Enhancement of synaptic strength in the somatosensory cortex following nerve injury does not parallel behavioural alterations.
Following infraorbital nerve transection, underlying mechanisms of the altered synaptic strength were studied in rat barrel cortex slice experiments. In addition to the in vitro electrophysiological studies, open-field tests were run to detect possible behavioural changes associated with cortical oversensitization. Enhanced NMDA receptor-mediated component of the evoked field response appeared in the barrel cortex after nerve injury. The alteration was transient, very distinct on the first day following injury, and almost returned to normal level by the end of the second week. Behavioural changes had not followed this time-course since long-lasting alterations were detected in the open-field test. These observations are in agreement with findings that showed biphasic regenerative processes following nerve injuries in other cortical areas.
Világi
I
I
Department of Physiology and Neurobiology, Eötvös Loránd University, H-1117 Budapest, Pázmány Péter sétány 1/C, Hungary. vilagildi@ludens.elte.hu
Bárdos
G
G
Dénes
K
K
Farkas
B
B
Friedrich
P
P
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation / Q000379:methods; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005106:Exploratory Behavior / Q000502:physiology; D020220:Facial Nerve Injuries / Q000503:physiopathology*; D005260:Female; D066298:In Vitro Techniques; D017774:Long-Term Potentiation / Q000187:drug effects / Q000528:radiation effects; D008297:Male; D009043:Motor Activity / Q000502:physiology; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013003:Somatosensory Cortex / Q000503:physiopathology*; D013997:Time Factors
D018691:Excitatory Amino Acid Antagonists; D015763:2-Amino-5-phosphonovalerate