The role of recall neurons in traumatic memories

This 2018 Swiss rodent study found: “Our data show that: A subset of memory recall–induced neurons in the DG [dentate gyrus] becomes reactivated after memory attenuation, The degree of fear reduction positively correlates with this reactivation, and The continued activity of memory recall–induced neurons is critical for remote fear memory attenuation. Although other brain areas … Continue reading The role of recall neurons in traumatic memories

The role of DNMT3a in fear memories

This 2018 Chinese rodent study found: “Elevated Dnmt3a [a DNA methyltransferase] level in the dorsal dentate gyrus (dDG) of hippocampus was associated with the absence of fear renewal in an altered context after extinction training. Overexpression and knockdown of Dnmt3a in the dDG regulated the occurrence of fear renewal in a bi-directional manner. We found … Continue reading The role of DNMT3a in fear memories

Sleep and adult brain neurogenesis

This 2018 Japan/Detroit review subject was the impact of sleep and epigenetic modifications on adult dentate gyrus neurogenesis: “We discuss the functions of adult‐born DG neurons, describe the epigenetic regulation of adult DG neurogenesis, identify overlaps in how sleep and epigenetic modifications impact adult DG neurogenesis and memory consolidation.. Whereas the rate of DG neurogenesis … Continue reading Sleep and adult brain neurogenesis

An emotional center of our brains

This 2018 McGill/UC San Diego rodent study subject was the dentate gyrus area of the hippocampus: “Early life experience influences stress reactivity and mental health through effects on cognitive-emotional functions that are, in part, linked to gene expression in the dorsal and ventral hippocampus. The hippocampal dentate gyrus (DG) is a major site for experience-dependent … Continue reading An emotional center of our brains

The mystery of humans’ evolved capability for adults to grow new brain cells

This 2016 German review discussed the evolution of human adult neurogenesis: “Mammalian adult hippocampal neurogenesis is a trait shaped by evolutionary forces that have contributed to the advantages in natural selection that are associated with the mammalian dentate gyrus. Adult hippocampal neurogenesis in mammals originates from an ectopic precursor cell population that resides in a … Continue reading The mystery of humans’ evolved capability for adults to grow new brain cells

Familiar stress opens up an epigenetic window of neural plasticity

This 2015 Italian rodent study found: “There is a window of plasticity that allows familiar and novel experiences to alter anxiety- and depressive-like behaviors, reflected also in electrophysiological changes in the dentate gyrus (DG). A consistent biomarker of mood-related behaviors in DG is reduced type 2 metabotropic glutamate (mGlu2), which regulates the release of glutamate. … Continue reading Familiar stress opens up an epigenetic window of neural plasticity

A molecular study of the epigenetic regulation of memory

This 2015 Norwegian rodent study provided: “New insights into the molecular underpinnings of synaptic plasticity. We report the first global transcriptome [all RNA found in specific cells] analysis of in vivo synaptic plasticity, using the well-established model of LTP [long-term potentiation, an increase in synaptic strength that underlies memory] in the rat dentate gyrus [a … Continue reading A molecular study of the epigenetic regulation of memory

Problematic research on the hippocampus part of the limbic system

This 2014 UK human study of the CA3 region of the hippocampus found: “Individual differences in subjective mnemonic experience can be accurately predicted from measurable differences in the anatomy and neural coding of hippocampal region CA3.” I emailed the authors as follows: “I read the “CA3 size predicts the precision of memory recall” study, and … Continue reading Problematic research on the hippocampus part of the limbic system

Early emotional experiences change our brains: Childhood maltreatment is associated with reduced volume in the hippocampus

This 2011 human study by the grandfather of hippocampus stress studies, Martin Teicher, quantified childhood maltreatment using the Adverse Childhood Experiences study and Childhood Trauma Questionnaire scores: “The strongest associations between maltreatment and volume were observed in the left CA2-CA3 and CA4-DG subfields, and were not mediated by histories of major depression or posttraumatic stress … Continue reading Early emotional experiences change our brains: Childhood maltreatment is associated with reduced volume in the hippocampus