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Loss of Arc renders the visual cortex impervious to the effects of sensory experience or deprivation.

McCurry CL, Shepherd JD, Tropea D, Wang KH, Bear MF, Sur M - Nat. Neurosci. (2010)

Bottom Line: A myriad of mechanisms have been suggested to account for the full richness of visual cortical plasticity.We found that visual cortex lacking Arc is impervious to the effects of deprivation or experience.These data suggest that Arc is required for the experience-dependent processes that normally establish and modify synaptic connections in visual cortex.

View Article: PubMed Central - PubMed

Affiliation: Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.

ABSTRACT
A myriad of mechanisms have been suggested to account for the full richness of visual cortical plasticity. We found that visual cortex lacking Arc is impervious to the effects of deprivation or experience. Using intrinsic signal imaging and chronic visually evoked potential recordings, we found that Arc(-/-) mice did not exhibit depression of deprived-eye responses or a shift in ocular dominance after brief monocular deprivation. Extended deprivation also failed to elicit a shift in ocular dominance or open-eye potentiation. Moreover, Arc(-/-) mice lacked stimulus-selective response potentiation. Although Arc(-/-) mice exhibited normal visual acuity, baseline ocular dominance was abnormal and resembled that observed after dark-rearing. These data suggest that Arc is required for the experience-dependent processes that normally establish and modify synaptic connections in visual cortex.

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Arc−/− mice lack stimulus–selective response potentiation (SRP) whereas dark–reared mice exhibit enhanced SRP in V1. (a) WT mice exhibit large and sustained potentiation of binocular VEPs over many days of exposure to the same stimulus orientation (n=11). Responses to a control orthogonal stimulus (90°, open black circle) shown at day 6 were not significantly potentiated. Dark–reared mice have small VEPs at baseline, which become dramatically potentiated after exposure to the same stimulus orientation (n=12). Responses to a control orthogonal stimulus (90°, open red triangle) are significantly increased compared with baseline VEPs but are also significantly smaller than the SRP orientation at day 6. In contrast, Arc−/− mice exhibit no significant potentiation of responses to the same stimulus (n=16). Responses to the control orthogonal stimulus (90°, blue square) were also not significantly different from baseline, suggesting no general decrease in responses over time. (b) VEPs normalized to baseline values show that dark–reared mice exhibit a relative enhancement of potentiation as compared to light–reared mice, while Arc−/− mice show no relative potentiation of VEPs. (c) Average VEP waveforms at baseline (day 1) and after 5 days of repeated exposure to the same orientation (day 6).
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Figure 8: Arc−/− mice lack stimulus–selective response potentiation (SRP) whereas dark–reared mice exhibit enhanced SRP in V1. (a) WT mice exhibit large and sustained potentiation of binocular VEPs over many days of exposure to the same stimulus orientation (n=11). Responses to a control orthogonal stimulus (90°, open black circle) shown at day 6 were not significantly potentiated. Dark–reared mice have small VEPs at baseline, which become dramatically potentiated after exposure to the same stimulus orientation (n=12). Responses to a control orthogonal stimulus (90°, open red triangle) are significantly increased compared with baseline VEPs but are also significantly smaller than the SRP orientation at day 6. In contrast, Arc−/− mice exhibit no significant potentiation of responses to the same stimulus (n=16). Responses to the control orthogonal stimulus (90°, blue square) were also not significantly different from baseline, suggesting no general decrease in responses over time. (b) VEPs normalized to baseline values show that dark–reared mice exhibit a relative enhancement of potentiation as compared to light–reared mice, while Arc−/− mice show no relative potentiation of VEPs. (c) Average VEP waveforms at baseline (day 1) and after 5 days of repeated exposure to the same orientation (day 6).

Mentions: Another in vivo form of cortical response enhancement, SRP, results from brief exposure to sinusoidal gratings of a specific orientation16. Mechanistically, SRP exhibits hallmarks of LTP; it is NMDAR–dependent, and is blocked by a GluR1 C–terminal peptide, which inhibits insertion of AMPARs at synapses. Since Arc−/− mice exhibit a defect in open eye potentiation, we wondered whether SRP would also be disrupted due to a lack of Arc. Indeed, we found that Arc−/− mice had a severe deficit in SRP (Fig. 8) as compared to WT mice. This adds further weight to the idea that Arc is required for multiple forms of experience–dependent plasticity in V1.


Loss of Arc renders the visual cortex impervious to the effects of sensory experience or deprivation.

McCurry CL, Shepherd JD, Tropea D, Wang KH, Bear MF, Sur M - Nat. Neurosci. (2010)

Arc−/− mice lack stimulus–selective response potentiation (SRP) whereas dark–reared mice exhibit enhanced SRP in V1. (a) WT mice exhibit large and sustained potentiation of binocular VEPs over many days of exposure to the same stimulus orientation (n=11). Responses to a control orthogonal stimulus (90°, open black circle) shown at day 6 were not significantly potentiated. Dark–reared mice have small VEPs at baseline, which become dramatically potentiated after exposure to the same stimulus orientation (n=12). Responses to a control orthogonal stimulus (90°, open red triangle) are significantly increased compared with baseline VEPs but are also significantly smaller than the SRP orientation at day 6. In contrast, Arc−/− mice exhibit no significant potentiation of responses to the same stimulus (n=16). Responses to the control orthogonal stimulus (90°, blue square) were also not significantly different from baseline, suggesting no general decrease in responses over time. (b) VEPs normalized to baseline values show that dark–reared mice exhibit a relative enhancement of potentiation as compared to light–reared mice, while Arc−/− mice show no relative potentiation of VEPs. (c) Average VEP waveforms at baseline (day 1) and after 5 days of repeated exposure to the same orientation (day 6).
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Figure 8: Arc−/− mice lack stimulus–selective response potentiation (SRP) whereas dark–reared mice exhibit enhanced SRP in V1. (a) WT mice exhibit large and sustained potentiation of binocular VEPs over many days of exposure to the same stimulus orientation (n=11). Responses to a control orthogonal stimulus (90°, open black circle) shown at day 6 were not significantly potentiated. Dark–reared mice have small VEPs at baseline, which become dramatically potentiated after exposure to the same stimulus orientation (n=12). Responses to a control orthogonal stimulus (90°, open red triangle) are significantly increased compared with baseline VEPs but are also significantly smaller than the SRP orientation at day 6. In contrast, Arc−/− mice exhibit no significant potentiation of responses to the same stimulus (n=16). Responses to the control orthogonal stimulus (90°, blue square) were also not significantly different from baseline, suggesting no general decrease in responses over time. (b) VEPs normalized to baseline values show that dark–reared mice exhibit a relative enhancement of potentiation as compared to light–reared mice, while Arc−/− mice show no relative potentiation of VEPs. (c) Average VEP waveforms at baseline (day 1) and after 5 days of repeated exposure to the same orientation (day 6).
Mentions: Another in vivo form of cortical response enhancement, SRP, results from brief exposure to sinusoidal gratings of a specific orientation16. Mechanistically, SRP exhibits hallmarks of LTP; it is NMDAR–dependent, and is blocked by a GluR1 C–terminal peptide, which inhibits insertion of AMPARs at synapses. Since Arc−/− mice exhibit a defect in open eye potentiation, we wondered whether SRP would also be disrupted due to a lack of Arc. Indeed, we found that Arc−/− mice had a severe deficit in SRP (Fig. 8) as compared to WT mice. This adds further weight to the idea that Arc is required for multiple forms of experience–dependent plasticity in V1.

Bottom Line: A myriad of mechanisms have been suggested to account for the full richness of visual cortical plasticity.We found that visual cortex lacking Arc is impervious to the effects of deprivation or experience.These data suggest that Arc is required for the experience-dependent processes that normally establish and modify synaptic connections in visual cortex.

View Article: PubMed Central - PubMed

Affiliation: Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.

ABSTRACT
A myriad of mechanisms have been suggested to account for the full richness of visual cortical plasticity. We found that visual cortex lacking Arc is impervious to the effects of deprivation or experience. Using intrinsic signal imaging and chronic visually evoked potential recordings, we found that Arc(-/-) mice did not exhibit depression of deprived-eye responses or a shift in ocular dominance after brief monocular deprivation. Extended deprivation also failed to elicit a shift in ocular dominance or open-eye potentiation. Moreover, Arc(-/-) mice lacked stimulus-selective response potentiation. Although Arc(-/-) mice exhibited normal visual acuity, baseline ocular dominance was abnormal and resembled that observed after dark-rearing. These data suggest that Arc is required for the experience-dependent processes that normally establish and modify synaptic connections in visual cortex.

Show MeSH
Related in: MedlinePlus