Such learning is believed to emerge from alterations in network connectivity, but large-scale connectivity is difficult to measure directly, especially during learning.
After many years of using human pathology to determine relevancy of animal models to disease, the converse challenge emerged: would alterations in pathological cascades seen in animal models accurately predict human response to therapeutic interventions?
Comparative transcriptional analyses and mutant characterization have revealed that apomictic developments likely emerged after alterations in the prevailing transcriptional dynamics of reproductive tissues or cells of sexual plants [ 42].
These patients have reduced control of their social approach behavior, and it has been suggested that this impairment emerges from alterations in the prefrontal modulation of subcortical areas, such as the amygdala (Davidson et al. 2000; Blair 2004; Lewis et al. 2006; Sterzer and Stadler 2009).
While it is speculative to assume a common mechanism in generation of neurodegenerative defects in polyQ diseases, it emerges that alterations and damages to the mitochondrial system are highly relevant for the toxicity observable upon expression of polyQ proteins also in yeast.
These results imply that age-related changes can be very region-specific, and they implicate a link between neural changes and specific behavioral alterations emerging during aging.
Remarkably, the expression of endogenous PC3/Tis21, present in type-2/type-3 progenitor cells and in stage 6 (Calbindin-positive) terminally differentiated neurons, but absent in stage 5 neurons [15], follows a pattern fully compatible with the alterations emerging after ablation of PC3/Tis21 in the proliferation of progenitor cells and in the maturation of stage 5 neuron.
The emerging spectrum of alterations in tumors is complex and the identification of relevant genes and pathways remains a challenge.
Extensive sampling of metastatic sites at autopsy revealed 10 distinct PTEN alterations emerging under the selective pressure of PI(3 Kα inhibition [ 3], and five independent reversion events in a germline BRCA2 mutant carrier who progressed on olaparib and carboplatin [ 4].
While a considerable body of work is currently emerging on neurogenic alterations associated with the pathogenesis of AD, it is important to keep the role of neurogenesis in perspective given the relatively limited number of brain regions that are neurogenic.
