Multivariate functional neuroimaging analyses reveal that strength-dependent face expectations are represented in higher-level face-identity areas

Abstract

Perception is an active inference in which prior expectations are combined with sensory input. It is still unclear how the strength of prior expectations is represented in the human brain. The strength, or precision, of a prior could be represented with its content, potentially in higher-level sensory areas. We used multivariate analyses of functional resonance imaging data to test whether expectation strength is represented together with the expected face in high-level face-sensitive regions. Participants were trained to associate images of scenes with subsequently presented images of different faces. Each scene predicted three faces, each with either low, intermediate, or high probability. We found that anticipation enhances the similarity of response patterns in the face-sensitive anterior temporal lobe to response patterns specifically associated with the image of the expected face. In contrast, during face presentation, activity increased for unexpected faces in a typical prediction error network, containing areas such as the caudate and the insula. Our findings show that strength-dependent face expectations are represented in higher-level face-identity areas, supporting hierarchical theories of predictive processing according to which higher-level sensory regions represent weighted priors.

Unveiling coding of prediction and sharpening of perceptual features through multivariate pattern analysis

“…In summary, the study conducted by Blank et al (2023) makes a significant contribution to the growing body of evidence supporting PC theories. More importantly, this study demonstrates for the first time that the strength of expectation is selectively represented in higher-level brain regions, which also code expected content.…”

“…Blank et al (2023) utilised functional resonance imaging (fMRI) in conjunction with sophisticated multivariate techniques to address the question of how expectation strength and content are coded. Participants were presented with scene cues, which they used to predict the identities of faces with different probabilities: low (10%), intermediate (30%) or high (60%).…”

“…It is possible that expectation strength is explicitly coded at all levels of the processing hierarchy. However, by utilising a novel task, Blank et al (2023) offer new empirical evidence suggesting that higher-level brain regions encompass sensory predictions and also selectively represent the strength of these predictions. Furthermore, the study provides evidence for the sharpening of multivariate fMRI patterns during image repetition.…”

“…Here, we will discuss the significance and implications of their findings for future research, such as separating analyses for strong and weak predictions, in order to test contrasting theories, examining the impact of mental imagery on representational patterns, and exploring the connectivity between brain regions. Blank et al (2023) utilised functional resonance imaging (fMRI) in conjunction with sophisticated multivariate techniques to address the question of how expectation strength and content are coded. Participants were presented with scene cues, which they used to predict the identities of faces with different probabilities: low (10%), intermediate (30%) or high (60%).…”

“…However, these expectations are not all equal; they carry varying degrees of likelihood based on our past experiences, that is, we are likely to expect a colleague’s face at our workplace but a family member’s face at home. A recent study by Blank et al (2023) explores how the human brain handles the strength of these face-related expectations and whether they are represented in the same regions that code for the expected content itself, that is, facial stimuli. In line with predictive coding (PC) theories, which suggest perception is a hierarchical process, their findings provide first compelling evidence that the brain adapts its processing of anticipated faces based on how certain those expectations are, but only within high-level face-sensitive regions and not throughout the entire processing hierarchy.…”