# Show Reference: "Facilitation of face recognition through the retino-tectal pathway"

Facilitation of face recognition through the retino-tectal pathway Neuropsychologia, Vol. 51, No. 10. (August 2013), pp. 2043-2049, doi:10.1016/j.neuropsychologia.2013.06.018 by Tamami Nakano, Noriko Higashida, Shigeru Kitazawa
@article{nakano-et-al-2013,
abstract = {Saccadic reaction times demonstrate a facilitatory effect for faces. The facilitatory effect to faces disappeared with S-cone-isolating stimuli. S-cone-isolating stimuli do not activate the retino-tectal pathway. The retino-tectal pathway is likely responsible for the fast recognition of human faces. Humans can shift their gazes faster to human faces than to non-face targets during a task in which they are required to choose between face and non-face targets. However, it remains unclear whether a direct projection from the retina to the superior colliculus is specifically involved in this facilitated recognition of faces. To address this question, we presented a pair of face and non-face pictures to participants modulated in greyscale (luminance-defined stimuli) in one condition and modulated in a blue–yellow scale (S-cone-isolating stimuli) in another. The information of the S-cone-isolating stimuli is conveyed through the retino-geniculate pathway rather than the retino-tectal pathway. For the luminance stimuli, the reaction time was shorter towards a face than towards a non-face target. The facilitatory effect while choosing a face disappeared with the S-cone stimuli. Moreover, fearful faces elicited a significantly larger facilitatory effect relative to neutral faces, when the face (with or without emotion) and non-face stimuli were presented in greyscale. The effect of emotional expressions disappeared with the S-cone stimuli. In contrast to the S-cone stimuli, the face facilitatory effect was still observed with negated stimuli that were prepared by reversing the polarity of the original colour pictures and looked as unusual as the S-cone stimuli but still contained luminance information. These results demonstrate that the face facilitatory effect requires the facial and emotional information defined by luminance, suggesting that the luminance information conveyed through the retino-tectal pathway is responsible for the faster recognition of human faces.},
author = {Nakano, Tamami and Higashida, Noriko and Kitazawa, Shigeru},
doi = {10.1016/j.neuropsychologia.2013.06.018},
issn = {00283932},
journal = {Neuropsychologia},
keywords = {biology, eye-saccades, face-detection, face-recognition, saccades, sc, visual, visual-processing},
month = aug,
number = {10},
pages = {2043--2049},
posted-at = {2013-08-29 07:10:24},
priority = {2},
title = {Facilitation of face recognition through the retino-tectal pathway},
url = {http://dx.doi.org/10.1016/j.neuropsychologia.2013.06.018},
volume = {51},
year = {2013}
}


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Humans can orient towards emotional human faces faster than towards neutral human faces.

The time it takes to elicit a visual cortical response plus the time to elicit a saccade from cortex (FEF) is longer than the time it takes for humans to orient towards faces.

Nakano et al. take this as further evidence for a sub-cortical (retinotectal) route of face detection.

Patients with lesions in V1 or striate were found to still be able to discriminate gender and expression of faces.

Neurons in the monkey pulvinar react extremely fast to visually perceived faces (50ms).

The superior colliculus does not receive any signals from short-wavelength cones (S-cones) in the retina.

Nakano et al. presented an image of either a butterfly or a neutral or emotional face to their participants. The stimuli were either grayscale or color-scale images, where color-scale images were isoluminant and only varied in their yellow-green color values. Since information from S-cones does not reach the superior colliculus, these faces were presumably only processed in visual cortex.

Nakano et al. found that their participants reacted to gray-scale emotional faces faster than to gray-scale neutral faces and to gray-scale faces faster than to gray-scale butterflies. Their participants reacted somewhat faster to color-scale faces than to color-scale butterflies, but this effect was much smaller than for gray-scale images. Also, the difference in reaction time to color-scale emotional faces was not significantly different from that to color-scale neutral faces.

Nakano et al. take this as further evidence of sub-cortical face detection and in particular of emotional sub-cortical face detection.

Humans can orient towards human faces faster than towards other visual stimuli (within 100ms).

SC has been implicated as part of a subcortical visual pathway which may drive face detection and orienting towards faces in newborns.