Participation of frontal lobe neurons in the organization of successive inhibition and disinhibition of conditioned reflexes in the dog

Neuronal activity in g. proreus was studied during classical secretory conditioning and its differentiation in dogs. Three types of changes in neuronal reaction pattern were identified during differential conditioned stimulus compared to the pattern observed during positive conditioned stimulus. It has been shown that signal significance of the conditioned stimulus may be coded by specific distribution of interspike intervals in response to different conditioned stimuli. In situation of successive inhibition or disinhibition of the differentiation some neurones displayed simultaneous appearance of interspike intervals specific for responses to current and previously presented conditioned stimuli.     

Changes produced in neuronal excitability by subthreshold depolarization as a possible mechanism of interval selective relationships within the central nervous system

A neuronal process was identified inLymnaea stagnalis nerve cells which may be viewed as one of the mechanisms underlying the interval selectivity previously described in research into the functional relationships between mammalian brain cells. This process takes the form of regularly-occurring changes in excitability resulting in a high probability (of 0.6–1) of neuronal spike response to what had previously been subthreshold depolarizing current pulses following similar subthreshold (conditioning) pulses at intervals specific to each individual neuron. It was found that the cycle of change in neuronal excitability following threshold depolarization did not arise from temporal summation of electrotonic local or postsynaptic neuronal potentials; it was an endogenous (cytoplasmic) process insensitive to transmitter (acetylcholine) application but altering irreversibly under the effects of bombesin, one of the modulator peptides.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad; Institute of Experimental Medicine, Academy of Medical Sciences of the USSR, Leningrad. Translated from Neirofiziologya, Vol. 21, No. 3, pp. 291–299, May–June, 1989.     

Appearance of the flutter on the pulse wave

This work deals with the liquid flow in an elastic blood vessel. The mechanism of the initiation of standing waves was studied. Results of model experiments, both on the hydrodynamic stand and in the aorta of the living dog are presented.