Navegando por Autor "Medina, Jorge H."
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Artigo BDNF and memory processing(2014-01) Bekinschtein, Pedro; Cammarota, Martín Pablo; Medina, Jorge H.Brain-derived neurotrophic factor has emerged as one of the most important molecules involved in memory. Its wide role in different types of memories that depend on different structures as well as its involvement in distinct memory stages points at BDNF as one likely target to treat cognitive impairments and anxiety-related memory disorders. However, regulation of BDNF expression is very complex as well as its modes of action. Here we describe the latest research carried out on the function of BDNF in memory to illustrate such complexity.Artigo Consolidation of object recognition memory requires simultaneous activation of dopamine D1/D5 receptors in the amygdala and medial prefrontal cortex but not in the hippocampus(2013-11) Rossato, Janine I.; Radiske, Andressa; Kohler, Cristiano A.; Gonzalez, Carolina; Bevilaqua, Lia Rejane Müller; Medina, Jorge H.; Cammarota, Martín PabloThe mesocorticolimbic dopaminergic system includes the ventral tegmental area (VTA) and its projections to the amygdala (AMY), the hippocampus (HIP) and the medial prefrontal cortex (mPFC), among others. Object recognition (OR) long-term memory (LTM) processing requires dopaminergic activity but, although some of the brain regions mentioned above are necessary for OR LTM consolidation, their possible dopamine-mediated interplay remains to be analyzed. Using adult male Wistar rats, we found that posttraining microinjection of the dopamine D1/D5 receptor antagonist SCH23390 in mPFC or AMY, but not in HIP, impaired OR LTM. The dopamine D2 receptor agonist quinpirole had no effect on retention. VTA inactivation also hindered OR LTM, and even though this effect was unaffected by co-infusion of the dopamine D1/D5 receptor agonist SKF38393 in HIP, mPFC or AMY alone, it was reversed by simultaneous activation of D1/D5 receptors in the last two regions. Our results demonstrate that the mesocorticolimbic dopaminergic system is indeed essential for OR LTM consolidation and suggest that the role played by some of its components during this process is much more complex than previously thought.Artigo Functional integrity of the retrosplenial cortex is essential for rapid consolidation and recall of fear memory(2013) Katche, Cynthia; Dorman, Guido; Slipczuk, Leandro; Cammarota, Martín Pablo; Medina, Jorge H.Memory storage is a temporally graded process involving different phases and different structures in the mammalian brain. Cortical plasticity is essential to store stable memories, but little is known regarding its involvement in memory processing. Here we show that fear memory consolidation requires early post-training macromolecular synthesis in the anterior part of the retrosplenial cortex (aRSC), and that reversible pharmacological inactivation of this cortical region impairs recall of recent as well as of remote memories. These results challenge the generally accepted idea that neocortical areas are slow encoding systems that participate in the retrieval of remote memories only.Artigo Medial prefrontal cortex dopamine controls the persistent storage of aversive memories(2014-11-26) Gonzalez, María C.; Kramar, Cecilia P.; Tomaiuolo, Micol; Katche, Cynthia; Weisstaub, Noelia; Cammarota, Martín Pablo; Medina, Jorge H.Artigo Medial prefrontal cortex is a crucial node of a rapid learning system that retrieves recent and remote memories(2013) Gonzalez, Carolina; Kramar, Cecilia; Garagoli, Fernando; Rossato, Janine I.; Weisstaub, Noelia; Cammarota, Martín Pablo; Medina, Jorge H.The neocortex is thought to be a distributed learning system that gradually integrates semantic information into the initial mnemonic representation rapidly formed by the hippocampus after acquisition. Nevertheless, an emerging view suggests that some cortical regions, in particular the medial prefrontal cortex (mPFC), may also have a role during the initial steps of memory consolidation as well as in the recall of recent memories. Here, we show that mPFC plays a critical role during the first few hours of inhibitory avoidance memory consolidation and is necessary for the normal retrieval of both recent and remote memories, supporting the idea that involvement of neocortical areas in memory processing is not restricted to the late post-training consolidation phase.Artigo Molecular signatures and mechanisms of long-lasting memory consolidation and storage(2013) Katche, Cynthia; Cammarota, Martín Pablo; Medina, Jorge H.A body of evidence emerged in the last decade regarding late posttraining memory processing. Most of this new information comes from aversively motivated learning tasks that mainly depend on hippocampus, amygdala and insular cortex, and points to the involvement of long-lasting changes in gene expression and protein synthesis in late stages of memory consolidation and storage. Here, we describe recent advances in this field and discuss how recurrent rounds of macromolecular synthesis and its regulation might impact long-term memory storage.Artigo Nicotine modulates the long-lasting storage of fear memory(2013) Lima, Ramón H.; Radiske, Andressa; Köhler, Cristiano A.; Gonzalez, Maria Carolina; Bevilaqua, Lia Rejane Müller; Rossato, Janine I.; Medina, Jorge H.; Cammarota, Martín PabloLate post-training activation of the ventral tegmental area (VTA)–hippocampus dopaminergic loop controls the entry of information into long-term memory (LTM). Nicotinic acetylcholine receptors (nAChR) modulate VTA function, but their involvement in LTM storage is unknown. Using pharmacological and behavioral tools, we found that α7-nAChR-mediated cholinergic interactions between the pedunculopontine tegmental nucleus and the medial prefrontal cortex modulate the duration of fear-motivated memories, maybe by regulating the activation state of VTA–hippocampus dopamine connections.Artigo On the Role of Retrosplenial Cortex in Long-Lasting Memory Storage(2013) Katche, Cynthia; Dorman, Guido; Gonzalez, Carolina; Kramar, Cecilia P.; Slipczuk, Leandro; Rossato, Janine I.; Cammarota, Martín Pablo; Medina, Jorge H.The retrosplenial cortex (RSC) is involved in a range of cognitive functions. However, its precise involvement in memory processing is unknown. Pharmacological and behavioral experiments demonstrate that protein synthesis and c-Fos expression in the anterior part of RSC (aRSC) are necessary late after training to maintain for many days a fear-motivated memory. Long-lasting memory storage is regulated by D1/ D5 dopamine receptors in aRSC and depends on the functional interplay between dorsal hippocampus and aRSC. These results suggest that the RSC recapitulates some of the molecular events that occur in the hippocampus to maintain memory trace over time.Artigo Requirement for BDNF in the Reconsolidation of Fear Extinction(2015-04-22) Radiske, Andressa; Rossato, Janine I.; Köhler, Cristiano A.; Gonzalez, Maria Carolina; Medina, Jorge H.