2.6 Connecting the Brain's Components into Systems

Question 1

Advantage to primates

Answer 1

The advantage we have over other primates is that our brains are larger in absolute volume and weight; therefore, we have more neurons. In addition to neuron number, other aspects of brain structure might affect cognitive ability. But the number of neurons that an average neuron connects to actually does not change with increasing brain sizes. By maintaining absolute connectivity, not proportional connectivity, larger brains became less interconnected. But evolution came up with two clever solutions

Question 2

Minimizing connection lengths

Answer 2

short connections keep processing localized, with the result that the connection costs are less. Shorter axons take up less space, less energy is required for building and signaling is faster over shorter distance.

Question 3

Retaining a small number of very long connections between distant rites

Answer 3

primate brains in general and human brains in particular have developed what is known as ‘a small-world’ architecture. It combines very short, fast local connections with a few long-distance connections to communicate the results of local processing. This design allows both a high degree of local efficiency and, at the same time, quick communication to the global network.