Unraveling Brain Microcircuits, Dendritic Spines, and Synaptic Processing Using Multiple Complementary Approaches

Human cortical amygdala dendrites and spines morphology under open‐source three‐dimensional reconstruction procedures

“…We did not find aspiny or sparsely spiny neurons in our samples (Vásquez et al., 2018). Considering the likely increase in the synaptic processing in the human CoA, both the dendritic architecture and the spine heterogeneity seem to be closely related features that deserve further studies (De Felipe, 2011; Rasia‐Filho, 2022; Rasia‐Filho et al., 2021; Rollenhagen & Lübke, 2016; Spruston et al., 2013; Yuste, 2010). Spines can maximize connectivity by allowing a dendrite to connect with a larger number of axons at the same time that serve to shorten the wire and sample a wider choice of axons (Yuste, 2010).…”

“…Various methodological approaches have been developed over the last decades to unravel the morphological features of neurons and their diversity, forming the anatomical architecture of the mammalian brain (Bowman & Frankfurt, 2021; Lanciego & Wouterlood, 2011, 2020; Zeng, 2021). At the same time, dendritic spines have been described as multifunctional postsynaptic units that reflect cellular connectivity and enable multiple ways for function and plasticity in neurons (Chen & Sabatini, 2012; Cornejo et al., 2022; Hayashi‐Takagi et al., 2015; Helm et al., 2021; Rasia‐Filho, 2022; Rochefort & Konnerth, 2012; Spruston et al., 2013; Tønnesen and Nägerl, 2016; Yuste, 2010). However, the study of human dendrites and spines continues to be challenging due to the high complexity of the nervous tissue in our species (Shapson‐Coe et al., 2021) and some technical difficulties in the histological processing of postmortem samples (Dall´Oglio et al., 2015; Vásquez et al., 2018), although there has been excellent progress in characterizing neurons in acute slices from neurosurgical resections (Berg et al., 2021; Molnar et al., 2016; Planert et al., 2021).…”

“…Genetic, morphological, and functional features determine neuronal diversity and specialization in humans (Beed et al., 2020; Hodge et al., 2019; Hodge et al., 2020; Kalmbach et al., 2021), which include neurons with larger dendritic length and branch complexity (Benavides‐Piccione et al., 2020; Mohan et al., 2015) and spines with higher number and size (Dall´Oglio et al., 2015; Yuste, 2010, 2013). Currently, there are many frontiers to exploring the structure and integrated function of dendritic spines for normal synaptic plasticity (Chen & Sabatini, 2012; Helm et al., 2021; Kasai et al., 2021; Mederos et al., 2018; Rasia‐Filho, 2022) and their changes in brain disorders (Bączyńska et al., 2021; Chidambaram et al., 2019).…”

Morphological heterogeneity of neurons in the human central amygdaloid nucleus

“…Next approaches can combine the present CeA neuron‐type morphological variety in humans with cross‐modality studies of genetic features and connectivity (see complementary discussion in Xu et al., 2018; Peng et al., 2021; Rasia‐Filho, 2022; Guerra et al., 2023; Piwecka et al., 2023). Subcortical neurons are more diverse than cortical ones (Siletti et al., 2023).…”

“…Fusiform neurons display two or three primary dendrites. The "third" dendrite needs to be studied with complementary techniques because, in some cases, it would resemble a thick and short primary dendrite or it would be an axon hillock (Wahle et al, 2022). For the latter, it was reported that the axonal initial segment can be (1) located either proximal or distal to the soma or (2) originate from a dendrite and have its initial segment starting directly at the axon origin or be located distally to it (Höfflin et al, 2017; see neuron #6 in Figure S3).…”