Summary - Neural Reuse and Recycling

The Adaptable Mind: What Neuroplasticity and Neural Reuse Tell Us about Language and Cognition - John Zerilli 2021

Neural Reuse and Recycling

“Neural reuse” refers to the exaptation of established and relatively fixed neural circuits without loss of original function/use. Reuse arises over the course of normal development and evolution. The evidence of this phenomenon speaks most loudly against the idea of strict domain-specificity. It seems that no area of the brain is exempt from redeployment, with areas of the brain traditionally considered to be among the most domain-specific (such as sensory areas) also contributing their computational/structural resources to other domains, including those involving language. The evidence supporting reuse takes many forms, among them evolutionary and developmental considerations, computational considerations, and the neuroimaging and biobehavioral literature.

1 This usage of “exaptation” is somewhat misleading, since exaptation usually implies loss of original function (see Godfrey-Smith 2001).

2 The evolutionary psychologist’s invocation of so-called debugging concerns is addressed in § 5.1.

3 “Tailarach space” is the three-dimensional human brain atlas used by neuroscientists for mapping locations in brain space—the correlation is counterintuitively reported as “negative” because in Tailarach space, the origin is set at the center of the brain, with regions posterior measured in negative coordinates.

4 Scattered activations can be explained other than by the suggestion that local circuits are relatively fixed. I return to this issue in Chapter 5 (see § 5.1).

5 Google scientists have pulled off something similar with Agent (Mnih et al. 2015).