The massa intermedia is found in many but not all human brains.

• A. It is found in all brains
• B. It is found in many but not all
• C. It is never present in humans
• D. It is involved in memory

Answer: (B)

The massa intermedia, or interthalamic adhesion, is a small band of gray matter that sometimes connects the left and right thalami across the third ventricle. Its presence varies among individuals—many brains have it, but it is absent in others. This variability is normal and does not imply any pathology. It also isn’t established as a memory-related structure; memory functions rely on broader networks involving the hippocampus, prefrontal cortex, and thalamus rather than this specific bridge. So the statement that it is found in many but not all human brains best captures what we know about this structure.