Invariant visual representation by single neurons in the human brain

• Published in: Nature Vol. 435; no. 7045; pp. 1102 - 1107
• Main Authors: Reddy, L, Quiroga, R. Quian, Kreiman, G, Fried, I, Koch, C
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 23-06-2005; Nature Publishing Group
• Subjects: Adolescent; Adult; Biological and medical sciences; Brain; Brain - cytology; Brain - physiology; Cognition & reasoning; Eye and associated structures. Visual pathways and centers. Vision; Eyes & eyesight; Face - anatomy & histology; Female; Fundamental and applied biological sciences. Psychology; Hippocampus - cytology; Hippocampus - physiology; Humans; Male; Memory; Memory - physiology; Middle Aged; Models, Neurological; Neurology; Neurons; Neurons - cytology; Neurons - physiology; Pattern Recognition, Visual - physiology; ROC Curve; Substrate Specificity; Temporal Lobe - cytology; Temporal Lobe - physiology; Vertebrates: nervous system and sense organs; Human; Temporal lobe; Neuron; Visual pathway; Memory; Vision; Central nervous system; Face; Long term; Encephalon
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature03687

It takes a fraction of a second to recognize a person or an object even when seen under strikingly different conditions. How such a robust, high-level representation is achieved by neurons in the human brain is still unclear. In monkeys, neurons in the upper stages of the ventral visual pathway respond to complex images such as faces and objects and show some degree of invariance to metric properties such as the stimulus size, position and viewing angle. We have previously shown that neurons in the human medial temporal lobe (MTL) fire selectively to images of faces, animals, objects or scenes. Here we report on a remarkable subset of MTL neurons that are selectively activated by strikingly different pictures of given individuals, landmarks or objects and in some cases even by letter strings with their names. These results suggest an invariant, sparse and explicit code, which might be important in the transformation of complex visual percepts into long-term and more abstract memories.