The Ever-Changing Morphology of Hippocampal Granule Neurons in Physiology and Pathology

Abstract

Newborn neurons are continuously added to the hippocampal dentate gyrus throughout adulthood. In this review, we analyze the maturational stages that newborn granule neurons go through, with a focus on their unique morphological features during each stage under both physiological and pathological circumstances. In addition, the influence of deleterious (such as schizophrenia, stress, Alzheimer's disease, seizures, stroke, inflammation, dietary deficiencies, or the consumption of drugs of abuse or toxic substances) and neuroprotective (physical exercise and environmental enrichment) stimuli on the maturation of these cells will be examined. Finally, the regulation of this process by proteins involved in neurodegenerative and neurological disorders such as Glycogen synthase kinase 3β, Disrupted in Schizophrenia 1 (DISC-1), Glucocorticoid receptor, pro-inflammatory mediators, Presenilin-1, Amyloid precursor protein, Cyclin-dependent kinase 5 (CDK5), among others, will be evaluated. Given the recently acquired relevance of the dendritic branch as a functional synaptic unit required for memory storage, a full understanding of the morphological alterations observed in newborn neurons may have important consequences for the prevention and treatment of the cognitive and affective alterations that evolve in conjunction with impaired adult hippocampal neurogenesis.

Morphometry of ventral hippocampal neurons of CA1-CA4 fields in domestic cattle

“…W ciągu ostatnich dziesięcioleci stał się jednym z najintensywniej badanych obszarów mó-zgowia u ssaków. Morfologia i fizjologia hipokampa zostały szczegółowo opisane przez wielu autorów (1,12,24). Hipokamp właściwy (hippocampus proper) z polami CA1-CA4 oraz zakręt zębaty (gyrus dentatus) (DG) charakteryzują się odrębną strukturą warstwową.…”

Canonical Wnt-signaling modulates the tempo of dendritic growth of adult-born hippocampal neurons

“…A key step for the functional integration of adult-born dentate granule neurons is the development of a morphologically highly stereotypic dendritic arbor to receive afferents in the molecular layer (Goncalves, Schafer et al, 2016b). Disruption of dendritic arbor development of adult-born neurons is thought to contribute to cognitive and emotional deficits in aging, neurodegenerative and neuropsychiatric diseases, and to the development of an aberrant circuitry in epilepsy (Cho, Lybrand et al, 2015, Fitzsimons, van Hooijdonk et al, 2013, Jessberger & Parent, 2015, Kerloch, Clavreul et al, 2018, Kim, Liu et al, 2012, Li, Bien-Ly et al, 2009, Llorens-Martin, Rabano et al, 2015, Murphy, Hofacer et al, 2012, Sun, Halabisky et al, 2009, Trinchero, Buttner et al, 2017, Winner, Melrose et al, 2011.…”

“…Aging, neurodegenerative and -psychiatric diseases impede on the functional integration of adult-born hippocampal neurons (Fitzsimons et al, 2013, Kim et al, 2012, Li et al, 2009, Llorens-Martin et al, 2015, Sun et al, 2009, Trinchero et al, 2017, Winner et al, 2011.…”

Transduction efficacy and retrograde movement of a lentiviral vector pseudotyped by modified rabies glycoprotein throughout the trisynaptic circuit of the rat hippocampus

“…The output of CA1 goes to the subiculum and, from the subiculum, activity exits the hippocampus to target the entorhinal cortex (forming a loop) and more distant subcortical and cortical areas . Any pathologic change in the classic trisynaptic circuit triggers neurologic disturbances such as memory impairment and epileptogenesis . Therefore, the trisynaptic circuit is of great interest as a target for the treatment of neurologic diseases caused by a disturbance in this circuit.…”

“…2 Any pathologic change in the classic trisynaptic circuit triggers neurologic disturbances such as memory impairment and epileptogenesis. 3 Therefore, the trisynaptic circuit is of great interest as a target for the treatment of neurologic diseases caused by a disturbance in this circuit. The efficient delivery of therapeutic gene into this circuit with long-term expression provides a special opportunity to repair any disruptions.…”