figure 4: average dodger speeds are shown for ms (left panel) and nb (right panel) groups. dodging...
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Figure 4: Average dodger speeds are shown for MS (left panel) and NB (right panel) groups. Dodging (circles) and bracing (triangles) speeds are plotted for SAL (open symbols) and GAL (closed symbols) treated rats. Drug condition and lesion type had no effect on speed, and overall, rats reached higher speeds when engaging in dodging relative to bracing behaviors.
Galanthamine does not attenuate attentional or temporal impairments subsequent to cholinergic deafferentation of the cortex or hippocampus
M.M. Martin*; S.L. Weathered; S.J. Wagner; D.G. WallaceDept Psychology, Northern Illinois Univ, DeKalb IL, USA
Abstract
Long Evans female rats received injections of 192 IgG-Saporin (SAP) into the nucleus basalis (NB) or medial septum (MS). Rats in each lesion group were assigned to receive saline (SAL) or 3.0 mg/kg galanthamine (GAL) s.c. twice daily. Subsequent to recovery, rats (“dodgers”) were placed into an enclosure and provided a hazelnut in the presence of an unoperated conspecific (“robber”). All dodger rats engaged in food protection behaviors, such as dodging or bracing, to prevent the theft of the hazelnut. Several measures were analyzed to reflect attentional, motivational, and temporal influences on behavior.
Figure 2: Example topographies of dodging (left panels) and bracing (right panels) food protection behaviors are plotted with a dodger (blue) and robber (red). Initial body positions are indicated by black lines. The moment-to-moment speeds are plotted for each rat’s head during a dodge and brace (bottom panels). Dodging behavior results in a dramatic increase in speed and distance between heads. In contrast, bracing behavior is slower and results in a smaller terminal distance between heads.
The role of the basal forebrain cholinergic system in early symptomology of dementia of the Alzheimer’s type (DAT) remains an area of intense debate. Although involvement of the basalocortical cholinergic system in attentional processing has been established, function of the septohippocampal cholinergic system remains to be determined. A recent study demonstrated a double dissociation between these systems in the organization of rat food protection behavior that may parallel the attentional impairments and temporal disorientation observed during the early stages of DAT. The current study sought to examine whether an acetylcholinesterase inhibitor currently used for the treatment of DAT (i.e., galanthamine) could attenuate these deficits.
Correspondence:
M. Martin [email protected]
D. Wallace [email protected]
Web: www.niu.edu/user/tj0dgw1
Support Contributed By:
NINDS grant NS051218 (D Wallace)
2007 APA Dissertation Research Award (M Martin)
Method
Results
Conclusions
Figure 3: Total number of food protection behaviors (left panel) and percentage of successful behaviors (right panel) are shown for each drug condition and lesion type. Number of food protection behaviors did not differ by drug condition or lesion type. Drug condition also had no influence on percent of successful food protection; however, the NB groups were less successful in protecting food relative to the MS groups.
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Figure 5: Mean times spent engaged in food protection behaviors are shown for MS (left panel) and NB (right panel) groups. Times spent dodging (circles) and bracing (triangles) are plotted for SAL (open symbols) and GAL (closed symbols) treated rats. Drug condition had no effect on either group. Note that there is a lack of transition between time spent dodging and bracing for the MS groups (left panel), whereas the NB groups (right panel) exhibited a transition between primarily dodging in early samples to both dodging and bracing in late samples.
• Results of this study are consistent with previous research, with a double dissociation in roles of the basalocortical and septohippocampal cholinergic systems in organization of food protection behaviors.
• NB groups were significantly worse at protecting their food, although their behaviors remained temporally organized.
• MS groups displayed temporal disorganization of food protection behaviors, as evidenced in the lack of transition observed between time spent dodging and bracing for MS groups.
• Impairments in both groups persisted after administration of GAL.
• Results of this study suggest that the modest benefits afforded by galanthamine administration in DAT patients may not reflect improved attention or temporal orientation.
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Figure 1: Photographs of coronal sections stained for AChE are presented from representative MS SAL, MS GAL, NB SAL, and NB GAL rats (left panel). GAL resulted in an increased cortical staining in the MS GAL rats relative to MS SAL rats (middle panel) but had no effect in the NB groups (right panel).
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