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Evoked Response Potential (ERP) and Face Stimuli . N170: negative-going potential at 170 ms Largest over the right parietal lobe, also on the left parietal lobe. From Tanaka and Curran (2001). An Experiment. Show Faces and Words Embedded in Noise:. High Contrast Faces. Low Contrast Faces.
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Evoked Response Potential (ERP) and Face Stimuli • N170: negative-going potential at 170 ms • Largest over the right parietal lobe, also on the left parietal lobe. From Tanaka and Curran (2001)
An Experiment • Show Faces and Words Embedded in Noise: High Contrast Faces Low Contrast Faces Low Contrast Words High Contrast Words Noise Alone
High Contrast Faces Low Contrast Faces Low Contrast Words High Contrast Words Noise Alone The Important Stuff: For Noise-Alone Trials: * t(9) = 2.74, p = .023 Amplitude (V)
Main Result: • On noise-alone trials: Larger N170 when observers report seeing a face than when report seeing a word. • Occurs in 9 of the 10 subjects. • No other differences in any other channel at the P100, N170 or P300 components. • Unlikely to just reflect activity for an already-made decision. • Relates activity in the perceptual processing areas to the behavioral response. Greater activity in the N170 neurons is associated with ‘face’ responses to the noise-alone stimulus. One interpretation: Greater activity in the face processing region biases the response towards a ‘face’ response.