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Extended practice of a motor skill is associated with reduced metabolic activity in M1.

Picard N, Matsuzaka Y, Strick PL - Nat. Neurosci. (2013)

Bottom Line: After extended practice, we observed a profound reduction of metabolic activity in M1 for the performance of internally generated compared to visually guided tasks.These findings suggest that the development of skill through extended practice results in a reduction in the synaptic activity required to produce internally generated, but not visually guided, sequences of movements.Thus, practice leading to skilled performance results in more efficient generation of neuronal activity in M1.

View Article: PubMed Central - PubMed

Affiliation: Center for the Neural Basis of Cognition and Systems Neuroscience Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.

ABSTRACT
How does long-term training and the development of motor skills modify the activity of the primary motor cortex (M1)? To address this issue, we trained monkeys for ~1-6 years to perform visually guided and internally generated sequences of reaching movements. Then, we used [(14)C]2-deoxyglucose (2DG) uptake and single-neuron recording to measure metabolic and neuron activity in M1. After extended practice, we observed a profound reduction of metabolic activity in M1 for the performance of internally generated compared to visually guided tasks. In contrast, measures of neuron firing displayed little difference during the two tasks. These findings suggest that the development of skill through extended practice results in a reduction in the synaptic activity required to produce internally generated, but not visually guided, sequences of movements. Thus, practice leading to skilled performance results in more efficient generation of neuronal activity in M1.

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Comparison of activation measures in arm M1. (a) Peak activation was measured in 2 mm2 areas of interest over the most intense activation in arm M1. (b) Area measures were normalized by calculating the percentage of significantly activated pixels within each region of M1. We assessed group differences (Lick, n = 2; Rem and Repeating [internally-generated], n = 5; Track and Random [visually-guided], n = 5) with a 2-way (measure, group) ANOVA (d.f. = 2, 9) and post-hoc comparison of means. The probabilities shown are after Bonferroni correction. Error bars are s.d..
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Figure 4: Comparison of activation measures in arm M1. (a) Peak activation was measured in 2 mm2 areas of interest over the most intense activation in arm M1. (b) Area measures were normalized by calculating the percentage of significantly activated pixels within each region of M1. We assessed group differences (Lick, n = 2; Rem and Repeating [internally-generated], n = 5; Track and Random [visually-guided], n = 5) with a 2-way (measure, group) ANOVA (d.f. = 2, 9) and post-hoc comparison of means. The probabilities shown are after Bonferroni correction. Error bars are s.d..

Mentions: The high spatial resolution of 2DG uptake (~50–90 μm) allowed us to compare both the local peak intensity and the spatial extent of activation during visually-guided and internally-generated reaching movements. We measured local peak activation in 2 mm2 areas of interest. We defined the spatial extent of activation as the percentage of significantly activated pixels in arm M1. Peak activation during internally-generated movements was nearly half of that observed during visually-guided movements (Fig. 4a). Similarly, the area significantly activated during internally-generated movements amounted to only 22–35% of that activated during visually-guided movements (Fig. 4b). In essence, large portions of arm M1 (up to 86% in individual animals) were devoid of significant activation during the two internally-generated tasks.


Extended practice of a motor skill is associated with reduced metabolic activity in M1.

Picard N, Matsuzaka Y, Strick PL - Nat. Neurosci. (2013)

Comparison of activation measures in arm M1. (a) Peak activation was measured in 2 mm2 areas of interest over the most intense activation in arm M1. (b) Area measures were normalized by calculating the percentage of significantly activated pixels within each region of M1. We assessed group differences (Lick, n = 2; Rem and Repeating [internally-generated], n = 5; Track and Random [visually-guided], n = 5) with a 2-way (measure, group) ANOVA (d.f. = 2, 9) and post-hoc comparison of means. The probabilities shown are after Bonferroni correction. Error bars are s.d..
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Related In: Results  -  Collection

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Figure 4: Comparison of activation measures in arm M1. (a) Peak activation was measured in 2 mm2 areas of interest over the most intense activation in arm M1. (b) Area measures were normalized by calculating the percentage of significantly activated pixels within each region of M1. We assessed group differences (Lick, n = 2; Rem and Repeating [internally-generated], n = 5; Track and Random [visually-guided], n = 5) with a 2-way (measure, group) ANOVA (d.f. = 2, 9) and post-hoc comparison of means. The probabilities shown are after Bonferroni correction. Error bars are s.d..
Mentions: The high spatial resolution of 2DG uptake (~50–90 μm) allowed us to compare both the local peak intensity and the spatial extent of activation during visually-guided and internally-generated reaching movements. We measured local peak activation in 2 mm2 areas of interest. We defined the spatial extent of activation as the percentage of significantly activated pixels in arm M1. Peak activation during internally-generated movements was nearly half of that observed during visually-guided movements (Fig. 4a). Similarly, the area significantly activated during internally-generated movements amounted to only 22–35% of that activated during visually-guided movements (Fig. 4b). In essence, large portions of arm M1 (up to 86% in individual animals) were devoid of significant activation during the two internally-generated tasks.

Bottom Line: After extended practice, we observed a profound reduction of metabolic activity in M1 for the performance of internally generated compared to visually guided tasks.These findings suggest that the development of skill through extended practice results in a reduction in the synaptic activity required to produce internally generated, but not visually guided, sequences of movements.Thus, practice leading to skilled performance results in more efficient generation of neuronal activity in M1.

View Article: PubMed Central - PubMed

Affiliation: Center for the Neural Basis of Cognition and Systems Neuroscience Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.

ABSTRACT
How does long-term training and the development of motor skills modify the activity of the primary motor cortex (M1)? To address this issue, we trained monkeys for ~1-6 years to perform visually guided and internally generated sequences of reaching movements. Then, we used [(14)C]2-deoxyglucose (2DG) uptake and single-neuron recording to measure metabolic and neuron activity in M1. After extended practice, we observed a profound reduction of metabolic activity in M1 for the performance of internally generated compared to visually guided tasks. In contrast, measures of neuron firing displayed little difference during the two tasks. These findings suggest that the development of skill through extended practice results in a reduction in the synaptic activity required to produce internally generated, but not visually guided, sequences of movements. Thus, practice leading to skilled performance results in more efficient generation of neuronal activity in M1.

Show MeSH