Single-Unit Recordings Reveal the Selectivity of a Human Face Area

Abstract

The exquisite capacity of primates to detect and recognize faces is crucial for social interactions. Although disentangling the neural basis of human face recognition remains a key goal in neuroscience, direct evidence at the single-neuron level is limited. We recorded from face-selective neurons in human visual cortex in a region characterized by functional magnetic resonance imaging (fMRI) activations for faces compared with objects. The majority of visually responsive neurons in this fMRI activation showed strong selectivity at short latencies for faces compared with objects. Feature-scrambled faces and face-like objects could also drive these neurons, suggesting that this region is not tightly tuned to the visual attributes that typically define whole human faces. These single-cell recordings within the human face processing system provide vital experimental evidence linking previous imaging studies in humans and invasive studies in animal models.

An integrative view of human hippocampal function: Differences with other species and capacity considerations

“…This can validate or falsify theories that cannot be resolved with noninvasive methods. For example, in line with the finding of neurons responding to faces in the monkey temporal cortex (Freiwald & Tsao, 2010;Gross, 2008;Gross et al, 1972;Tsao et al, 2006) and human fMRI findings (Grill-Spector et al, 2017;Kanwisher, 2017;Kanwisher et al, 1997), neurons in the human occipitotemporal cortex showed strong responses to faces (Decramer et al, 2021). Likewise, in the human parahippocampal cortex, neurons were found to respond strongly to specific places (Mormann et al, 2017), consistent with the fMRI responses observed in the "parahippocampal place area" (Epstein & Kanwisher, 1998).…”

“…It could in principle be argued that this difference is due to a slower visual processing in humans compared to monkeys. However, responses in high level visual areas are at about 100–150 ms both in monkeys (for a summary, see table 1 in Mormann et al, 2008) and humans (Davidesco et al, 2014; Decramer et al, 2021; Jacques et al, 2016; Liu et al, 2009). Therefore, while in the monkey visual system the response onsets are dictated by a cascade of feedforward activations (Thorpe & Fabre‐Thorpe, 2001) that from high level visual areas send the information directly to the hippocampus (n.b.…”

Face pareidolia in male schizophrenia

“…This phenomenon reflects tuning to faces termed face pareidolia (from the ancient Greek παρά (para)-'next to it' and είδωλον (eidolon)-'shape, image'). In recent years, face pareidolia in face-like non-face images elicits great interest [66][67][68][69][70][71][72][73][74][75][76][77][78] (Fig. 1), primarily because their components do not automatically trigger face processing and, therefore, allow for a proper investigation of face tuning.…”

Preliminary evidence of an increased susceptibility to face pareidolia in postpartum women

“…As social primates, our wellbeing depends on our capacity to detect the faces of social agents. Thus, our sensitivity to faces and face-like patterns in the visual environment emerges immediately after birth [1][2][3], and is thought to underlie our propensity to perceive illusory faces in examples of face pareidolia [4][5][6][7][8][9][10][11][12][13][14][15][16] (figure 1a). But beyond the early stages of infancy, it is unclear whether our sensitivity to illusory faces changes across time.…”