Properties of associative long-lasting potentiation induced by cellular conditioning in the motor cortex of conscious cats.

摘要: Mechanisms of long-lasting potentiation synaptic responses induced in the thalamocortical and recurrent collateral pathways pyramidal tract were studied intracellular recordings from motor cortex unanesthetized, chronically implanted cats. The observations provide first description unanesthetized neocortex vivo. Monosynaptic excitatory postsynaptic potentials 2-5 mV amplitude evoked as test by stimulation thalamic ventrolateral nucleus at 0.1-0.5 Hz frequency. Pressure microinjections drugs ions also performed during recordings. In series experiments, paired with current injection-induced action an interstimulus interval set between 0-200 ms Pairings (30-100 x) 58% cells. increased typically initiated their usually lasted over period Increases not correlated statistically significant changes electrical membrane properties (resting potential, input resistance, time constant, spike threshold) or parameters afterpotentials. failure to induce increases efficacy unpaired stimuli (pseudoconditioning) demonstrated associative property potentiation. a second differential cell conditioning was employed. This paradigm explicitly response without noticeable modification pseudorandomly tested conjointly same neuron. These input-specificity third subthreshold depolarizing pulses summated firing recorded neuron pairing. Long-lasting occurred 55% inputs. Pseudoconditioning did these fourth employed neurons which activity suppressed intracellularly injected lidocaine derivative. 50% attempts when current-induced depolarizations greater than 30 mV. results suggest that induction can be successful absence sodium spikes fifth homosynaptic high-frequency tetanization (80-200 for 5-15 s) applied afferents.(ABSTRACT TRUNCATED AT 400 WORDS)