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Brain Signals of Face Processing as Revealed by Event-Related Potentials.

Olivares EI, Iglesias J, Saavedra C, Trujillo-Barreto NJ, Valdés-Sosa M - Behav Neurol (2015)

Bottom Line: This early response is thought to reflect the detection of certain primary structural aspects indicating the presence grosso modo of a face within the visual field.The posterior-temporal N170 is more sensitive to the detection of faces as complex-structured stimuli and, therefore, to the presence of its distinctive organizational characteristics prior to within-category identification.In turn, the relatively late and probably more rostrally generated N250r and N400-like responses might respectively indicate processes of access and retrieval of face-related information, which is stored in long-term memory (LTM).

View Article: PubMed Central - PubMed

Affiliation: Departamento de Psicología Biológica y de la Salud, Facultad de Psicología, Universidad Autónoma de Madrid, 28049 Madrid, Spain.

ABSTRACT
We analyze the functional significance of different event-related potentials (ERPs) as electrophysiological indices of face perception and face recognition, according to cognitive and neurofunctional models of face processing. Initially, the processing of faces seems to be supported by early extrastriate occipital cortices and revealed by modulations of the occipital P1. This early response is thought to reflect the detection of certain primary structural aspects indicating the presence grosso modo of a face within the visual field. The posterior-temporal N170 is more sensitive to the detection of faces as complex-structured stimuli and, therefore, to the presence of its distinctive organizational characteristics prior to within-category identification. In turn, the relatively late and probably more rostrally generated N250r and N400-like responses might respectively indicate processes of access and retrieval of face-related information, which is stored in long-term memory (LTM). New methods of analysis of electrophysiological and neuroanatomical data, namely, dynamic causal modeling, single-trial and time-frequency analyses, are highly recommended to advance in the knowledge of those brain mechanisms concerning face processing.

No MeSH data available.


Related in: MedlinePlus

Time-frequency plots derived from wavelet transformations of multiple EEG trials in a subject. Induced activity in form of event-related spectral perturbation (ERSP (a)) and of the inter-trial phase coherence (ITC) as a measure of phase consistence among trials (b), both represented for recording sites Cz and Pz of the International 10/20 System and elicited in a face-feature matching task (see, e.g., [8]). Observe how induced activity (ERSP) is larger (red colour) in the middle of the epoch for low frequencies and around 200 msec for high ones. In turn, ITC is larger for very low frequencies along the epoch and for other somewhat higher oscillations at the beginning of the epoch.
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fig3: Time-frequency plots derived from wavelet transformations of multiple EEG trials in a subject. Induced activity in form of event-related spectral perturbation (ERSP (a)) and of the inter-trial phase coherence (ITC) as a measure of phase consistence among trials (b), both represented for recording sites Cz and Pz of the International 10/20 System and elicited in a face-feature matching task (see, e.g., [8]). Observe how induced activity (ERSP) is larger (red colour) in the middle of the epoch for low frequencies and around 200 msec for high ones. In turn, ITC is larger for very low frequencies along the epoch and for other somewhat higher oscillations at the beginning of the epoch.

Mentions: The development of computing and methodological tools for signal processing in laboratories devoted to electroencephalographic (EEG) research has increased notably in the last decades the interest for the study of brain oscillations and allowed the advance in the interpretation of their functional meaning [119]. A consequence of this development is that evoked responses are no longer considered mere increases in signal amplitude with fixed time course and fixed polarity, arising overlaid on “spontaneous EEG” and detected via trial averaging. Instead, they are thought to reflect, at least partially, a reset of ongoing oscillations and are mainly studied via time-frequency analyses ([120, 127–132]) (Figure 3).


Brain Signals of Face Processing as Revealed by Event-Related Potentials.

Olivares EI, Iglesias J, Saavedra C, Trujillo-Barreto NJ, Valdés-Sosa M - Behav Neurol (2015)

Time-frequency plots derived from wavelet transformations of multiple EEG trials in a subject. Induced activity in form of event-related spectral perturbation (ERSP (a)) and of the inter-trial phase coherence (ITC) as a measure of phase consistence among trials (b), both represented for recording sites Cz and Pz of the International 10/20 System and elicited in a face-feature matching task (see, e.g., [8]). Observe how induced activity (ERSP) is larger (red colour) in the middle of the epoch for low frequencies and around 200 msec for high ones. In turn, ITC is larger for very low frequencies along the epoch and for other somewhat higher oscillations at the beginning of the epoch.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4487272&req=5

fig3: Time-frequency plots derived from wavelet transformations of multiple EEG trials in a subject. Induced activity in form of event-related spectral perturbation (ERSP (a)) and of the inter-trial phase coherence (ITC) as a measure of phase consistence among trials (b), both represented for recording sites Cz and Pz of the International 10/20 System and elicited in a face-feature matching task (see, e.g., [8]). Observe how induced activity (ERSP) is larger (red colour) in the middle of the epoch for low frequencies and around 200 msec for high ones. In turn, ITC is larger for very low frequencies along the epoch and for other somewhat higher oscillations at the beginning of the epoch.
Mentions: The development of computing and methodological tools for signal processing in laboratories devoted to electroencephalographic (EEG) research has increased notably in the last decades the interest for the study of brain oscillations and allowed the advance in the interpretation of their functional meaning [119]. A consequence of this development is that evoked responses are no longer considered mere increases in signal amplitude with fixed time course and fixed polarity, arising overlaid on “spontaneous EEG” and detected via trial averaging. Instead, they are thought to reflect, at least partially, a reset of ongoing oscillations and are mainly studied via time-frequency analyses ([120, 127–132]) (Figure 3).

Bottom Line: This early response is thought to reflect the detection of certain primary structural aspects indicating the presence grosso modo of a face within the visual field.The posterior-temporal N170 is more sensitive to the detection of faces as complex-structured stimuli and, therefore, to the presence of its distinctive organizational characteristics prior to within-category identification.In turn, the relatively late and probably more rostrally generated N250r and N400-like responses might respectively indicate processes of access and retrieval of face-related information, which is stored in long-term memory (LTM).

View Article: PubMed Central - PubMed

Affiliation: Departamento de Psicología Biológica y de la Salud, Facultad de Psicología, Universidad Autónoma de Madrid, 28049 Madrid, Spain.

ABSTRACT
We analyze the functional significance of different event-related potentials (ERPs) as electrophysiological indices of face perception and face recognition, according to cognitive and neurofunctional models of face processing. Initially, the processing of faces seems to be supported by early extrastriate occipital cortices and revealed by modulations of the occipital P1. This early response is thought to reflect the detection of certain primary structural aspects indicating the presence grosso modo of a face within the visual field. The posterior-temporal N170 is more sensitive to the detection of faces as complex-structured stimuli and, therefore, to the presence of its distinctive organizational characteristics prior to within-category identification. In turn, the relatively late and probably more rostrally generated N250r and N400-like responses might respectively indicate processes of access and retrieval of face-related information, which is stored in long-term memory (LTM). New methods of analysis of electrophysiological and neuroanatomical data, namely, dynamic causal modeling, single-trial and time-frequency analyses, are highly recommended to advance in the knowledge of those brain mechanisms concerning face processing.

No MeSH data available.


Related in: MedlinePlus