Diencephalon: a key structure in the “central nervous system.” Includes everything with the name “thalamus.” (S.Goldberg, 3) The paired “caudal” parts of the “forebrain” from which the “thalamus,”  “hypothalamus,”  “epithalamus,” and “subthalamus” are derived. (MeSH)

Can be seen in a neuroanatomical inconsistency: some anatomists place it in the “brainstem” and others place it in the “forebrain.” (Kolb, 48) (While) the hypothalamus is the master controller of most of our more "visceral" functions, the thalamus is said to be that of a relay station for sensory information traveling up to the cerebral hemispheres. (Bainbridge, 204-205)


Diencephalic Nuclei: those lining the "third ventricle." Involved in "memory." (Blumenfeld, 829)

Epithalamus: the “dorsal”  “posterior” subdivision of the diencephalon. (MeSH) A dorsal segment of the diencephalon containing the "pineal body." (American Heritage Medical Dictionary)

Hypothalamic Sulcus: the boundary between the thalamus and the hypothalamus. A groove located along the lateral walls of the “third ventricle.” (Patestas, 77)

Hypothalamus: the master control center in our brain regulating many automatic functions vital to life. (Fields, 254) Integrates the functions of the “endocrine” and the “autonomic nervous system.” (Patestas, 345) While the thalamus monitors the organism’s world outside, the hypothalamus monitors the organism’s internal states and helps maintain them within parameters. (Goldberg2, 30) Acts like a thermostat by sensing changes in body "temperature" and then sending signals to different parts of the body to adjust the temperature. (Chudler, 19) Regulates “instinctive” behaviors (and) is "plastic." (Doidge, 97) “Hormones” from the hypothalamus and pituitary gland, and the "adrenal glands," control responses to “trauma.” (Lewis, 149) Has primary control over our drives for eating, sleeping, aggression, and sex. Interacts with the “olfactory system.” (Herz, 10) Involved in regulating "metabolic" functions, hormone production, and various basic drives such as aggression, fear, and sexuality. (Ramachandran, 10) The hypothalamus is the master controller of most of our more “visceral” functions. If we are cold, it tries to warm us; if we are hungry, it tries to makes us eat; if it is time to fight, then it drives our aggression. A great deal of information flows into the hypothalamus from just about every part of the brain and body. Once it has decided what to do, it can send out signals to other parts of the nervous system to control aspects of behavior, and it can help us by releasing hormones. (Bainbridge, 206) Contains neurons that send their “axons” into the “pituitary glad.” The hypothalamus controls the pituitary. This link between our neural and hormone system also ties “emotions” and sexual activity to our higher cognitive systems. (Fields, 254) Editor’s note - some authors include the hypothalamus as a part of the “limbic system.”

Arcurate Nucleus: a group of cell bodies that project to the ‘hypophysis.’ (Patestas, 47) Helps control the functions of the anterior “pituitary gland,” which synthesizes and releases various “endocrine”  “hormones” into the bloodstream. (Patestas, 363)

Mammillary Bodies: part of the “Papez circuit.” The “hippocampal formation” sends fibers to the mammillary bodies, and other nuclei of the hypothalamus. The mammillary bodies send the majority of their output fibers to the “anterior nuclear group” of the thalamus, which in turn, projects back to the “cingulate cortex.” (Patestas, 353)

Subthalamus: nuclear region just lateral to the hypothalamus; lesions may result in “hemiballismus.” (S.Goldberg, 95) The subthalamic nuclei and fiber tract form the subthalamus (Patestas, 77)

Subthalamic Nucleus: located in the ventral “thalamus.” (Patestas, 77) Lens-shaped structure. The subthalamic nucleus and pathways traversing this region are concerned with the integration of "somatic" “motor” function. (MeSH)

Thalamus: oval-shaped mass of “gray matter,” embedded deep within the “white matter” of each “cerebral hemisphere.” (Patestas, 385) Located right in the center of the brain. Often described as a ‘relay station’ because all sensory information except “smell” passes through it before reaching the outer cortical ‘mantle.’ (Ramachandran, 10) Information arising from the “basal ganglia,”  “cerebellum,”  “limbic system,” and “sensory” systems is relayed to the thalamus. It serves as the main entrance via which information reaches the “cerebral cortex.” (Patestas, 385) Receives and modifies sensory impulses which it projects throughout the brain. (Fisch, 2) Receives its major inputs from the sense organs and relays them for more sophisticated processing. (RamachandranTTB, 18) Nearly all pathways that project to the "cerebral cortex" do so via "synaptic" relays in the thalamus. (Blumenfeld, 282) Every sensory system must send a signal to the thalamus and ask permission to connect to the rest of the brain, however not the nerves carrying information about smell. (Medina, 213) A massive switch box for sensory information streaming into the brain en route to the “cerebral cortex.” (Fields, 254) Neuroscientists often speak of the thalamus, but in reality there are two of them. Together the ‘thalami’ make up the bulk of the ‘interbrain’ and form an important component of the sensory system. Plays a role in movement, alertness, and other non-sensory functions. (Bainbridge, 203-204) Input from the eyes enters the thalamus and then takes the “pathway” to the “visual cortex” and/or the pathway to the “amygdala.” The pathway to the amygdala is “low road” and thus faster. (Goleman, 15) By setting up recursive “loops” between itself and nearly all parts of the ‘higher’ brain, the thalamus plays a major role in regulating arousal, awareness, and mental activity. (Blakeslee, 191) Plural - ‘thalami.’ Adjective - ‘thalamic.’

Anterior Nuclear Group: consists of a composite of three subnuclei: the ‘anteroventral,’  ‘anteromedial,’ and ‘anterodorsal subnuclei. Functions in the expression of "emotions." Believed to be associated with “learning” and “memory” processes. Also associated with “attention.” (Patestas, 389) Also referred to as ‘anterior nuclei of the thalamus.’

Internal Medullary Lamina: a Y-shaped layer of white matter (that) partitions the thalamus into three main groups of nuclei, the anterior, medial, and lateral groups. (Patestas, 388)

Lateral Nuclear Group: consists of numerous subnuclei that collectively form the largest nuclear group of the thalamus. (Patestas, 391)

Dorsal Tier: connected with the association areas of the cerebral cortex, and function in the integration of sensory input. (Patestas, 392)

Pulvinar Nucleus: the expanded posterior end of the thalamus. (OxfordMed) The most prominent nucleus of the thalamus. Functions in the integration of visual, auditory, and "somatosensory" information. Has reciprocal projections with the association areas of the parietal, temporal, and occipital lobes. Also receives sensory information from the components of the “visual system,” the 'medial geniculate nucleus,’ and the “cerebellum.” (Patestas, 392) Also referred to as 'pulvinar."

Ventral Tier: the nuclei residing in the anterior aspect of the ventral tier serve as relay stations of the “somatic” motor system and the brainstem “reticular formation.” The nuclei residing in the posterior aspect serve as relay stations for all of the sensory systems. (Patestas, 392)

Lateral Geniculate Nucleus (LGN): one of many nuclei in the thalamus. Six-layered. Its neurons project into the “primary visual cortex.” The "axons” of most neurons making up the “optic nerve” descend into the LGN. (Koch, 339) The optic nerves connect with the LGN. Has two “magnocellular” layers that receive input mainly from ”rods” and four “parvocellular” layers that receive input mainly from “cones.” (Kolb, 279) An area located in the middle of the brain. You can sort of think of it as an ‘air traffic control tower’ and it’s going to process and push information to the very back of the brain. (Visual) signals get routed to the back of the brain - an area called the “occipital lobe,” and particularly to “V1.” (Medina, BSP37)

Medial Nuclear Group: includes the ‘dorsomedial nucleus’ and the ‘midline nuclei.’ (Patestas, 391)

Dorsomedial Nucleus: functions in the processing of information related to emotion (and memory). (Patestas, 391) Also referred to as ‘thalamic medio-dorsal nucleus.’

Magnocellular Division: associated with limbic system components such as the amygdala, and the “orbitofrontal cortex.” (Patestas, 391)

Parvocellular Division: has reciprocal connections with the prefrontal "association cortex," which functions in the integration of sensory information associated with higher order cognitive function. (Patestas, 391)

Midline Nuclei: function in the modulation of cortical excitability. (Patestas, 391)