97. Behavioral Neuroanatomy

Question 1

How is a network defined?

Where do focal lesions do most damage to a network?

Answer 1

fMRI defines a network by areas of brain with same activity in same time-course; correlate to fx by comparing to abnormal

Lesions that disrupt connector instead of hub cause more damage

Question 2

What are the 4 main networks with their PHYSICAL functions? What happens to damage to one of them?

Answer 2

1. Right dlPFC/Parietal Cortex: visual spatial orientation
   - damage: hemispatial neglect
2. PCC/vmPFC (limbics): learning/memory
   - damage: amnesia, emotion dysregulation, apathy, confusion
3. Language: left hemisphere perisylvian region, pulvinar thalamus, BG
   - damage: Brocas and Wernickes aphasia
4. Executive Fx: prefrontal cortex, BG, cerebellum
   - damage: impulsive/automatic behaviors, poor planning/judgment/decision-making (poor Stroop effect)

Question 3

What are the 2 networks associated with PSYCH illness? What happens with damage here and what dz processes act here?

Answer 3

1. Default-Mode Network
   - damage: deficits of memory/internal thought
   - dz: AD, MDD (low connections), Schizophrenia (high connections)
   - degree of sx correlates to degree of damage
2. Salience Network
   - damage: deficits of emotional/reward regulation
   - dz: FTD, Schizophrenia, MDD

Overlap of dz b/w networks suggest less structural differences in psych illness! (many commonalities for multiple psych illnesses)

Question 4

How can we use networks as innervation targets?

Answer 4

TMS: non-invasive shock - specific activation of cortical neurons

• target default mode/hippocampal network - stimulates hippocampus - ENHANCEMENT - improves memory and reversing age-related memory decline
• tx diseases that need DBS less invasively