title: Looking for a face in the crowd: fixation-related potentials in an eye-movement visual search task.
abstract: Despite the compelling contribution of the study of event related potentials (ERPs) and eye movements to cognitive neuroscience, these two approaches have largely evolved independently. We designed an eye-movement visual search paradigm that allowed us to concurrently record EEG and eye movements while subjects were asked to find a hidden target face in a crowded scene with distractor faces. Fixation event-related potentials (fERPs) to target and distractor stimuli showed the emergence of robust sensory components associated with the perception of stimuli and cognitive components associated with the detection of target faces. We compared those components with the ones obtained in a control task at fixation: qualitative similarities as well as differences in terms of scalp topography and latency emerged between the two. By using single trial analyses, fixations to target and distractors could be decoded from the EEG signals above chance level in 11 out of 12 subjects. Our results show that EEG signatures related to cognitive behavior develop across spatially unconstrained exploration of natural scenes and provide a first step towards understanding the mechanisms of target detection during natural search.
authors.affiliation: Department of Engineering, University of Leicester, Leicester LE1 7RH, UK.
authors.forename: Lisandro N
authors.initials: LN
authors.lastname: Kaunitz
authors.affiliation: Laboratorio de Neurociencia Integrativa, Departamento de Física, FCEyN UBA and IFIBA, Conicet, Pabellón 1, Ciudad Universitaria, 1428 Ciudad Autónoma de Buenos Aires, Argentina; Universidad Diego Portales, Santiago, Chile.
authors.forename: Juan E
authors.initials: JE
authors.lastname: Kamienkowski
authors.affiliation: Department of Engineering, University of Leicester, Leicester LE1 7RH, UK; Centre for Systems Neuroscience, University of Leicester, Leicester LE1 7QR, UK.
authors.forename: Alexander
authors.initials: A
authors.lastname: Varatharajah
authors.affiliation: Laboratorio de Neurociencia Integrativa, Departamento de Física, FCEyN UBA and IFIBA, Conicet, Pabellón 1, Ciudad Universitaria, 1428 Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Mariano
authors.initials: M
authors.lastname: Sigman
authors.affiliation: Department of Engineering, University of Leicester, Leicester LE1 7RH, UK; Centre for Systems Neuroscience, University of Leicester, Leicester LE1 7QR, UK.
authors.forename: Rodrigo Quian
authors.initials: RQ
authors.lastname: Quiroga
authors.affiliation: Department of Engineering, University of Leicester, Leicester LE1 7RH, UK; Centre for Systems Neuroscience, University of Leicester, Leicester LE1 7QR, UK. Electronic address: mji3@le.ac.uk.
authors.forename: Matias J
authors.initials: MJ
authors.lastname: Ison
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D005074:Evoked Potentials, Visual; D005145:Face; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology*; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D012438:Saccades / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*; D055815:Young Adult
keywords: EEG; Faces; Natural scenes; Oddball; Visual search