Explicit Encoding of Multimodal Percepts by Single Neurons in the Human Brain

Rodrigo Quian Quiroga*, Alexander Kraskov, Christof Koch, Itzhak Fried

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Different pictures of Marilyn Monroe can evoke the same percept, even if greatly modified as in Andy Warhol's famous portraits. But how does the brain recognize highly variable pictures as the same percept? Various studies have provided insights into how visual information is processed along the "ventral pathway," via both single-cell recordings in monkeys [1, 2] and functional imaging in humans [3, 4]. Interestingly, in humans, the same "concept" of Marilyn Monroe can be evoked with other stimulus modalities, for instance by hearing or reading her name. Brain imaging studies have identified cortical areas selective to voices [5, 6] and visual word forms [7, 8]. However, how visual, text, and sound information can elicit a unique percept is still largely unknown. By using presentations of pictures and of spoken and written names, we show that (1) single neurons in the human medial temporal lobe (MTL) respond selectively to representations of the same individual across different sensory modalities; (2) the degree of multimodal invariance increases along the hierarchical structure within the MTL; and (3) such neuronal representations can be generated within less than a day or two. These results demonstrate that single neurons can encode percepts in an explicit, selective, and invariant manner, even if evoked by different sensory modalities.

Original languageEnglish
Pages (from-to)1308-1313
Number of pages6
JournalCurrent Biology
Issue number15
StatePublished - 11 Aug 2009
Externally publishedYes


FundersFunder number
National Institute of Mental Health
National Institute of Neurological Disorders and StrokeR01NS033221
Defense Advanced Research Projects Agency
G. Harold and Leila Y. Mathers Charitable Foundation
Medical Research Council
Engineering and Physical Sciences Research Council




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