Functional Equivalence Model Research Articles

Examining the Equivalence Between Imagery and Execution—Does Imagery Comprise the Intended Spatial Trajectory?

The functional equivalence model suggests a common internal representation initiates both imagery and execution. This suggestion is supported by the mental chronometry effect, where there is a positive relation between task difficulty (as defined by the Index of Difficulty; ID) and imagined movement time. The present study extends this logic by examining whether imagery captures the spatial trajectory. Participants were initially tasked with the imagery and execution of a rapid aiming movement under different IDs. These initial attempts were adapted to configure auditory tones at early (25%) and late (75%) intervals for a separate set of imagery trials. If a tone had sounded, participants had to estimate post-trial where their imagined limb would have been located. The findings revealed increases in ID that coincided with increases in imagined and executed movement times. However, participant mean and standard deviation of estimated locations revealed limited differences between the early and late tones. Further inspection revealed some evidence for these estimated locations shifting further along in space following more rapid imagined movements. While equivalence is clearly evident within the temporal domain, there is comparatively little to suggest that this logic extends to the resolution required for simulating the spatial characteristics of movement.

Getting the most out of imagery: PETTLEP and ESports

Abstract The PETTLEP model of imagery developed by Holmes, P. S., & Collins, D. J. (2001. The PETTLEP approach to motor imagery: A functional equivalence model for sport psychologists. Journal of Applied Sport Psychology, 13, 60–83) is used to guide mental skills practitioners and researchers when designing mental imagery interventions for performance enhancement. The PETTLEP acronym represents Physical, Task, Timing, Learning, Emotion, and Perspective aspects of mental images. Using the PETTLEP model to guide imagery optimizes the effectiveness of the imagery.

Design of a functionally equivalent mental simulation protocol for learning cardiac arrest skills

Mental simulation assists learners in repetitive, solitary, deliberate practice. Mental simulation can complement laboratory simulation-based learning and clinical practice in learning skills and increasing self-efficacy [1]. Mental simulation is a quasi-sensory or quasi-perceptual experience without stimuli and overt physical movement. Mental simulation occurs when one imitates actions in an imaged state but does not trigger the action itself [2]. Mental simulation is based on the ‘simulation theory of action’. This theory suggests that observing an action, imaging an action, or understanding an action will activate the neural networks involved in the actual execution of that action. While these states differ, there is a partial overlap between covert and overt action [2]. The images produced during mental simulation must be vivid or high-fidelity to activate the said neural networks. Higher fidelity images create greater ‘functional equivalence’, increasing the likelihood that the imager will learn from their experience [3]. The aim was to create a mental simulation protocol rich in motor and sensory cues that would assist pre-registration nurses [students] in imagining performing cardiac arrest skills. The protocol had to be designed to increase the mental simulation exercise’s functional equivalence and increase the possibility that learning would take place. The protocol had several elements to improve functional equivalence, and these were: i) a narrated audio script with embedded sound effects that described the scenario. The script was based on PETTLEP mental simulation framework (physical, environment, task, timing, learning, emotion and perspective) [3]. The author used a tripartite script design. The scripts were designed between 1) the [first] author, 2) the [2015] BLS and ALS guidelines, and 3) students with real-world cardiac arrest experience; ii) a first-person [1-P] film of a cardiac arrest to assist in evoking high-fidelity images from a 1-P perspective; iii) a patient back story; iv) resuscitation algorithms, and v) a glossary of terms to help inexperienced students to understand cardiac arrest terminology. The glossary would assist students in turning language into images. This novel approach to creating a mental simulation protocol created a scenario rich in detail and rich in stimulus, response and meaning cues that could help students learn cardiac arrest skills outside the simulation laboratory. This is a new and novel way to design mental simulation protocols for learning cardiac arrest skills outside the simulation laboratory. 1. Geoffrion R, Gebhart J, Dooley Y, Bent A, Dandolu V, Meeks R, Baker K, Tang S, Ross S, Robert M. The mind’s scalpel in surgical education: a randomised controlled trial of mental imagery. Int J Obstet Gy. 2012;119(9):1040–1048. 2. Jeannerod M. Neural Simulation of Action: A Unifying Mechanism for Motor Cognition. NeuroImage Clin. 2001;14(1 pt. 2):S103–109. 3. Holmes PS, Collins DJ. The PETTLEP Approach to Motor Imagery: A Functional Equivalence Model for Sport Psychologists. J. Appl. Sport Psychol. 2001;13(1):60–83.

Frontal brain areas are more involved during motor imagery than during motor execution/preparation of a response sequence

Results of several neuroimaging studies support the functional equivalence model, which states that motor imagery (MI) and motor execution (ME) involve the same processes, except for the final execution component. In contrast, the motor-cognitive model implies that MI additionally involves frontal executive control processes. However, according to some authors MI may actually be more comparable to motor preparation (MP). In the current electroencephalographic study, a version of the discrete sequence production paradigm was employed in which human participants initially had to prepare a sequence of five finger movements that subsequently had to be executed, imagined, or withheld. MI, ME, and MP were compared by computing event-related (de)-synchronization in the theta, alpha/mu, and beta bands. Results revealed a major increase in frontal theta power during MI as compared to ME and MP. At the end of the examined intervals, a posterior reduction in alpha power was present during ME and MP, but not during MI. Finally, above sensorimotor areas a decrease in beta power was observed that was most pronounced in the case of ME. The increase of frontal theta activity during MI may reflect increased effort, while the absence of a reduction in posterior alpha power suggests no major involvement of visuospatial attention and/or visual imagery. The present findings favor the motor-cognitive model, as it predicts extra involvement of frontal executive processes during MI.

Executive functions in motor imagery: support for the motor-cognitive model over the functional equivalence model

The motor-cognitive model holds that motor imagery relies on executive resources to a much greater extent than do overt actions. According to this view, engaging executive resources with an interference task during motor imagery or overt actions will lead to a greater lengthening of the time required to imagine a movement than to execute it physically. This model is in contrast to a currently popular view, the functional equivalence model, which holds that motor imagery and overt action use identical mental processes, and thus should be equally affected by task manipulations. The two competing frameworks were tested in three experiments that varied the amount and type of executive resources needed to perform an interference task concurrent with either an overt or imagined version of a grasping and placing action. In Experiment 1, performing a concurrent calculation task led to a greater lengthening of the time required to execute motor imagery than overt action relative to a control condition involving no interference task. Further, an increase in the number of responses used to index performance affected the timing of motor imagery but not overt actions. In Experiment 2, a low-load repetition task interfered with the timing of motor imagery, but less so than a high load calculation task; both tasks had much smaller effects on overt actions. In Experiment 3, a word generation task also interfered with motor imagery much more than with overt actions. The results of these experiments provide broad support for the motor-cognitive model over the functional equivalence model in showing that interfering with executive functions had a much greater impact on the timing of motor imagery than on overt actions. The possible roles of different executive processes in motor imagery are discussed.

The motor-cognitive model of motor imagery: Evidence from timing errors in simulated reaching and grasping.

Motor imagery represents an important but theoretically underdeveloped area of research in psychology. The motor-cognitive model of motor imagery was presented, and contrasted with the currently prevalent view, the functional equivalence model. In 3 experiments, the predictions of the two models were pitted against each other through manipulations of task precision and the introduction of an interference task, while comparing their effects on overt actions and motor imagery. In Experiments 1a and 1b, the motor-cognitive model predicted an effect of precision whereby motor imagery would overestimate simulated movement times when a grasping action involved a high level of precision; this prediction was upheld. In Experiment 2, the motor-cognitive model predicted that an interference task would slow motor imagery to a much greater extent than it would overt actions; this prediction was also upheld. Experiment 3 showed that the effects observed in the previous experiments could not be due to failures to match the motor imagery and overt action tasks. None of the above results were explainable by either a strong version of the functional equivalence model, or any reasonable adaptations thereof. It was concluded that the motor-cognitive model may represent a theoretically viable advance in the understanding of motor imagery. (PsycINFO Database Record

Functional Comparison of the Hoxa 4, Hoxa 10, and Hoxa 11 Homeoboxes

A number of models attempt to explain the functional relationships of Hox genes. The functional equivalence model states that mammalian Hox-encoded proteins are largely functionally equivalent, and that Hox quantity is more important than Hox quality. In this report, we describe the results of two homeobox swaps. In one case, the homeobox of Hoxa 11 was replaced with that of the very closely related Hoxa 10. Developmental function was assayed by analyzing the phenotypes of all possible allele combinations, including the swapped allele, and null alleles for Hoxa 11 and Hoxd 11. This chimeric gene provided wild-type function in the development of the axial skeleton and male reproductive tract, but served as a hypomorph allele in the development of the appendicular skeleton, kidneys, and female reproductive tract. In the other case, the Hoxa 11 homeobox was replaced with that of the divergent Hoxa 4 gene. This chimeric gene provided near recessive null function in all tissues except the axial skeleton, which developed normally. These results demonstrate that even the most conserved regions of Hox genes, the homeoboxes, are not functionally interchangeable in the development of most tissues. In some cases, developmental function tracked with the homeobox, as previously seen in simpler organisms. Homeoboxes with more 5′ cluster positions were generally dominant over more 3′ homeoboxes, consistent with phenotypic suppression seen in Drosophila. Surprisingly, however, all Hox homeoboxes tested did appear functionally equivalent in the formation of the axial skeleton. The determination of segment identity is one of the most evolutionarily ancient functions of Hox genes. It is interesting that Hox homeoboxes are interchangeable in this process, but are functionally distinct in other aspects of development.

The PETTLEP Approach to Motor Imagery: A Functional Equivalence Model for Sport Psychologists

The PETTLEP Approach to Motor Imagery: A Functional Equivalence Model for Sport Psychologists

The PETTLEP Approach to Motor Imagery: A Functional Equivalence Model for Sport Psychologists

This paper supports the contention that the brain stores memories in the form of a central representation that is accessed by both physical preparation and execution and, more importantly, by motor imagery associated with this preparation and execution. Considerable evidence in support of shared central and vegetative structures suggests that sport psychologists should consider more closely aspects of the performer's responses to the physical skill when providing imagery interventions and not rely on “traditional,” more clinically orientated, methods of delivery. Many texts provide a schedule of factors and techniques for psychologists, athletes, and coaches to consider but with a limited theoretical explanation of why these factors are the crucial concerns. We, therefore, propose an evidence-based, 7-point checklist that includes: physical, environmental, task, timing, learning, emotional, and perspective elements of imagery delivery highlighting the minimum requirement areas in which sport psychologists should monitor the equivalence to the physical task in order to enhance the efficacy of their practice.