Neural Activity in Frontal Cortical Cell Layers: Evidence for Columnar Sensorimotor Processing

摘要

The mammalian frontal cortex (FCx) is at the top of thenbrainʼs sensorimotor hierarchy and includes cells in the supragranularnLayer 2/3, which integrate convergent sensory informationnfor transmission to infragranular Layer 5 cells to formulatenmotor system outputs that control behavioral responses. Functionalninteraction between these two layers of FCx was examinednusing custom-designed ceramic-based microelectrodenarrays (MEAs) that allowed simultaneous recording of firing patternsnof FCx neurons in Layer 2/3 and Layer 5 in nonhuman primatesnperforming a simple goo-go discrimination task. Thisnunique recording arrangement showed differential encoding ofntask-related sensory events by cells in each layer with Layer 2/3ncells exhibiting larger firing peaks during presentation of go targetnand no-go target task images, whereas Layer 5 cells showednmore activity during reward contingent motor responses in thentask. Firing specificity to task-related events was further demonstratednby synchronized firing between pairs of cells in differentnlayers that occupied the same vertically oriented “column”non the MEA. Pairs of cells in different layers recorded at adjacentn“noncolumnar” orientations on the MEA did not show synchronizednfiring during the same task-related events. The resultsnprovide required evidence in support of previously suggestedntask-related sensorimotor processing in the FCx via functionallynsegregated minicolumns. ■