Biology subjects

Lukasiewicz, K.

Publications and source records attributed to Lukasiewicz, K..

4 recordsLinked to original sources

bioRxiv2024

Projections from thalamic nucleus reuniens to medial septum enable extinction of remote fear memory

Aversive experiences lead to the formation of long-lasting memories. Despite the need to better understand how enduring fear memories can be attenuated, the underlying brain circuits remain largely unknown. In this study, employing a combination of genetic manipulations, neuronal circuit mapping, and chemogenetics in mice, we identify a new projection from the thalamic nucleus reuniens (RE) to the medial septum (MS), and show that this circuit is involved in the extinction of remote (30-day old), but not recent (1-day old), fear memories. These findings provide the first functional description of the RE[->]MS circuit and highlight the significance of the thalamo-septal regions in memory organization as a function of memory age, a phenomenon known as systems consolidation.

neuroscience↗

bioRxiv2023

Identification of neuronal ensembles involved in remote fear memory extinction impairments

Remote memory consolidation, extinction, and its impairments have been of interest to researchers for years, especially due to its clinical relevance in patients with emotional disorders, like PTSD (Post Traumatic Stress Disorder), anxiety, and phobias. Its neuronal substrates are key elements to understand the persistent nature of remote memory and open a new perspective to novel therapeutic approaches for human fear-related disorders. While the majority of reports investigate the mechanisms and ensembles of recent fear memory extinction (hours to days following conditioning), only a few refer to the remote time point (i.e. weeks after conditioning), usually describing successful memory extinction. The neuronal correlates of impaired remote fear memory extinction were yet beyond the scope. Here we present selective impairment of contextual remote fear memory extinction in alpha calcium/calmodulin-dependent protein kinase II (CaMKII) autophosphorylation-limited mice (T286A+/-). To map brain regions involved in this phenomenon, we applied screening of c-Fos expression, a neuroplasticity marker, across 23 brain areas following contextual fear conditioning and extinction of recent (1-day old) and remote (30-days old) fear memory in WT and T286A+/- mice. Following impaired remote fear memory extinction in T286A+/- mice, we found upregulated c-Fos expression in the entorhinal cortex (ENT), nucleus reuniens (RE), centromedial (CM), mediodorsal (MD), anterodorsal (AD) thalamic nuclei, and medial septum (MS), compared to WT animals performing normal remote fear memory extinction. Thus our data suggest that CaMKII-autophosphorylation-dependent c-Fos expression in these areas controls distant contextual fear extinction and may shed light on these brain regions as potential targets for therapeutic strategies against emotional disorders such as PTSD.

animal behavior and cognition↗

bioRxiv2020

PSD-95 in dorsal CA1 contributes to the persistence of fear memory

The ability to extinguish fearful memories is essential for survival. Accumulating data indicate that the dorsal CA1 area (dCA1) contributes to this process. However, the cellular and molecular basis of fear memory extinction remains poorly understood. Postsynaptic density protein 95 (PSD-95) regulates the structure and function of glutamatergic synapses. Here, using dCA1-targeted genetic and chemogenetic manipulations in vivo combined with PSD-95 immunostaining and 3D electron microscopy ex vivo, we demonstrate that phosphorylation of PSD-95 at serine 73 PSD-95(S73) is necessary for contextual fear extinction-induced expression of PSD-95 and synaptic plasticity. Moreover, PSD-95(S73) phosphorylation is not necessary for fear memory formation and recall but is required for extinction of contextual fear. Overall, our data shows how PSD-95-dependent synaptic plasticity in the hippocampus contributes to the persistence of fear memories.

neuroscience↗

bioRxiv2019

Contribution of PSD-95 protein to reward location memory

The molecular mechanisms involved in formation of memory are still poorly understood. We focus here on the function of post-synaptic density protein 95 (PSD-95) and its phosphorylation by CaMKII in spontaneous learning about reward location in female mice. We show that formation of reward location memory leads to downregulation of PSD-95 protein in dendritic spines of the stratum radiatum, area CA1, and selective shrinkage of dendritic spines that contain PSD-95. ShRNA-driven, long-term downregulation of PSD-95 in the area CA1 decreases precision of memory. Autophosphorylation deficient CaMKII mutant mice (CaMKII:T286A) need more time than wild-type animals to learn the location of reward. The same impairment is observed after CA1-targeted overexpression of CaMKII phosphorylation-deficient form of PSD-95 (PSD-95:S73A). In contrast to young adult mice, in aged animals reward location learning affects only spines that lack PSD-95. The frequency and size of the spines without PSD-95 are increased, while shRNA targeted to PSD-95 affects neither speed of learning nor precision of memory indicating alternative mechanisms to support successful memory formation in old mice. Altogether, our data suggest that dynamic regulation of PSD-95 expression is a mechanism that accelerates learning and improves precision of reward location memory in young mice. The function of PSD-95 in memory processes changes in aged animals.

neuroscience↗