© 2006 Springer Science+Business Media, LLC. All rights reserved. 6. Conclusions: The data discussed above indicate that the study of c-fos expression has greatly contributed to our knowledge of the brain processing of stressors. The use of IEGs other than c-fos (e.g., zif268, arc) reveals activation of brain areas not detected with c-fos, even though evaluation of other markers of neuronal activation (for example, phosphorylation of CREB) could be important in generating a complete picture of brain areas activated under stress. The expression of effector IEGs, such as arc, can provide researchers with additional important information concerning brain areas where synaptic plasticity associated to stress exposure may take place. However, much of the IEG response to stress remains to be characterized in order for a complete picture of brain processing of stressors emerges, and this includes: (a) a more complete characterization of the relationship between neuronal depolarization and IEG expression, (b) the description of the effects of neurotransmitters on stress-induced IEG expression (a topic not discussed in the present review), (c) the characterization of neuronal phehotypes activated during the stress response, and (d) the use of complementary approaches (e.g., lesions, tract-tracing studies, region-specific conditional expression or repression of particular IEGs in mutant mice) which should allow for directly testing hypotheses regarding the hierarchical control of the response to stress, an aspect poorly understood in this field, with the exception of the HPA axis. Finally, a more thorough characterization of the functional role of the protein products encoded by IEGs may shed light onto the precise adaptive values that result from their increased expression. This information will likely to reveal key aspects of the neural response to stress and will rival the critical importance of IEG expression in the mapping of brain activity.
|Title of host publication||Immediate Early Genes in Sensory Processing, Cognitive Performance and Neurological Disorders|
|Number of pages||22|
|Publication status||Published - 1 Jan 2006|