Place learning strategy of substantia nigra pars compacta-lesioned rats.

Abstract

The substantia nigra pars compacta (SNc) and the dorsal striatum are often considered to be necessary for stimulus-response (S-R) habit learning, whereas the dorsal hippocampus is considered to be necessary for relational (declarative) memory. Spatial learning is a kind of relational learning that occurs when a rat is released from different locations (variable start) in a water maze to find a submerged platform that is kept in a constant location. However, when the rat is always released from the same starting position (constant start), it can learn to find the platform oriented by a fixed configuration of cues, that is, by S-R learning. To test the critical role of the SNc in S-R and relational learning, the authors tested adult male Wistar rats, sham-operated or with a lesion in the SNc, in these 2 versions of the water maze task. The SNc lesion was induced by bilateral intranigral infusion of 0.5 micromol 1-methyl-4-phenyl- 1,2,3,6-tetrahydropyridine. Although the SNc-lesioned rats learned the variable-start version as effectively as sham rats did, they were significantly impaired in learning the constant-start version of the task.

A rotarod test for evaluation of motor skill learning

“…In rodents, dopamine depletion impairs spatial memory tasks (Da Cunha et al, 2006;Ferro et al, 2005;Miyoshi et al, 2002). Our study has confirmed that this is also true in motor learning.…”

Is there a geometric module for spatial orientation? Insights from a rodent navigation model.

“…not able to learn this task (see also Figure 9C, left). Thus, the model is consistent with the experimental data showing that intact animals rely strongly on the locale strategy in this task and that lesions of the hippocampus (or NA) disrupt learning, whereas lesions along the taxon pathway (i.e., SNc or CP) do not produce any impairment (Da Cunha et al, 2006;Morris et al, 1982). Moreover, an analysis of the escape latency (see Figure 9A, left) revealed that when using locale strategy, the simulated rat learned rapidly during the first four to five trials and achieved, after approximately 15 trials, an asymptotic performance (Morris, 1981).…”

Intranigral LPS Administration Produces Dopamine, Glutathione but not Behavioral Impairment in Comparison to MPTP and 6-OHDA Neurotoxin Models of Parkinson’s Disease

“…Some models of PD are achieved by the use of neurotoxins, in particular 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), 6-hydroxydopamine (6-OHDA), and recently the endotoxin found in the outer membrane of gram-negative bacteria, lipopolysaccharide (LPS) [1][2][3]. In most of the studies of PD models, several of the motor, cognitive, affective, neurochemical, inflammatory and sleep disruptions encountered in the human disease are partially recapitulated by MPTP, 6-OHDA and LPS [4][5][6][7][8][9][10][11][12][13][14].…”