[Functional action of nonfocused ultrasound on the somatosensory cortex and striatum in rats]

Evoked potentials of the simmetric points of the striatum and the medullar reticular formation were investigated in immobilized albino rats under the ultrasound action on the cortical representation of one of the stimulated forepaws. It is found that the doze of the flat continuously radiated ultrasound which reversiblly depresses the functional activity in the cortex and in the ipsilateral striatum depends on the intensity and duration of the influence (intensity 3 w/sm2--time up to 15 s; time 120 s--intensity up to 1.2 w/sm2). Repeated application of the same doze ultrasound reduces the amplitude of the evoked potential and evoked significantly less effect than the previous one. The amplitude decrease of evoked potentials in the contralateral striatum and the reticular formation occurs only in response to the stimuli applied to the foriepaw the cortical representation of which is affected by ultrasound. The amplitude of all the potentials decreases in the ipsilateral striatum. The border between reversible and irreversible potential changes is individual for every animal.