Uniquely hominid features of adult human astrocytes

By N. Oberheim, T. Takano, Xiaoning Han, Wei He, J. Lin, Fushun Wang, Qiwu Xu, J. Wyatt, W. Pilcher, Jeffrey G. Ojemann and 3 more. Journal of Neuroscience, 2009

1,338 citations recorded by the source corpus.

Defining the microanatomic differences between the human brain and that of other mammals is key to understanding its unique computational power. Although much effort has been devoted to comparative studies of neurons, astrocytes have received far less attention. We report here that protoplasmic astrocytes in human neocortex are 2.6-fold larger in diameter and extend 10-fold more GFAP (glial fibrillary acidic protein)-positive primary processes than their rodent counterparts. In cortical slices prepared from acutely resected surgical tissue, protoplasmic astrocytes propagate Ca2+ waves with a speed of 36 μm/s, approximately fourfold faster than rodent. Human astrocytes also transiently increase cystosolic Ca2+ in response to glutamatergic and purinergic receptor agonists. The human neocortex also harbors several anatomically defined subclasses of astrocytes not represented in rodents. These include a population of astrocytes that reside in layers 5–6 and extend long fibers characterized by regularly spaced varicosities. Another specialized type of astrocyte, the interlaminar astrocyte, abundantly populates the superficial cortical layers and extends long processes without varicosities to cortical layers 3 and 4. Human fibrous astrocytes resemble their rodent counterpart but are larger in diameter. Thus, human cortical astrocytes are both larger, and structurally both more complex and more diverse, than those of rodents. On this basis, we posit that this astrocytic complexity has permitted the increased functional competence of the adult human brain.

Subfields: Cellular and Molecular Neuroscience, Neurology, Physiology

View Paper: https://www.semanticscholar.org/paper/d7ab8e4768329cd667607316f8cd5e5d1e98a9d9

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Citations in the corpus

Astrocytes: biology and pathology (2009, background): “The human cerebral neocortex contains multiple subtypes of astrocytes, including types that do not appear to exist in rodent cortex [170].”
Purification and characterization of progenitor and mature human astrocytes reveals transcriptional and functional differences with mouse (2015, positive): “Previous studies found that human astrocytes are larger than mouse and rat astrocytes in vivo (Oberheim et al., 2006, 2009).”
Glia and pain: Is chronic pain a gliopathy? (2013, background): “Glial cells in the PNS consist of satellite glial cells (SGCs) in the dorsal root ganglia (DRGs) and trigeminal ganglia (TGs) and Schwann cells in the peripheral nerves.”
The Biology of Regeneration Failure and Success After Spinal Cord Injury. (2018, background): “Thus the farther away the astrocyte is from the lesion epicenter, even as axons and oligodendrocytes are dying in their midst, the less severe the reactivity (289, 408).”
Imaging brain microstructure with diffusion MRI: practicality and applications (2019, background): “Astrocytes have somas of about 10 μm in diameter from which many processes extend in a star‐shaped formation, with an overall diameter of about 150 μm.(55) They perform a plethora of functions, e.”
Forebrain engraftment by human glial progenitor cells enhances synaptic plasticity and learning in adult mice (2013, background): “Other engrafted human cells exhibited the long, varicosity-studded processes of varicose projection astrocytes, a second class of hominid astrocytes (Oberheim et al., 2009).”
Cell biology of astrocyte-synapse interactions (2017, positive): “Astrocyte-Synapse Interactions Are Disrupted in Neurodevelopmental Disorders Alteration in synapse formation, synaptic function, and synaptic remodeling has been implicated in a number of neurodevelopmental disorders, including autism spectrum disorder (ASD) (Parikshak et al., 2013).”
The blood-brain barrier: an engineering perspective (2013, background): “Morphologically, astrocytes are usually star shaped with many processes or protrusions emanating from the cell body, with an overall diameter of about 140 μm in the human brain (Oberheim et al., 2009).”
Astrocytes Control Synapse Formation, Function, and Elimination (2015, neutral): “W.-S. Chung et al. 2 disease and postinjury conditions, astrocytes lose their tiling and display intermingled process morphology (Oberheim et al. 2009).”
Regulation of synaptic connectivity by glia (2010, background): “For example, the human brain contains several more populations of astrocytes than the rodent brain, and human astrocytes are up to threefold larger and more ramified than their rodent counterpart”
Astrocyte reactivity and reactive astrogliosis: costs and benefits. (2014, background): “A single protoplasmic astrocyte in the human brain accommodates within its domain as many as two million neuronal synapses (161).”