Limits...
Differential effects of tactile high- and low-frequency stimulation on tactile discrimination in human subjects.

Ragert P, Kalisch T, Bliem B, Franzkowiak S, Dinse HR - BMC Neurosci (2008)

Bottom Line: T-HFS-effects were stable for at least 24 hours whereas t-LFS-induced changes recovered faster.No changes were observed when the stimulated area was very small (< 1 mm2) indicating special requirements for spatial summation.Our results demonstrate differential effects of such protocols in a frequency specific manner that might be related to LTP- and LTD-like changes in human subjects.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Neuroinformatics, Department of Theoretical Biology, Experimental Neurobiology Lab, Ruhr-University, 44780 Bochum, Germany. patrick.ragert@uni-duesseldorf.de

ABSTRACT

Background: Long-term potentiation (LTP) and long-term depression (LTD) play important roles in mediating activity-dependent changes in synaptic transmission and are believed to be crucial mechanisms underlying learning and cortical plasticity. In human subjects, however, the lack of adequate input stimuli for the induction of LTP and LTD makes it difficult to study directly the impact of such protocols on behavior.

Results: Using tactile high- and low-frequency stimulation protocols in humans, we explored the potential of such protocols for the induction of perceptual changes. We delivered tactile high-frequency and low-frequency stimuli (t-HFS, t-LFS) to skin sites of approximately 50 mm2 on the tip of the index finger. As assessed by 2-point discrimination, we demonstrate that 20 minutes of t-HFS improved tactile discrimination, while t-LFS impaired performance. T-HFS-effects were stable for at least 24 hours whereas t-LFS-induced changes recovered faster. While t-HFS changes were spatially very specific with no changes on the neighboring fingers, impaired tactile performance after t-LFS was also observed on the right middle-finger. A central finding was that for both t-LFS and t-HFS perceptual changes were dependent on the size of the stimulated skin area. No changes were observed when the stimulated area was very small (< 1 mm2) indicating special requirements for spatial summation.

Conclusion: Our results demonstrate differential effects of such protocols in a frequency specific manner that might be related to LTP- and LTD-like changes in human subjects.

Show MeSH

Related in: MedlinePlus

Effects of small field t-HFS and small field t-LFS on discrimination thresholds of the right d2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2244613&req=5

Figure 4: Effects of small field t-HFS and small field t-LFS on discrimination thresholds of the right d2.

Mentions: Prior to small-field t-HFS, all subjects achieved a stable baseline performance (rmANOVA with factor SESSION: F(3,12) = 0.986; p = 0.432; n = 5). Stimulating the right index-finger (d2) using 20 minutes of small-field t-HFS resulted in no comparable changes of tactile discrimination thresholds (pre: 1.67 ± 0.17 mm; post: 1.77 ± 0.15 mm, rmANOVA pre vs. post: F(1,4) = 2.283; p = 0.205; n = 5, see Fig. 4).


Differential effects of tactile high- and low-frequency stimulation on tactile discrimination in human subjects.

Ragert P, Kalisch T, Bliem B, Franzkowiak S, Dinse HR - BMC Neurosci (2008)

Effects of small field t-HFS and small field t-LFS on discrimination thresholds of the right d2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2244613&req=5

Figure 4: Effects of small field t-HFS and small field t-LFS on discrimination thresholds of the right d2.
Mentions: Prior to small-field t-HFS, all subjects achieved a stable baseline performance (rmANOVA with factor SESSION: F(3,12) = 0.986; p = 0.432; n = 5). Stimulating the right index-finger (d2) using 20 minutes of small-field t-HFS resulted in no comparable changes of tactile discrimination thresholds (pre: 1.67 ± 0.17 mm; post: 1.77 ± 0.15 mm, rmANOVA pre vs. post: F(1,4) = 2.283; p = 0.205; n = 5, see Fig. 4).

Bottom Line: T-HFS-effects were stable for at least 24 hours whereas t-LFS-induced changes recovered faster.No changes were observed when the stimulated area was very small (< 1 mm2) indicating special requirements for spatial summation.Our results demonstrate differential effects of such protocols in a frequency specific manner that might be related to LTP- and LTD-like changes in human subjects.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute for Neuroinformatics, Department of Theoretical Biology, Experimental Neurobiology Lab, Ruhr-University, 44780 Bochum, Germany. patrick.ragert@uni-duesseldorf.de

ABSTRACT

Background: Long-term potentiation (LTP) and long-term depression (LTD) play important roles in mediating activity-dependent changes in synaptic transmission and are believed to be crucial mechanisms underlying learning and cortical plasticity. In human subjects, however, the lack of adequate input stimuli for the induction of LTP and LTD makes it difficult to study directly the impact of such protocols on behavior.

Results: Using tactile high- and low-frequency stimulation protocols in humans, we explored the potential of such protocols for the induction of perceptual changes. We delivered tactile high-frequency and low-frequency stimuli (t-HFS, t-LFS) to skin sites of approximately 50 mm2 on the tip of the index finger. As assessed by 2-point discrimination, we demonstrate that 20 minutes of t-HFS improved tactile discrimination, while t-LFS impaired performance. T-HFS-effects were stable for at least 24 hours whereas t-LFS-induced changes recovered faster. While t-HFS changes were spatially very specific with no changes on the neighboring fingers, impaired tactile performance after t-LFS was also observed on the right middle-finger. A central finding was that for both t-LFS and t-HFS perceptual changes were dependent on the size of the stimulated skin area. No changes were observed when the stimulated area was very small (< 1 mm2) indicating special requirements for spatial summation.

Conclusion: Our results demonstrate differential effects of such protocols in a frequency specific manner that might be related to LTP- and LTD-like changes in human subjects.

Show MeSH
Related in: MedlinePlus