Serão oradores Vasco de Almeida (Departamento de Física da UBI) e Marta Teixeira, do IBILI de Coimbra.
Resumo:
ERP (event related potential) responses to infrequent, task relevant stimuli, often include an attention related component, the P300, occurring independently from target sensory modality, whenever a discrimination task is required. In this study we wanted to investigate the relation between the psychophysical detection of low-level sub and supraliminal visual features and their neurophysiological correlates at the event level (single trial). For that we have conducted 2 experimental oddball tasks, manipulating sub and supraliminal physical variations in feature intensity of colour, luminance and phase offset perceptual modalities and inspected their output in the P300 ERP component. Single trial P300 classification results showed that this component can be detected in single cognitive events and proved the detection of subliminal stimuli of which the subject is unaware. We conclude that it is possible to establish direct links between psychophysical events of distinct salience intensities and neurophysiological responses at the event level.