Effects of postnatal blockade of cortical activity with tetrodotoxin upon the development and plasticity of vibrissa-related patterns in the somatosensory cortex of hamsters.
Several previous studies have shown that postnatal blockade of thalamocortical activity with either tetrodotoxin (TTX) or the N-methyl-D-aspartate (NMDA) receptor antagonist D,L-2-amino-5-phosphonovalerate (APV) does not prevent the formation of vibrissa-related patterns in the primary somatosensory cortex of rats. One limitation of these studies is that this pattern forms very shortly after birth in rats, and there may be only a very limited time over which it may be influenced by activity blockade. In the present study, the effect of activity blockade was evaluated in a more altricial rodent, the hamster. The present study showed that a pattern of thalamocortical afferents corresponding to the vibrissae is not observed until the fourth postnatal day in hamsters. Nevertheless, application of TTX-impregnated implants to the cortices of newborn hamsters had no qualitative or quantitative effect upon vibrissa-related patterns in the primary somatosensory cortices of these animals. Moreover, TTX implants did not prevent the changes in patterns that followed cauterization of a row of vibrissa follicles.
Chiaia
N L
NL
Department of Anatomy, Medical College of Ohio, Toledo 43699.
Fish
S E
SE
Bauer
W R
WR
Figley
B A
BA
Eck
M
M
Bennett-Clarke
C A
CA
Rhoades
R W
RW
D000344:Afferent Pathways / Q000187:drug effects; D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000187:drug effects*; D006224:Cricetinae; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects; D009473:Neuronal Plasticity / Q000187:drug effects*; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects; D012683:Sensory Deprivation / Q000502:physiology; D013003:Somatosensory Cortex / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects*; D013779:Tetrodotoxin / Q000494:pharmacology*; D013787:Thalamic Nuclei / Q000187:drug effects; D014738:Vibrissae / Q000294:innervation*
D016194:Receptors, N-Methyl-D-Aspartate; D013779:Tetrodotoxin