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Overview
- Neuroplasticity allows for brain adaptation and rewiring, even in adulthood.
- Early critical periods exist, but plasticity continues throughout life.
- Therapy leverages plasticity to treat neurological and psychological conditions.
Adult Neuroplasticity: Research Findings
- Michael Merzenich’s studies on adult monkeys:
- Cut sensory nerves in the hand → Brain areas reorganized.
- Adjacent brain regions invaded the inactive areas.
- Demonstrated use it or lose it principle.
- Edward Taube’s research on deafferentation:
- Cutting nerves in monkeys showed cortical reorganization.
- Learned nonuse: When the good hand was available, the injured hand remained unused.
- Constraining the good hand forced reactivation of movement in the injured hand.
Human Plasticity and Phantom Limbs
- Phantom limb phenomenon: Amputees often feel their missing limb.
- Somatosensory remapping:
- Face area invaded the hand area in the brain.
- Touching the face caused sensations in the phantom limb.
- Mirror therapy for phantom pain:
- Using a mirror to reflect the intact limb tricked the brain into ‘seeing’ movement.
- Helped relieve pain and restore normal perception.
Pain and Neuroplasticity
- Pain is modulated by psychological factors:
- Hypnosis can reduce perceived pain.
- The prefrontal cortex can inhibit pain perception via the limbic system.
- Gate theory of pain:
- Pain signals are modulated at the spinal cord and brain level.
- Endorphins and opioids reduce pain perception.
Constraint-Induced Therapy (CI Therapy)
- Developed based on learned nonuse in stroke patients.
- Key principle: Constraining the good limb forces the affected limb to relearn movement.
- Massed practice principle:
- Intensive, short-term training is more effective than prolonged, low-frequency training.
- Acetylcholine and dopamine facilitate learning through reinforcement.
Language and Plasticity: Critical Periods
- Early exposure to language is essential for fluency.
- Adults can still learn, but plasticity is reduced.
- Immersion vs. traditional learning:
- Total immersion leads to faster language acquisition.
- Similar to CI therapy, restricting reliance on the native language improves learning.
Neuropeptides and Social Bonding
- Oxytocin (the bonding hormone) enhances attachment and trust.
- Neuroplastic role of oxytocin:
- Helps parents adapt to caregiving roles.
- Reduces fear response in the amygdala.
- Applications in therapy:
- Could be used to treat social anxiety and PTSD.
Mirror Neurons and Empathy
- Discovered in primates:
- Watching an action activates the same neurons as performing the action.
- Pain and empathy:
- Seeing someone in pain activates the observer’s pain-related brain regions.
- Social emotions (e.g., disgust, fear) share neural circuits with physical sensations.
- Implications for therapy:
- Could enhance social learning and emotional understanding in disorders like autism.
Neuroplastic Therapy for OCD
- Traditional exposure therapy:
- Gradual exposure to triggers reduces anxiety.
- Innovative phone-based therapy:
- Watching videos of oneself touching contaminants reduced symptoms.
- 20% symptom reduction, 40% increase in cognitive flexibility.
- Implications for treatment:
- Could be expanded for phobias, anxiety, and PTSD.
Conclusion
- Neuroplasticity provides new therapeutic approaches.
- Brain rewiring can occur at any age, with proper stimulus and reinforcement.
- Next lecture will explore Memory and Genius, focusing on how neuroplasticity affects learning and intelligence.