Abstract

1. % Trial Time Brace Dodge . . . . . . Organization of food protection behavior is differentially influenced by hippocampal and cortical cholinergic deafferentationM.M. Martin*; L.A. Carter; J.L. Jones; S.S. Winter; D.G. WallaceDept Psychology, Northern Illinois Univ., DeKalb, IL, USA 742.6 Abstract Results Figure 6: Temporal organization of food protection behaviors normalized by consumption time are plotted for representative control (top row), MS SAP (middle row), and NB SAP (bottom row) rats. Closed circles represent dodges, and open circles represent braces. Figure 2: Behaviors were recorded from underneath, as shown in a photograph of the apparatus with a dodger and robber present (left column). Digitized examples are shown for a dodge (middle column) and brace (right column) by a dodger rat (blue) in an attempt to escape the robber rat (red). Dots represent digitization of the rats’ bodies: tip of nose, between the forelimbs, and base of tail. Black lines represent the starting locations of the dodger and robber rats (middle and right columns). Studies have demonstrated different roles for hippocampal and cortical cholinergic function in processing of temporal information in standard interval timing procedures. Previous work has suggested that rats use temporal information to organize their food protection behaviors as well. The present study examined the role of hippocampal and cortical cholinergic function on the organization of food protection behavior. Figure 7: Sum of time spent dodging and bracing are presented for control (left panel), MS SAP (middle panel), and NB SAP (right panel) groups for early and late samples. The control and NB SAP groups demonstrated an interaction between time spent dodging and bracing in early versus late samples of eating a single food item. The MS SAP group spent more time dodging than bracing and unlike the control and NB SAP groups, did not modulate time spent dodging and bracing. Method Figure 3: Time to consume a hazelnut (left column), total number of food protection behaviors (middle column) and percentage of successful behaviors (right column) are shown across groups. There was no group difference in time to consume a hazelnut or total number of food protection behaviors; however, the NB group was less successful in protecting food than control and MS groups. Female Long Evans rats received either injections of 192 IgG-Saporin (SAP) or saline (control) into the medial septum (MS) or nucleus basalis (NB). Subsequent to recovery, rats were placed into an enclosure and provided a hazelnut in the presence of an unoperated conspecific. All rats engaged in dodging or bracing behaviors to prevent the theft of the hazelnut. Dodging involves the rat placing the food item in its mouth in order to use both fore- and hind limbs to escape the approaching conspecific. In contrast, bracing enables a rat’s forelimbs to maintain contact with the food item, and only the hind limbs are used to make shorter lateral movements. Several measures were analyzed to reflect attentional, motivational, and temporal influences on behavior. Conclusions Figure 4: Distance (left panels) and average speed (right panels) are plotted separately for dodging and bracing behaviors. No group differences were observed in either measure. • Groups did not differ in amount of time to eat a food item, number of food protection behaviors, distance traveled, or average speed, suggesting groups possessed similar motivation and motor abilities. • The NB SAP rats were less successful in protecting their food and initiated dodges when the robber was farther away, relative to control and MS SAP groups. These impairments are consistent with an attentional deficit. • The MS SAP group displayed a disruption in temporal organization of food protection behaviors, relative to control and NB SAP groups. This impairment is consistent with a deficit in temporal organization of food protection behavior. • These results demonstrate a double dissociation between NB SAP and MS SAP involvement in organization of food protection behavior. Figure 1: Photographs of coronal sections stained for AChE are presented from representative control, MS SAP, and NB SAP rats (left figure). The reduction in AChE was primarily restricted to the hippocampus in the MS SAP group and primarily restricted to the cortex in the NB SAP group (right figure). Control Figure 5: Initial (left panel) and terminal (right panel) distances between the noses of the dodger and robber rats are plotted separately for dodging and bracing behaviors. The NB group initiated dodges at a farther distance from the robber than the other groups. No group differences were observed at the initiation of bracing or at the termination of dodging or bracing behaviors. MS SAP NB SAP * Correspondence: M. Martin mmarti14@students.niu.edu D. Wallace dwallace@niu.edu Web: www.niu.edu/user/tj0dgw1 Support Contributed By: NINDS grant NS051218