Natural grouping of neural responses reveals spatially segregated clusters in prearcuate cortex.
A fundamental challenge in studying the frontal lobe is to parcellate this cortex into "natural" functional modules despite the absence of topographic maps, which are so helpful in primary sensory areas. Here we show that unsupervised clustering algorithms, applied to 96-channel array recordings from prearcuate gyrus, reveal spatially segregated subnetworks that remain stable across behavioral contexts. Looking for natural groupings of neurons based on response similarities, we discovered that the recorded area includes at least two spatially segregated subnetworks that differentially represent behavioral choice and reaction time. Importantly, these subnetworks are detectable during different behavioral states and, surprisingly, are defined better by "common noise" than task-evoked responses. Our parcellation process works well on "spontaneous" neural activity, and thus bears strong resemblance to the identification of "resting-state" networks in fMRI data sets. Our results demonstrate a powerful new tool for identifying cortical subnetworks by objective classification of simultaneously recorded electrophysiological activity.
Department of Neurobiology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Center for Neural Science, New York University, New York, NY 10003, USA. Electronic address: roozbeh@nyu.edu.
Roozbeh
R
Kiani
Department of Neurobiology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
Christopher J
CJ
Cueva
Department of Neurobiology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
John B
JB
Reppas
Department of Neurobiology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA; Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, 1400-038 Lisbon, Portugal.
Diogo
D
Peixoto
Department of Neurosurgery, Palo Alto Medical Foundation, Palo Alto, CA 94301, USA.
Stephen I
SI
Ryu
Department of Neurobiology and Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA.
William T
WT
Newsome
D000465:Algorithms; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001931:Brain Mapping / Q000379:methods; D016000:Cluster Analysis; D005625:Frontal Lobe / Q000502:physiology*; D000882:Haplorhini; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods; D009434:Neural Pathways / Q000502:physiology*; D014793:Visual Cortex / Q000502:physiology*