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Rapid Bidirectional Reorganization of Cortical Microcircuits.

Albieri G, Barnes SJ, de Celis Alonso B, Cheetham CE, Edwards CE, Lowe AS, Karunaratne H, Dear JP, Lee KC, Finnerty GT - Cereb. Cortex (2014)

Bottom Line: We found that there was rapid expansion followed by retraction of whisker cortical maps.Despite the rapid increase in local excitatory connectivity, the average strength and synaptic dynamics did not change, which suggests that new excitatory connections rapidly acquire the properties of established excitatory connections.Hence, the changes in local excitatory connectivity did not occur in all circuits involving pyramidal neurons.

View Article: PubMed Central - PubMed

Affiliation: MRC Centre for Neurodegeneration Research, King's College London, Institute of Psychiatry (Box44), London SE5 8AF, UK Current address: Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.

No MeSH data available.


Related in: MedlinePlus

Spared whisker representations enlarge after whisker trimming. (A) Schematic illustrating the relative position of SI, SII, and the parietal ventral area (PV) in a coronal slice through whisker barrel cortex. Dashed line bisects SI and SII. Whisker barrel columns are marked A–E. Red circle, SI PBR evoked by whisker deflection. (B) Schematic of trimming protocol (open circle denotes trimmed whisker) and deflection of right C1–4 whiskers. Left C1–4 whiskers not shown. (C and E) Group statistical parametric maps of BOLD responses evoked by 5 Hz whisker deflection in sham-trimmed rats (C, n = 26 rats), and after whisker trimming for 3 days (D, n = 15 rats) and 7 days (E, n = 28 rats). Pseudocolored voxels have a positive (red) or negative (blue) BOLD signal that is significantly different from baseline. Pseudocolor scale bar applies to (C and E). Numbers indicate rostro-caudal distance from bregma.
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BHU098F1: Spared whisker representations enlarge after whisker trimming. (A) Schematic illustrating the relative position of SI, SII, and the parietal ventral area (PV) in a coronal slice through whisker barrel cortex. Dashed line bisects SI and SII. Whisker barrel columns are marked A–E. Red circle, SI PBR evoked by whisker deflection. (B) Schematic of trimming protocol (open circle denotes trimmed whisker) and deflection of right C1–4 whiskers. Left C1–4 whiskers not shown. (C and E) Group statistical parametric maps of BOLD responses evoked by 5 Hz whisker deflection in sham-trimmed rats (C, n = 26 rats), and after whisker trimming for 3 days (D, n = 15 rats) and 7 days (E, n = 28 rats). Pseudocolored voxels have a positive (red) or negative (blue) BOLD signal that is significantly different from baseline. Pseudocolor scale bar applies to (C and E). Numbers indicate rostro-caudal distance from bregma.

Mentions: Early processing of touch sensory information in rodent neocortex occurs in distinct maps that lie in SI and secondary somatosensory cortex (SII) with a third rudimentary map in the parietal ventral area (Chapin and Lin 1984; Benison et al. 2007) (Fig. 1A). Experience-dependent plasticity of whisker maps was induced in adult somatosensory cortex by daily bilateral trimming of all whiskers except for the C row (Fig. 1B). This protocol facilitates detection of plasticity in SI because it enables the representation of spared whiskers to expand in multiple directions. We simulated normal whisking in the MRI scanner by passively deflecting the right-sided C1–C4 whiskers at 5 Hz and used the evoked BOLD signal as a read-out of reorganization of whisker cortical maps (Fig. 1B). In control rats, synchronous deflection of the C1–C4 whiskers evoked a PBR in contralateral SI that extended over 2 imaging slices in the group statistical map (Fig. 1C). In contrast, deflection of the spared whiskers after trimming for either 3 days (Fig. 1D; Supplementary Material and Fig. 2) or 7 days (Fig. 1E) elicited PBRs in the grouped data that extended over 6 contiguous slices in contralateral SI, SII, and the parietal ventral area. The grouped data also showed negative BOLD responses in contralateral somatosensory cortex after 3 days (Fig. 1D), but not after 7 days of trimming (Fig. 1E).Figure 1.


Rapid Bidirectional Reorganization of Cortical Microcircuits.

Albieri G, Barnes SJ, de Celis Alonso B, Cheetham CE, Edwards CE, Lowe AS, Karunaratne H, Dear JP, Lee KC, Finnerty GT - Cereb. Cortex (2014)

Spared whisker representations enlarge after whisker trimming. (A) Schematic illustrating the relative position of SI, SII, and the parietal ventral area (PV) in a coronal slice through whisker barrel cortex. Dashed line bisects SI and SII. Whisker barrel columns are marked A–E. Red circle, SI PBR evoked by whisker deflection. (B) Schematic of trimming protocol (open circle denotes trimmed whisker) and deflection of right C1–4 whiskers. Left C1–4 whiskers not shown. (C and E) Group statistical parametric maps of BOLD responses evoked by 5 Hz whisker deflection in sham-trimmed rats (C, n = 26 rats), and after whisker trimming for 3 days (D, n = 15 rats) and 7 days (E, n = 28 rats). Pseudocolored voxels have a positive (red) or negative (blue) BOLD signal that is significantly different from baseline. Pseudocolor scale bar applies to (C and E). Numbers indicate rostro-caudal distance from bregma.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

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BHU098F1: Spared whisker representations enlarge after whisker trimming. (A) Schematic illustrating the relative position of SI, SII, and the parietal ventral area (PV) in a coronal slice through whisker barrel cortex. Dashed line bisects SI and SII. Whisker barrel columns are marked A–E. Red circle, SI PBR evoked by whisker deflection. (B) Schematic of trimming protocol (open circle denotes trimmed whisker) and deflection of right C1–4 whiskers. Left C1–4 whiskers not shown. (C and E) Group statistical parametric maps of BOLD responses evoked by 5 Hz whisker deflection in sham-trimmed rats (C, n = 26 rats), and after whisker trimming for 3 days (D, n = 15 rats) and 7 days (E, n = 28 rats). Pseudocolored voxels have a positive (red) or negative (blue) BOLD signal that is significantly different from baseline. Pseudocolor scale bar applies to (C and E). Numbers indicate rostro-caudal distance from bregma.
Mentions: Early processing of touch sensory information in rodent neocortex occurs in distinct maps that lie in SI and secondary somatosensory cortex (SII) with a third rudimentary map in the parietal ventral area (Chapin and Lin 1984; Benison et al. 2007) (Fig. 1A). Experience-dependent plasticity of whisker maps was induced in adult somatosensory cortex by daily bilateral trimming of all whiskers except for the C row (Fig. 1B). This protocol facilitates detection of plasticity in SI because it enables the representation of spared whiskers to expand in multiple directions. We simulated normal whisking in the MRI scanner by passively deflecting the right-sided C1–C4 whiskers at 5 Hz and used the evoked BOLD signal as a read-out of reorganization of whisker cortical maps (Fig. 1B). In control rats, synchronous deflection of the C1–C4 whiskers evoked a PBR in contralateral SI that extended over 2 imaging slices in the group statistical map (Fig. 1C). In contrast, deflection of the spared whiskers after trimming for either 3 days (Fig. 1D; Supplementary Material and Fig. 2) or 7 days (Fig. 1E) elicited PBRs in the grouped data that extended over 6 contiguous slices in contralateral SI, SII, and the parietal ventral area. The grouped data also showed negative BOLD responses in contralateral somatosensory cortex after 3 days (Fig. 1D), but not after 7 days of trimming (Fig. 1E).Figure 1.

Bottom Line: We found that there was rapid expansion followed by retraction of whisker cortical maps.Despite the rapid increase in local excitatory connectivity, the average strength and synaptic dynamics did not change, which suggests that new excitatory connections rapidly acquire the properties of established excitatory connections.Hence, the changes in local excitatory connectivity did not occur in all circuits involving pyramidal neurons.

View Article: PubMed Central - PubMed

Affiliation: MRC Centre for Neurodegeneration Research, King's College London, Institute of Psychiatry (Box44), London SE5 8AF, UK Current address: Division of Neurobiology, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, UK.

No MeSH data available.


Related in: MedlinePlus