Cytoarchitecture of the ferret suprasylvian gyrus correlated with areas containing multiunit responses elicited by stimulation of the face.
The cytoarchitecture was studied in a segment of the ferret suprasylvian gyrus containing at least two and possibly four somesthetic representations of the face that were observed in the primary somatosensory cortex. These representations were restricted to the crown of the gyrus and were surrounded by somesthetically unresponsive cortex that extended down both sides to the base of adjacent sulci. Numerous cytoarchitectonic subdivisions were found on a qualitative basis, and were confirmed quantitatively by cluster analyses and relevant statistical tests of 10 prominent features from layers III, IV, and V. Four distinct cytoarchitectonic subdivisions, each with a well-developed and homogeneous granular layer IV, were found distributed from anterior to posterior along the crown of the gyrus at sites corresponding to the locations of the four facial representations. The surrounding unresponsive cortex had a fragmented cytoarchitecture, especially along the medial bank and base of the coronal sulcus. This unresponsive cortex separated the facial representations from the body representations, which were located on the adjacent posterior cruciate gyrus. Most of the unresponsive subdivisions had a heterogeneous or agranular layer IV and fairly well-developed sublamination in layer III, which may be indicative of extensive corticocortical connections. One set of unresponsive subdivisions had comparable cytoarchitectures that directly bordered the facial representations. Another set of unresponsive subdivisions with comparable architectures occupied most of the lateral bank of the gyrus. The implications of multiple representations and cytoarchitectonic fragmentation of the ferret primary somatosensory cortex are discussed in relation to the organization of the primary somatosensory cortex in other species.
Department of Anatomy, Cell Biology, and Neurobiology, Albany Medical College, New York 12208.
F L
FL
Rice
C M
CM
Gomez
S S
SS
Leclerc
R W
RW
Dykes
J S
JS
Moon
K
K
Pourmoghadam
D000344:Afferent Pathways / Q000166:cytology; D000818:Animals; D001931:Brain Mapping; D002452:Cell Count; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005145:Face / Q000294:innervation*; D005289:Ferrets / Q000033:anatomy & histology*; D013003:Somatosensory Cortex / Q000166:cytology*; D013045:Species Specificity; D009435:Synaptic Transmission / Q000502:physiology; D014738:Vibrissae / Q000294:innervation