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Henry H Yin - One of the best experts on this subject based on the ideXlab platform.
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ventral tegmental dopamine neurons control the impulse vector during motivated behavior
Current Biology, 2020Co-Authors: Ryan N Hughes, Konstantin I Bakhurin, Elijah A Petter, Glenn D R Watson, Namsoo Kim, Alexander D Friedman, Henry H YinAbstract:The ventral tegmental area (VTA) is a major source of dopamine, especially to the limbic brain regions. Despite decades of research, the function of VTA dopamine neurons remains controversial. Here, using a novel head-fixed behavioral system with five orthogonal force sensors, we show for the first time that the activity of dopamine neurons precisely represents the impulse vector (force exerted over time) generated by the animal. Distinct populations of VTA dopamine neurons contribute to components of the impulse vector in different Directions. Optogenetic excitation of these neurons shows a linear relationship between signal injected and impulse generated. Optogenetic inhibition paused force generation or produced force in the Backward Direction. At the same time, these neurons also regulate the initiation and execution of anticipatory licking. Our results indicate that VTA dopamine controls the magnitude, Direction, and duration of force used to move toward or away from any motivationally relevant stimuli.
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ventral tegmental dopamine neurons control the impulse vector during motivated behavior
bioRxiv, 2020Co-Authors: Ryan N Hughes, Konstantin I Bakhurin, Elijah A Petter, Glenn D R Watson, Namsoo Kim, Alexander D Friedman, Henry H YinAbstract:Abstract The Ventral Tegmental Area (VTA) is a major source of dopamine, especially to the limbic brain regions. Despite decades of research, the function of VTA dopamine neurons remains controversial. Here, using a novel head-fixed behavioral system with five orthogonal force sensors, we show for the first time that distinct populations of VTA dopamine activity precisely represent the impulse vector (force exerted over time) generated by the animal. Optogenetic excitation of VTA dopamine neurons quantitatively determines impulse in the forward Direction, and optogenetic inhibition produces impulse in the Backward Direction. At the same time, these neurons also regulate the initiation and execution of anticipatory licking. Our results indicate that VTA controls the magnitude, Direction, and duration of force used to move towards or away from any motivationally relevant stimuli. One Sentence Summary VTA dopamine biDirectionally controls impulse vector and anticipatory behavior
Ryan N Hughes - One of the best experts on this subject based on the ideXlab platform.
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ventral tegmental dopamine neurons control the impulse vector during motivated behavior
Current Biology, 2020Co-Authors: Ryan N Hughes, Konstantin I Bakhurin, Elijah A Petter, Glenn D R Watson, Namsoo Kim, Alexander D Friedman, Henry H YinAbstract:The ventral tegmental area (VTA) is a major source of dopamine, especially to the limbic brain regions. Despite decades of research, the function of VTA dopamine neurons remains controversial. Here, using a novel head-fixed behavioral system with five orthogonal force sensors, we show for the first time that the activity of dopamine neurons precisely represents the impulse vector (force exerted over time) generated by the animal. Distinct populations of VTA dopamine neurons contribute to components of the impulse vector in different Directions. Optogenetic excitation of these neurons shows a linear relationship between signal injected and impulse generated. Optogenetic inhibition paused force generation or produced force in the Backward Direction. At the same time, these neurons also regulate the initiation and execution of anticipatory licking. Our results indicate that VTA dopamine controls the magnitude, Direction, and duration of force used to move toward or away from any motivationally relevant stimuli.
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ventral tegmental dopamine neurons control the impulse vector during motivated behavior
bioRxiv, 2020Co-Authors: Ryan N Hughes, Konstantin I Bakhurin, Elijah A Petter, Glenn D R Watson, Namsoo Kim, Alexander D Friedman, Henry H YinAbstract:Abstract The Ventral Tegmental Area (VTA) is a major source of dopamine, especially to the limbic brain regions. Despite decades of research, the function of VTA dopamine neurons remains controversial. Here, using a novel head-fixed behavioral system with five orthogonal force sensors, we show for the first time that distinct populations of VTA dopamine activity precisely represent the impulse vector (force exerted over time) generated by the animal. Optogenetic excitation of VTA dopamine neurons quantitatively determines impulse in the forward Direction, and optogenetic inhibition produces impulse in the Backward Direction. At the same time, these neurons also regulate the initiation and execution of anticipatory licking. Our results indicate that VTA controls the magnitude, Direction, and duration of force used to move towards or away from any motivationally relevant stimuli. One Sentence Summary VTA dopamine biDirectionally controls impulse vector and anticipatory behavior
Peter J Biggs - One of the best experts on this subject based on the ideXlab platform.
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measurement of the leakage radiation from linear accelerators in the Backward Direction for 4 6 10 15 and 18 mv x ray energies
Health Physics, 2007Co-Authors: Adnan Jaradat, Peter J BiggsAbstract:The x-ray leakage from the housing of a therapy x-ray source is regulated to be <0.1% of the useful beam exposure at 1 m from the source. It is to be expected that the machine leakage in the Backward Direction would be less because the gantry and stand contain significant amounts of additional metal to attenuate the x rays. A reduction in head leakage in this Direction will have a direct effect on the thickness of the shielding wall behind the linear accelerator. However, no reports have been published to date on measurements in this area. The x-ray leakage in the Backward Direction has been measured from linacs having energies of 4, 6, 10, 15, and 18 MV using a 100 cm ionization chamber and Al2O3 dosimeters. The leakage was measured at nine different positions over the rear wall using a 3 x 3 matrix with a 1-m separation between adjacent horizontal and vertical points with either the leftmost or rightmost column aligned with the target and isocenter. In general, the leakage is less than the canonical value, but the exact value depends on energy, gantry angle, and measurement position. There is significantly greater attenuation directly behind the gantry stand for all energies. Leakage at 10 MV for some positions exceeded 0.1%. Additionally, neutron leakage measurements were made for 10, 15, and 18 MV x-ray beams using track-etch detectors. The average neutron leakage was less than 0.1% except for 18 MV, where neutron leakage was more than 0.1% of the useful beam at some positions.
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su ff t 315 measurement of the leakage from linear accelerators in the Backward Direction for 4 6 10 15 and 18 mv x rays
Medical Physics, 2005Co-Authors: Adnan Jaradat, Peter J BiggsAbstract:Purpose: NCRP 49 stipulates that the x‐ray leakage from the housing of an x‐ray source > 500 kV should be no more than 0.1% of the useful beam exposure at 1m from the source. This figure is used by manufacturers to design the shielding in linacs and by physicists when designing room shielding. It is expected that the machine leakage in the Backward Direction would be less since the gantry and stand contain significant amounts of metal to attenuate x‐rays. Method and Materials: X‐ray leakage has been measured from linacs having energies of 4, 6, 10, 15 and 18 MV using chambers and TLDs. Measurements were made for 9 positions at the rear wall in the linac room on a 2m × 2m grid covering one side of the linac, starting from a line through he isocenter and target, and for the four cardinal gantry angles: 0°, 90°, 180° and 270°. A 100cc ionization chamber was used because of its high sensitivity; the chamber was calibrated against a Farmer chamber using the method of Biggs and Nogueira1. The TLDs read neutron as well as x‐ray dose. Results: The ion chamber results show that the leakage is greatest when the gantry is horizontal with the head on the same side as the chamber and least when it is on the opposite side. The readings for gantry angles of 0° and 180° lie midway between those extremes. The greatest leakage is for 10 MV (0.041%), followed by 18 MV (0.028%), 6 MV (0.016%), 15 MV (0.011%) and 4 MV (0.006%) [numbers refer to average of 9 points]. Conclusion: These average values are significantly lower than 0.1%, although at some locations, the value does exceed 0.1%, but only for 10 and 18 MV.
Alexander D Friedman - One of the best experts on this subject based on the ideXlab platform.
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ventral tegmental dopamine neurons control the impulse vector during motivated behavior
Current Biology, 2020Co-Authors: Ryan N Hughes, Konstantin I Bakhurin, Elijah A Petter, Glenn D R Watson, Namsoo Kim, Alexander D Friedman, Henry H YinAbstract:The ventral tegmental area (VTA) is a major source of dopamine, especially to the limbic brain regions. Despite decades of research, the function of VTA dopamine neurons remains controversial. Here, using a novel head-fixed behavioral system with five orthogonal force sensors, we show for the first time that the activity of dopamine neurons precisely represents the impulse vector (force exerted over time) generated by the animal. Distinct populations of VTA dopamine neurons contribute to components of the impulse vector in different Directions. Optogenetic excitation of these neurons shows a linear relationship between signal injected and impulse generated. Optogenetic inhibition paused force generation or produced force in the Backward Direction. At the same time, these neurons also regulate the initiation and execution of anticipatory licking. Our results indicate that VTA dopamine controls the magnitude, Direction, and duration of force used to move toward or away from any motivationally relevant stimuli.
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ventral tegmental dopamine neurons control the impulse vector during motivated behavior
bioRxiv, 2020Co-Authors: Ryan N Hughes, Konstantin I Bakhurin, Elijah A Petter, Glenn D R Watson, Namsoo Kim, Alexander D Friedman, Henry H YinAbstract:Abstract The Ventral Tegmental Area (VTA) is a major source of dopamine, especially to the limbic brain regions. Despite decades of research, the function of VTA dopamine neurons remains controversial. Here, using a novel head-fixed behavioral system with five orthogonal force sensors, we show for the first time that distinct populations of VTA dopamine activity precisely represent the impulse vector (force exerted over time) generated by the animal. Optogenetic excitation of VTA dopamine neurons quantitatively determines impulse in the forward Direction, and optogenetic inhibition produces impulse in the Backward Direction. At the same time, these neurons also regulate the initiation and execution of anticipatory licking. Our results indicate that VTA controls the magnitude, Direction, and duration of force used to move towards or away from any motivationally relevant stimuli. One Sentence Summary VTA dopamine biDirectionally controls impulse vector and anticipatory behavior
Namsoo Kim - One of the best experts on this subject based on the ideXlab platform.
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ventral tegmental dopamine neurons control the impulse vector during motivated behavior
Current Biology, 2020Co-Authors: Ryan N Hughes, Konstantin I Bakhurin, Elijah A Petter, Glenn D R Watson, Namsoo Kim, Alexander D Friedman, Henry H YinAbstract:The ventral tegmental area (VTA) is a major source of dopamine, especially to the limbic brain regions. Despite decades of research, the function of VTA dopamine neurons remains controversial. Here, using a novel head-fixed behavioral system with five orthogonal force sensors, we show for the first time that the activity of dopamine neurons precisely represents the impulse vector (force exerted over time) generated by the animal. Distinct populations of VTA dopamine neurons contribute to components of the impulse vector in different Directions. Optogenetic excitation of these neurons shows a linear relationship between signal injected and impulse generated. Optogenetic inhibition paused force generation or produced force in the Backward Direction. At the same time, these neurons also regulate the initiation and execution of anticipatory licking. Our results indicate that VTA dopamine controls the magnitude, Direction, and duration of force used to move toward or away from any motivationally relevant stimuli.
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ventral tegmental dopamine neurons control the impulse vector during motivated behavior
bioRxiv, 2020Co-Authors: Ryan N Hughes, Konstantin I Bakhurin, Elijah A Petter, Glenn D R Watson, Namsoo Kim, Alexander D Friedman, Henry H YinAbstract:Abstract The Ventral Tegmental Area (VTA) is a major source of dopamine, especially to the limbic brain regions. Despite decades of research, the function of VTA dopamine neurons remains controversial. Here, using a novel head-fixed behavioral system with five orthogonal force sensors, we show for the first time that distinct populations of VTA dopamine activity precisely represent the impulse vector (force exerted over time) generated by the animal. Optogenetic excitation of VTA dopamine neurons quantitatively determines impulse in the forward Direction, and optogenetic inhibition produces impulse in the Backward Direction. At the same time, these neurons also regulate the initiation and execution of anticipatory licking. Our results indicate that VTA controls the magnitude, Direction, and duration of force used to move towards or away from any motivationally relevant stimuli. One Sentence Summary VTA dopamine biDirectionally controls impulse vector and anticipatory behavior
