Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2012 Jul;122(7):2690-701.
doi: 10.1172/JCI63060. Epub 2012 Jun 18.

Disrupted cortical function underlies behavior dysfunction due to social isolation

Tomoyuki Miyazaki  1 , Kenkichi Takase, Waki Nakajima, Hirobumi Tada, Daisuke Ohya, Akane Sano, Takahisa Goto, Hajime Hirase, Roberto Malinow, Takuya Takahashi
Affiliations

Disrupted cortical function underlies behavior dysfunction due to social isolation

Tomoyuki Miyazaki et al. J Clin Invest. 2012 Jul.

Erratum in

  • J Clin Invest. 2014 Jun 2;124(6):2807

Abstract

Stressful events during early childhood can have a profound lifelong influence on emotional and cognitive behaviors. However, the mechanisms by which stress affects neonatal brain circuit formation are poorly understood. Here, we show that neonatal social isolation disrupts molecular, cellular, and circuit developmental processes, leading to behavioral dysfunction. Neonatal isolation prevented long-term potentiation and experience-dependent synaptic trafficking of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors normally occurring during circuit formation in the rodent barrel cortex. This inhibition of AMPA receptor trafficking was mediated by an increase of the stress glucocorticoid hormone and was associated with reduced calcium/calmodulin-dependent protein kinase type II (CaMKII) signaling, resulting in attenuated whisker sensitivity at the cortex. These effects led to defects in whisker-dependent behavior in juvenile animals. These results indicate that neonatal social isolation alters neuronal plasticity mechanisms and perturbs the initial establishment of a normal cortical circuit, which potentially explains the long-lasting behavioral effects of neonatal stress.

PubMed Disclaimer

Figures

Figure 1
Figure 1. Social isolation disrupts experience-dependent synaptic delivery of AMPA receptors in the developing rat barrel cortex.
(A–C) Top insets: time line of experiments. R1, GFP-GluR1–expressing neurons; non, nonexpressing neurons. (A) Isolation during P7–P11 disrupted GluR1 delivery at P12–P14 (*P < 0.05, R1 versus non; n = 8 nonisolated control, n = 9 isolated). (B) Removal of mother during P7–P11 (mother removed) did not disrupt GluR1 delivery at P12–P14 (*P < 0.05, R1 versus non; n = 8) (left). Blockade of whisker input during removal of mother (whisker mask) did not prevent GluR1 delivery (*P < 0.05, R1 versus non; n = 5) (right). (C) Isolation (P4–P7) disrupted GluR1 delivery during P12–P14 (*P < 0.05, R1 versus non; n = 6). (D) A/N ratio at P14 was lower with rats isolated than nonisolated rats (*P < 0.05, isolated vs, nonisolated; n = 18). (E) A/N ratio at P14 of pups, either mother removed or whisker masked, was comparable with nonisolated rats, but larger than isolated animals (n = 16) (*P < 0.05, compared with nonisolated [n = 15], mother removed [n = 17], whisker mask [n = 21] animals; F(3,65) = 4.022). (F) A/N ratio at P14 was lower with rats isolated at P4–P7 than nonisolated rats (*P < 0.05, isolated vs. nonisolated; n = 15 nonisolated control animals, n = 18 isolated animals). Scale bars: 20 pA/20 ms (A, D); 10 pA/20 ms (B); 10 pA/15 ms (E, F). Data were analyzed by paired, 2-tailed t test (A–D, F) or 1-way factorial ANOVA (E).
Figure 2
Figure 2. Social isolation disrupts LTP in the developing rat barrel cortex.
LTP was induced by pairing 3-Hz stimulation with depolarization of the postsynaptic neuron (+20 mV) for 90 seconds. Recordings were maintained for at least 40 minutes after pairing. Mean amplitude between 30 minutes and 40 minutes after LTP induction was normalized to baseline amplitude (right). Social isolation during P7–P11 (A: *P < 0.05, nonisolated induced pathway vs. isolated induced pathway; n = 6 per each group) and P4–P7 (B: *P < 0.05, nonisolated induced pathway vs. isolated induced pathway; n = 5 per each group) prevented LTP at P14 in the barrel cortex. (C) Social isolation during P4–P7 partially blocked LTP in the barrel cortex at P27 (*P < 0.05, nonisolated induced pathway vs. isolated induced pathway; n = 6 nonisolated control animals, n = 8 isolated animals). Ind, LTP-inducing pathway; cont, control pathway; noniso, nonisolated animals; iso, isolated animals. Data were analyzed by paired, 2-tailed t test.
Figure 3
Figure 3. Increased glucocorticoid mediates synaptic plasticity disruption by isolation.
(A and B) Isolation increased free corticosterone levels from blood samples collected at 1 hour and 6 hours after the initiation of isolation (*P < 0.05 compared with control animals, A: isolated at P4–P7, assayed at P4 and P7, B: isolated at P7–P11, assayed at P7 and P11; n = 10). (C) Administration of RU486 prevented the disruption of GluR1 delivery by isolation at P7–P11 (*P < 0.05, R1 versus non; n = 5), while vehicle showed no effects (n = 5). (D) A/N ratio at P14 of isolated pups with RU486 was comparable with nonisolated, but larger than isolated animals without RU486 (F[2,41] = 3.481, *P < 0.05, isolated vs. nonisolated, isolated versus RU486; n = 15). (E) Administration of corticosterone (Cort) disrupted synaptic GluR1 delivery of animals housed in a normal environment (n = 8). (F) A/N ratio at P14 of nonisolated pups treated with corticosterone (n = 12) was lower than nonisolated (F(2,35) = 3.395, *P < 0.05, nonisolated vs. isolated, nonisolated vs. Cort, n = 15), but comparable with isolated rats (n = 16). (G) Attenuated LTP at P14 of animals treated with corticosterone (*P < 0.05, control vs. corticosterone-injected animals; n = 7 nonisolated control animals, n = 8 nonisolated animals with corticosterone). Ind, LTP-inducing pathway; cont, control pathway. Scale bars: 10 pA/20 ms (C, E); 10 pA/15 ms (D, F). Data were analyzed by paired, 2-tailed t test (A–C, E, G) or 1-way factorial ANOVA (D, F).
Figure 4
Figure 4. Mechanisms underlying isolation-induced disruption of synaptic AMPA receptor delivery.
(A) Immunohistostaining of the barrel cortex of animals at P11 with anti-GR antibody. (B) Nuclear fraction contained larger amount of GR at 3 hours after social isolation than nonisolated animals. The amount of GR in the nuclear fraction of isolated animals was normalized to nonisolated rats (*P < 0.05, isolated vs. nonisolated; n = 6 per each group). (C) Local injection of RU486 during social isolation prevented the disruption of synaptic GluR1 delivery by social isolation. Top inset showed time line of experimental manipulations (see text) (*P < 0.05, R1 versus non; n = 9 isolated with RU486, n = 7 isolated with vehicle). (D) Social isolation decreased phosphorylation of CaMKII at Thr286 compared with nonisolated rats. Phosphorylation level (calculated as the ratio to total CaMKII) of rats with social isolation in the presence of RU486 was comparable to nonisolated rats (F(2,11) = 8.163, *P < 0.05; n = 5 per each group). (E) Social isolation decreased phosphorylation of Ser831 of GluR1 compared with nonisolated rats. Phosphorylation level of rats with social isolation in the presence of RU486 was comparable to nonisolated rats but larger than isolated animals without RU486 (F(2,45) = 6.950, *P < 0.05; n = 12 per each group). (F) No delivery of 831A (R1 831A) at layer 4-2/3 synapses in the barrel cortex of intact rats at P12–P14 (n = 16). Scale bars: 200 μm (A); 100 μm (A, inset); 10 pA/20 ms. (B, D, and E); 20 pA/20 ms (C). Lanes were run on the same gel but are noncontiguous. Data were analyzed by paired, 2-tailed t test (B, C, F) or 1-way factorial ANOVA (D, E).
Figure 5
Figure 5. Social isolation attenuates the sensitivity of whiskers.
Responses (field EPSP slopes and the frequency of spikes) in layer 2/3 neurons of the barrel column to the deflection of principal whiskers. (A and B) The sensitivity of whiskers was attenuated by social isolation. (A) Rats with social isolation exhibited lower-field EPSP slopes than control animals, indicating attenuated sensitivity of whiskers (*P < 0.05, nonisolated versus isolated; n = 10 per each group). (B) Rats with social isolation exhibited lower spike frequency (spike number during 5–50 ms from whisker stimulation) than control animals, indicating decreased sensitivity of whiskers (*P < 0.05, nonisolated versus isolated; n = 10 per each group). (C) Wire electrode was implanted into almost identical tangential location of barrel column (arrowhead indicates the location of the implanted electrode) throughout experiments (left). Example of implanted electrode into the layer 2/3 of the barrel cortex (right). Coronal cortical slices infected with GFP-GluR1ct–expressing virus. The electrode was implanted into layer 2/3 of the barrel cortex (layer numbers are indicated). Scale bar: 500 μm. (D) Rats with GFP-GluR1ct (C tail) expression exhibited lower-field EPSP slopes than GFP-expressing animals, indicating decreased sensitivity of whiskers by the expression of GFP-GluR1ct (*P < 0.05, GFP versus C tail; C tail, n = 7, GFP, n = 4). Data were analyzed by paired, 2-tailed t test.
Figure 6
Figure 6. Social isolation disrupts behavior dependent on whisker-barrel function.
(A) Schematic of gap-crossing test. The gap was widened until rats could no longer cross (middle, SU), and then the gap was narrowed until they could cross (right: SL). Difference between SU and SL is indicated by ΔS (see text and Methods for details). (B) Rats with GFP expression in the barrel cortex showed lower ΔS than GFP-GluR1ct–expressing (C tail) animals, indicating that GFP-expressing animals have better distance detection ability than GFP-GluR1ct–expressing animals (*P < 0.05, GFP versus C tail; n = 8 per each group). (C) Isolated rats showed higher ΔS than nonisolated rats, indicating worse distance detection. Isolated rats treated with RU486 showed lower ΔS than untreated isolated rats, indicating RU486 rescued distance detection of isolated rats (F(5,45) = 8.668, *P < 0.05 compared with nonisolated [n = 9] and isolated postnatal P4–P7 with RU486 [n = 9] animals, #P < 0.05 compared with nonisolated and isolated P7–P11 with RU486 [n = 8] animals). RU486 treatment alone had no effect on distance detection (n = 8). Data were analyzed by paired, 2-tailed t test (B) or 1-way factorial ANOVA (C).
See this image and copyright information in PMC

References

    1. Hu H, et al. Emotion enhances learning via norepinephrine regulation of AMPA-receptor trafficking. Cell. 2007;131(1):160–173. doi: 10.1016/j.cell.2007.09.017. - DOI - PubMed
    1. Enthoven L, Oitzl MS, Koning N, van der Mark M, de Kloet ER. Hypothalamic-pituitary-adrenal axis activity of newborn mice rapidly desensitizes to repeated maternal absence but becomes highly responsive to novelty. Endocrinology. 2008;149(12):6366–6377. doi: 10.1210/en.2008-0238. - DOI - PubMed
    1. McEwen BS. Protective and damaging effects of stress mediators: central role of the brain. Dialogues Clin Neurosci. 2006;8(4):367–381. - PMC - PubMed
    1. Insel TR, Fernald RD. How the brain processes social information: searching for the social brain. Annu Rev Neurosci. 2004;27:697–722. doi: 10.1146/annurev.neuro.27.070203.144148. - DOI - PubMed
    1. Khonicheva NM, Loseva EV, Chabak-Garbach R, Loriya MV, Airapetyants MG. A special case of learning disorder in isolant rats as a model of disintegration. Neurosci Behav Physiol. 2006;36(6):597–603. doi: 10.1007/s11055-006-0063-3. - DOI - PubMed

Publication types

MeSH terms

Substances