BDNF and Learning: Evidence that Instrumental Training Promotes Learning within the Spinal Cord by Up-Regulating BDNF Expression

Neuroscience, 2007 · DOI: 10.1016/j.neuroscience.2007.05.051 · Published: September 21, 2007

Simple Explanation

This research explores how the spinal cord learns a simple task even without input from the brain. Rats with spinal cord injuries were trained to flex their leg to avoid a mild shock. The study found that learning this task increased the levels of a protein called BDNF (brain-derived neurotrophic factor) and related molecules in the spinal cord. Blocking BDNF or a related protein, CaMKII, prevented the rats from learning, while adding BDNF helped them learn more easily. This suggests BDNF is key for spinal cord learning.

Study Duration

Not specified

Participants

Adult male Sprague-Dawley rats (90–100 days old)

Evidence Level

Level 2: Experimental study on rats

Key Findings

1
Instrumental learning in spinally transected rats increased mRNA levels of BDNF, CaMKII, CREB, and synapsin I in the lumbar spinal cord.
2
The increases in BDNF, CREB, and CaMKII were proportional to the learning performance, suggesting a direct link between these molecules and spinal learning.
3
Pretreatment with a BDNF inhibitor (TrkB-IgG) or a CaMKII inhibitor (AIP) blocked the facilitatory effect of instrumental training on subsequent learning, while intrathecal administration of BDNF facilitated learning with a high response criterion.

Research Summary

This study demonstrates that the spinal cord can learn a sensorimotor task independently of the brain, and that this learning is associated with increased expression of BDNF and related molecules (CaMKII, CREB, synapsin I) in the lumbar spinal cord. Blocking BDNF or CaMKII impairs the ability of instrumental training to facilitate subsequent learning, while administration of BDNF enhances learning, suggesting that BDNF is both necessary and sufficient for this facilitatory effect. These findings suggest that BDNF-mediated synaptic plasticity plays a crucial role in spinal cord learning and may have implications for functional recovery after spinal cord injury.

Practical Implications

Rehabilitation Strategies

The study supports the use of rehabilitation strategies that promote instrumental learning to enhance recovery after spinal cord injury.

Therapeutic Targets

BDNF and CaMKII could be potential therapeutic targets for promoting spinal cord plasticity and improving motor function after injury.

Understanding Spinal Learning

The study enhances our understanding of the molecular mechanisms underlying spinal cord learning and its potential role in functional recovery.

Study Limitations

1
The study was conducted on rats, and the results may not directly translate to humans.
2
The specific mechanisms by which BDNF and CaMKII influence synaptic plasticity in the spinal cord require further investigation.
3
The long-term effects of BDNF treatment on spinal cord learning and functional recovery were not assessed.

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