Topography
The brain fills the cranial cavity. The olfactory bulbs, well developed although proportionally smaller than in the dog, sit in the ethmoidal fossa rostral to the orbits. The cerebral hemispheres fill most of the vault; the cerebellum lies caudal to them in the caudal cranial fossa, separated from the cerebrum by the tentorium cerebelli, whose bony part (tentorium cerebelli osseum) is especially well developed in the cat. The brainstem rests on the floor of the skull and leaves through the foramen magnum towards the atlas.
Parts
- Cerebrum: two gyrencephalic hemispheres (with gyri and sulci), joined by the corpus callosum. The cruciate sulcus (sulcus cruciatus) marks the motor cortex dorsally; caudally, the lateral gyrus holds the visual cortex, one of the most studied in neurophysiology. Includes the olfactory bulbs and tracts.
- Cerebellum: median vermis and lateral hemispheres. Coordinates posture and movement.
- Brainstem (truncus encephali): midbrain, pons and medulla oblongata. Most cranial nerves arise from it.
Clinical relevance
- Feline infectious peritonitis (FIP): its neurological form is one of the most common causes of central nervous system disease in young cats (pyogranulomatous meningoencephalitis, ependymitis and obstructive hydrocephalus).
- Hepatic encephalopathy: in cats with a portosystemic shunt it causes ptyalism, behavioural changes and seizures.
- Meningioma: the most common primary intracranial tumour of the cat, typical of older animals; it is usually well demarcated and can often be removed surgically.
- Cerebellar hypoplasia: a sequel of feline panleukopenia virus infection during gestation or the neonatal period; causes non-progressive intention tremor and hypermetria.
- Thiamine deficiency: with raw-fish or poorly formulated diets; causes vestibular signs and ventroflexion of the neck.
3D model
Surface from a T1 MRI population template of domestic cats (Cornell feline atlas), divided into cerebrum, cerebellum and brainstem by intensity segmentation (the transverse fissure and fourth ventricle form the borders) and fitted to the cranial cavity of the atlas skull.