PT  - JOURNAL ARTICLE
AU  - Christopher R. Nolan
AU  - Joyce M.G. Vromen
AU  - Allen Cheung
AU  - Oliver Baumann
TI  - Evidence against the Detectability of a Hippocampal Place Code Using Functional Magnetic Resonance Imaging
AID  - 10.1523/ENEURO.0177-18.2018
DP  - 2018 Jul 01
TA  - eneuro
PG  - ENEURO.0177-18.2018
VI  - 5
IP  - 4
4099  - http://www.eneuro.org/content/5/4/ENEURO.0177-18.2018.short
4100  - http://www.eneuro.org/content/5/4/ENEURO.0177-18.2018.full
SO  - eNeuro2018 Jul 01; 5
AB  - Individual hippocampal neurons selectively increase their firing rates in specific spatial locations. As a population, these neurons provide a decodable representation of space that is robust against changes to sensory- and path-related cues. This neural code is sparse and distributed, theoretically rendering it undetectable with population recording methods such as functional magnetic resonance imaging (fMRI). Existing studies nonetheless report decoding spatial codes in the human hippocampus using such techniques. Here we present results from a virtual navigation experiment in humans in which we eliminated visual- and path-related confounds and statistical limitations present in existing studies, ensuring that any positive decoding results would represent a voxel-place code. Consistent with theoretical arguments derived from electrophysiological data and contrary to existing fMRI studies, our results show that although participants were fully oriented during the navigation task, there was no statistical evidence for a place code.