Mapping the Brain in 1861: The Hidden World of Each Region

Hippocrates, known as the father of ancient Greek medicine, recognised that the brain provides the physical basis for our thoughts and emotions. Another important Greek physician, Galen, stated: “The place from which the nerves originate is also the centre of the soul”. However, advanced research into the idea that different brain regions specialise in particular functions could not be undertaken before the 1800s. Until then, progress on this subject was limited.

In 1796, German neuroanatomist Franz Joseph Gall proposed that mental abilities such as language and music should be understood as functions of specific suborgans. The theory viewed the brain as a mosaic of suborgans specialised for particular abilities. However, he mistakenly supported the idea that their relative size and efficiency could be inferred from the size of bumps and areas on the skull (phrenology).

In 1861, French physician Pierre Broca discovered a particular brain region involved in speech. His findings came from examining two patients who lost the ability to speak after damage to a particular area in the front of the brain’s left hemisphere. Today this is called “Broca’s area”. Interestingly, when this region is gradually damaged, for example by a brain tumour, speech may be substantially preserved. This suggests that speech functions can move to other brain regions, supporting the concept of brain plasticity: the ability to adapt structurally and functionally to changing circumstances and conditions.

Further evidence that particular brain regions have specific functions came in the 1870s from German researchers Gustav Fritsch and Eduard Hitzig. Their experiments in dogs showed that electrical stimulation of brain areas could trigger localised body movements. 

In the 1940s, Canadian researchers Wilder Penfield and Herbert Jasper extended this work. They showed that electrically stimulating the motor cortex, which controls movement, could cause contractions on the opposite side of the body. They also produced detailed functional maps of the motor and sensory areas, which control movement, sensation and perception. Their work further strengthened the idea that specific brain regions have particular functions.

Explanation of the Article Image: 

The brain’s hemispheres: 

• Blue: The parietal lobe integrates information from the senses and contributes to using objects and spatial perception. 
• Pink: The occipital lobe processes visual information.
• Green: The temporal lobe processes sound, smell and stimuli such as places and faces. 
• Red: The frontal lobe supports conscious thought; damage can cause changes in mood. 
• Purple: The cerebellum, located below, links sensory information with movement and helps maintain balance.

Historical Figures Mentioned: Hippocrates of Cos (460 B.C.– 377 B.C.), Galen of Pergamon (129 – 199), Franz Joseph Gall (1758–1828), Pierre Paul Broca (1824 – 1880), Gustav Theodor Fritsch (1838 – 1927), Eduard Hitzig (1839– 1907), Wilder Graves Penfield (1891 –1976), Herbert Henri Jasper (1906–1999)

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