Abstract
The present study investigated implicit and explicit recognition processes of rapidly perceptually learned objects by means of steady-state visual evoked potentials (SSVEP). Participants were initially exposed to object pictures within an incidental learning task (living/non-living categorization). Subsequently, degraded versions of some of these learned pictures were presented together with degraded versions of unlearned pictures and participants had to judge, whether they recognized an object or not. During this test phase, stimuli were presented at 15 Hz eliciting an SSVEP at the same frequency. Source localizations of SSVEP effects revealed for implicit and explicit processes overlapping activations in orbito-frontal and temporal regions. Correlates of explicit object recognition were additionally found in the superior parietal lobe. These findings are discussed to reflect facilitation of object-specific processing areas within the temporal lobe by an orbito-frontal top-down signal as proposed by bi-directional accounts of object recognition.
Highlights
Object recognition relies on the activity of cortically widespread networks which represent various stimulus features and which are distributed across different functional areas in the brain [1,2]
In an EEG study they confronted their participants with a series of words which were either presented for the first time or with words which were previously presented during an incidental learning phase
The contrast between recognized versus unrecognized objects will reflect the activation of explicit processes that allow for conscious perception
Summary
Object recognition relies on the activity of cortically widespread networks which represent various stimulus features and which are distributed across different functional areas in the brain [1,2]. In line with stimulus repetition studies, they concluded that a cortical hierarchy of object representations exists in the temporal lobe Based on these results one can assume that cortical regions reflecting explicit and implicit object perception processes overlap to a certain degree. We suppose that prior exposure to the original image (a) triggers early, low-level perceptual processing of the fragmented version (i.e. automatic, implicit, without conscious recognition), and (b) increases the probability of consciously recognizing the fragmented object (i.e. explicit retrieval of the object representation).Experiments relying on the rapid perceptual learning of degraded pictures have the advantage that the physical stimulus parameters of recognized and unrecognized objects are highly comparable (i.e. the only difference is recognition performance). We expect implicit processes to occur within this network, even in the absence of successful object recognition
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
