History of Neuroscience: Key Figures and Concepts in Brain Localization

Edwin Smith Papyrus

Oldest known medical textbook; 48 case studies (head injuries, broken bones); first recorded use of the word 'brain'; notes lateralized motor impairments and speech loss.

Hippocrates

Greek physician; stated brain (not heart) is the seat of thought, sensation, and emotion; linked epilepsy and other conditions to speech impairment; introduced Hippocratic Oath.

Claudius Galen

Greek physician in Roman Empire; wrote 400+ works on anatomy/physiology; believed blood carried 'vital spirits' released by the brain; dissected animals (including an elephant).

Andreas Vesalius

Renaissance physician/anatomist; performed systematic dissections (often on stolen corpses); advanced knowledge of nervous system anatomy.

René Descartes

Philosopher/physician; 'I think, therefore I am'; speculated on relationship between mind and brain.

Franz-Joseph Gall

Austrian physician; founder of phrenology (brain regions have specialized functions); although phrenology is discredited, he and Spurzheim advanced neuroanatomy.

Phrenology

Pseudoscience claiming skull shape reflects mental abilities and traits; historically influential despite being false. also states that brain function is localized to certain parts of the brain.

Marie-Jean-Pierre Flourens

French anatomist; opposed phrenology; argued complex functions cannot be localized precisely; stressed holistic brain function.

Jean-Baptiste Bouillaud

Described motor aphasia; proposed anterior brain lobes as the seat of speech production.

Pierre Paul Broca

Identified 'Broca's Area' (left inferior frontal gyrus); autopsy of patient Leborgne showed damage caused speech loss ('aphemia'); understanding intact.

Carl Wernicke

Identified 'Wernicke's Aphasia': fluent but nonsensical speech with impaired comprehension; lesion in left temporal/parietal junction.

John Hughlings Jackson

Distinguished automatic vs. propositional speech; argued localization of speech deficits ≠ localization of speech itself.

Pierre Marie

Coined term anarthria to describe articulatory disorders.

Hugo Liepmann

Defined apraxia: inability to perform purposeful movements despite intact motor function.

Henry Head

Studied thalamus in emotion and consciousness; argued brain areas contribute to symbolic language but not specific 'centers.' Equipotentialist

Walter Cannon

Proposed thalamic theory of emotion (thalamus = feeling, hypothalamus = expression); coined term homeostasis - maintaining a steady state in body systems

James Papez

Named the limbic system as central to emotion.

Karl Lashley

Proposed mass action theory - the greater the lesion, the larger the impairment. Tested this theory on rats. brain functions are distributed, not localized; emphasized diffuse neural activity. Equipotentialist.

Wilder Penfield

Neurosurgeon; electrical stimulation of temporal lobe produced vivid memory 'flashbacks'; concluded no single brain region houses consciousness.

Current consensus on brain function

While no part of the brain is ever inactive, the general consensus is that during certain brain functions, one part of the brain will be more active than the other. A mix of Equipotentialism and localization - the brain functions at an in between. Some parts of the brain have a more important role to play in cognitive processes