Intro to NBB (Glendinning)

Question 1

Explain the concept of localization.

Answer 1

Specific brain regions have specific functions (i.e. motor, vision, language, emotion)

*Localization does NOT mean hard-wiring (i.e. sensations on tongue can pass through visual cortex - use tongue to “see” objects)

Localization = basis for MRI

Question 2

Define and describe neuroplasticity.

Answer 2

Changes in neurons and pathways in response to experience -> Potential that brain has to reorganize by creating new neural pathways to adapt

Example: London taxi drivers have measurably larger hippocampus size than that of bus drivers (who drive the same route every day) - cabbies rely on hippocampus constantly for navigation

Question 3

Explain the difference between a focal and a diffuse lesion.

Answer 3

Focal lesion: infection, tumor, or injury that develops at restricted area of neural tissue

Diffuse lesion: neurodegenerative diseases, psychiatric disorders, inflammatory disorders, infections, malnutrition, genetic disorders, compression of the brain
*Diagnosis depends on SYMPTOMS and PATTERNS OF SYMPTOMS

Question 4

Discuss the relevance of temporal characteristics of neurological symptoms to making a diagnosis.

Answer 4

1. Episodic - migraine, seizures
2. Recent-onset and episode (headache, pain) - expanding brain tumor
3. Relapsing, remitting - MS
4. Sudden onset, lasting deficits - stroke (cerebrovascular accident)
5. Slow, progressive (Neurodegenerative diseases: PD, Alzheimer’s disease)
6. Progressive over short time period (Expanding tumor, expanding pressure)

Question 5

Explain the various forms of neuronal branching and neuron-to-neuron communication.

Answer 5

Neuronal Branching:

1. Unipolar (pseudo-): only one process that leaves cell body (axons and dendrites arise from single process, i.e. sensory neurons in dorsal root ganglia)
2. Bipolar (often sensory neuron neurons - vision/olfaction - single axon and dendrite arising from cell body)
3. Multipolar

Neuron-to-neuron communication occurs at synapses:
Divergence vs. Convergence
- Divergence: enabled by axon collaterals (info can be sent to multiple parts of the nervous system… pathway 1 vs pathway 2)
- Convergence: Integration of inhibitory and excitatory information/Comparisons / examples: sensory systems, motor systems, associative learning

CNS neuron types:

1. Interneurons - neurons that form connections within the CNS
2. Local interneurons - neurons that connect to cells in the immediate region
3. Projection interneurons - neurons that project to more distant areas of the CNS (make up TRACTS which are components of PATHWAYS)

Question 6

Define basic terms related to neuroanatomical groups of cell bodies and axons.

Answer 6

Cluster of nuclei - cell bodies = “nucleus” or “ganglia” in PNS

Cluster of axons: “tract”, “nerve”, “fascicles”, “commissure” (R-L)

Question 7

Describe the basic functions of neurons and glial cells.

Answer 7

Nervous system composed of neurons + glial cells

Neurons = basic units of signaling (10%)

Glial cells = support (non-neuronal) cells (90%)
- Schwann cells: myelin production (PNS)

• Astrocytes (CNS):
• > component of BBB (control K+ and cerebral blood flow)
• > remove K+ from ECF at nodes of Ranvier during AP and neurotransmitters from synaptic clefts (i.e. glutamate regulation prevents excitotoxicity)
• > communicate through GLIOTRANSMITTERS (D-serine, glutamate, ATP) in response to adjacent synaptic activity
• > produce neurotrophic factors
• > produce scar tissue in response to CNS injury
• Oligodendrocytes: myelin production (CNS)
• Microglia: scavenger cells of the CNS, produce growth factors
• Ependymal cells (CNS) - line ventricles and central canal of spinal cord

Question 8

List the types of cellular changes that can underlie neuroplasticity.

Answer 8

Axon sprouting

Dendritic branching synaptogenesis

Neurogenesis

Angiogenesis

Question 9

What (6) things does the neurological exam assess?

Answer 9

1. Mental Status (cognition, alertness, language)
2. Cranial Nerves
3. Motor function
4. Reflexes
5. Coordination and gait
6. Sensory function