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T F Ladygina

Publications and source records attributed to T F Ladygina.

8 recordsLinked to original sources
PubMed1986

Evoked potentials of the auditory cortex of the porpoise, Phocoena phocoena.

Evoked potential (EP) recordings in the auditory cortex of the porpoise, Phocoena phocoena, were used to obtain data characterizing the auditory perception of this dolphin. The frequency threshold curves showed that the lowest EP thresholds were within 120-130 kHz. An additional sensitivity peak was observed between 20 and 30 kHz. The minimal EP threshold to noise burst was 3 X 10(-4) - 10(-3) Pa. The threshold for response to modulations in sound intensity was below 0.5 dB and about 0.1% for frequency modulations. Special attention was paid to the dependence of the auditory cortex EP on the temporal parameters of the acoustic stimuli: sound burst duration, rise time, and repetition rate. The data indicate that the porpoise auditory cortex is adapted to detect ultrasonic, brief, fast rising, and closely spaced sounds like echolocating clicks.

Acoustic Stimulation↗
PubMed1985

[Topical organization of somatic projections to the cerebral cortex of the seal Callorhinus ursius].

Somatotopic projections in the cerebral cortex of the fur seal (Callorhinus ursinus) were determined by microelectrode recordings of the multiple unit activity. Somatosensory cortical area is restricted rostrally by postcruciate and coronal sulci, caudally by anterior suprasylvain sulcus and dorsomedially by ansate sulcus. The somatotopic map in this area is oriented in such a way that the head projection is positioned ventrolaterally and that of the hindlimb dorsomedially. The projection area of the forelimb is immersed in the coronal sulcus. Marked disproportions are observed in the projections of different parts of the soma; the head projection has a relatively large magnification factor and within it the vibrissae are presented with the largest magnification.

Animals↗
PubMedDate not supplied

[Localization of the sensory projection areas in the cerebral cortex of the dolphin, Tursiops truncatus].

Using the evoked potential technique, studies have been made on localization of the projectional sensory areas in the cerebral cortex (visual, acoustic and somatosensory) of the porpoise T. truncatus. Distribution of these projectional areas in the porpoise is quite different as compared to that in other mammals. Visual and acoustic areas are shifted to the dorsal part of the hemisphere, all the sensory areas investigated exhibit a direct contact with each other.

Animals↗
PubMedDate not supplied

[Multiple sensory projections in the dolphin cerebral cortex].

The paper presents characteristics of evoked potentials appearing in response to afferent stimuli in the dolphin visual and auditory cortical areas. Both the visual and auditory areas are divided into zones which generate evoked potentials different in form and temporal parameters. They may be regarded as multiple projection zones of the visual and auditory analysers respectively.

Animals↗