RT Journal Article
SR Electronic
T1 Microcircuitry of Agranular Frontal Cortex: Testing the Generality of the Canonical Cortical Microcircuit
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 5355
OP 5369
DO 10.1523/JNEUROSCI.5127-13.2014
VO 34
IS 15
A1 David C. Godlove
A1 Alexander Maier
A1 Geoffrey F. Woodman
A1 Jeffrey D. Schall
YR 2014
UL http://www.jneurosci.org/content/34/15/5355.abstract
AB We investigated whether a frontal area that lacks granular layer IV, supplementary eye field, exhibits features of laminar circuitry similar to those observed in primary sensory areas. We report, for the first time, visually evoked local field potentials (LFPs) and spiking activity recorded simultaneously across all layers of agranular frontal cortex using linear electrode arrays. We calculated current source density from the LFPs and compared the laminar organization of evolving sinks to those reported in sensory areas. Simultaneous, transient synaptic current sinks appeared first in layers III and V followed by more prolonged current sinks in layers I/II and VI. We also found no variation of single- or multi-unit visual response latency across layers, and putative pyramidal neurons and interneurons displayed similar response latencies. Many units exhibited pronounced discharge suppression that was strongest in superficial relative to deep layers. Maximum discharge suppression also occurred later in superficial than in deep layers. These results are discussed in the context of the canonical cortical microcircuit model originally formulated to describe early sensory cortex. The data indicate that agranular cortex resembles sensory areas in certain respects, but the cortical microcircuit is modified in nontrivial ways.