Production of Anxiety Behavior and Avoidance Conditioning by Stimulation of Bulbar Reticular Formation

Conclusions

Behavioral responses, characterized by signs of anxiety, do not solely originate from suprabulbar sites, but also may be produced from ventromedial reticular areas of the medulla. The close correspondence between median response latencies in avoidance conditioning produced during stimulation in this region of the medulla and time intervals elapsing between initial increased arousal and appearance of overt signs of apprehension resulting from the same stimulation, suggests development of a negative “effect” resulting in avoidance behavior rather than direct induction of complex motor responses. Absence of directional tendencies in random escape experiments implies that classical ascending sensory pathways are not directly involved in these effects. Apparently the medullary reticular formation not only participates in respiratory, vasomotor and spinal reflex events but is also involved in certain aspects of conscious behavior associated with emotional signs.