Functional columns in the primate prefrontal cortex revealed by optical imaging in vitro.
Although the functional column has been implicated in the dorsolateral prefrontal cortex (DLPFC) of primates, its dynamics and even existence are still uncertain. We performed optical recording with a voltage-sensitive dye (RH482) in brain slices obtained from the principal sulcal region (area 46) of macaque monkeys. Columnar activity was evoked by electrical stimulation of the middle layer (lower layer III or layer IV); this activity consisted of two components: probably action potentials and excitatory postsynaptic potentials. The width of the columnar activity was saturated when the current intensity of stimulation exceeded a certain level, that is, approximately 900 microm at the peak with this intensity. The stimulation of different sites within the same slice activated different columnar activities with only slight overlaps. Furthermore, similar columnar activity appeared when a different site within the area with columnar activity was stimulated. These findings suggest that the primate DLPFC consists of functional columns formed by excitatory synaptic connections.
Hirata
Yoshihiro
Y
Laboratory of Cognitive Neurobiology, Hokkaido University Graduate School of Medicine, Kita-ku, Sapporo, Japan.
Sawaguchi
Toshiyuki
T
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D004396:Coloring Agents; D003627:Data Interpretation, Statistical; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D005260:Female; D007736:Kynurenic Acid / Q000494:pharmacology; D008251:Macaca; D008297:Male; D017397:Prefrontal Cortex / Q000502:physiology*; D017470:Receptors, Glutamate / Q000187:drug effects; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013569:Synapses / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology
D004396:Coloring Agents; D018691:Excitatory Amino Acid Antagonists; D017470:Receptors, Glutamate; D026941:Sodium Channel Blockers; D013779:Tetrodotoxin; D007736:Kynurenic Acid