Stress-induced dendritic remodeling in the prefrontal cortex is circuit specific - PubMed (original) (raw)

Stress-induced dendritic remodeling in the prefrontal cortex is circuit specific

Rebecca M Shansky et al. Cereb Cortex. 2009 Oct.

Abstract

Chronic stress exposure has been reported to induce dendritic remodeling in several brain regions, but it is not known whether individual neural circuits show distinct patterns of remodeling. The current study tested the hypothesis that the projections from the infralimbic (IL) area of the medial prefrontal cortex (mPFC) to the basolateral nucleus of the amygdala (BLA), a pathway relevant to stress-related mental illnesses like depression and post-traumatic stress disorder, would have a unique pattern of remodeling in response to chronic stress. The retrograde tracer FastBlue was injected into male rats' BLA or entorhinal cortex (EC) 1 week prior to 10 days of immobilization stress. After cessation of stress, FastBlue-labeled and unlabeled IL pyaramidal neurons were loaded with fluorescent dye Lucifer Yellow to visualize dendritic arborization and spine density. As has been previously reported, randomly selected (non-FastBlue-labeled) neurons showed stress-induced dendritic retraction in apical dendrites, an effect also seen in EC-projecting neurons. In contrast, BLA-projecting neurons showed no remodeling with stress, suggesting that this pathway may be particularly resilient against the effects of stress. No neurons showed stress-related changes in spine density, contrasting with reports that more dorsal areas of the mPFC show stress-induced decreases in spine density. Such region- and circuit-specificity in response to stress could contribute to the development of stress-related mental illnesses.

PubMed Disclaimer

Figures

Figure 1.

Figure 1.

FastBlue injection. Representative syringe placement for retrograde tracer FastBlue injections in the BLA (a), representative Fastblue diffusion into the BLA (b), and schematic of maximal observed diffusion into the BLA (c). Adapted from Paxinos and Watson (2005).

Figure 2.

Figure 2.

Ten days immobilization stress causes decreased weight gain. Stressed animals gained significantly less weight than control animals over the course of the study. *P < 0.04.

Figure 3.

Figure 3.

Randomly selected neurons and EC-projecting neurons, but not BLA-projecting neurons, show retraction with stress. Representative randomly selected neuron apical dendrite Neurolucida tracings from control (a) and stressed (b) animals. In rats exposed to stress, apical dendrites in randomly selected IL layer II/III pyramidal neurons show reduced number of branch points (c) and overall dendritic length (d) when compared with control rats. Sholl analysis suggests that these changes are accounted for by retraction in intermediate dendrites, approximately 120–180 μm from the soma (e). Apical dendrites in amygdala-projecting IL layer II/III pyramidal neurons show no change in branch points (f) or in overall dendritic length (g) when compared with control rats. Moreover, there were no group differences at any distance from the soma (h). Apical dendrites in EC-projecting layer II/III neurons showed significantly reduced number of branch points (i) and overall dendritic length (j), but no significant changes at individual distances from the soma (k). *P < 0.05; **P < 0.01.

Figure 4.

Figure 4.

Stress does not alter spine density in the IL. Representative randomly selected neuron apical dendrite segments from control (a) and stressed (b) animals. Neither randomly selected neurons nor BLA-projecting nor EC-projecting neurons showed any significant change in spine density with stress.

Similar articles

Cited by

References

    1. Arnsten AFT. Through the looking glass: differential noradrenergic modulation of prefrontal cortical function. Neural Plasticity. 2000;7:133–146. - PMC - PubMed
    1. Bouras C, Kovari E, Hof PR, Riederer BM, Giannakopoulos P. Anterior cingulate cortex pathology in schizophrenia and bipolar disorder. Acta Neuropathol. 2001;102:373–379. - PubMed
    1. Drevets WC. Neuroimaging abnormalities in the amygdala in mood disorders. Ann N Y Acad Sci. 2003;985:420–444. - PubMed
    1. Frodl T, Meisenzahl EM, Zetzsche T, Born C, Jager M, Groll C, Bottlender R, Leinsinger G, Moller HJ. Larger amygdala volumes in first depressive episode as compared to recurrent major depression and healthy control subjects. Biol Psychiatry. 2003;53:338–344. - PubMed
    1. Hendler T, Rotshtein P, Yeshurun Y, Weizmann T, Kahn I, Ben-Bashat D, Malach R, Bleich A. Sensing the invisible: differential sensitivity of visual cortex and amygdala to traumatic context. Neuroimage. 2003;19:587–600. - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources