1 / 20

Critique of “strengthening of horizontal cortical connection following skill Learning”

Critique of “strengthening of horizontal cortical connection following skill Learning”. Group B4: Premraj Yogarajah Ruth Pedrosa Shawn Thadeaus Netra Malhotra. Schedule of Events. Summary of article Factors affecting MEP amplitude Control for Variables LTP and Memory

calvin
Download Presentation

Critique of “strengthening of horizontal cortical connection following skill Learning”

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Critique of “strengthening of horizontal cortical connection following skill Learning” Group B4: PremrajYogarajah Ruth Pedrosa Shawn Thadeaus NetraMalhotra

  2. Schedule of Events • Summary of article • Factors affecting MEP amplitude • Control for Variables • LTP and Memory • Effects of Aging on LTP • Motor learning in humans • What we know today

  3. RUTH Brief Summary METHOD: • Trained rats in skilled reaching task (3-5 days) • Coronial brain slices prepared • Examined effect of training on strength of horizontal intracortical connections (layer II/III)

  4. Results: • Skill learning changes strength of connections in M1 • First direct evidence - plasticity of intracortical connections associated with learning a new motor skill

  5. PREM Factors Affecting MEP Amplitude • Age • Resting motor threshold Muller-Dahlhaus, J.F.M, et al. 2007. Iterindividual variability and age-dependency of motor cortical plasticity induced by paired associative stimulation. Exp Brain Res. 187: 467-475

  6. PREM Age Figure 1. Age of individual vs. the amplitude of the motor-evoked potential of individual. Muller-Dahlhaus, J.F.M, et al. 2007. Iterindividual variability and age-dependency of motor cortical plasticity induced by paired associative stimulation. Exp Brain Res. 187: 467-475

  7. PREM Resting Motor Threshold Figure 3. Resting motor threshold of individual vs. the amplitude of the motor-evoked potential of individual. Muller-Dahlhaus, J.F.M, et al. 2007. Iterindividual variability and age-dependency of motor cortical plasticity induced by paired associative stimulation. Exp Brain Res. 187: 467-475

  8. Control for Variability • Design of experiment eliminates most variables found among the test subjects • Individual served as both control and test subject Hodgson R.A., et al. 2004. Training-induced and electrically induced potentiation in the neocortex. Neurobiology of Learning and Memory. 83: 22-23.

  9. LTP and Memory • Trained hemisphere less amenable to further LTP induction • Absence of LTP and the affect on learning Hodgson R.A., et al. 2004. Training-induced and electrically induced potentiation in the neocortex. Neurobiology of Learning and Memory. 83: 22-23.

  10. Age-related changes in anatomy and neurophysiology in aged rats • Loss of functional synapses • Decreased strength of NMDA-receptor response: ↑ in threshold for LTP induction • Calcium dyregulation - ↑ threshold in LTP induction, ↓ threshold in LTD induction

  11. Effects of Aging on LTP • ↑ age leads to LTP induction impairment • Tasks- learned slower, forgotten quickly • LTP in adult rats may induce LTD in aged rats

  12. Effects of Aging on Relationships between Physiology, Plasticity, and Cognition

  13. Sequential Neural Changes during Motor Learning in Schizophrenia • Same methodology METHOD: • Neural changes from learning a motor task • Visual guided reaching • PET Rowland, L.M., Shadmehr, R., Kravitz, D. & Holcomb, H. H. (2008). Sequential Neural Changes during motor learning in schizophrenia. Psychiatry Res. 163(1): 1-12

  14. Schizophrenics and Healthy Volunteers • Schizophrenic – deficiency constructing representations • Do they use the same brain regions as healthy individuals ? Rowland, L.M., Shadmehr, R., Kravitz, D. & Holcomb, H. H. (2008). Sequential Neural Changes during motor learning in schizophrenia. Psychiatry Res. 163(1): 1-12

  15. Found: Rowland, L.M., Shadmehr, R., Kravitz, D. & Holcomb, H. H. (2008). Sequential Neural Changes during motor learning in schizophrenia. Psychiatry Res. 163(1): 1-12

  16. What we know today… • MSL operates as the interaction of two orthogonal connections - intracortical serial connections (horizontal arrows) - cortico–BG/cortico–CB loop circuits (vertical arrows)

  17. Figure 3: Motor sequence is learned through cortex–Basil Ganglia and cortex–Cerebellum loop circuits independently, and in different coordinates (spatial and motor).

  18. Basal Ganglia • Spatial sequence • Reversible blockade of the anterior striatum (associative region) deficits in learning new sequences • Blockade of the posterior striatum (motor region)disruptions in the execution of learned sequences

  19. Cerebellum • Blockade disrupts learning of complex goal directed behaviors • Cerebellar lesions impair motor sequence learning • Long-term memories for motor skills may be stored in the CB

  20. CONCLUSION

More Related