OBSERVATIONS ON THE BEHAVIOR AND NEUROPHYSIOLOGY OF ACUTE THIAMIN DEFICIENT CATS

Abstract

1. A dietary regime, having as a feature the use of crystalline vit. supplements given both orally and intraperit., has been shown to meet the requirements for the production of specific thiamine deficiency. Thus, the diet was shown to maintain the animal in normal health if thiamine was added. Further the disorders arising while the animals were on diet, namely, anorexia in the early period and postural disturbances and convulsions in the critical stage were specifically alleviated within a period of a day after the inj. of thiamine. Inj. of other B complex vits. had no effect. The development of thiamine deficiency in the cat may be divided into 3 stages: induction stage, characterized by the development of anorexia; critical stage, characterized by the sudden appearance of many neurological disorders, particularly of the postural mechanisms, and usually short tonic convulsive seizures. The animal becomes progressively weaker and passes into the terminal stage where the animal is prostrate and cannot be recovered; death follows within a day or two. A detailed study of the reflex activities of cats in the critical stage revealed impairment of labyrinthine righting reactions as shown by the abnormal head position and loss of righting in air; vestibulo-ocular reflex as indicated by the decreased nystagmus time; and pupillary light reflex as revealed by the increase in pupil size. Dysfunction of the cerebullum was suggested by the presence of asynergia, ataxia, and dys-metria. A consideration of the reflex pathways involved in the reactions which showed impairment revealed that all of them have synaptic centers in the midbrain. This is proposed as the probable locus of the functional lesion giving rise to the observed nervous disorders.