Neural correlates of licking behavior modulated by target position in the striatal matrix compartment.
The striatum is a major cortical input site of the basal ganglia and plays a critical role in the control of orofacial movements such as licking. However, how striatal activity relates to the spatial features of licking behavior remains unclear. In this study, we examined whether neural activity in the striatal matrix and striosomal compartments is associated with the spatial position of a licking target during an operant task. Head-fixed male mice performed a licking task in which the target positions were varied across three spatial dimensions. Using fiber photometry in Calb1-IRES-Cre (n = 7) and Pdyn-IRES-Cre (n = 6) mice, we recorded calcium signals from matrix and striosomal neurons. Associations between neural activity, target position, and behavioral variables were quantified using linear mixed-effects modeling with cross-validation. Matrix activity prior to the first detected lick was associated with reaction time and the dorsal-ventral target position. During licking, matrix activity was associated with the anterior-posterior and medial-lateral positions, independent of reaction time and lick count, whereas striosomal activity was associated with the dorsal-ventral position. These associations were correlational and differed in strength. The association between matrix activity and the anterior-posterior and medial-lateral positions was the most robust. The present findings are limited to male mice and to the hemisphere ipsilateral to the spout.
The Basal Ganglia Over 500 Million Years.
The lamprey belongs to the phylogenetically oldest group of vertebrates that diverged from the mammalian evolutionary line 560 million years ago. A comparison between the lamprey and mammalian basal ganglia establishes a detailed similarity regarding its input from cortex/pallium and thalamus, as well as its intrinsic organisation and projections of the output nuclei. This means that the basal ganglia circuits now present in rodents and primates most likely had evolved already at the dawn of vertebrate evolution. This includes the 'direct pathway' with striatal projection neurons (SPNs) expressing dopamine D1 receptors, which act to inhibit the tonically active GABAergic output neurons in globus pallidus interna and substantia nigra pars reticulata that at rest keep the brainstem motor centres under tonic inhibition. The 'indirect pathway' with dopamine D2 receptor-expressing SPNs and intrinsic basal ganglia nuclei is also conserved. The net effect of the direct pathway is to disinhibit brainstem motor centres and release motor programs, while the indirect pathway instead will suppress motor activity. Transmitters, connectivity and membrane properties are virtually identical in lamprey and rodent basal ganglia. We predict that the basal ganglia contains a series of modules each controlling a given pattern of behaviour including locomotion, eye-movements, posture, and chewing that contain both the direct pathway to release a motor program and the indirect pathway to inhibit competing behaviours. The phasic dopamine input serves value-based decisions and motor learning. During vertebrate evolution with a progressively more diverse motor behaviour, the number of modules will have increased progressively. These new modules with a similar design will be used to control newly developed patterns of behaviour - a process referred to as exaptation.
Voltage imaging of neurons distributed across entire brains of larval zebrafish.
Neurons interact in networks distributed throughout the brain. While much effort has focused on whole-brain calcium imaging, advances in genetically encoded voltage indicators raise the question of whether it might be possible to image neuronal voltage across entire brains. Achieving this requires a microscope with high volumetric imaging rates and signal-to-noise ratio. Here we present a remote-scanning light-sheet microscope capable of imaging genetically encoded voltage indicator-expressing neurons distributed throughout much of the brain of larval zebrafish at a volumetric rate of 200.8 Hz. We measured voltage traces from approximately one-quarter of all brain neurons. We found that neurons firing at different times during a sequence occupied different locations: visually evoked sequences mapped across the optic tectum, whereas stimulus-independent bursts were mapped across the cerebellum and medulla. Imaging voltage of neurons distributed in many brain regions may open new frontiers for understanding fundamental neural system operations.
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Progress in Voltage Imaging
Recent advances in the field of Voltage Imaging, with a special focus on new constructs and novel implementations.
Basal Ganglia Advances
Basal Ganglia Advances is a collection highlighting research on the structure, function, and disorders of the basal ganglia. It features studies spanning neuroscience, clinical insights, and computational models, serving as a hub for advances in movement, cognition, and behavior.
Navigation & Localization
Work related to place tuning, spatial navigation, orientation and direction. Mainly includes articles on connectivity in the hippocampus, retrosplenial cortex, and related areas.
Most Popular Recent Articles
Voltage imaging of neurons distributed across entire brains of larval zebrafish.
Neurons interact in networks distributed throughout the brain. While much effort has focused on whole-brain calcium imaging, advances in genetically encoded voltage indicators raise the question of whether it might be possible to image neuronal voltage across entire brains. Achieving this requires a microscope with high volumetric imaging rates and signal-to-noise ratio. Here we present a remote-scanning light-sheet microscope capable of imaging genetically encoded voltage indicator-expressing neurons distributed throughout much of the brain of larval zebrafish at a volumetric rate of 200.8 Hz. We measured voltage traces from approximately one-quarter of all brain neurons. We found that neurons firing at different times during a sequence occupied different locations: visually evoked sequences mapped across the optic tectum, whereas stimulus-independent bursts were mapped across the cerebellum and medulla. Imaging voltage of neurons distributed in many brain regions may open new frontiers for understanding fundamental neural system operations.
Highly attenuated dendritic propagation of isolated synaptic potentials in vivo.
The integration of synaptic inputs is a fundamental function of neurons. In the traditional model, excitatory inputs are summed at the soma to generate action potentials. However, how synaptic inputs are integrated by dendrites in vivo remains poorly explored. We used intravital two-photon dendritic imaging with a genetically encoded voltage indicator (accelerated sensor of action potentials 5) together with somatic whole-cell patch clamp recordings to investigate how synaptic depolarizations are transferred to the soma in pyramidal neurons of the mouse somatosensory cortex. We studied the integration of synaptic inputs under spontaneous and sensory-evoked conditions, as well as following electrical and optogenetic stimulation. In all cases, while multiple inputs evoked measurable depolarizations in the cell body, isolated synaptic potentials were strongly attenuated. Our results suggest that isolated synaptic inputs have a minimal contribution to somatic depolarization, whereas coincident inputs within short temporal windows are more effective, indicating a regime of dendritic integration that favors coincident or clustered neuronal activity in cortical networks.
A novel technique for initially unresectable locally advanced pancreatic body cancer: pre-resection portal vein reconstruction.
Distal pancreatectomy with celiac axis resection (DP-CAR) is performed for locally advanced pancreatic body cancers involving the common hepatic artery (CHA) and/or celiac axis (CA). This procedure becomes especially intractable in cases of portal vein (PV) invasion due to poor mobility around both the CA and PV. However, no previous reports have described the surgical strategies for such difficult situations. To overcome the difficulty of CA and PV invasion, we devised a novel procedure called "pre-resection portal vein reconstruction." In this procedure, PV reconstruction using an inferior mesenteric vein patch graft is implemented after division of the CHA and pancreatic neck. The greatest advantage of this procedure is improved mobility around the pancreatic body after PV reconstruction, thereby enabling a subsequent sequential approach around the superior mesenteric artery, abdominal aorta, and CA root. "Pre-resection portal vein reconstruction" is an option for locally advanced pancreatic body cancers with both CA and PV invasion.