the control group. In contrast, the neurometric measures were more sensitive to the difference in cognitive decline between the two clinical groups. It is concluded that both P3 ERP measures and standard neurometric tests are individually useful and complementary for tracking cognitive decline in the diagnosis and treatment of opportunistic HIV-associated central nervous system impairments.
Neuroreport 08/2004; 15(10):1675-8. · 1.66 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Mismatch negativity (MMN), a component of the event-related potential, reflects the processing associated with low-probability (deviant) stimuli over and above that required for high-probability (standard) stimuli. Occurring 100-250 ms post stimulus, MMN is evident in the enhanced negativity generated in response to deviant relative to standard stimuli. Traditionally, the MMN waveform is calculated by subtracting the averaged waveform of all standard stimuli from the averaged waveform of all deviant stimuli collected during the same test session. To investigate whether an unbroken, extended string of standard stimuli may minimize baseline processing, thereby resulting in a more robust measure of MMN, 11 participants were exposed to two contiguous blocks of 1000 trials, each beginning with 60 uninterrupted standard stimuli followed by 940 randomized standard and deviant trials. Negativity related to standard stimuli was minimized in the average of uninterrupted standard stimuli from the second block of trials only while negativity related to uninterrupted standards in the first block of trials was increased relative to all other conditions. The present findings suggest that a familiar, uninterrupted string of standard stimuli, presented midway through an experimental session, may provide a useful alternative baseline for the calculation of MMN.
International Journal of Psychophysiology 03/2004; 51(3):201-8. · 2.14 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The onset and time-course of HIV-associated cognitive de¢cits are not well established. The present experiment compared physiolo-gical and neurometric assessments of cognitive decline in HIV-asymptomatic, HIV-symptomatic, and HIV-negative control adult women. The P3 component of standard auditory, event-related electrical potentials of the brain (ERP) and standard nerurometric (pencil and paper) test scores were recorded.The P3 ERP measures di¡erentiated both of the clinical HIV groups from the control group. In contrast, the neurometric measures were more sensitive to the di¡erence in cognitive decline between the two clinical groups. It is concluded that both P3 ERP measures and standard neurometric tests are individually useful and complementary for tracking cognitive decline in the diagnosis and treatment of opportunistic HIV-associated central nervous system impair-ments. NeuroReport 15:1675^1678 c 2004 Lippincott Williams & Wilkins.
