H. Shibuya et T. Yamamoto, ELECTROPHYSIOLOGICAL AND MORPHOLOGICAL FEATURES OF RAT CLAUSTRAL NEURONS - AN INTRACELLULAR STAINING STUDY, Neuroscience, 85(4), 1998, pp. 1037-1049
The electrophysiological and morphological features of neurons in the
rat rostral claustrum were examined using intracellular recording and
staining methods in vivo. A total of 31 neurons were analysed electrop
hysiologically, and 21 of these were stained well with intracellular b
iocytin injection. The following electrophysiological properties were
analysed by intracellular current injection: firing properties, the sh
ape of single action potentials and input resistance. The firing patte
rns of the claustral neurons seemed to be similar to those of regular
spiking cells in the cerebral cortex. They had action potentials with
a maximum rate of rise much higher than that of fall, and showed spike
-frequency adaptation during long depolarizing pulses. The morphologic
al analysis demonstrated that the claustral neurons were of various ty
pes: the somata were polygonal, triangular, ovoid, round, or fusiform,
sometimes with a stout dendrite. Such a dendrite extended toward the
superficial layers in the more rostral orbital cortex, and was reveale
d to be a distorted apical dendrite by a three-dimensional computer-ai
ded system. The embryological origin of the claustrum has been a matte
r of controversy: two main hypotheses of cortical germinal origin and
ganglionic eminence origin. Considering the firing patterns and morpho
logical features, the present findings suggest that the neurons in the
rostral claustrum share some physiological characteristics with corti
cal neurons in rats. (C) 1998 IBRO. Published by Elsevier Science Ltd.