Paul B. Farel, PhD
Professor

Education:

AB, University of California, Berkeley 1966
MA, University of California, Los Angeles 1967
PhD, University of California, Los Angeles 1970

Neural Development and Regeneration

(click for larger image & description)

Using both mammalian and non-mammalian species, we have evidence that neuron number increases in many regions of the nervous system as juveniles attain adult size. Neuron proliferation has been ruled out as contributing to the increase in neuron number. Instead, a pool of committed, but incompletely differentiated immature neurons complete their differentiation during normal postnatal development, presumably in response to the demands of increasing body size. Such findings are of exceptional interest to developmental neurobiologists for two reasons. First, neuron addition in juveniles implies that mechanisms thought to be restricted to narrow windows of embryonic development may in fact persist through the life of the animal. Second, if developmental mechanisms of neuron addition persist into postnatal life, then the possibility of enlisting these mechanisms to restore neurons lost to injury or disease becomes more salient.

We are currently investigating how neurons are recruited during growth of the juvenile. We are also pursuing studies that demonstrate that differentiation of these immature neurons can occur following injury to neighboring regions of the nervous system, perhaps contributing to functional recovery following injury or disease. 

Paul Farel teaches in MS1 Block 3 and serves as Chair of the Health Sciences Library Advisory Committee. He is also a member of the Faculty Grievance Committee.

Farel P. Late differentiation contributes to the apparent increase in sensory neuron number in juvenile rat. (2003) Dev. Brain Res. 144(1):91-8

Farel PB. (2002) Sensory neuron addition in juvenile rat: Time course and specificity. J. Comp Neurol. 449:158-162.

Farel PB. (2002) Trust but verify:  The necessity of empirical verification in quantitative anatomy. Anat. Rec. 269: 157-161

Farel PB. (2001) Neuron addition and neurogenesis are not interchangeable terms
Anat Rec 265: 159.

Farel PB and DL McIlwain. (2000) Neuron addition and enlargement in juvenile and adult animals. Brain Res. Bull. 53: 537-546.

Berg JS and PB Farel. (2000) Developmental regulation of sensory neuron number and limb innervation in the mouse. Dev. Brain Res. 125: 21-30.

Farel PB and A Boyer. (1999) Transient effects of nerve injury on estimates of sensory neuron number in juvenile bullfrog. J. Comp. Neurol.410: 171-177 .

Meeker ML and PB Farel. (1997) Neuron Addition During Growth Of The Postmetamorphic Bullfrog: Sensory Neuron and Axon Number. J. Comp. Neurol.389: 569-576.

Popken GJ and PB Farel. (1997) Sensory neuron number in lumbar dorsal root ganglia of neonatal and adult rat determined by conventional and steroeological counting methods. J. Comp. Neurol. 386:8-15