Nutrient-dependent / pheromone-controlled construction of brainstem circuits

 8/7/2013 Video Cover Featured in The Journal of Neuroscience

Excerpt: The video uses nanoscale resolution images from serial block-face scanning electron microscopy (SBEM) of the developing mouse auditory brainstem during the first few days of its development. It depicts research that focuses on brainstem circuits that perform the initial calculation of source location based on delays in arrival of a sound at the two ears.

My comment: Construction of these brainstem circuits occurs after nutrient-dependent ecological niche construction and pheromone-controlled social niche construction have enabled neurogenic niche construction.

COVER IMAGE: Cover legend: This video demonstrates the process for reconstructing objects from a set of images. It begins by traveling through a series of images obtain with serial block-face scanning electron microscopy from the developing mouse auditory brainstem. The view then zooms into a portion of the image plane and elements of a single cell in the medial nucleus of the trapezoid body are highlighted: The nucleus of the cell is colored red, the cell body gold and a large calyx-forming input (calyx of Held) is colored blue. The cell body is ~20 μm across. The image zooms further into the segmented cell to reveal subcellular organelles including endoplasmic reticulum and mitochondria then passes across the membrane of the cell into the calyx of Held that contacts the cell, revealing synaptic vesicles and thickened membrane areas indicative of synaptic contacts. The view moves out of the nerve terminal into a complex neuropil, showing the large volume of open space in the developing brain. A single axon is highlighted in blue, and the process of segmentation across image planes is illustrated by extracting the rendered object as successive image planes are removed. The resulting rendering of the calyx of Held is displayed, illustrating its many fine processes. After rotating the rendered calyx, the postsynaptic neuron is displayed and the entire synaptic complex is then rotated. The image on the issue cover depicts the calyx of Held partially extracted from the image volume. For more information, see the article by Holcomb et al. (pages 12954–12969)

My comment: The repeated claim that random mutations are the substrates on which natural selection acts is made in the extant literature on mutation-driven evolution. There is no scientific evidence to support that claim or anyone who has responded to my requests for details about how random mutations are naturally selected. If you watch this video depiction of the synaptic complex and insist on touting random mutations theory as an explanation for adaptive evolution, which is clearly nutrient-dependent and pheromone-controlled, you will probably be among those who are even now being ridiculed for their nonsensical approach to the biology of behavior. When others walk away from you after laughing in your face at your ridiculous theory of mutation-driven speciation, remember the complexity that has been detailed here and the examples of ecological, social, neurogenic, and socio-cognitive niche construction that show how adaptive evolution occurs (sans mutations).

Author: James Kohl

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