10 Things About the Human Brain Science Still Can’t Explain

Your brain is the most familiar thing in your life, yet science still cannot fully explain what it creates. From consciousness and memory to dreams, imagination, intelligence, and identity, the deepest mysteries are not always hidden somewhere in space—they are inside your own head. Brenda Milner’s work with patient H.M. transformed our understanding of memory, while researchers including Francis Crick, Christof Koch, Eugene Aserinsky, Nathaniel Kleitman, Mark Solms, and Robert Shulman helped reveal different pieces of the brain’s extraordinary machinery. The brain contains roughly 86 billion neurons, yet neuron count alone does not explain intelligence. The hippocampus plays a crucial role in memory, but memories are distributed across broader neural systems. The sleeping brain remains active, while the exact purpose of dreaming remains an active scientific question. The brain consumes roughly 20% of resting energy despite representing only about 2% of adult body weight. The hardest mystery may be how physical neural activity becomes subjective experience and a persistent sense of self. By the end, you will understand why the greatest mystery in neuroscience may not be what the brain does, but how the brain becomes the person asking the question. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ SOURCES ━━━━━━━━━━━━━━━━━━━━━━━━━━━━ MEMORY AND HIPPOCAMPUS Brenda Milner, 1950s–1990s. Research on patient H.M. and human memory systems. This work established that hippocampal damage can severely impair new episodic memory while leaving some forms of learning intact. MEMORY ENGRAMS Choucry, Nomoto & Inokuchi, 2024. “Engram mechanisms of memory linking and identity.” Nature Reviews Neuroscience. This review examines how neuronal ensembles can encode and connect memories. REM SLEEP Aserinsky & Kleitman, 1953; Liu, 2024. Research on the discovery of rapid eye movement sleep and its relationship to dreaming. DREAMING AND CONSCIOUSNESS Hobson, 2009. “REM sleep and dreaming: towards a theory of protoconsciousness.” Nature Reviews Neuroscience. This work examines dreaming as a possible model for understanding conscious brain states. BRAIN ENERGY Shulman, Rothman, Behar & Hyder, 2004. “Energetic basis of brain activity: implications for neuroimaging.” Trends in Neurosciences. This source discusses the brain’s unusually high energy and oxygen requirements. CONSCIOUSNESS Luppi, 2024. “What anaesthesia reveals about human brains and consciousness.” Nature Human Behaviour. This article examines how anesthesia and neuroimaging can help investigate consciousness. HASHTAGS #brainmysteries #neuroscience #humanbrain #psychology #science