discussion

Question 1

increased cortical excitability

Answer 1

• During active movement = increased responsiveness of brains motor cortex. SAI helps monitor the balance of inhibitory and exhibitory neuron firing. During active movement, excitation strengthens creating an imbalance causing the inhibitory effect of SAI including suppression to reduce.
• priority in brain reducing inhibitory processes and maintain motor control

Question 2

integration of sensory and motor information

Answer 2

• leads on. brain adjusts to the interaction of sensory and motor to allow for a smoother movement and the integration of motor and sensory information is the key modulator to this reduction.
• when at rest it is the sensory input from peripheral nerves than is involved in SAI, and inhibits motor cortex. whereas during movement the motor system is more responsive to this interaction reduces the strength of SAI. prevents over-inhibition of the motor systems = smooth movement

Question 3

FDI more dominant in finger movements compared to TE

Answer 3

• The FDI important for the index fingers adducti0on and abduction and helps stabilise the fingers for gripping and pinching. It is crucial for coordination and control as well as for the thumb which research could say is more important for the Jenga task explaining the larger SAI effect
• However, the thenar eminence is crucial for thumb movements like flexion and abduction and helps to pick up small objects. So, this would counter what we found.
• This takes us nicely into a limitation which could be the TE being 3 muscles, meaning it was less about the strength and importance but more about the clear signal we could receive from the FDI in comparison

Question 4

limitations

Answer 4

• A limitation could be the TE being 3 muscles, meaning it was less about the strength and importance but more about the clear signal we could receive from the FDI in comparison

Question 5

real world applications

Answer 5

1. Neurorehab for stroke
   - Studying short afferent inhibition can help understand how the brain inhibitory circuits adapt after stroke allowing therapies to be created to increase plasticity in patients going through recovery.
   - If we can see a change in a patients SAI for example them weakening, then rehabilitation programs can be designed to tailor individual patient’s sensorimotor deficits
   - Then use SAI strength as a biomarker for recovery
2. Mechanisms behind neurological disorders
   - SAI is linked to different pathways in the brain responsible for different neuro disorders. Use SAI to identify pathway disruptions – cholinergic pathway linked to Alzheimer’s.
   - Understanding how SAI integrates sensory input with motor output changes in disorders

Question 6

future research

Answer 6

• Which dip is which? Inhibition of brain or spine – would need electrodes running up the whole arm to measure when the signal is reaching where at what time point
• What are the underlying mechanisms of SAI?