The Disordered Mind: What Unusual Brains Tell Us About Ourselves

by Eric R. Kandel

In schizophrenia, synaptic pruning appears to go haywire during adolescence, snipping off far too many dendritic spines (fig. 4.4). Consequently, the pyramidal neurons are left with too few synaptic connections in the prefrontal cortex to form the robust neural circuits we need for an adequate working memory and other complex cognitive functions. This excessive-pruning hypothesis for schizophrenia, first proposed by Irwin Feinberg, now at the University of California, Davis,2 has been documented by David Lewis and Jill Glausier at the University of Pittsburgh.3 A similar defect is thought to affect pyramidal neurons located in the hippocampus of people with schizophrenia, which would adversely affect memory.