Differential activity profile of cAMP-dependent protein kinase isoforms during long-term memory consolidation in the crab Chasmagnathus

The isoforms of cAMP-dependent protein kinase (PKA) show distinct biochemical properties and subcellular localization, suggesting different physiological functions, and conferring the fine-tuning between the activation of cAMP-PKA cascade and the cellular response. The critical role of PKA in memory and synaptic plasticity has been extensively demonstrated both in vertebrates and invertebrates, but the role of PKA isoforms is a matter of debate. Here we present experimental data showing differential PKA activation profiles after two different experiences: an instance of associative contextual learning (context-signal learning) and a single exposure to a novel context, both in the learning and memory model of the crab Chasmagnathus. Differences were found in the temporal course of activation and in the involvement of PKA isoforms. We found increased PKA activity immediately and 6 h after context-signal training correlating with the critical periods during which pharmacological inhibition of PKA disrupts memory formation. In contrast, PKA activity increased immediately but not 6 h after single exposure to a novel context. The amounts of PKA I and PKA II holoenzymes were analyzed to determine changes in holoenzyme levels and/or differential activation induced by both experiences. Results indicate that context-induced PKA activation is at least in part due to PKA II, and that PKA activation 6 h after context-signal learning coincides with an increase in the total level of PKA I. Considering the higher sensitivity of PKA I to cAMP, its increment can account for the PKA activation found 6 h after training and is proposed as a novel mechanism providing the prolonged PKA activation during memory consolidation.     

Anomalous experiences and schizotypy: which comes first? The Hermit Crab syndrome hypothesis

This study confirms findings of previous research as they state that some triggering events or anomalous experiences can give rise to a disruption of cognitive processes and emotional changes in a predisposed person. Furthermore, our research states that the cognitive process and change of world view (paradigm shift (PS)) accompanying some paranormal experiences (PEs) could facilitate the development of a schizotypal personality structure. For the purposes of this study, 675 young people aged between 13 and 25 years old (M?=?16.8, SD?=?1.9) completed the Schizotypal Personality Questionnaire, the Revised and Modified Paranormal Belief Scales, the measurement of eight kinds of PE and a self-reported measurement of change of world view. The results confirm the mediating role of PS between paranormal practices and schizotypy as the cognitive process contributing to symptom formation as well as to symptom maintenance. The said results also confirm the existence of cognitive–emotional stages, also called Hermit Crab syndrome, in the process of the “paranormalisation” of reality.