H. Bornschein

Spezifische Schädigung von Netzhautelementen durch Jodazetat

The effect of iodoacetate (20 mg/kg sc. 32 mg/kg) on the structures of the retina was investigated in rabbits. The left, and then the right, eye was tested after a period of 22 and 38 days respectively following the intravenous administration of the substance. At both times the electroretinogram was completely extinguished. Histological examination revealed selective destruction of rods and cones, whereas bipolars and ganglion cells were more resistent.

Über die Frequenzabhängigkeit reversibler Änderungen der Cochlearpotentiale bei temporärer Anoxie

Seven experiments were carried out on guinea-pigs. The results obtained showed that the depression of the cochlear potential under anoxia was not only independent of the intensity, which was already proved by previous experiments, but also of the frequency of the stimuli.

Die Beeinflussung der Mikrophonpotentiale durch endocochleare Applikation von Jodacetat

The microphonic potentials of the cat were found to be reduced by endocochlear application of iodoacetate. The rate of decrease was markedly influenced by the intensity of the stimulus.The microphonic potentials of the cat were found to be reduced by endocochlear application of iodoacetate. The rate of decrease was markedly influenced by the intensity of the stimulus.

Beitrag zur Analyse des postmortalen Verhaltens der Cochlearpotentiale

The rapid initial drop of cochlear potentials after ligation of the aorta was investigated in twelve experiments on guinea-pigs. The loss began after 3·2±0·9 sec latency with the most rapid rate of decline and reached in 60 sec an amount of 5·7±0·8 db. The variability of the subsequentpost mortem response was significantly greater (loss after 5 min: 10·9±2·7 db). The correlation coefficient of the values was positive and slightly significant. Hypoxæmic state before ligation of the aorta had no influence on the behaviour of the potentials. This suggests a remarkable lack of oxygen reserves in the organ of Corti.

Elektroretinogramm und Netzhautstruktur der Sumpfohreule (Asio flammeus)

Single flash and flicker electroretinograms were recorded for a nocturnal owl and the results discussed in terms of its retinal structure. The differences both in electrical response and in retinal structure between the owl and the pigeon were less than those found between nocturnal and diurnal mammals.

Die Bedeutung konstanter Temperaturbedingungen für ERG-Untersuchungen bei Kleinsäugern

In anesthetized albino rats, the body temperature drops rapidly, causing changes in amplitude and temporal course of the electroretinogram. Normal conditions can be restored by radiating heat, whereas thermal isolation of the body was found insufficient to preserve normal temperature of the exposed eye.In anesthetized albino rats, the body temperature drops rapidly, causing changes in amplitude and temporal course of the electroretinogram. Normal conditions can be restored by radiating heat, whereas thermal isolation of the body was found insufficient to preserve normal temperature of the exposed eye.

Nachweis einer physiologischen Spontanaktivität in Einzelfasern des N. opticus der Katze

Spike potentials were recorded with metal micro-electrodes from single fibers in the intracranial part of the cats optic nerve with the retina left completely intact. All units studied as yet showed a marked spontaneous activity irrespective of differences in their response to light stimuli. The spontaneous activity in the intracranial part of the optic nerve could be suppressed reversibly by increasing the intraocular pressure up to 200 mm Hg. Thus spontaneous activity has been verified as a normal feature of the retina. A spontaneous firing rate of 22±11/s after 1 h dark adaptation was found in altogether 12 well-isolated fiber units.

Der Einfluss der Reizbedingungen auf den initialen Abfall der Cochlearpotentiale bei totaler Ischämie

The rapid initial drop of the cochlear microphonic potential following compression of the aorta was studied in guinea pigs. The intensity of the stimulus, either continuous or intermittent, was without influence on the half-time of amplitude (t/2=52±7 s;n=18). From this it is concluded that the metabolism of the generator responsible for the cochlear microphonic is unaffected by the type or intensity of stimulation. The lower resistance of the neural action potential to ischemia was confirmed (t/2=18±2 s;n=5).

Die Intensitätsfunktion der Cochlearpotentiale nach intravitalem und postmortalem akustischem Trauma

Experiments on acoustic trauma were performed in 53 guinea pigs. The consequent fall of the aural microphonics is shown to consist of two different components. An acoustic trauma, effected 60 min after death, reduced the post mortem response by at least the same extent as the normal microphonics in the living animal.

Über einen Bahnung seffekt bei sukzessiver Einwirkung von vestibulären und optokinetischen Reizen

In the rabbit rotatory vestibular stimulation followed by optokinetic stimulation has a persisting facilitatory effect on the latter. The facilitation is independent of the direction of the second stimulus relative to the first one. It can therefore not be explained on the basis of the well-known addition effect in simultaneous stimulation. The neurophysiological and biological aspects of the phenomenon are discussed.