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Biomedical subjects

G H Fromm

Publications and source records attributed to G H Fromm.

At least 55 records · Page 3Linked to original sources
PubMed1980

Bicuculline and neuronal activity in motor cortex.

We have studied the effects of bicuculline applied in microgram quantities to the precruciate gyrus (motor cortex) of cat upon visually evoked and spontaneous single-unit and slow-wave activity. The bicuculline produced an increase in both the visually evoked and the spontaneous unit activity. A surface negative component of the slow-wave response was markedly enhanced by the bicuculline. This component was associated with an intense suppression of spontaneous single-unit activity. Therefore, we have found that bicuculline has a convulsant effect upon single-unit activity as previously reported by others. However, we also found that bicuculline potentiates a process which appears associated with an enhancement of inhibition.

Animals↗
PubMed1980

Antiabsence drugs and inhibitory pathways.

Conditioning stimuli to the coronal gyrus or periventricular gray matter inhibit the activity of spinal trigeminal neurons. Valproate decreased the corticofugal inhibition of the spinal trigeminal nucleus, as did ethosuximide, trimethadione, and imipramine. Valproate and ethosuximide also decreased the periventricular inhibition of the spinal trigeminal nucleus, indicating that antiabsence drug depress subcortical inhibitory pathways as well as pathways of cortical origin. These results support the hypothesis that ability to depress inhibitory pathways is an important characteristic of antiabsence drugs. The effect of valproate and ethosuximide on periventricular inhibition also suggests that these anticonvulsants may act by preventing the spread of seizure activity through subcortical pathways.

Animals↗
PubMed1978

Postnatal development of visually evoked activity within motor cortex of cat.

1. The development of visually evoked activity within motor cortex was studied in chloralose-anesthetized kittens of 3, 4, and 5 mo of age and adult cats. 2. The slow-wave response from motor cortex of the adult cat is a triphasic negative-positive-negative wave. In 3-mo-old kittens the response is only a long-duration negative wave, while at 4 mo the positive and late negative waves emerge, and at 5 mo of age the adult form of the response is present. 3. Single neurons in the adult respond to the light during the positive component of the slow-wave response. When only the negative wave is present in kittens of 3 and 4 mo of age, neurons do not respond to the photic stimulus. At 5 mo of age the correlation between unit activity and the positive component of the response is identical to the adult. 4. The laminar analysis of the positive component of the response suggests that it originates relatively superficially in cortex and migrates down toward the deeper layers. Its correlation with unit activity indicates that the positive component represents excitatory postsynaptic potentials. 5. These results are consistent with an excitatory drive on neurons within motor cortex undergoing development change until the 5th mo of life.

Aging↗
PubMed1978

Imipramine in absence and myoclonic-astatic seizures.

A double-blind crossover study with imipramine was conducted in 10 patients with absence and myoclonic-astatic seizures who had not responded to conventional medications. Imipramine produced a significant initial decrease in seizure frequency in 5 of the 10 patients, and in 2 patients the beneficial effect was maintained for more than 1 year. An open trial of imipramine in another 16 patients showed an initial reduction in seizure frequency in 10 patients (63 percent), and this decrease persisted for more than 1 year in 4 patients (25 percent). The effect of imipramine on the EEG did not always correlate with the clinical response. Serum content of imipramine in the patients who showed a long-term response was 40 to 120 ng per milliliter, on a total daily dose of 0.7 to 3.5 mg per kilogram. These results suggest that imipramine is a valuable addition to the treatment of seizures.

Adolescent↗
PubMed1975

Chloralose induced alteration of visually evoked response from specific and non-specific regions of cat neocortex.

Visually evoked response (VER) and EEG from the motor cortex (precruciate gyrus) and the visual cortex (marginal gyrus) of cats were recorded from 4 to 7 h after the injection of anesthetic doses of alpha-chloralose. During the recording period the VER from the precruciat gyrus showed a 200-300% increase in amplitude while the VER from the marginal gyrus rarely varied more than 50% in amplitude, and did so independent of the changes in the VER from the precruciate gyrus. The number of large amplitude spikes in the EEG from the precruciate gyrus also increased dramatically during the recording period, but no definite correlation between changes in VER amplitude and in the number of spikes in the EEG could be demonstrated. These observations suggest a functional separation between specific and nonspecific sensory pathways, with the latter showing a considerably greater sensitivity to level of anesthesia.

Animals↗