scholarly journals Dorsomedial prefrontal neural ensembles reflect changes in task utility

2020 ◽  
Author(s):  
Blake S. Porter ◽  
Kristin L. Hillman
Keyword(s):  
Single Unit ◽  
Optimal Choice ◽  
Weight Lifting ◽  
Anterior Cingulate ◽  
Dorsomedial Prefrontal Cortex ◽  
Neural Ensembles ◽  
Behavioral States ◽  
Time And Energy ◽  
Task Representations ◽  
Lifting Task

AbstractWhen performing a physically demanding behavior, sometimes the optimal choice is to quit the behavior rather than persist and waste time and energy. The dorsomedial prefrontal cortex (dmPFC), consisting of the anterior cingulate cortex and secondary motor area, likely contributes towards such utility assessments. Here, we examined how rodent dmPFC single unit and ensemble level activity corresponded to changes in motivation and quitting in an effortful weight lifting task. Rats carried out two task paradigms: one that became progressively more physically demanding over time and a second fixed effort version. Rats could quit the task at any time. Dorsomedial PFC neurons were highly responsive to each behavioral stage of the task, consisting of rope pulling, reward retrieval, and reward area leaving. Activity was highest early in sessions, commensurate with the highest relative task utility, then decreased until the point of quitting. Neural ensembles showed stable task representations across the entirety of sessions. However, these representations drifted and became more distinct over the course of the session. These results suggest that dmPFC neurons represent behavioral states that are dynamically modified as behaviors lose their utility, culminating in task quitting.

scholarly journals Dorsomedial prefrontal neural ensembles reflect changes in task utility that culminate in task quitting

2021 ◽  
Author(s):  
Blake Scott Porter ◽  
Kristin L Hillman
Keyword(s):  
Single Unit ◽  
Optimal Choice ◽  
Weight Lifting ◽  
Anterior Cingulate ◽  
Male Rat ◽  
Dorsomedial Prefrontal Cortex ◽  
Neural Ensembles ◽  
Behavioral States ◽  
Lifting Task ◽  
Over Time

When performing a physically demanding behavior, sometimes the optimal choice is to quit the behavior rather than persist in order to minimize energy expenditure for the benefits gained. The dorsomedial prefrontal cortex (dmPFC), consisting of the anterior cingulate cortex and secondary motor area, likely contributes towards such utility assessments. Here, we examined how male rat dmPFC single unit and ensemble level activity corresponded to changes in motivation and quitting in an effortful weight lifting task. Rats carried out two task paradigms: one that became progressively more physically demanding over time and a second fixed effort version. Rats could quit the task at any time. Dorsomedial PFC neurons were highly responsive to each behavioral stage of the task, consisting of rope pulling, reward retrieval, and reward area leaving. Activity was highest early in sessions, commensurate with the highest relative task utility, then decreased until the point of quitting. Neural ensembles consistently represented the sequential behavioral phases of the task. However, these representations were modified over time and became more distinct over the course of the session. These results suggest that dmPFC neurons represent behavioral states that are dynamically modified as behaviors lose their utility, culminating in task quitting.

scholarly journals A novel weight lifting task for investigating effort and persistence in rats

2019 ◽  
Author(s):  
Blake Porter ◽  
Kristin L. Hillman
Keyword(s):  
Food Delivery ◽  
Video Tracking ◽  
Weight Lifting ◽  
Recording Equipment ◽  
Single Plane ◽  
Action Sequence ◽  
Total N ◽  
Lever Pressing ◽  
Lifting Task

AbstractHere we present a novel effort-based task for laboratory rats: the weight lifting task (WLT). Studies of effort expenditure in rodents have typically involved climbing barriers within T-mazes or operant lever pressing paradigms. These task designs have been successful for neuropharmacological and neurophysiological investigations, but both tasks involve simple action patterns prone to automatization. Furthermore, high climbing barriers present risk of injury to animals and/or tethered recording equipment. In the WLT, a rat is placed in a large rectangular arena and tasked with pulling a rope 30 cm to trigger food delivery at a nearby spout; weights can be added to the rope in 45 g increments to increase the intensity of effort. As compared to lever pressing and barrier jumping, 30 cm of rope pulling is a multi-step action sequence requiring sustained effort. The actions are carried out on the single plane of the arena floor, making it safer for the animal and more suitable for tethered equipment and video tracking. A microcontroller and associated sensors enable precise timestamping of specific behaviors to synchronize with electrophysiological recordings. The rope and reward spout are spatially segregated to allow for spatial discrimination of the effort zone and the reward zone. We validated the task across five cohorts of rats (total n=35) and report consistent behavioral metrics. The WLT is well-suited for neuropharmacological and/or in vivo neurophysiological investigations surrounding effortful behaviors, particularly when wanting to probe different aspects of effort expenditure (intensity vs. duration).

Capturing Three-Dimensional In Vivo Lumbar Intervertebral Joint Kinematics Using Dynamic Stereo-X-Ray Imaging

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Ameet K. Aiyangar ◽  
Liying Zheng ◽  
Scott Tashman ◽  
William J. Anderst ◽  
Xudong Zhang
Keyword(s):  
Lumbar Spine ◽  
Three Dimensional ◽  
Lumbar Vertebrae ◽  
Lumbar Vertebra ◽  
Weight Lifting ◽  
Data Set ◽  
X Ray ◽  
Biomechanical Models ◽  
Lifting Task

Availability of accurate three-dimensional (3D) kinematics of lumbar vertebrae is necessary to understand normal and pathological biomechanics of the lumbar spine. Due to the technical challenges of imaging the lumbar spine motion in vivo, it has been difficult to obtain comprehensive, 3D lumbar kinematics during dynamic functional tasks. The present study demonstrates a recently developed technique to acquire true 3D lumbar vertebral kinematics, in vivo, during a functional load-lifting task. The technique uses a high-speed dynamic stereo-radiography (DSX) system coupled with a volumetric model-based bone tracking procedure. Eight asymptomatic male participants performed weight-lifting tasks, while dynamic X-ray images of their lumbar spines were acquired at 30 fps. A custom-designed radiation attenuator reduced the radiation white-out effect and enhanced the image quality. High resolution CT scans of participants' lumbar spines were obtained to create 3D bone models, which were used to track the X-ray images via a volumetric bone tracking procedure. Continuous 3D intervertebral kinematics from the second lumbar vertebra (L2) to the sacrum (S1) were derived. Results revealed motions occurring simultaneously in all the segments. Differences in contributions to overall lumbar motion from individual segments, particularly L2–L3, L3–L4, and L4–L5, were not statistically significant. However, a reduced contribution from the L5–S1 segment was observed. Segmental extension was nominally linear in the middle range (20%–80%) of motion during the lifting task, but exhibited nonlinear behavior at the beginning and end of the motion. L5–S1 extension exhibited the greatest nonlinearity and variability across participants. Substantial AP translations occurred in all segments (5.0 ± 0.3 mm) and exhibited more scatter and deviation from a nominally linear path compared to segmental extension. Maximum out-of-plane rotations (<1.91 deg) and translations (<0.94 mm) were small compared to the dominant motion in the sagittal plane. The demonstrated success in capturing continuous 3D in vivo lumbar intervertebral kinematics during functional tasks affords the possibility to create a baseline data set for evaluating the lumbar spinal function. The technique can be used to address the gaps in knowledge of lumbar kinematics, to improve the accuracy of the kinematic input into biomechanical models, and to support development of new disk replacement designs more closely replicating the natural lumbar biomechanics.

Performance of a weight-lifting task by normal and deafferented monkeys.

1989 ◽  
Vol 103 (2) ◽  
pp. 273-282 ◽  
Author(s):  
Richard M. Wylie ◽  
C. F. Tyner
Keyword(s):  
Weight Lifting ◽  
Lifting Task

scholarly journals Regional activity in the rat anterior cingulate cortex and insula during persistence and quitting in a physical-effort task

2020 ◽  
Author(s):  
Blake S. Porter ◽  
Kunling Li ◽  
Kristin L. Hillman
Keyword(s):  
Anterior Cingulate Cortex ◽  
Internal State ◽  
Field Potential ◽  
Cingulate Cortex ◽  
Brain Regions ◽  
Weight Lifting ◽  
Anterior Cingulate ◽  
Male Rats ◽  
Physical Effort ◽  
Internal States

AbstractAs animals carry out behaviors, particularly costly ones, they must constantly assess whether or not to persist in the behavior or quit. The anterior cingulate cortex (ACC) has been shown to assess the value of behaviors and to be especially sensitive to physical effort costs. Complimentary to these functions, the insula is thought to represent the internal state of the animal including factors such as hunger, thirst, and fatigue. Utilizing a novel weight lifting task for rats, we characterized the local field potential (LFP) activity of the ACC and anterior insula (AI) during effort expenditure. In the task male rats are challenged to work for sucrose reward, which costs progressively more effort over time to obtain. Rats are able to quit the task at any point. We found modest shifts in LFP theta (7-9 Hz) activity as the task got progressively more difficult in terms of absolute effort expenditure. However, when the LFP data were analyzed based on the rat’s relative progress towards quitting the task, or performance state, substantial shifts in LFP power in the theta and gamma (55-100 Hz) frequency bands were observed in ACC and AI. Both ACC and AI theta power decreased as the rats got closer to quitting, while ACC and AI gamma power increased. Furthermore, coherency between ACC and AI in the delta (2-4 Hz) range shifted alongside the rat’s performance state. Overall we show that ACC and AI LFP activity changes correlate to the rats’ relative performance state in an effort-based task.Significance StatementAnimals need to assess whether or not a behavior is worth pursuing based on their internal states (e.g., hunger, fatigue) and the costs and benefits of the behavior. However, internal states often change as behaviors are carried out, such as becoming fatigued, necessitating constant reassessment as to whether to continue the behavior or quit. We characterized brain activity in the anterior cingulate cortex and insula, brain regions involved in cost-benefit decision making and internal state representations, respectively, as rats carried out a challenging physical-effort task. Both brain regions showed significant shifts in activity as the rats approached their quitting point. Our study provides one of the first characterizations of neural activity as an animal decides to quit an effortful task.

scholarly journals Anterior cingulate is a source of valence-specific information about value and uncertainty

2016 ◽  
Author(s):  
Ilya E. Monosov
Keyword(s):  
Expected Value ◽  
Anterior Cingulate ◽  
Specific Information ◽  
Cortical Circuits ◽  
Top Down ◽  
Behavioral Diversity ◽  
Specific Manner ◽  
Behavioral States ◽  
Reward And Punishment

SummaryExpectations of rewards and punishments can promote similar behavioral states, such as vigilance, as well as distinct behavioral states, such as approach or avoidance. However, the cortical circuits that underlie this behavioral diversity are poorly understood. In a Pavlovian procedure in which monkeys displayed a diverse repertoire of reward, punishment, and uncertainty related behaviors not mandated by the task, I show that many anterior-cingulate (ACC) neurons represent expected value and uncertainty in a valence-specific manner, for example about either rewards or punishments. This flexibility may facilitate the top-down control of many reward- and punishment-related actions and behavioral states.

scholarly journals The geometry of abstraction in hippocampus and pre-frontal cortex

2018 ◽  
Author(s):  
Silvia Bernardi ◽  
Marcus K. Benna ◽  
Mattia Rigotti ◽  
Jérôme Munuera ◽  
Stefano Fusi ◽  
...  
Keyword(s):  
Frontal Cortex ◽  
Cognitive Flexibility ◽  
Anterior Cingulate ◽  
Stimulus Response ◽  
Hidden Variable ◽  
Neural Ensembles ◽  
Neural Representations ◽  
Cognitive Operations ◽  
Task Conditions ◽  
The Brain

The curse of dimensionality plagues models of reinforcement learning and decision-making. The process of abstraction solves this by constructing abstract variables describing features shared by different specific instances, reducing dimensionality and enabling generalization in novel situations. Here we characterized neural representations in monkeys performing a task where a hidden variable described the temporal statistics of stimulus-response-outcome mappings. Abstraction was defined operationally using the generalization performance of neural decoders across task conditions not used for training. This type of generalization requires a particular geometric format of neural representations. Neural ensembles in dorsolateral pre-frontal cortex, anterior cingulate cortex and hippocampus, and in simulated neural networks, simultaneously represented multiple hidden and explicit variables in a format reflecting abstraction. Task events engaging cognitive operations modulated this format. These findings elucidate how the brain and artificial systems represent abstract variables, variables critical for generalization that in turn confers cognitive flexibility.

Effects of Pain on Motor Performance

1990 ◽  
Vol 12 (4) ◽  
pp. 353-365 ◽  
Author(s):  
Bottom W. Brewer ◽  
Judy L. Van Raalte ◽  
Darwyn E. Linder
Keyword(s):  
College Students ◽  
Adverse Effects ◽  
Motor Performance ◽  
Task Complexity ◽  
Weight Lifting ◽  
Future Research ◽  
Pressure Pain ◽  
Golf Putting ◽  
Male College ◽  
Lifting Task

The effects of experimentally induced pressure pain on the performance of a weight lifting task, a simple golf putting task, and a complex golf putting task were examined in male college students. It was found that pain did not affect performance of the weight lifting task, slightly hampered performance of the simple putting task, and severely hampered performance of the complex putting task. Because the adverse effects of pain increased with task complexity, the findings are consistent with the notion mat pain is a form of arousal and mat pain affects performance in a manner similar to arousal. Limitations of the present experiments and directions for future research are discussed.

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