Development of the GABAergic and glutamatergic neurons of the lateral hypothalamus

The expression of transcription factors in the human fetal subthalamic nucleus suggests its origin from the first hypothalamic prosomere

In this study, we analyzed the spatio-temporal pattern of expression of specific transcription factors (PITX2, FOXA1, BARHL1, FOXP1, FOXP2) in the human fetal subthalamic nucleus and its neighboring structures from 11 postconceptional weeks (PCW) to 3 postnatal months. We found that all analyzed transcription factors are expressed already during the early fetal period (at 11 PCW). Both FOXP1- and FOXP2-immunoreactive cells were found in the subthalamic nucleus as well as in the striatum, thalamus, reticular nucleus, but not in the zona incerta. FOXP2-ir cells were also found in the lateral hypothalamic-supramamillary area (LHA-SMA) and internal pallidal segment.On the other hand, PITX2, FOXA1 and BARHL1 were expressed exclusively in the subthalamic nucleus and LHA-SMA, from 11 PCW until the birth, the only exception being gradual loss of BARHL1 expression in the LHA-SMA during the late fetal period.Our findings present the first evidence in the human fetal brain that neurons of the subthalamic nucleus do not originate in the diencephalon, as was proposed by classical histological studies, but instead share a common hypothalamic (hp1 prosomere) origin with neurons of the LHA-SMA group, as proposed by the prosomeric model of brain development.

Hyperexcitation of the glutamatergic neurons in lateral hypothalamus induced by chronic pain contributes to depression-like behavior and learning and memory impairment in male mice

Chronic pain can induce mood disorders and cognitive dysfunctions, such as anxiety, depression, and learning and memory impairment in humans. However, the specific neural network involved in anxiety- and depression-like behaviors and learning and memory impairment caused by chronic pain remains poorly understood. In this study, behavioral test results showed that chronic pain induced anxiety- and depression-like behaviors, and learning and memory impairment in male mice. c-Fos immunofluorescence and fiber photometry recording showed that glutamatergic neurons in the LH of mice with chronic pain were selectively activated. Next, the glutamatergic neurons of LH in normal mice were activated using optogenetic and chemogenetic methods, which recapitulates some of the depressive-like behaviors, as well as memory impairment, but not anxiety-like behavior. Finally, inhibition of glutamatergic neurons in the LH of mice with chronic pain, effectively relieved anxiety- and depression-like behaviors and learning and memory impairment. Taken together, our findings suggest that hyperexcitation of glutamatergic neurons in the LH is involved in depression-like behavior and learning and memory impairment induced by chronic pain.