[Relationship of decerebrate rigidity maintenance with muscular contraction permanence after spinal cord section in dogs].

The mammalian spinal cord seems to be capable of information retation in simmilar fashion to the cerebral cortex memory storation. The intercollicular transection otherwise, relieving bulbar and mesencephalic areas from cerebral and cerebelar influences produces tetanic contraction on antigravidity muscles due to somatory with stimuli originated from muscle spindle. This phenomena is very suitable to memory retention studies since myotatic reflex is monossinaptic, occurs in this case, on a simple nervous structure (the spinal cord) and can be easily identified and quantitified, through muscular responses. In the present work, decerebrate rigidity effects upon spinal cord before and after spinal section, was studied. Physiological parameters were recorded in order to maintain the experimental condition of the dogs, as close as possible to normal, Our results showed that thirty and forty-five minutes in time difference of decerebrate rigidity influence on spinal motoneurons has little effects in tetany persistance after spinal section. However, ninety minutes period of time between the two transections produces considerable increase in rigidity permanence after spinal cord section. The relationship of our results with differents types of memory and the basic mechanism involved in the response is unknown and will be the subject of future investigations.