Invariant Synapse Density and Neuronal Connectivity Scaling in Primate Neocortical Evolution
| Autor: | Jeroen B. Smaers, Mary Ann Raghanti, Cheryl D. Stimpson, Patrick R. Hof, Kimberley A. Phillips, Bob Jacobs, Sarah B. Miller, Chet C. Sherwood, Molly Karl |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Adult
Male Primates Cognitive Neuroscience Neocortex Biology Visual processing Synapse Cellular and Molecular Neuroscience Young Adult Primary Visual Cortex medicine Animals Humans Temporal cortex Neurons Brain Mass Biological Evolution Temporal Lobe medicine.anatomical_structure Visual cortex Brain size Synapses Original Article Female Neuron Neuroscience |
| Zdroj: | Cereb Cortex |
| Popis: | Synapses are involved in the communication of information from one neuron to another. However, a systematic analysis of synapse density in the neocortex from a diversity of species is lacking, limiting what can be understood about the evolution of this fundamental aspect of brain structure. To address this, we quantified synapse density in supragranular layers II–III and infragranular layers V–VI from primary visual cortex and inferior temporal cortex in a sample of 25 species of primates, including humans. We found that synapse densities were relatively constant across these levels of the cortical visual processing hierarchy and did not significantly differ with brain mass, varying by only 1.9-fold across species. We also found that neuron densities decreased in relation to brain enlargement. Consequently, these data show that the number of synapses per neuron significantly rises as a function of brain expansion in these neocortical areas of primates. Humans displayed the highest number of synapses per neuron, but these values were generally within expectations based on brain size. The metabolic and biophysical constraints that regulate uniformity of synapse density, therefore, likely underlie a key principle of neuronal connectivity scaling in primate neocortical evolution. |
| Databáze: | OpenAIRE |
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