Memory persistence induced by environmental enrichment is dependent on different brain structures.

Environmental enrichment (EE) has been demonstrated to have a beneficial effect on different functions of the central nervous system in several mammal species, being used to improve behavior and cell damage in various neurological and psychiatric diseases. However, little has been investigated on the effect of EE in healthy animals, particularly regarding its impact on memory persistence and the brain structures involved. Therefore, here we verified in male Wistar rats that contextual fear conditioning (CFC) memory persistence, tested 28 days after the CFC training session, was facilitated by 5 weeks of exposure to EE, with no effect in groups tested 7 or 14 days after CFC training.

Involvement of medial prefrontal cortex canonical Wnt/β-catenin and non-canonical Wnt/Ca signaling pathways in contextual fear memory in male rats.

Wnt proteins activate different signaling pathways, such as the canonical Wnt/β-catenin signaling pathway and non-canonical β-catenin-independent signaling pathway and have been related to several functions in central nervous system, including learning and memory. However, whether these signaling pathways are required in the medial prefrontal cortex (mPFC) for fear memory acquisition, consolidation and retrieval remains unclear. To address this question, we submitted male rats to a contextual fear conditioning (CFC) paradigm, and administered canonical Wnt/β-catenin and non-canonical Wnt/Ca signaling pathways inhibitors, DKK1 and SFRP1, respectively, into the prelimbic (PrL) subdivision of the mPFC at different moments and evaluated short-term and long-term memory acquisition, consolidation and retrieval.

Modulation of Carbonic Anhydrases Activity in the Hippocampus or Prefrontal Cortex Differentially Affects Social Recognition Memory in Rats.

Growing evidence indicates that brain carbonic anhydrases (CAs) are key modulators in cognition, particularly in recognition and aversive memories. Here we described a role for these enzymes also in social recognition memory (SRM), defined as the ability to identify and recognize a conspecific, a process that is of paramount importance in gregarious species, such as rodents and humans. Male adult Wistar rats were submitted to a social discrimination task and, immediately after the sample phase, received bilateral infusions of vehicle, the CAs activator D-phenylalanine (D-Phen, 50 nmols/side), the CAs inhibitor acetazolamide (ACTZ; 10 nmols/side) or the combination of D-Phen and ACTZ directly in the CA1 region of the dorsal hippocampus or in the medial prefrontal cortex (mPFC).

PKMζ Maintains Remote Contextual Fear Memory by Inhibiting GluA2-Dependent AMPA Receptor Endocytosis in the Prelimbic Cortex.

Fear memories allow animals to recognize and adequately respond to dangerous situations. The prelimbic cortex (PrL) is a crucial node in the circuitry that encodes contextual fear memory, and its activity is central for fear memory expression over time. However, while PrL has been implicated in contextual fear memory storage, the molecular mechanisms underlying its maintenance remain unclear.

Involvement of medial prefrontal cortex NMDA and AMPA/kainate glutamate receptors in social recognition memory consolidation.

Social recognition memory (SRM) enables the distinction between familiar and strange conspecifics, a fundamental ability for sociable species, such as rodents and humans. There is mounting evidence that the medial prefrontal cortex plays a prominent role both in shaping social behavior and in recognition memory. Glutamate is the major excitatory neurotransmitter in the brain, and activity of its ionotropic receptors is known to mediate both synaptic plasticity and consolidation of various types of memories.