Avitaminosis B 1 and Pigeon Brain Potentials

Abstract

Since vitamin B₁ lack disturbs the normal carbohydrate metabolism of brain, it was desirable to follow its influence on brain potentials. Pigeons were standardized on a stock diet for 30 days, then on a diet of polished rice and salt. 1 Although deficient in other nutritional elements, only vitamin B₁ lack could play a rôle within the time limits, for typical beri-beri symptoms (opisthotonus) developed in 30–40 days. A small portion of the calvarium over the occipital portion of one cerebral hemisphere was removed under nembutal (30 mg/kg, sufficient to relax the rigid muscles) and the exposed brain kept moist and warm with Ringer. Potentials were led off (different electrode on exposed brain; indifferent on bone over opposite hemisphere) with Ag-AgCl wick electrodes, 2 amplified and recorded with a crystograph. When desired, 2–5 mg of crystalline vitamin B₁ were injected intramuscularly, administered orally, or both. At the conclusion of the experiment, the scalp was sewn together. Despite the absence of aseptic technique no sepsis resulted and repeated records could be obtained from one bird.

Normal brain potentials (Fig. la). A predominant 10–25 per sec. rhythm of 10–30μV is usually superimposed on one of 2–5 per sec. and 80–100μV. A 35–50 per sec. rhythm of less than 10μV is often superimposed on both of the preceding ones. Occasional “spike-like” potentials of 100μV and more interrupt the slower waves. The several frequencies are not very regular, individually or in their sequence.

Potentials from the avitaminous brain (Fig. 1b) are more regular than in the normal. The fastest rhythm is unchanged or decreased, the slower ones are increased in amplitude by as much as 100%, and more and larger spikes appear.

Administration of vitamin B₁ does not influence potentials of the normal brain.