1. Ascribing functions to brain regions The limbic system
3 October 2008
Ascribing functions to brain regions
The limbic system
Cranial nerves (names, numbers, & functions)
Anatomy of the spinal cord and spinal nerves
Somatic and Autonomic Motor Systems

2. How do we know the functions of various brain regions?
Table 6.07
How do we know the functions of various brain regions?
Analogy: experiments to discover the function of a battery in a car.
Correlations of deficits of stroke victims with brain regions affected.
Selective ablations and spreading necrosis.
Selective electrical and chemical microstimulation

3. Figure 6.40
The Limbic System

4. Table 6.08

5. Dorsal roots = sensory (afferent)
Figure 6.41
Dorsal roots = sensory (afferent)
Ventral roots = motor (efferent, both somatic and autonomic)
Gray matter regions of brain and spinal cord
“Pinched nerves” and bulging discs
Ascending and descending axonal tracts in white matter not anatomically delineated.

6. Explanation for Cervical and lumbar enlargements of spinal cord.
Figure 6.42
Explanation for Cervical and lumbar enlargements of spinal cord.
Spinal nerves named for vertebral level.
Using patient’s localization of symptoms with knowledge of dermatomes to determine which spinal nerve is affected by damage.
Epidural injections into region of cauda equina of Lidocaine-like agents to block action potentials in sensory and motor axons without risk of damage to spinal cord.

7. Somatic = excitatory only at NMJ (ex. Reduced muscle tone)
Figure 6.43
Locations of neuronal cell bodies, ganglia, pharmacology of the neuromuscular junction (NMJ) at skeletal muscle (nAChR)
Diagram of NMJ compared to synaptic varicosities characteristic of autonomic postganglionic axons.
Locations and proximities of target cells and distributions of receptors on target cells.
Somatic = excitatory only at NMJ (ex. Reduced muscle tone)
Autonomic= exitatory or inhibitor y depending on NTs and their receptors.

8. Parasympathetic (cranio-sacral) division)
Figure 6.44
Parasympathetic (cranio-sacral) division)
Dual innervation with antogonistic effects
Sympathetic (thoraco-lumbar) division