Medial dorsal nucleus
|Brain: Medial dorsal nucleus|
MNG = Midline nuclear group
AN = Anterior nuclear group
MD = Medial dorsal nucleus
VNG = Ventral nuclear group
VA = Ventral anterior nucleus
VL = Ventral lateral nucleus
VPL = Ventral posterolateral nucleus
VPM = Ventral posteromedial nucleus
LNG = Lateral nuclear group
PUL = Pulvinar
MTh = Metathalamus
LG = Lateral geniculate nucleus
MG = Medial geniculate nucleus
|Latin||nucleus mediodorsalis thalami|
It relays inputs from the amygdala and olfactory cortex and projects to the prefrontal cortex and the limbic system and in turn relays them to the Pre-Frontal Association Cortex. As a result, it plays a crucial role in attention, planning, organization, abstract thinking, multi-tasking, and active memory.
By stereology the number of brain cells in the region has been estimated to around 6.43 million neurons in the adult human brain and 36.3 million glial cells, and with the newborn having quite different numbers: around 11.2 million neurons and 10.6 million glial cells.
Damage to the medial dorsal nucleus has been associated with Korsakoff's syndrome.
Role in pain processing
While both the ventral and medial dorsal nuclei process pain, the medial dorsal nucleus bypasses primary cortices, sending their axons directly to secondary and association cortices. The cells also send axons directly to many parts of the brain, including nuclei of the limbic system such as the lateral nucleus of the amygdala, the anterior cingulate, and the hippocampus. This part of the sensory system, known as the non-classical or extralemniscal system is less accurate, and less detailed in regards to sensory signal analysis. This processing is known colloquially as "fast and dirty" rather than the "slow and accurate" system of classical or lemniscal system. This pathway activates parts of the brain that evoke emotional responses.
- Li XB, Inoue T, Nakagawa S, Koyama T (May 2004). "Effect of mediodorsal thalamic nucleus lesion on contextual fear conditioning in rats". Brain Res. 1008 (2): 261–72. doi:10.1016/j.brainres.2004.02.038. PMID 15145764.
- Jacob Jelsing, Anders Hay-Schmidt, Tim Dyrby, Ralf Hemmingsen, Harry B. M. Uylings, Bente Pakkenberg (2006). "The prefrontal cortex in the Göttingen minipig brain defined by neural projection criteria and cytoarchitecture". Brain Research Bulletin 70 (4–6): 322–336. doi:10.1016/j.brainresbull.2006.06.009. PMID 17027768.
- Maja Abitz, Rune Damgaard Nielsen, Edward G. Jones, Henning Laursen, Niels Graem and Bente Pakkenberg (2007). "Excess of Neurons in the Human Newborn Mediodorsal Thalamus Compared with That of the Adult". Cerebral Cortex 17 (11): 2573–2578. doi:10.1093/cercor/bhl163. PMID 17218480.