Voltage-sensitive dye imaging of intervibrissal fur-evoked activity in the rat somatosensory cortex.
The intervibrissal fur-evoked activity in the rat somatosensory cortex was investigated using high-resolution optical imaging with a voltage-sensitive dye. The optical imaging revealed that the intervibrissal fur representation forms a U-shaped band around the borders of the posteromedial barrel subfield (PMBSF), and that this representation is characterized by a rostral-to-caudal somatotopic organization. When GABA(A)-mediated inhibition was partially suppressed by treatment with bicuculline, stimulation of the intervibrissal fur elicited spreading of an excitation wave in an area outside the PMBSF. The spreading wave propagated in both directions along the aforementioned U-shaped band of cortex, but barely invaded the center of the PMBSF. These imaging results suggest a distinct subdivision of cortex adjacent to, but outside, the PMBSF in the rat somatosensory cortex; this region receives input from intervibrissal fur, and seems to process its sensory information through well-developed local horizontal connections.
Takashima
Ichiro
I
Neuroscience Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba 305-8568, Japan. i.takashima@aist.go.jp
Kajiwara
Riichi
R
Iijima
Toshio
T
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D001931:Brain Mapping; D004396:Coloring Agents; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000502:physiology*; D018756:GABA Antagonists / Q000494:pharmacology; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000201:enzymology / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013003:Somatosensory Cortex / Q000502:physiology*; D014738:Vibrissae / Q000294:innervation*; D005680:gamma-Aminobutyric Acid / Q000187:drug effects
D004396:Coloring Agents; D018756:GABA Antagonists; D005680:gamma-Aminobutyric Acid; D001640:Bicuculline