The functional role of glutamatergic (vGluT2) neurons in the pedunculopontine nucleus (PPN) in modulating motor activity remains controversial. Here, we demonstrated that the activity of vGluT2 neurons in the rostral PPN is correlated with locomotion and ipsilateral head-turning. Beyond these motor functions, we found that these rostral PPN-vGluT2 neurons remarkably respond to salient stimuli. Furthermore, we systematically traced the upstream and downstream projections of these neurons and identified two downstream projections from these neurons to the caudal pontine reticular nucleus/anterior gigantocellular reticular nucleus (PnC/GiA) and the zona incerta (ZI). Our findings indicate that the projections to the PnC/GiA inhibit movement, consistent with 'pause-and-play' behavior, whereas those to the ZI promote locomotion, and others respond to a new 'pause-switch-play' pattern. Collectively, these findings elucidate the multifaceted influence of the PPN on motor functions and provide a robust theoretical framework for understanding its physiological and potential therapeutic implications.
Pedunculopontine Tegmental Nucleus/physiology* ; Animals ; Neural Pathways/physiology* ; Vesicular Glutamate Transport Protein 2/metabolism* ; Locomotion/physiology* ; Glutamic Acid/metabolism* ; Neurons/physiology* ; Male ; Mice ; Motor Activity/physiology* ; Zona Incerta/physiology*

Defensive behaviors induced by innate fear or Pavlovian fear conditioning are crucial for animals to avoid threats and ensure survival. The zona incerta (ZI) has been demonstrated to play important roles in fear learning and fear memory, as well as modulating auditory-induced innate defensive behavior. However, whether the neuronal subtypes in the ZI and specific circuits can mediate the innate fear response is largely unknown. Here, we found that somatostatin (SST)-positive neurons in the rostral ZI of mice were activated by a visual innate fear stimulus. Optogenetic inhibition of SST-positive neurons in the rostral ZI resulted in reduced flight responses to an overhead looming stimulus. Optogenetic activation of SST-positive neurons in the rostral ZI induced fear-like defensive behavior including increased immobility and bradycardia. In addition, we demonstrated that manipulation of the GABAergic projections from SST-positive neurons in the rostral ZI to the downstream nucleus reuniens (Re) mediated fear-like defensive behavior. Retrograde trans-synaptic tracing also revealed looming stimulus-activated neurons in the superior colliculus (SC) that projected to the Re-projecting SST-positive neurons in the rostral ZI (SC-ZIr^SST-Re pathway). Together, our study elucidates the function of SST-positive neurons in the rostral ZI and the SC-ZIr^SST-Re tri-synaptic circuit in mediating the innate fear response.
Mice ; Animals ; Zona Incerta/metabolism* ; Neurons/metabolism* ; Fear/physiology* ; Somatostatin/metabolism*

Zona Incerta ; Prefrontal Cortex ; Fear ; Neural Pathways

OBJECTIVE: To explore the regulatory effects of GABAergic neurons in the zona incerta (ZI) on sevoflurane and propofol anesthesia. METHODS: Forty-eight male C57BL/6J mice divided into 8 groups (n=6) were used in this study. In the study of sevoflurane anesthesia, chemogenetic experiment was performed in 2 groups of mice with injection of either adeno-associated virus carrying hM3Dq (hM3Dq group) or a virus carrying only mCherry (mCherry group). The optogenetic experiment was performed in another two groups of mice injected with an adeno-associated virus carrying ChR2 (ChR2 group) or GFP only (GFP group). The same experiments were also performed in mice for studying propofol anesthesia. Chemogenetics or optogenetics were used to induce the activation of GABAergic neurons in the ZI, and their regulatory effects on anesthesia induction and arousal with sevoflurane and propofol were observed; EEG monitoring was used to observe the changes in sevoflurane anesthesia maintenance after activation of the GABAergic neurons. RESULTS: In sevoflurane anesthesia, the induction time of anesthesia was significantly shorter in hM3Dq group than in mCherry group (P < 0.05), and also shorter in ChR2 group than in GFP group (P < 0.01), but no significant difference was found in the awakening time between the two groups in either chemogenetic or optogenetic tests. Similar results were observed in chemogenetic and optogenetic experiments with propofol (P < 0.05 or 0.01). Photogenetic activation of the GABAergic neurons in the ZI did not cause significant changes in EEG spectrum during sevoflurane anesthesia maintenance. CONCLUSION Activation of the GABAergic neurons in the ZI promotes anesthesia induction of sevoflurane and propofol but does not affect anesthesia maintenance or awakening.
Male ; Animals ; Mice ; Mice, Inbred C57BL ; Propofol/pharmacology* ; Sevoflurane/pharmacology* ; Zona Incerta ; Anesthesia, General ; GABAergic Neurons

Parkinson's disease (PD) is the second most common and fastest-growing neurodegenerative disorder. In recent years, it has been recognized that neurotransmitters other than dopamine and neuronal systems outside the basal ganglia are also related to PD pathogenesis. However, little is known about whether and how the caudal zona incerta (ZIc) regulates parkinsonian motor symptoms. Here, we showed that specific glutamatergic but not GABAergic ZIc
Animals ; Mice ; Neurons ; Parkinson Disease ; Parkinsonian Disorders ; Substantia Nigra ; Zona Incerta

The zona incerta (ZI) is involved in various functions and may serve as an integrative node of the circuits for global behavioral modulation. However, the long-range connectivity of different sectors in the mouse ZI has not been comprehensively mapped. Here, we obtained whole-brain images of the input and output connections via fluorescence micro-optical sectioning tomography and viral tracing. The principal regions in the input-output circuits of ZI GABAergic neurons were topologically organized. The 3D distribution of cortical inputs showed rostro-caudal correspondence with different ZI sectors, while the projection fibers from ZI sectors were longitudinally organized in the superior colliculus. Clustering results show that the medial and lateral ZI are two different major functional compartments, and they can be further divided into more subdomains based on projection and input connectivity. This study provides a comprehensive anatomical foundation for understanding how the ZI is involved in integrating different information, conveying motivational states, and modulating global behaviors.
Animals ; Mice ; Zona Incerta ; GABAergic Neurons ; Connectome

Deep brain stimulation (DBS) surgery is an important treatment for patients with Parkinson's disease in the middle and late stages. The accuracy of the implantation of electrode at the location of the nuclei directly determines the therapeutic effect of the operation. At present, there is no single imaging method that can obtain images with electrodes, nuclei and their positional relationship. In addition, the subthalamic nucleus is small in size and the boundary is not obvious, so it cannot be directly segmented. In this paper, a complete end-to-end DBS effect evaluation pipeline was constructed using magnetic resonance (MR) data of T1, T2 and SWI weighted by DBS surgery. Firstly, the images of preoperative and postoperative patients are registered and normalized to the same coordinate space. Secondly, the patient map is obtained by non-rigid registration of brain map and preoperative data, as well as the preoperative nuclear cluster prediction position. Then, a three-dimensional (3D) image of the positional relationship between the electrode and the nucleus is obtained by using the electrode path in the postoperative image and the result of the nuclear segmentation. The 3D image is helpful for the evaluation of the postoperative effect of DBS and provides effective information for postoperative program control. After analysis, the algorithm can achieve a good registration between the patient's DBS surgical image and the brain map. The error between the algorithm and the expert evaluation of the physical coordinates of the center of the thalamus is (1.590 ± 1.063) mm. The problem of postoperative evaluation of the placement of DBS surgical electrodes is solved.
Brain Mapping ; methods ; Deep Brain Stimulation ; Electrodes, Implanted ; Humans ; Imaging, Three-Dimensional ; Magnetic Resonance Imaging ; Multimodal Imaging ; Parkinson Disease ; surgery ; Subthalamic Nucleus

OBJECTIVE: Globus pallidus interna (GPi) is acknowledged as an essential treatment for advanced Parkinson’s disease (PD). Nonetheless, the neurotransmitter study about its results is undiscovered. The goal of this research was to examine influences of entopeduncular nucleus (EPN) stimulation, identical to human GPi, in no-lesioned (NL) rat and 6-hydroxydopamine (6-HD)-lesioned rat on glutamate change in the striatum.METHODS: Extracellular glutamate level changes in striatum of NL category, NL with deep brain stimulation (DBS) category, 6-HD category, and 6-HD with DBS category were examined using microdialysis and high-pressure liquid chromatography. Tyrosine hydroxylase (TH) immunoreactivities in substantia nigra and striatum of the four categories were also analyzed.RESULTS: Extracellular glutamate levels in the striatum of NL with DBS category and 6-HD with DBS category were significantly increased by EPN stimulation compared to those in the NL category and 6-HD category. EPN stimulation had no significant effect on the expression of TH in NL or 6-HD category.CONCLUSION: Clinical results of GPi DBS are not only limited to direct inhibitory outflow to thalamus. They also include extensive alteration within basal ganglia.
Animals ; Basal Ganglia ; Chromatography, Liquid ; Deep Brain Stimulation ; Entopeduncular Nucleus ; Globus Pallidus ; Glutamates ; Glutamic Acid ; Humans ; Microdialysis ; Neurotransmitter Agents ; Oxidopamine ; Parkinson Disease ; Rats ; Substantia Nigra ; Thalamus ; Tyrosine 3-Monooxygenase

Deep brain stimulation (DBS) of the zona incerta has shown promising results in the reduction of medically refractory movement disorders. However, evidence supporting its efficacy in movement disorders secondary to hemorrhagic stroke or hemichoreoathetosis is limited. We describe a 48-year-old man who developed progressive hemichoreoathetosis with an arrhythmic, proximal tremor in his right arm following a thalamic hemorrhagic stroke. Pharmacological treatment was carried out with no change in the Abnormal Involuntary Movement Scale (AIMS) score after 4 weeks (14). After six sessions of botulinum toxin treatment, a subtle improvement in the AIMS score (13) was registered, but no clinical improvement was noted. The arrhythmic proximal movements were significantly improved after DBS of the zona incerta with a major decrease in the patient’s AIMS score (8). The response to DBS occurring after the failure of pharmacological and botulinum toxin treatments suggests that zona incerta DBS may be an alternative for postthalamic hemorrhage movement disorders.
Abnormal Involuntary Movement Scale ; Arm ; Botulinum Toxins ; Chorea ; Deep Brain Stimulation ; Hemorrhage ; Herpes Zoster ; Humans ; Middle Aged ; Movement Disorders ; Stroke ; Tremor ; Zona Incerta

OBJECTIVE: Directional leads are used for deep brain stimulation (DBS). Two of the four contacts of the leads are divided into three parts, enabling controlled stimulation in a circumferential direction. The direction of adverse effects evoked by DBS in the subthalamic nucleus (STN) and stimulation strategies using directional leads were evaluated. METHODS: Directional leads were implanted into the bilateral STN of six parkinsonian patients (1 man, 5 women; mean age 66.2 years). The contact centers were located within the upper border of the STN, and the locations were identified electrically using microrecordings. Adverse effects were evaluated with electrical stimulation (30 μs, 130 Hz, limit 11 mA) using the directional part of each lead after surgery, and the final stimulation direction was investigated. Unified Parkinson's disease rating scale (UPDRS) scores were evaluated before and after DBS. RESULTS: Fifty-six motor and four sensory symptoms were evoked by stimulation; no adverse effect was evoked in 14 contacts. Motor and sensory symptoms were evoked by stimulation in the anterolateral direction and medial to posterolateral direction, respectively. Stimulation in the posteromedial direction produced adverse effects less frequently. The most frequently used contacts were located above the STN (63%), followed by the upper part of the STN (32%). The mean UPDRS part III and dyskinesia scores decreased after DBS from 30.2 ± 11.7 to 7.2 ± 2.9 and 3.3 ± 2.4 to 0.5 ± 0.8, respectively. CONCLUSION: The incidence of adverse effects was low for the posteromedial stimulation of the STN. Placing the directional part of the lead above the STN may facilitate the control of dyskinesia.
Deep Brain Stimulation ; Dyskinesias ; Electric Stimulation ; Female ; Humans ; Incidence ; Parkinson Disease ; Pilot Projects ; Subthalamic Nucleus