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Progress in Brain Research 2011Neurons in the midbrain superior colliculus (SC) have the ability to integrate information from different senses to profoundly increase their sensitivity to external... (Review)
Review
Neurons in the midbrain superior colliculus (SC) have the ability to integrate information from different senses to profoundly increase their sensitivity to external events. This not only enhances an organism's ability to detect and localize these events, but to program appropriate motor responses to them. The survival value of this process of multisensory integration is self-evident, and its physiological and behavioral manifestations have been studied extensively in adult and developing cats and monkeys. These studies have revealed, that contrary to expectations based on some developmental theories this process is not present in the newborn's brain. The data show that is acquired only gradually during postnatal life as a consequence of at least two factors: the maturation of cooperative interactions between association cortex and the SC, and extensive experience with cross-modal cues. Using these factors, the brain is able to craft the underlying neural circuits and the fundamental principles that govern multisensory integration so that they are adapted to the ecological circumstances in which they will be used.
Topics: Adaptation, Physiological; Animals; Brain Mapping; Mesencephalon; Neural Pathways; Neuronal Plasticity; Psychomotor Performance; Sensation
PubMed: 21741550
DOI: 10.1016/B978-0-444-53752-2.00007-2 -
Neuron Jan 2004Midbrain dopamine neurons are thought to encode the difference between predicted and actual reward on conditioning tasks. Successful models assumed a simple form of...
Midbrain dopamine neurons are thought to encode the difference between predicted and actual reward on conditioning tasks. Successful models assumed a simple form of prediction that depended only on currently available information. In this issue of Neuron, Nakahara and colleagues record from dopamine neurons in alert monkeys and show that the neurons can encode predictions that are not so restricted, taking into account the context of past trends.
Topics: Animals; Dopamine; Haplorhini; Mesencephalon; Models, Neurological; Photic Stimulation; Reward
PubMed: 14741097
DOI: 10.1016/s0896-6273(04)00009-1 -
Cell Reports Aug 2021The mesencephalic locomotor region (MLR) serves as an interface between higher-order motor systems and lower motor neurons. The excitatory module of the MLR is composed...
The mesencephalic locomotor region (MLR) serves as an interface between higher-order motor systems and lower motor neurons. The excitatory module of the MLR is composed of the pedunculopontine nucleus (PPN) and the cuneiform nucleus (CnF), and their activation has been proposed to elicit different modalities of movement. However, how the differences in connectivity and physiological properties explain their contributions to motor activity is not well known. Here we report that CnF glutamatergic neurons are more electrophysiologically homogeneous than PPN neurons and have mostly short-range connectivity, whereas PPN glutamatergic neurons are heterogeneous and maintain long-range connections, most notably with the basal ganglia. Optogenetic activation of CnF neurons produces short-lasting muscle activation, driving involuntary motor activity. In contrast, PPN neuron activation produces long-lasting increases in muscle tone that reduce motor activity and disrupt gait. Our results highlight biophysical and functional attributes among MLR neurons that support their differential contribution to motor behavior.
Topics: Adolescent; Animals; Basal Ganglia; Gait; Humans; Locomotion; Male; Mesencephalon; Midbrain Reticular Formation; Neurons; Pedunculopontine Tegmental Nucleus
PubMed: 34433068
DOI: 10.1016/j.celrep.2021.109594 -
Molecular Neurobiology Feb 2014Parkinson's disease (PD) is a major neurodegenerative chronic disease, most likely caused by a complex interplay of genetic and environmental factors. Information on... (Review)
Review
Parkinson's disease (PD) is a major neurodegenerative chronic disease, most likely caused by a complex interplay of genetic and environmental factors. Information on various aspects of PD pathogenesis is rapidly increasing and needs to be efficiently organized, so that the resulting data is available for exploration and analysis. Here we introduce a computationally tractable, comprehensive molecular interaction map of PD. This map integrates pathways implicated in PD pathogenesis such as synaptic and mitochondrial dysfunction, impaired protein degradation, alpha-synuclein pathobiology and neuroinflammation. We also present bioinformatics tools for the analysis, enrichment and annotation of the map, allowing the research community to open new avenues in PD research. The PD map is accessible at http://minerva.uni.lu/pd_map .
Topics: Animals; Computational Biology; Humans; Mesencephalon; Nerve Net; Parkinson Disease; Proteolysis; Signal Transduction
PubMed: 23832570
DOI: 10.1007/s12035-013-8489-4 -
Current Opinion in Neurobiology Apr 2015Gamma-band (25-140Hz) oscillations are ubiquitous in mammalian forebrain structures involved in sensory processing, attention, learning and memory. The optic tectum (OT)... (Review)
Review
Gamma-band (25-140Hz) oscillations are ubiquitous in mammalian forebrain structures involved in sensory processing, attention, learning and memory. The optic tectum (OT) is the central structure in a midbrain network that participates critically in controlling spatial attention. In this review, we summarize recent advances in characterizing a neural circuit in this midbrain network that generates large amplitude, space-specific, gamma oscillations in the avian OT, both in vivo and in vitro. We describe key physiological and pharmacological mechanisms that produce and regulate the structure of these oscillations. The extensive similarities between midbrain gamma oscillations in birds and those in the neocortex and hippocampus of mammals, offer important insights into the functional significance of a midbrain gamma oscillatory code.
Topics: Animals; Attention; Biological Clocks; Gamma Rhythm; Humans; Mesencephalon; Nerve Net
PubMed: 25485519
DOI: 10.1016/j.conb.2014.11.006 -
Cellular and Molecular Life Sciences :... Sep 2013The midbrain-hindbrain boundary (MHB) is a highly conserved vertebrate signalling centre, acting to pattern and establish neural identities within the brain. While the... (Review)
Review
The midbrain-hindbrain boundary (MHB) is a highly conserved vertebrate signalling centre, acting to pattern and establish neural identities within the brain. While the core signalling pathways regulating MHB formation have been well defined, novel genetic and mechanistic processes that interact with these core components are being uncovered, helping to further elucidate the complicated networks governing MHB specification, patterning and shaping. Although formation of the MHB organiser is traditionally thought of as comprising three stages, namely positioning, induction and maintenance, we propose that a fourth stage, morphogenesis, should be considered as an additional stage in MHB formation. This review will examine evidence for novel factors regulating the first three stages of MHB development and will explore the evidence for regulation of MHB morphogenesis by non-classical MHB-patterning genes.
Topics: Animals; Body Patterning; Gene Expression Regulation, Developmental; Humans; Mesencephalon; Mice; Models, Neurological; Morphogenesis; Rhombencephalon; Signal Transduction; Zebrafish
PubMed: 23307071
DOI: 10.1007/s00018-012-1240-x -
Current Opinion in Neurobiology Aug 2011A midbrain network interacts with the well-known frontoparietal forebrain network to select stimuli for gaze and spatial attention. The midbrain network, containing the... (Review)
Review
A midbrain network interacts with the well-known frontoparietal forebrain network to select stimuli for gaze and spatial attention. The midbrain network, containing the superior colliculus (SC; optic tectum, OT, in non-mammalian vertebrates) and the isthmic nuclei, helps evaluate the relative priorities of competing stimuli and encodes them in a topographic map of space. Behavioral experiments in monkeys demonstrate an essential contribution of the SC to stimulus selection when the relative priorities of competing stimuli are similar. Neurophysiological results from the owl OT demonstrate a neural correlate of this essential contribution of the SC/OT. The multi-layered, spatiotopic organization of the midbrain network lends itself to the analysis and modeling of the mechanisms underlying stimulus selection for gaze and spatial attention.
Topics: Animals; Attention; Choice Behavior; Discrimination, Psychological; Humans; Mesencephalon; Nerve Net; Neural Pathways; Perception; Physical Stimulation
PubMed: 21696945
DOI: 10.1016/j.conb.2011.05.024 -
FEBS Letters Dec 2015
Topics: Animals; Dopaminergic Neurons; Humans; Mesencephalon; Neurogenesis; Parkinson Disease; Synaptic Transmission
PubMed: 26581860
DOI: 10.1016/j.febslet.2015.11.008 -
Current Opinion in Neurobiology Dec 2023Midbrain dopaminergic neurons are a relatively small group of neurons in the mammalian brain controlling a wide range of behaviors. In recent years, increasingly... (Review)
Review
Midbrain dopaminergic neurons are a relatively small group of neurons in the mammalian brain controlling a wide range of behaviors. In recent years, increasingly sophisticated tracing, imaging, transcriptomic, and machine learning approaches have provided substantial insights into the anatomical, molecular, and functional heterogeneity of dopaminergic neurons. Despite this wealth of new knowledge, it remains unclear whether and how the diverse features defining dopaminergic subclasses converge to delineate functional ensembles within the dopaminergic system. Here, we review recent studies investigating various aspects of dopaminergic heterogeneity and discuss how development, behavior, and disease influence subtype characteristics. We then outline what further approaches could be pursued to gain a more inclusive picture of dopaminergic diversity, which could be crucial to understanding the functional architecture of this system.
Topics: Animals; Mesencephalon; Brain; Dopaminergic Neurons; Mammals
PubMed: 37972537
DOI: 10.1016/j.conb.2023.102811 -
Developmental Biology Apr 2007Dopaminergic neurons in the midbrain (mDNs) play a central role in the regulation of voluntary movement as well as other complex behaviors, and their loss is associated... (Review)
Review
Dopaminergic neurons in the midbrain (mDNs) play a central role in the regulation of voluntary movement as well as other complex behaviors, and their loss is associated with Parkinson's disease (PD). The development of functional mDNs from multipotent progenitors is orchestrated by cell-intrinsic factors and cell-extrinsic environmental cues in a series of stages: early midbrain patterning, specification of mitotic precursors, postmitotic mDN development, and functional maturation. Of particular interest is how extracellular information is integrated with cell-intrinsic developmental programs. Cell fate mapping studies suggest that the stem-like progenitors for mDNs reside at the ventral midline floor plate, a region that also serves as a source of inductive signals for mDN specification such as Sonic Hedgehog (SHH). Cell replacement therapies, and in particular the use of embryonic or adult stem cell-derived dopaminergic neurons, offer potential novel treatment venues for PD, but such strategies require a detailed understanding of mDN development.
Topics: Animals; Cell Differentiation; Dopamine; Gene Expression Regulation, Developmental; Humans; Mesencephalon; Mesenchymal Stem Cells; Neurons
PubMed: 17331494
DOI: 10.1016/j.ydbio.2007.01.032