Functional features of wind-sensitive receptors triggering the wing muscle neurons of the desert locust, Calliptamus barbarus]

At each side of the head of C. barbarus, 5 receptive fields were found triggering the activity of neurons which directly control the work of wing apparatus. Total number of wind-sensitive receptors (presented by trichoid sensillae) amounts up to 200. Lateral receptive fields 1 and 5 are most developed and contain 24 +/- 5 and 23 +/- 4 sensillae respectively. In the response of a receptor to adequate stimulation, two components may be differentiated--phasic and tonic ones. The discharge frequency of the tonic component is equal to 90--100 impulses per sec. Simultaneous recording of impulse activity in axons of two receptors reveals a possibility of interaction of the receptors. In the experiments performed, this peripheral interaction was of the inhibitory nature. Functional peculiarities of the receptor investigated are discussed.     

Mapping of the genes for ribosomal proteins S26, L19, and L32 on human chromosomes

A fragment of cDNA and an intron-containing fragment of the human L19 ribosomal protein (RPL19) gene, and introns of the human ribosomal proteins S26 (RPS26) and L32 (RPL32) genes were cloned and sequenced. The intron-containing genes of these ribosomal proteins were mapped to human chromosomes by means of polymerase chain reaction (PCR) using a human/rodent hybrid DNA panel.     

A comparison of the contractile properties of the muscles of the lower extremities in man

The physiological features of two antagonistic muscle groups, the dorsiflexors and plantar flexors of the ankle, have been compared in 11 healthy subjects aged 15-17 years (+/- SE; 16 +/- 1.2 years). Contractile properties of plantar flexors of the foot, namely of tibialis anterior (TA) and extensors triceps surae (TS) have been estimated by mechanical parameters of voluntary and electrically evoked contractions. All test subjects exhibited tolerance to supramaximal force of electric stimulation of n. tibialis and n. peroneus profundus at a frequency of 150 impulses.s-1 (for TS) and 150 impulses.s-1 and 250 impulses.s-1 (for TA). TA displayed high velocity and force-velocity properties (p < 0.05-0.001); TS had high force parameters (p < 0.05-0.01). The magnitude of force deficiency observed during voluntary contraction of these muscles is lower in TA and higher in TS (p < 0.05). The results permit supposing that differences in contractile properties of the muscles under study depend on a various specific contribution of peripheral and CNS factors.     

Impulse activity of visual cortex neurons at successive stages of instrumental behavior

Dynamics of spike activity of 62 units was studied in the projection visual area of the cerebral cortex in unrestrained cats during their performance of a conditioned alimentary instrumental reaction. Analysis of the activity of each unit was made at intervals from the beginning of the conditioned signal (light or sound) to the beginning of lapping milk which appeared in the feeding trough after the cat pressed the pedal. It has been found that the form of activity of the cortical unit greatly depends on the modality of the conditioned stimulus (light or sound). As to the final stages of instrumental behaviour and the achievment of the positive result, the degree of participation of cortical visual units in their formation does not depend on the modality of the conditioned signal.