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Parahippocampal gyrus Interpeduncular nuclei
Figure 20-3. Major subcortical structures of the limbic system. The fornix projects from the hippocampal forma-
tion to the septal nuclei (precommissural fornix) and to the mamillary body (postcommissural fornix). The major
pathway from the amygdaloid nucleus is the stria terminalis, which terminates in the septal nuclei and in the
hypothalamus. The stria medullaris of the thalamus connects the septal nuclei to the habenular nucleus.
(Reprinted with permission from Carpenter MB, Sutin J: Human Neuroanatomy. Baltimore, Williams & Wilkins,
1983, p 618.)
1. Orbitofrontal cortex (see Figure 1-2)
—mediates the conscious perception of sm ell.
-has reciprocal connections with the mediodorsal nucleus of the thala-
-is interconnected via the medial forebrain bundle with the septal area
and hypothalamic nucle i.
2. Mediodorsal nucleus of the thalamus
-has reciprocal connections with the orbitofrontal and prefrontal cor-
tices and the hypothalamus. -receives input from the amygdaloid
nucleus, -plays a role in affective behavior and memory.
3. Anterior nucleus of the thalamus
-receives input from the mamillary nucleus via the mamillothalamic
tract and fornix.
308 / Neuroanatomy
-projects to the cingulate gyrus.
—is a major link in the limbic circuit of Papez.
4. Septal area (see Figures 1-4 and 23-IB)
-is a telencephalic structure.
-consists of a cortical septal area, which includes the paraterminal
gyrus and the subcallosal area.
-consists of a subcortical septal area (the septal nuclei), which lies
between the septum pellucidum and the anterior commissu re.
—has reciprocal connections with the hippocampal formation via the
—has reciprocal connections with the hypothalamus via the medial fore-
-projects via the stria medullaris (thalami) to the habenular nucleus.
5. Limbic lobe (see Figure 23-LB)
-includes the subcallosal area, the paraterminal gyrus, the cingu-