THE CEREBRUM 167 



painful sensibility and the entire series of pleasurable and pain- 

 ful qualities; for the thalamic centers when isolated from their 

 cortical connections are found to be concerned mainly with 

 affective experience, and destructive lesions which involve the 

 cortex alone do not disturb the painful and affective qualities of 

 sensation (see p. 253). 



The relations of the thalamic nuclei and of some of the tracts 

 connected with them are shown as seen from above in Fig. 77 

 and in a section parallel with the median plane in Fig. 78. 



THE DIENCEPHALON 

 I. Epithalamus. 



1 . Chorioid plexus of the third ventricle. 



2. Pineal body (epiphysis). 



3. Habenula (receives the stria medullaris from the olfactory centers 



and sends fibers to the cerebral peduncle). 



II. Thalamus. 



1. Dorsal part. 



(1) Medial group of nuclei. 



(a) Medial nucleus (receives fibers from the olfactory area 

 and neothalamus and from the trigeminal lemniscus; 

 sends fibers to the olfactory area, corpus striatum, 

 subthalamus, and probably cerebral cortex). 



(6) Anterior (or dorsal) nucleus (receives fibers from the 

 mammillary body and sends fibers to the corpus stri- 

 atum). 



(2) Lateral group of nuclei (neothalamus). 



(a) Lateral, ventral, and posterior nuclei (receive the 

 medial, spinal, and trigeminal lemnisci ; connect with 

 parietal and frontal cortex by ascending and descend- 

 ing somesthetic projection fibers). 



(6) Pulvinar and lateral geniculate body (receive optic 

 tracts; connect with occipital cortex by ascending 

 and descending optic projection fibers). 



(c) Medial geniculate body (receives the lateral or acoustic 

 lemniscus; connects with temporal cortex by ascend- 

 ing and descending auditory projection fibers). 



[The two geniculate bodies = metathalamus, B. N. A.] 



2. Ventral part, or subthalamus (a motor coordination center re- 



ceiving fibers from the dorsal part of the thalamus, from the 

 corpus striatum and from the pyramidal tract; sends fibers to 

 the pedunculus cerebri; comprises the body of Luys, Forel's 

 field H 2 , and some adjacent gray matter; is continuous behind 

 with the substantia nigra of the cerebral peduncle). 



III. Hypothalamus. 



1. Tuber cinereum (olfacto-visceral correlation center). 



2. Mammillary body (receives fibers from the olfactory centers; sends 



fibers to the cerebral peduncle and nucleus anterior thalami). 



3. Hypophysis. 



