GCS

Response

Score

Open spontaneously

4

Open to verbal command

3

Open to pain

2

No eye opening

1

Orientated

5

Confused

4

Inappropriate words

3

Incomprehensible sounds

2

No verbal response

1

Obeys commands

6

Localising pain

5

Withdrawal from pain

4

Flexion to pain

3

Extension to pain

2

No motor response

1

Decorticate posturing

Decerebrate posturing

◦ Abnormal flexion
◦ Decorticate rigidity
◦ Flexor posturing
◦ Decorticate response

◦ Abnormal extension
◦ Decerebrate rigidity
◦ Extensor posturing
◦ Decerebrate response

Above the intercollicular line at the level of the red nucleus.

Below the intercollicular line at the level of the red nucleus.

Disconnection of high cerebral centres from inhibiting rubrospinal tract and vestibulospinal tract

Disconnecting high cerebral centres from inhibiting Vestibulospinal tract →

Rubrospinal tract only extends down to the thoracic cord and therefore has effects on upper limbs and not lower limbs → flexion of upper limbs
Vestibulospinal tract has effect on both upper and lower limbs → extension of lower limbs (since upper limbs are dominated by rubrospinal tract only lower limb effects are seen)

Excitatory effect on extensor motor neurons in the spine,
Inhibition of flexor motor neurons. 
 
Vestibulospinal tract has effect on both upper and lower limbs → extension of upper and lower limbs