The nervous pathway SHANDONG UNIVERSITY Liu Zhiyu

一、 Sensory Pathways

proprioceptive and fine touch pathway of trunk and limbs

1. proprioceptive and fine touch pathway of trunk and limbs Primary Neuron Cell bodies are located in the ganglion of spinal n. transmit sensory input from joint, muscle, tendon to the posterior funiculus of the spinal cord form the Fasciculus cuneatus and Fasciculus gracilis

1. proprioceptive and fine touch pathway of trunk and limbs Secondary Neuron Cell bodies are located in Nucleus gracilis and Nucleus cuneatus Send out fibers Cross to the opposite by decussation of medial lemniscus Ascends as medial lemniscus Third Neuron cell bodis are located in the thalamus send out fibers to form central thalamic radiation project to the somatic sensory cortex

III II I VPL nucleus Medial lemniscus Nucleus gracilis central thalamic radiations Medial lemniscus Nucleus gracilis Nucleus cuneatus Decussation of medial lemniscus II Fasciculus cuneatus Spinal ganglion I Fasciculus gracilis

Fasciculus cuneatus (above T4) 1. proprioceptive and fine touch pathway of trunk and limbs Spinal ganglion muscles,tendons,joints and periosteum Central processes Peripheral processes ipsilateral posterior funiculus of spinal cord I Receptor for fine touch in skin Gracile nucleus cuneate nucleus Fasciculus cuneatus (above T4) Fasciculus gracilis (below T5) Decussation of medial lemniscus medial lemniscus II ventral posterolateral nucleus (VPL) supeior 2/3 of postcentral gyrus and posterior part of the paracentral lobule, Precentral gyrus central thalamic radiations Posterior limb of internal capsule III

Pain,temperature and simple touch pathway of trunk and limbs

III II I central thalamic radiations ventral posterolateral nucleus Spinal lemniscus Ⅰ、Ⅳ、Ⅶ of posterior horn spinothalamic tract II spinal ganglia I

Pain,temperature and simple touch pathway of trunk and limbs Primary Neuron Cell bodies are located in the ganglion of spinal n. Relay sensory input from the periphery to the posterior horn of the spinal cord Synapses with the secondary neurons in the posterior horn of spinal cord

Pain,temperature and simple touch pathway of trunk and limbs Secondary Neuron located in the Ⅰ、Ⅳ、Ⅶ of posterior horn of spinal cord Send out fibers cross to the opposite side through the anterior white commissures and form the spinothalamic tract Third Neuron the third neurons located in the thalamus send out fibers to form central thalamic radiation project to the somatic sensory cortex

Pain,temperature and simple touch pathway of trunk and limbs Spinal ganglion Skin exteroceptor Central processes Posterior root Peripheral processes I Ⅰ、Ⅳ、Ⅶ of posterior horn Ascending 1 - 2 segments lateral spinothalamic tract (pain and temperature) II anterior spinothalamic tract (simple touch) ventral posterolateral nucleus (VPL) central thalamic radiations Posterior limb of internal capsule supeior 2/3 of posterior gyrus and posterior part of the paracentral lobule III

Pain, temperature and simple touch pathway of head and face

III II I central thalamic radiations pontine nucleus of trigeminal n ventral posteromedial nucleus (VPM) III central thalamic radiations pontine nucleus of trigeminal n II trigeminal ganglion trigeminal lemniscus I Spinal tract of trigeminal n. spinal nucleus of trigeminal n.

Pain,temperature and simple touch pathway of head and face trigeminal ganglion Skin and mucosa of head and face Trigeminal n. Central processes Peripheral processes Root of trigeminal n. I pontine nucleus of trigeminal n. ventral posteromedial nucleus (VPM) trigeminal lemniscus II spinal nucleus of trigeminal n. III central thalamic radiations Posterior limb of internal capsule inferior 1/3 of posterior gyrus

cortex of paleocerebellum Spinal ganglion receptor cortex of paleocerebellum

（三）visual pathway

（三）visual pathway Optic n. Optic chiasma receptor bipolar cell ganglion cell Optic n. Optic chiasma cone cell rod cell Lateral geniculate body Decussation of fibers from nasal halves of retina Fibers from temporal halves of retina uncrossed Optic Radiation Both banks of calcarine sulcus Optic tract

① Blindness of eye of corresponding side ② bitemporal hemianopia of visual field ③ Blindness in nasal half of visual field of corresponding side ④ Homonymous hemianopia of visual field in both eye

2. pupillary reflexes retina Contraction of pupil Optic n. Sphincter pupillae Ciliary ganglion Optic chiasma Postganglionic fibers Oculumotot n. Optic tract Ciliary ganglion E-W nucleus Brachium of superior colliculus Pretectal region Oculumotot n. accessory nuclei of III Pretectal region

2. pupillary reflexes

The acoustic(auditory) pathway medial geniculate body acoustic radiation inferior colliculus cochlear nuclei Spiral organ cochlear ganglion

The acoustic(auditory) pathway cochlear nuclei cochlear ganglion Trapezoid body Spiral organ Cochlear nerve Lateral lemniscus medial geniculate body inferior colliculus acoustic radiation transverse temporal gyri Brachium of inferior colliculus Posterior limb of internal capsule

III II I VPL nucleus Medial lemniscus Nucleus gracilis central thalamic radiations Medial lemniscus Nucleus gracilis Nucleus cuneatus Decussation of medial lemniscus II Fasciculus cuneatus Spinal ganglion I Fasciculus gracilis

III II I central thalamic radiations ventral posterolateral nucleus Spinal lemniscus Ⅰ、Ⅳ、Ⅶ of posterior horn spinothalamic tract II spinal ganglia I