Frontal, parietal, temporal and occipital — with a fifth, the insula, hidden in the depths of the Sylvian fissure
The five divisions of each cerebral hemisphere
Science · Medicine & the body
The brain's lobes
Broca's area localised 1861
Medicine — neuroanatomy of the cerebral cortex
Each cerebral hemisphere is conventionally divided into four lobes, named after the skull bones above them: frontal, parietal, temporal and occipital, with a fifth, the insula, buried in the depths of the lateral fissure. The divisions are marked by landmarks any anatomist can point to — the central sulcus between frontal and parietal, the lateral or Sylvian fissure above the temporal lobe — and they map roughly onto function: movement and planning at the front, touch and space above, hearing and memory at the side, vision at the back.
How to spot them
- ▸Four lobes per hemisphere plus the insula, each named for the skull bone over it
- ▸Central sulcus (fissure of Rolando) between frontal and parietal; lateral (Sylvian) fissure above the temporal
- ▸Broca's area at the front for producing speech, Wernicke's at the side for understanding it
- ▸Precentral gyrus = motor, postcentral gyrus = sensory, with the homunculus laid out across both
- ▸The cerebellum and brainstem are not lobes of the cerebrum
Key facts
The central sulcus, also called the fissure of Rolando
The groove separating the frontal from the parietal division
Broca's area in the left inferior frontal gyrus and Wernicke's in the superior temporal gyrus (1861)
The two classic language regions: production and comprehension
The precentral gyrus for movement and the postcentral gyrus for touch, facing each other across a groove
Primary motor and primary somatosensory cortex
Wilder Penfield's grotesquely distorted little man, with huge hands and lips
The cortical homunculus, mapped by stimulating conscious patients
A tamping iron through the head of a Vermont railway foreman in 1848 (1848)
Phineas Gage — the case that tied personality to the frontal region
The calcarine sulcus and area V1, at the very back of the head
Primary visual cortex, in the occipital division
Roger Sperry's patients whose corpus callosum had been cut, and the 1981 Nobel Prize (1981)
Cutting the corpus callosum revealed the two hemispheres working separately
Key ideas
- The divisions are anatomical conveniences named after bone, not functional units — but they correlate remarkably well with what the cortex underneath does.
- Function is localised but not neatly parcelled: language, for example, depends on a network linking frontal and temporal regions through the arcuate fasciculus.
Quick-fire facts
- •Four lobes per hemisphere — frontal, parietal, temporal, occipital — named after the overlying skull bones; the insula is a fifth, sometimes with a limbic lobe as a sixth
- •The central sulcus (fissure of Rolando) divides frontal from parietal; the lateral or Sylvian fissure divides temporal from frontal and parietal
- •The frontal lobe holds the primary motor cortex (precentral gyrus), Broca's area and the prefrontal cortex
- •Paul Broca localised speech production in 1861 in a patient known as 'Tan'; Carl Wernicke described the comprehension area in 1874
- •The parietal lobe holds the primary somatosensory cortex (postcentral gyrus); right parietal damage can cause hemispatial neglect
- •The temporal lobe contains the primary auditory cortex in Heschl's gyrus, and the hippocampus and amygdala lie within it
- •The occipital lobe contains primary visual cortex (V1) around the calcarine sulcus
- •The insula, or island of Reil, handles taste and interoception
- •Korbinian Brodmann divided the cortex into 52 numbered areas in 1909; Broca's area is Brodmann areas 44 and 45
- •Phineas Gage survived an iron bar passing through his left frontal lobe in 1848; the case was reported by John Harlow
- •Roger Sperry shared the 1981 Nobel Prize in Physiology or Medicine for work on split-brain patients
- •The two hemispheres are joined by the corpus callosum, a band of some 200 million nerve fibres
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Sources
- OpenStax, Rice University — Anatomy and Physiology 2e — The Central Nervous System
- Henry Gray (Susan Standring, ed.) — Gray's Anatomy