32 Brain & Behavior IX

Question 1

What is Callosal AGENESIS

Answer 1

BORN WITHOUT a corpus callosum

= “naturally” split-brained

Question 2

In corpus agenesis, what STRUCTURES can remain at the site of corpus callosum?

Answer 2

Probst’s bundles

= REMNANTS of corpus callosum that failed to cross midline

Question 3

Compare callosal agenesis SYMPTOMS with that of Split-Brain?

Answer 3

Callosal agenesis:
= LESS disconnection (Probst’s bundles remain?)
= EASILY NAME objects/words in EITHER visual field
= SLOW interhemispheric transmission time

Question 4

Compare the TRANSMISSION time of callosal agenesis with NORMAL people

Answer 4

Callosal agenesis = 20-30ms

Normal brains = 4-6ms

Question 5

Hypothesis for WHY people with callosal agenesis seem relatively NORMAL?

Answer 5

• COMPENSATION and neural PLASTICITY which develops EARLY, to compensate for lack of inter-hemispheric transmission
• Probst’s bundles?