scholarly journals An Agent-Specific Stochastic Model of Generalized Reaching Task Difficulty

2021 ◽  
Vol 11 (10) ◽  
pp. 4330
Author(s):  
Andrea Lucchese ◽  
Salvatore Digiesi ◽  
Kübra Akbaş ◽  
Carlotta Mummolo
Keyword(s):  
Stochastic Model ◽  
Task Difficulty ◽  
Motor Task ◽  
Younger Adults ◽  
Reaching Task ◽  
Index Of Difficulty ◽  
Young Subjects ◽  
Aged Subjects ◽  
Spatial Trajectories ◽  
Repetitive Motor

The ability of an agent to accomplish a trajectory during a certain motor task depends on the fit between external (environment) and internal (agent) constraints, also known as affordance. A model of difficulty for a generalized reaching motor task is proposed as an affordance-related measure, as perceived by a specific agent for a given environment and task. By extending the information-based Index of Difficulty of a trajectory, a stochastic model of difficulty is formulated based on the observed variability of spatial trajectories executed by a given agent during a repetitive motor task. The model is tested on an experimental walking dataset available in the literature, where the repetitive stride movement of differently aged subjects (14 “old” subjects aged 50–73; 20 “young” subjects aged 21–37) at multiple speed conditions (comfortable, ~30% faster, ~30% slower) is analyzed. Reduced trajectory variability in older as compared to younger adults results in a higher Index of Difficulty (slower: +24%, p < 0.0125; faster: +38%, p < 0.002) which is interpreted in this context as reduced affordance. The model overcomes the limits of existing difficulty measures by capturing the stochastic dependency of task difficulty on a subject’s age and average speed. This model provides a benchmarking tool for motor performance in biomechanics and ergonomics applications.

Generation and Associative Encoding in Young and Old Adults

2008 ◽  
Vol 55 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Laurence Taconnat ◽  
Charlotte Froger ◽  
Mathilde Sacher ◽  
Michel Isingrini
Keyword(s):  
Task Difficulty ◽  
Generation Effect ◽  
Elderly Adults ◽  
Generation Task ◽  
Younger Adults ◽  
Old Adults ◽  
Strength Of Association ◽  
Target Words

Abstract. The generation effect (i.e., better recall of the generated items than the read items) was investigated with a between-list design in young and elderly participants. The generation task difficulty was manipulated by varying the strength of association between cues and targets. Overall, strong associates were better recalled than weak associates. However, the results showed different generation effect patterns according to strength of association and age, with a greater generation effect for weak associates in younger adults only. These findings suggest that generating weak associates leads to more elaborated encoding, but that elderly adults cannot use this elaborated encoding as well as younger adults to recall the target words at test.

scholarly journals Hyperbrain features of team mental models within a juggling paradigm: a proof of concept

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2457 ◽  
Author(s):  
Edson Filho ◽  
Maurizio Bertollo ◽  
Gabriella Tamburro ◽  
Lorenzo Schinaia ◽  
Jonas Chatel-Goldman ◽  
...  
Keyword(s):  
Mental Models ◽  
Task Difficulty ◽  
Functional Organization ◽  
Cooperative Behavior ◽  
Motor Task ◽  
Small World ◽  
Proof Of Concept ◽  
Frequency Bands ◽  
Functional Connections ◽  
Graph Metrics

BackgroundResearch on cooperative behavior and the social brain exists, but little research has focused on real-time motor cooperative behavior and its neural correlates. In this proof of concept study, we explored the conceptual notion of shared and complementary mental models through EEG mapping of two brains performing a real-world interactive motor task of increasing difficulty. We used the recently introduced participative “juggling paradigm,” and collected neuro-physiological and psycho-social data. We were interested in analyzing the between-brains coupling during a dyadic juggling task, and in exploring the relationship between the motor task execution, the jugglers’skill level and the task difficulty. We also investigated how this relationship could be mirrored in the coupled functional organization of the interacting brains.MethodsTo capture the neural schemas underlying the notion of shared and complementary mental models, we examined the functional connectivity patterns and hyperbrain features of a juggling dyad involved in cooperative motor tasks of increasing difficulty. Jugglers’ cortical activity was measured using two synchronized 32-channel EEG systems during dyadic juggling performed with 3, 4, 5 and 6 balls. Individual and hyperbrain functional connections were quantified through coherence maps calculated across all electrode pairs in the theta and alpha bands (4–8 and 8–12 Hz). Graph metrics were used to typify the global topology and efficiency of the functional networks for the four difficulty levels in the theta and alpha bands.ResultsResults indicated that, as task difficulty increased, the cortical functional organization of the more skilled juggler became progressively more segregated in both frequency bands, with a small-world organization in the theta band during easier tasks, indicative of a flow-like state in line with the neural efficiency hypothesis. Conversely, more integrated functional patterns were observed for the less skilled juggler in both frequency bands, possibly related to cognitive overload due to the difficulty of the task at hand (reinvestment hypothesis). At the hyperbrain level, a segregated functional organization involving areas of the visuo-attentional networks of both jugglers was observed in both frequency bands and for the easier task only.DiscussionThese results suggest that cooperative juggling is supported by integrated activity of specialized cortical areas from both brains only during easier tasks, whereas it relies on individual skills, mirrored in uncorrelated individual brain activations, during more difficult tasks. These findings suggest that task difficulty and jugglers’ personal skills may influence the features of the hyperbrain network in its shared/integrative and complementary/segregative tendencies.

Comparison of the Production of Cyclic AMP in Response to Parathyroid Hormone in Fibroblasts from Aged Subjects and Young Subjects: Lack of an Age-Dependent Decrease

Gerontology ◽  
1990 ◽  
Vol 36 (5-6) ◽  
pp. 249-255 ◽  
Author(s):  
Shigeto Morimoto ◽  
Shoshi Takamoto ◽  
Shunji Imanaka ◽  
Shoichi Kitano ◽  
Yoshiyuki Miyashita ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Cyclic Amp ◽  
Age Dependent ◽  
Young Subjects ◽  
Aged Subjects

Effect of Task Difficulty on Muscle Activation Patterns during Rapid Single-Joint Movements

2002 ◽  
Vol 94 (3_suppl) ◽  
pp. 1157-1167 ◽  
Author(s):  
Sangbum Park
Keyword(s):  
Task Difficulty ◽  
Muscle Activation ◽  
Biceps Brachii ◽  
Elbow Flexion ◽  
Movement Initiation ◽  
Antagonist Muscle ◽  
Muscle Activation Patterns ◽  
Movement Organization ◽  
Agonist And Antagonist ◽  
Index Of Difficulty

This study investigated the effect of spatial accuracy demands on movement organization by analyzing the amplitude of the agonist and antagonist muscle activities emerging during horizontal elbow-flexion movements toward spatial targets of varying difficulties. 8 subjects performed elbow-flexion movements toward targets of 3 sizes, located at 2 distances, as rapidly and accurately as possible. For each movement, the elbow angles and the activities of biceps brachii, brachioradialis, and lateral and long heads of triceps brachii were measured. Analysis on the kinematic variables indicated that final elbow angle and peak velocity decreased with increasing index of difficulty of the task in both movement-amplitude conditions. However, movement time increased with increasing index of difficulty. The amplitude of agonist and antagonist muscle activities measured for 100 msec. before movement initiation was also shown to decrease with increasing index of difficulty. Agonist and antagonist muscle activities measured during acceleration phase displayed similar patterns with those of premovement. These results suggest that the task difficulty affects movement organization, and the control system decreases the amplitude of agonist and antagonist muscle activities with an increase in the index of difficulty to enhance the controllability of the limb.

Caffeine Enhances Initial but Not Extended Learning of a Proprioceptive-Based Discrimination Task in Nonsmoking Moderate Users

1996 ◽  
Vol 82 (3) ◽  
pp. 891-898 ◽  
Author(s):  
L. Stephen Miller ◽  
Scott E. Miller
Keyword(s):  
Discrimination Task ◽  
Motor Task ◽  
Response Duration ◽  
Operant Response ◽  
Fine Motor ◽  
Response Force ◽  
Initial Learning ◽  
Duration Of Response ◽  
Aged Subjects ◽  
Fine Motor Performance

We examined the effects of caffeine on fine motor performance and learning using a multiple-force discrimination task. 93 college-aged subjects performed this task on which multiple measurements were made in an operant response paradigm. Quantitative measures of accuracy of response, duration of response, latency of response, force, and variability of force were examined. Significant interactions for caffeine dose by session on accuracy of response and latency of response indicated that caffeine enhanced the initial learning of a proprioceptive motor task but did not improve performance beyond that of normal practice.

Some effects of work loading in a repetitive motor task.

1954 ◽  
Vol 48 (6) ◽  
pp. 455-467 ◽  
Author(s):  
Ina McD. Bilodeau ◽  
Edward A. Bilodeau
Keyword(s):  
Motor Task ◽  
Repetitive Motor

scholarly journals Are there Any Differences in Simple and Random Choice Motor Task Performance between Young and Middle-Aged Adults?

2018 ◽  
Vol 3 (90) ◽  
Author(s):  
Rima Solianik ◽  
Vaida Aleknavičiūtė ◽  
Albertas Skurvydas ◽  
Marius Brazaitis
Keyword(s):  
Reaction Time ◽  
Motor Performance ◽  
Motor Task ◽  
Individual Variability ◽  
Maximal Velocity ◽  
Middle Aged ◽  
Random Choice ◽  
Simple Task ◽  
Aged Subjects ◽  
Speed Accuracy

Research background and hypothesis. Most studies are based on elderly subjects’ results, so there is a need to explore if motor performance changes begin in the middle age. We hypothesize that (i) middle-aged subjects use “play it safe” strategy, which depends on the type of tasks (simple vs. random choice); (ii) middle-aged subjects will show higher intra-individual performance variability compared to young adults, furthermore, simple task will show  lower performance variability.Research aim was to establish if there were any movement performance differences during simple and random  choice motor task performance between young and middle-aged adults.Research methods. Middle-aged and young adults performed two speed-accuracy tasks. During simple task  participants had to reach the same target which appeared in the same place and during random choice task the target  appeared randomly in one of the three different places.Research results. Data showed that middle-aged group had slower (p < 0.05) reaction time and maximal velocity,  whereas movement path length was more accurate (p < 0.05) than that in the young adult group. Comparing different  tasks it was observed that during simple task reaction time was faster (p < 0.05) than in the random choice task in  both groups. Intra-individual variability of reaction time and maximal velocity was higher (p < 0.05) in the middle-aged group, whereas no changes were observed between different tasks.Discussion  and  conclusion.  Motor  performance  strategy  “play  it  safe”  is  already  observed  for  the  middle- aged population: they decrease maximal velocity and reaction time in order to make movement more accurate.  Additionally, they demonstrate task-independent higher intra-individual variability of reaction time and maximal  velocity showing changes in CNS integrity compared to young adults.Keywords: aging, speed-accuracy tasks, intra-individual variability.

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