Read this about how close we are biologically to elephants (also dolphins, whales and great apes) and tell me if the issue is complicated.
Spindle neurons, also called von Economo neurons (VENs), are a specific class of neurons that are characterized by a large spindle-shaped soma (or body), gradually tapering into a single apical axon in one direction, with only a single dendrite facing opposite. Other neurons tend to have many dendrites, and the polar-shaped morphology of spindle neurons is unique. A neuron's dendrites receive signals, and its axon sends them.
Spindle neurons are found in two very restricted regions in the brains of hominids—the family of species comprising humans and other great apes—the anterior cingulate cortex (ACC) and the fronto-insular cortex (FI). Recently they have been discovered in the dorsolateral prefrontal cortex of humans.[1] Spindle cells are also found in the brains of the humpback whales, fin whales, killer whales, sperm whales,[2][3] bottlenose dolphin, Risso’s dolphin, beluga whales,[4] African and Asian elephants,[5] and to a lesser extent in macaque monkeys[6] and raccoons.[7] The appearance of spindle neurons in distantly related clades suggests that they represent convergent evolution, specifically an adaptation to larger brains.
Austrian psychiatrist and neurologist Constantin von Economo (1876–1931) discovered spindle neurons and described them in 1929, which is why they are sometimes called von Economo neurons.[8]
Spindle neurons are relatively large cells that may allow rapid communication across the relatively large brains of great apes, elephants, and cetaceans. Although rare in comparison to other neurons, spindle neurons are abundant, and large, in humans. However, the concentration of spindle cells has been measured to be three times higher in cetaceans in comparison to humans.[3][9] They have only been found thus far in the anterior cingulate cortex (ACC), fronto-insular cortex (FI), and the dorsolateral prefrontal cortex.
Evolutionary significance[edit]
The observation that spindle neurons only occur in a highly significant group of animals (from a human point of view) has led to speculation that they are of great importance in human evolution and/or brain function. Their restriction (among the primates) to great apes leads to the hypothesis that they developed no earlier than 15-20 million years ago, prior to the divergence of orangutans from the African great apes. The discovery of spindle neurons in diverse whale species[3][4] has led to the suggestion that they are "a possible obligatory neuronal adaptation in very large brains, permitting fast information processing and transfer along highly specific projections and that evolved in relation to emerging social behaviors."[4]p. 254 Their presence in the brains of these species supports this theory, pointing towards the existence of these specialized neurons only in highly intelligent mammals, and may be an example of convergent evolution.[10] Recently, primitive forms of spindle neurons have also been discovered in macaque monkey brains[11] and raccoons.[7]
https://en.wikipedia.org/wiki/Spindle_neuron
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