Ocular artifacts in EEG and event-related potentials I: Scalp topography

Lins, Otávio Gomes; Picton, Terence W.; Berg, Patrick; Scherg, Michael

doi:10.1007/bf01234127

Cited by 296 publications

(236 citation statements)

References 32 publications

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“…The idea that electrophysiological findings can be explained by oculomotor behavior is not new (Walter, 1938), nor does it seem that we have stopped finding potentially interesting effects that might simply be due to even small eye movements (e.g., Yuval-Greenberg, Tomer, Keren, Nelken, & Deouell, 2008). The electrical artifact caused by a blink or saccadic eye movement of more than 1-2 degrees is fairly large (approximately 16 μV per degree of eye movement) and can be detected with electrooculogram (EOG) recordings (Hillyard & Galambos, 1970; Lins, Picton, Berg, & Scherg, 1993). These EOG recordings are good at detecting blinks and changes in eye position caused by saccades relative to fixation but are not sensitive to slow shifts in fixation that accumulate across trials (e.g., when the task-relevant stimuli always appear at the same peripheral location).…”

Section: Fundamentals Of Rigorous Erp Studiesmentioning

confidence: 99%

A brief introduction to the use of event-related potentials in studies of perception and attention

Woodman

2010

Attention, Perception & Psychophysics

252

205

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Due to the precise temporal resolution of electrophysiological recordings, the event-related potential (ERP) technique has proven particularly valuable for testing theories of perception and attention. Here, I provide a brief tutorial of the ERP technique for consumers of such research and those considering the use of human electrophysiology in their own work. My discussion begins with the basics regarding what brain activity ERPs measure and why they are well suited to reveal critical aspects of perceptual processing, attentional selection, and cognition that are unobservable with behavioral methods alone. I then review a number of important methodological issues and often forgotten facts that should be considered when evaluating or planning ERP experiments.

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Section: Fundamentals Of Rigorous Erp Studiesmentioning

confidence: 99%

A brief introduction to the use of event-related potentials in studies of perception and attention

Woodman

2010

Attention, Perception & Psychophysics

252

205

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“…Saccade potentials are caused by rotation of this corneoretinal dipole. Blink potentials are caused by the eyelid sliding down over the positively charged cornea, permitting current to flow up toward the forehead region~Lins, Picton, Berg, & Scherg, 1993a;Matsuo, Peters, & Reilly, 1975!. Contrary to widespread beliefs, the eyeball does not roll upward during normal blinks~Collewijn, Van Der Steen, & Steinman, 1985!.…”

Section: (Iv) Artifact Compensation Procedures Must Be Documented Clementioning

confidence: 99%

Guidelines for using human event-related potentials to study cognition: Recording standards and publication criteria

et al. 2000

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Event-related potentials~ERPs! recorded from the human scalp can provide important information about how the human brain normally processes information and about how this processing may go awry in neurological or psychiatric disorders. Scientists using or studying ERPs must strive to overcome the many technical problems that can occur in the recording and analysis of these potentials. The methods and the results of these ERP studies must be published in a way that allows other scientists to understand exactly what was done so that they can, if necessary, replicate the experiments. The data must then be analyzed and presented in a way that allows different studies to be compared readily. This paper presents guidelines for recording ERPs and criteria for publishing the results.Descriptors: Event-related potentials, Methods, Artifacts, Measurement, Statistics Event-related potentials~ERPs! are voltage fluctuations that are associated in time with some physical or mental occurrence. These potentials can be recorded from the human scalp and extracted from the ongoing electroencephalogram~EEG! by means of filtering and signal averaging. Although ERPs can be evaluated in both frequency and time domains, these particular guidelines are concerned with ERPs recorded in the time domain, that is, as waveforms that plot the change in voltage as a function of time. These waveforms contain components that span a continuum between the exogenous potentials~obligatory responses determined by the physical characteristics of the eliciting event in the external world! and the endogenous potentials~manifestations of information processing in the brain that may or may not be invoked by the eliciting event!.1 Because the temporal resolution of these measurements is on the order of milliseconds, ERPs can accurately measure when processing activities take place in the human brain. The spatial resolution of ERP measurements is limited both by theory and by our present technology, but multichannel recordings can allow us to estimate the intracerebral locations of these cerebral processes. The temporal and spatial information provided by ERPs may be used in many different research programs, with goals that range from understanding how the brain implements the mind to making specific diagnoses in medicine or psychology. Data cannot have scientific value unless they are published for evaluation and replication by other scientists. These ERP guidelines are therefore phrased primarily in terms of publication criteria. The scientific endeavor consists of three main steps, and these map well onto the sections of the published paper. The first step is the most important but the least well understood-the discovery of Address reprint requests to: Terence W. Picton, Rotman Research Institute,

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“…A participant's data were kept if after removal of these epochs at least two thirds of the trials remained and the HEOG did not exceed 4 μV at any time sample after averaging across trials (similar to Woodman and Luck, 2003b). This corresponds to~0.25°and a propagated voltage of~0.1 μV at posterior channels (Lins et al, 1993). For the remainder of the epoch (600-2500 ms), participant-specific thresholds removed drifts and eye blinks observed on scalp channels, while retaining the speaking-related motor activity that was part of the task.…”

Section: Eeg Recording and Preprocessingmentioning

confidence: 99%

Lateralized electrical brain activity reveals covert attention allocation during speaking

2017

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A B S T R A C TSpeakers usually begin to speak while only part of the utterance has been planned. Earlier work has shown that speech planning processes are reflected in speakers' eye movements as they describe visually presented objects. However, to-be-named objects can be processed to some extent before they have been fixated upon, presumably because attention can be allocated to objects covertly, without moving the eyes. The present study investigated whether EEG could track speakers' covert attention allocation as they produced short utterances to describe pairs of objects (e.g., "dog and chair"). The processing difficulty of each object was varied by presenting it in upright orientation (easy) or in upside down orientation (difficult). Background squares flickered at different frequencies in order to elicit steady-state visual evoked potentials (SSVEPs). The N2pc component, associated with the focusing of attention on an item, was detectable not only prior to speech onset, but also during speaking. The time course of the N2pc showed that attention shifted to each object in the order of mention prior to speech onset. Furthermore, greater processing difficulty increased the time speakers spent attending to each object. This demonstrates that the N2pc can track covert attention allocation in a naming task. In addition, an effect of processing difficulty at around 200-350 ms after stimulus onset revealed early attention allocation to the second to-be-named object. The flickering backgrounds elicited SSVEPs, but SSVEP amplitude was not influenced by processing difficulty. These results help complete the picture of the coordination of visual information uptake and motor output during speaking.

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Ocular artifacts in EEG and event-related potentials I: Scalp topography

Cited by 296 publications

References 32 publications

A brief introduction to the use of event-related potentials in studies of perception and attention

A brief introduction to the use of event-related potentials in studies of perception and attention

Guidelines for using human event-related potentials to study cognition: Recording standards and publication criteria

Lateralized electrical brain activity reveals covert attention allocation during speaking

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