A disconnection analysis of hippocampal function

Beyond Memory, Navigation, and Inhibition: Behavioral Evidence for Hippocampus-Dependent Cognitive Coordination in the Rat

“…Injecting tetrodotoxin (TTX) into both hippocampi confirmed the task was hippocampus dependent (Cimadevilla et al, 2000a). Unilateral hippocampal dysfunction spared learning in other spatial tasks (Olton et al, 1982;Sutherland et al, 1983;Fenton and Bureš, 1993;Fenton et al, 1995;Moser and Moser, 1998), and we wanted to confirm this for place avoidance as a basis for studying how information is organized between the hippocampi. Injecting TTX into one dorsal hippocampus unexpectedly abolished learning, consolidation, and retrieval of place avoidance on the rotating arena (Cimadevilla et al, 2001).…”

Disconnection of the Entorhinal Cortex and Dorsomedial Striatum Impairs the Sensitivity to Instrumental Contingency Degradation

“…In contrast, in animals subjected to sham lesions we observed only minimal damage along the injection cannulae tracks with no damage to the respective target area. We did not include a further control group with combined unilateral lesions of the pDMS and EC in the same hemisphere, as numerous studies using disconnection designs showed that ipsilateral lesions of two interconnected structures in the same hemisphere do not impair behavior relative to the effect of crossed disconnection lesions (Chudasama et al, 2003;Dunnett et al, 2005;Hauber and Sommer, 2009;Olton et al, 1982;Warburton et al, 2000).…”

Neuroprotection in Animal Models of Global Cerebral Ischemia

“…Cognitive functions have also been assessed in rodents through conditioned avoidance tasks (Block, 1999;Kofler et al, 2004;. Several paradigms in the Morris water maze and in the eight-arms radial Olton maze, that have been used in most of neuroprotection studies in which cognitive functions are assessed, have proven to be useful for testing hippocampal, striatum and prefrontal cortex functioning as end points of brain damage or neuroprotection after global cerebral ischemia (Morris, 1984;Olton et al, 1982). Hippocampal functioning has been evaluated in rats and mice through some behavioral paradigms that require the integrity of this brain structure and related structures in the temporal lobe (Barnes, 1979;Morris et al, 1982Morris et al, , 1990, in order to configure cognitive spatial representations, i.e., a cognitive spatial map (Cassels, 1998;Jarrad, 1993;McDonald and White, 1994;1995;Moser et al, 1993).…”

“…Spatial working memory can be evaluated by using the 8-arms Olton radial maze (Myhrer, 2003;Olton, 1983Olton, , 1987Olton et al, 1982;Shibata et al, 2007). For a daily standard evaluation all eight arms are baited and the rat is allowed to collect food from each arm; the number of errors, defined as a re-entry into an arm that had already been visited, is recorded in order to evaluate withholding and updating of information about each arm visited and rewarding obtained.…”

“…An alternative maze configuration in which only some of the eight arms are baited allows to evaluate reference memory besides working memory through recording of the number of reference memory errors (number of entries into unbaited arms) and working memory errors (re-entry into an already visited arm). Performance in the Olton maze requires an adequate functioning of hippocampalprefrontocortical neuronal circuits, and is a reliable parameter of morpho-functional integrity of these brain structures after ischemia and neuroprotection (Cassel et al, 1998;Fritts et al, 1998;Izaki et al, 2008;Kolb, 1990, Kolb et al 1982Laroche et al, 2000;Olton et al, 1982;Seamans et al, 1995;Winocur, 1982). An aquatic version of the 8-arm radial maze has also been described (Kolb et al, 1982), and used to correlate hippocampal pyramidal neurons damage and working memory performance (Nelson et al 1997).…”