Interaction between the nature of the information and the cognitive requirement of the task in problem solving in mice

5-HT1A receptors and memory

The study of 5-hydroxytryptamine (5-HT) systems has benefited from the identification, classification and cloning of multiple 5-HT receptors (5-HT(1)-5-HT(7)). Increasing evidence suggests that 5-HT pathways, reuptake site/transporter complex and 5-HT receptors represent a strategic distribution for learning and memory. A key question still remaining is whether 5-HT markers (e.g., receptors) are directly or indirectly contributing to the physiological and pharmacological basis of memory and its pathogenesis or, rather, if they represent protective or adaptable mechanisms (at least in initial stages). In the current paper, the major aim is to revise recent advances regarding mammalian 5-HT(1A) receptors in light of their physiological, pathophysiological and therapeutic implications in memory. An attempt is made to identify and discuss sources of discrepancies by employing an analytic approach to examine the nature and degree of difficulty of behavioral tasks used, as well as implicating other factors (for example, brain areas, training time or duration, and drug administration) which might offer new insights into the understanding and interpretation of these data. In this context, 8-OH-DPAT deserves special attention since for many years it has been the more selective 5-HT drug and, hence, more frequently used. As 5-HT(1A) receptors are key components of serotonergic signaling, investigation of their memory mechanisms and action sites and the conditions under which they might operate, could yield valuable insights. Moreover, selective drugs with agonists, neutral antagonists or inverse agonist properties for 5-HT(1A) (and 5-HT(7)) receptors may constitute a new therapeutic opportunity for learning and memory disorders.

Spatial choices of rats based on abstract visual information: Pattern- or configuration-discrimination?

Animals demonstrate their ability to represent a geometric configuration of their environment and to use this information for spatial decisions in their response space in many situations. In presented experiment, we examined the ability of rats to interpret a configuration of abstract visual stimuli to make spatial decisions in a real response space. We tested whether they are able to interpret spatial configuration of abstract stimuli or whether they perceive such visual stimuli simply as geometric patterns associated to particular spatial choices. The rats were tested in a Skinner box with four nosing holes in the transparent front wall through which a computer screen was visible. According to the visual stimuli on the screen, the rats should choose the appropriate nosing hole to obtain a reward. We compared two groups of rats: the first group was exposed to the visual stimuli designed as a representation of the response space: the position of rewarded nosing hole was shown in relation to other nosing holes. The second group was exposed to one of four geometric patterns associated to one of the four nosing holes but without any implicit information about the response space. The results suggested that rats using the stimuli with information about configuration were significantly more successful than rats trained to respond to visual stimuli unrelated to the geometry of the environment.