Abstract
BACKGROUND: Understanding the underlying neuronal mechanism for three-dimensional object recognition is a challenging research theme. Event-related potentials (ERPs) has been frequently reported to be related to object recognition learning1, 2. We previously reported3 that the ERP component of N1 of subjects with object discrimination learning experience was significantly different from those without learning. However, its dependence to the performance of object discrimination remains unclear. AIMS & OBJECTIVES: The purpose of this study is to understand how the ERP components changes accompanying to object recognition learning. We investigated the relation between the ERP components and the performance of object discrimination task. METHODS: Thirty three university students participated in the experiment (ages 18–25 years, with the mean age of 22.4). The experiment was approved by the research Ethics Committee of Kagoshima University (H29SE001), all procedures are conducted under the guidance of human research. High-density electroencephalograms were recorded while participants trained themselves with novel objects by performing an object recognition task. Two object sets, each of them comprised 4 objects with 4 different views, were used in the experiment. We recorded in the first training session and the session once after reaching criterion performance of 80%. ERPs were obtained averaged for the first 100 artifact-free trials of first training session and last 100 artifact-free trials of the session after enough training. RESULTS: We analyzed the ERP component, N1, obtained during the presentation of sample images. In any of the conditions, we could always confirm a significant negative peak at about 150 ms after stimulus onset. It usually demonstrated a dominant peak of N1 at electrode T5 or T6. As shown in Figure 1, the N1 amplitudes at T6 were plotted against the performance of the object discrimination task. The amplitude demonstrated statistical positive correlation to the performance (r = 0.37, p <0.05). DISCUSSION & CONCLUSION: Considering the continuum of object discrimination task performance, we selected to use the correlation between the electrophysiological ERP features and behavioral performance. In the present study, we demonstrated significant correlation between the N1 amplitude and the object discrimination task performance. Such significance of correlation suggests the existence of good indices for the evaluation of the behavioral performance by ERP features. It is expected of the application of such electrophysiological indices in others such as brain-machine-interface. REFERENCES: 1.Tanaka, J. et al. (1999) ‘Tracking the time course of object categorization using event-related potentials’, Neuroreport, 10, pp. 829–835. 2.Vogel, E.K. and Luck, S.J. (2000) ‘The visual N1 component as an index of a discrimination process’, Psychophysiology, 37, pp. 190–203. 3.Wang, G. and Kameda, S. (2005) ‘Event-related potential component associated with the recognition of three-dimensional objects’, Neuroreport, 16, pp. 767–771.