Lesions were placed in pathways anatomically associated with some septal projections to assess their individual contributions to the enhanced active avoidance performance and passive avoidance deficit found after large septal lesions. Septal and stria medullaris-habenular lesions impaired performance on a food-reinforced passive avoidance task, while fornix lesions had little effect. Septal, stria medullaris-habenular, and fornix lesions all enhanced two-way shuttle-box avoidance performance and led to greater resistance to extinction of this task with massed trials. The results do not support a unitary conceptualization of septal function; instead, they suggest that the various behavioral effects associated with septal lesions are mediated over different projections.
Lesions were placed in tracts associated with the septum to assess their contributions to decrements observed on DRL performance following large septal lesions. Septal lesions and large fornical lesions, which disrupted both dorsal fornical and fimbrial fibers, produced marked deficits. However, smaller lesions restricted to the medial aspects of the fornix, sparing the fimbria, had little effect. Lesions of the stria medullaris produced less severe deficits which were more transient than those found after the other lesions. The results suggest that septal connections with fields CA 3 and CA 4 of the hippocampus via the fimbria form a major component of a system important in response inhibition and timing behavior. The rostral field CA 1 and associated fibers in the dorsal and postcommissural fornix were not implicated in such an inhibitory function.
Active-and passive-avoidance performance were examined in rats with lesions in the interpeduncular nucleus, ventral tegmentum, combined interpeduncular nucleus and ventral tegmentum, and the stria medullaris-habenula. Impaired passive-avoidance performance was noted in all groups with lesions, whereas only the groups with lesions in the interpeduncular nucleus and stria medullaris-habenular nucleus had facilitated active-avoidance performance. The results suggest that the stria medullaris tract, habenular nucleus, habenulopeduncular tract, and interpeduncular nucleus serve as significant anatomical pathways concerned with the acquisition of both active-and passive-avoidance performance, whereas pathways traveling in the ventral tegmental area dorsal to the interpeduncular nucleus arc involved only in passive-avoidance responding.Since McCleary's (1961) analysis of avoidance performance following septal lesions, a number of investigators have attempted to specify the anatomical pathways associated with the behavioral changes observed after this lesion. Since it is often assumed that limbic midbrain pathways are disrupted following septal lesions, it is important to ask which pathways are pertinent in avoidance performance, and whether the disruption of a given septal pathway leads to behavioral changes characteristic of subjects with septal lesions on all tasks, or on only some.Recently, Van Hoesen, MacDougall, and Mitchell (1969) found that active-and passive-avoidance performance were selectively affected following the disruption of pathways carrying septal fibers. Complete or partial fimbria-dorsal fornix tractotomy facilitated active-avoidance performance, but produced no passive-avoidance deficit
Male rats were maintained on rat chow supplemented with 5% evening primrose oil for 2 weeks. Mesenteric perfusions were then performed, half with and half without albumin. Albumin was found to increase the yield of fatty acids and reduce eicosanoid levels. Perfusions without albumin decreased fatty acid release, increased eicosanoid levels, and showed a decrease in protein concentration over time. The value of albumin as a "trap" for fatty acids during perfusion experiments depends upon what parameter is to be measured.
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