Intact spatial discrimination performance but impaired reaction time performance after frontal cortex lesions in the rat

Abstract

SUMMARYIn the present study the consequences of frontal cortex (FC) lesions on spatial discl-iminatiol7 learning and reaction time performance were assessed in rats. Spatial working-and reference memory were tested simultaneously in a cone field task. It was found that FC lesions did not impair both aspects of spatial discrimination performance in this task. In a choice reaction time task the FC lesion decreased the response speed (reaction time and motor time). Detailed analysis of the reaction times indicated that these effects could be attributed to an impaired motor preparation and/or an attention deficit. The present study suggests that claims of deficit in learning and memory following FC lesions should take into account possible effects of motor pl-epal-ation/execLrtioll and attention.KEY WORDS: frontal cortex, spatial, reaction time, working memory, reference memory, attentionIn an extensive review on the role of the frontal cortex (FC) Kolb indicated that the main function of this part of the FC could be related with the temporal organization of behavior in rats [3Oj. Similar to humans and non-human primates, sub-regions of the frontal cortex of the rat can be dissociated on basis of anatomy and cognitive functions [ 1,18,26,28,30,3 1,42,45], but see [ 11,401. With respect to lesions of the medial FC, which may be regarded as the rat homologue of the dorsolatcral prefrontal cortex of primates [24,31], there appears to be a discrepancy between the data

GABAA but not GABAB receptors in the rostral anterior cingulate cortex selectively modulate pain-induced escape/avoidance behavior

“…The current data are further supported by research reporting that prefrontal cortex lesions in rats did not lead to a disruption of working memory measured by the radial arm maze as opposed to prefrontal cortex lesions that included the prelimbic and infralimbic cortices (Fritts et al, 1998). Additional research indicates that following frontal cortex lesions, there is no impairment of working memory or reference memory (Blokland et al, 2003).…”

“…The current data are further supported by research reporting that prefrontal cortex lesions in rats did not lead to a disruption of working memory measured by the radial arm maze as opposed to prefrontal cortex lesions that included the prelimbic and infralimbic cortices (Fritts et al, 1998). Additional research indicates that following frontal cortex lesions, there is no impairment of working memory or reference memory (Blokland et al, 2003).Although evidence suggests that the ACC is involved in various aspects of learning and memory, it is unlikely that these phenomena alter place escape/avoidance behavior. The most parsimonious explanation is that the stimulus that is administered in the dark side of the chamber is more aversive to L5 ligated animals and thus, they escape/avoid that stimulus.…”

Long‐term effects of immunotoxic cholinergic lesions in the septum on acquisition of the cone‐field task and noncognitive measures in rats

“…Thus, the findings with fimbria lesions suggest that compromised hippocampal functioning affects spatial discrimination learning in the cone-field task. The notion that the cone-field discrimination task is hippocampus-dependent is further supported by the observation that lesioning of the hippocampus (Blokland, University Maastricht, unpublished observation), but not of the prefrontal cortex (Blokland et al, 2003), impairs task acquisition. In addition, this test appears to be much more complex than the radial arm maze task or the Morris water escape task, as supported by the observation that even after extensive training (i.e., more than 400 trials), intact rats are still unable to perform it error free .…”