The anatomy of the caudal zona incerta in rodents and primates

Abstract

SummaryThe caudal zona incerta is the target of a recent modification of established procedures for deep brain stimulation (DBS) for Parkinson's disease and tremor. The caudal zona incerta contains a number of neuronal populations that are distinct in terms of their cytoarchitecture, connections, and pattern of immunomarkers and is located at a position where a number of major tracts converge before turning toward their final destination in the forebrain. However, it is not clear which of the anatomical features of the region are related to its value as a target for DBS. This paper has tried to identify features that distinguish the caudal zona incerta of rodents (mouse and rat) and primates (marmoset, rhesus monkey, and human) from the remainder of the zona incerta. We studied cytoarchitecture, anatomical relationships, the pattern of immunomarkers, and gene expression in both of these areas. We found that the caudal zona incerta has a number of histological and gene expression characteristics that distinguish it from the other subdivisions of the zona incerta. Of particular note are the sparse population of GABA neurons and the small but distinctive population of calbindin neurons. We hope that a clearer appreciation of the anatomy of the region will in the end assist the interpretation of cases in which DBS is used in human patients.

Lateral Hypothalamus GABAergic Neurons Modulate Consummatory Behaviors Regardless of the Caloric Content or Biological Relevance of the Consumed Stimuli

“…Controlling the spread of virus transduction is difficult, and in fact in our LH study we Lateral hypothalamus GABA and reward consumption M Navarro et al observed strong virus transduction in GABAergic neurons in both the LH and ZI. Similar to the LH, much of the ZI is comprised of a dense population of GABAergic neurons (Watson et al, 2014). Although little is known about the functional role of the ZI, the subthalamus region, which includes the ZI, has been implicated in modulating consumption of natural and drug rewards (Lardeux et al, 2009).…”

Interleaving Stimulation in Parkinson’s Disease, Tremor, and Dystonia

“…The area posterior to the STN that includes the cZI is referred to as the posterior subthalamic area. Differences between the rostral and caudal portions are evident in projections as well as cell type [17, 18]. The region surrounding the ZI (including the caudal and rostral portions) includes 3 main structures involved in motor control: the cerebellothalamic tract, prelemniscal radiation, and the pallidothalamic tract [17-19].…”

Zona incerta as a therapeutic target in Parkinson’s disease

“…The most knowledge about the ZI anatomy and physiology comes from studies in rodents, however, their results only partly can be compared with those obtained in some other species and humans [65,66]. The ZI in rats extends from rostral regions of the thalamus to the rostral pole of the red nucleus [66,67] and in humans from the rostral regions of the thalamus to the level of the rostral pole of the medial geniculate nucleus [66]. The ZI has been divided in rats into 4 main sectors: rostral, dorsal, ventral and caudal [66,67], although borders between them are not clear [68].…”