The activation of visual face memory and explicit face recognition are delayed in developmental prosopagnosia

Abstract

Individuals with developmental prosopagnosia (DP) are strongly impaired in recognizing faces, but the causes of this deficit are not well understood. We employed event-related brain potentials (ERPs) to study the time-course of neural processes involved in the recognition of previously unfamiliar faces in DPs and in age-matched control participants with normal face recognition abilities. Faces of different individuals were presented sequentially in one of three possible views, and participants had to detect a specific Target Face ("Joe"). EEG was recorded during task performance to Target Faces, Nontarget Faces, or the participants' Own Face (which had to be ignored).The N250 component was measured as a marker of the match between a seen face and a stored representation in visual face memory. The subsequent P600f was measured as an index of attentional processes associated with the conscious awareness and recognition of a particular face. Target Faces elicited reliable N250 and P600f in the DP group, but both of these components emerged later in DPs than in control participants.This shows that the activation of visual face memory for previously unknown learned faces and the subsequent attentional processing and conscious recognition of these faces are delayed in DP. N250 and P600f components to Own Faces did not differ between the two groups, indicating that the processing of long-term familiar faces is less affected in DP. However, P600f components to Own Faces were absent in two participants with DP who failed to recognize their Own Face during the experiment.These results provide new evidence that face recognition deficits in DP may be linked to a delayed activation of visual face memory and explicit identity recognition mechanisms.

Face identity matching is selectively impaired in developmental prosopagnosia

“…This conclusion is in line with previous DP studies that investigated the activation of longer-term memory representations during the recognition of famous faces or previously learned target faces Parketny et al, 2015), and found that such recognition processes give rise to N250 components in participants with DP (see , for further discussion).…”

“…During the successful recognition of familiar faces and of learned target faces, an enhanced negativity at lateral posterior electrodes emerges at around 250 ms after stimulus onset (Gosling & Eimer, 2011;Tanaka, Curran, Porterfield, & Collins, 2006). This N250 component, which is assumed to reflect the activation of a stored representation of a particular individual face in longer-term visual memory, has also been observed for individuals with DP Parketny, Towler, & Eimer, 2015). However, the N250 in response to a learned target face was delayed in DPs as compared to age-matched control participants (Parketny et al, 2015), suggesting that such identity matching processes are 5 triggered less rapidly in DP.…”

“…This N250 component, which is assumed to reflect the activation of a stored representation of a particular individual face in longer-term visual memory, has also been observed for individuals with DP Parketny, Towler, & Eimer, 2015). However, the N250 in response to a learned target face was delayed in DPs as compared to age-matched control participants (Parketny et al, 2015), suggesting that such identity matching processes are 5 triggered less rapidly in DP. A similar N250 component has also been found in tasks where two face images are shown in quick succession.…”

The Cognitive and Neural Basis of Developmental Prosopagnosia

“…While the ERP study by Eimer et al (2012) investigated the recognition of famous faces, which are likely to be represented in long-term memory, a recent experiment (Parketny, Towler, & Eimer, 2015) studied the processes that are responsible for the recognition of previously unfamiliar but now task-relevant faces in DP. In an experimental paradigm developed by Tanaka et al (2006), single face images were presented sequentially, and participants had to respond to a previously studied but otherwise unknown target face ("Joe"), while ignoring other task-irrelevant distractor faces.…”

“…In line with this hypothesis, reaction times to correctly detected target faces were about 150 ms slower in the DP group relative to the control group. The inclusion of participants' own faces in this study (Parketny et al, 2015) allowed us to investigate whether face-based self-recognition processes might also be impaired in DP. Overall, own faces elicited very similar N250 and P600f components in DPs and controls, suggesting that the activation of long-term representations of one's own face in visual memory and the subsequent explicit recognition of this face is not generally selectively impaired in DP.…”