Functional and Structural Properties of Dentate Granule Cells with Hilar Basal Dendrites in Mouse Entorhino-Hippocampal Slice Cultures

Abstract

During postnatal development hippocampal dentate granule cells (GCs) often extend dendrites from the basal pole of their cell bodies into the hilar region. These so-called hilar basal dendrites (hBD) usually regress with maturation. However, hBDs may persist in a subset of mature GCs under certain conditions (both physiological and pathological). The functional role of these hBD-GCs remains not well understood. Here, we have studied hBD-GCs in mature (≥18 days in vitro) mouse entorhino-hippocampal slice cultures under control conditions and have compared their basic functional properties (basic intrinsic and synaptic properties) and structural properties (dendritic arborisation and spine densities) to those of neighboring GCs without hBDs in the same set of cultures. Except for the presence of hBDs, we did not detect major differences between the two GC populations. Furthermore, paired recordings of neighboring GCs with and without hBDs did not reveal evidence for a heavy aberrant GC-to-GC connectivity. Taken together, our data suggest that in control cultures the presence of hBDs on GCs is neither sufficient to predict alterations in the basic functional and structural properties of these GCs nor indicative of a heavy GC-to-GC connectivity between neighboring GCs.

Repetitive magnetic stimulation induces plasticity of inhibitory synapses

“…7b ). The uncaging responses were blocked by the GABA A R inhibitor SR95531 and did not occur when the laser beam was directed on the neurophil in the neighbourhood of the patched CA1 pyramidal neurons (that is, >10 μm away from the soma or closest dendrite) 29 . Responses to RuBi-GABA uncaging at somatic locations were not significantly different in the two groups, whereas dendritic GABA responses were markedly decreased in the rMS group ( Fig.…”

“…Simultaneous whole-cell patch-clamp recordings of neurons were carried out as described previously 5 29 . Slice cultures prepared from GAD65-GFP 24 or GAD67-GFP mice were used to readily identify interneurons projecting their axons on dendrites or the soma of CA1 pyramidal neurons, respectively.…”

Septo-temporal distribution and lineage progression of hippocampal neurogenesis in a primate (Callithrix jacchus) in comparison to mice

“…An earlier report found that 20% of granule cells belong to a larger subpopulation in adult rhesus monkey and baboons ( Seress and Frotscher, 1990 ), which is close to the average of 15% observed in marmosets. Heterogeneity has also been reported for variations in apical and/or basal dendrites in mice, primates and humans ( Seress and Mrzljak, 1987 ; Seress and Frotscher, 1990 ; Becker et al, 2012 ), and for protein expression in granule cell axon terminals in mice ( Rekart and Routtenberg, 2010 ). The functional significance of morphological granule cell diversity remains unclear, but it is intriguing that even among the adult-born granule cells, two distinct groups of neurons can be differentiated based on their spike responses ( Brunner et al, 2014 ).…”

Suppression of Adult Neurogenesis Increases the Acute Effects of Kainic Acid

“…These dendrites have more excitatory input (Thind et al, 2008), so they may promote excitability (Ribak et al, 2000; Shapiro et al, 2005; Ribak et al, 2012, but see Becker et al, 2012). There are other abnormalities that can develop also, such as hypertrophy (Pun et al, 2012) or malalignment (Murphy et al, 2012).…”