Effect Of Electrical Stimulation Of Diencephalon On Somatic Movement In Gekko Gecko

The brain of the reptiles consist of medulla, midbrain, diencephalon, cerebellum, cerebrum , and occurred neopallium but the neopallium was not very developed. The surfaces of the brains haven't the sulcus and gytus , do the reptiles have the motor area, where are they? There are few researches about this , some researchers thought the midbrain was the motor area of the reptiles. There are not researches of ralation about diencephalon and somatic movement in reptiles so far. This article studied the relation between the somatice movements of Gekko gecko and diencephalon by electrical stimulation and electrolytic lesions and studied the projections of the diencephalon by horseradish peroxidase tracing.The first part of the research is effects of electrical stimulation of diencephalon on somatic movements in Gekko gecko under anesthesia. The animals were anaesthetized by intraperitoneal injuction of 30mg/kg pentobarbital sodium. We used biphysic rectangular pulses, continuous single stimulus, 80Hz, the stimulation time and the amplitude were controllable. Studies suggested that electrical stimulation of area lateralis hypothalami, nucleus lentiformis thalami and nucleus profundus mesencephali could make the spine of the animals contralaterally bend. Ipsilateral bent of the animals' spines appeared when we stimulated the ventral part of the pretectal area and lateral forebrain bundle, ventral peduncle. Pupil dilation occurred when we stimulated periventricular preoptic area, nucleus supraopticus and tractus opticus. The animals opened their mouth when we stimulated the surface of the pretectal area. Breathing speeded up when we stimulated nucleus pretectalis and nucleus dorsomedialis thalami.The second part of the research is about the effects of electrical stimulation of diencephalon on somatic movements in sober and free animals. Under anesthesia we impanted metal microelectrodes in the diencephalon of the animals at first, then we beginned the electrical stimulation experiments when the animals waked. The research showed that the animal turned ipsilaterally when stimulated nucleus profundus mesencephali, the head turned contralaterally when stimulated ventral part of the pretectal area, opened their mouth when we stimulated the surface of the pretectal area. This revealed the animals could move when we stimulated diencephalon, the diencephalon and somatic movements were interrelated. Under anesthesia or in sober the animals occurred opening mouths when we stimulated the surface of the pretectal area. But at the same point the result had slight differences between the two electrical stimulation experiments, for example nucleus profundus mesencephali. In sober animals replicated experiments at the same point had different results sometimes, are there anyother reasons except anesthesia and the fixed state? It needs further study.The third part is electrolytic lesions experiments: electrolytic lesions(0.2mA DC, 30s) were placed in some area of diencephalon under anesthesia. We observated the movement changes of the animals before and after lesions, there were two indexes avervage velocity and general course. The rusults showed that the electrolytic lesions of nucleus interstitialis had no obvious effects on movement. However, the number of this group was small and need further study.The last part of my article is about the research of projections of the diencephalon by horseradish peroxidase tracing. The results showed that the ventral thalamus recepted prjection from ipsilateral nucleus dorsolateralis thalami, nucleus suprapeduncularis and nucleus dorsolateralis hypothalami; the fibers mainly projected to lateral forebrain bundle, medial forebrain bundle, tractus septohypothalamicus, nucleus dorsolateralis thalami, nucleus suprapeduncularis and nucleus dorsolateralis hypothalami, projected ipsilaterally. A little neuron in telencephalon projected to dorsal thalamus, ipsilateral projection were more than the contralaterral. Area lateralis hypothalami mainly recepted periventricularis hypothalami, nucleus ventromedialis hypothalami and the wall of diacele. The fibers projected to tractus opticus basalis mainly ipsilaterally. The tractus opticus basalis mainly recepted projection from bilateral nucleus supraopticus, the fibers mainly projected to the tractus opticus and lateral forebrain bundle ipsilaterally.