Document Detail

Postural responses explored through classical conditioning.
MedLine Citation:
PMID:  19635526     Owner:  NLM     Status:  MEDLINE    
The purpose of the study was to determine whether the central nervous system (CNS) requires the sensory feedback generated by balance perturbations in order to trigger postural responses (PRs). In Experiment 1, twenty-one participants experienced toes-up support-surface tilts in two blocks. Control blocks involved unexpected balance perturbations whereas an auditory tone cued the onset of balance perturbations in Conditioning blocks. A single Cue-Only trial followed each block (Cue-Only(Control) and Cue-Only(Conditioning) trials) in the absence of balance perturbations. Cue-Only(Conditioning) trials were used to determine whether postural perturbations were required in order to trigger PRs. Counter-balancing the order of Control and Conditioning blocks allowed Cue-Only(Control) trials to examine both the audio-spinal/acoustic startle effects of the auditory cue and the carryover effects of the initial conditioning procedure. In Experiment 2, six participants first experienced five consecutive Tone-Only trials that were followed by twenty-five conditioning trials. After conditioning, five Tone-Only trials were again presented consecutively to first elicit and then extinguish the conditioned PRs. Surface electromyography (EMG) recorded muscle activity in soleus (SOL), tibialis anterior (TA) and rectus femoris (RF). EMG onset latencies and amplitudes were calculated together with the onset latency, peak and time-to-peak of shank angular accelerations. Results indicated that an auditory cue could be conditioned to initiate PRs in multiple muscles without balance-relevant sensory triggers generated by balance perturbations. Postural synergies involving excitation of TA and RF and inhibition of SOL were observed following the Cue-Only(Conditioning) trials that resulted in shank angular accelerations in the direction required to counter the expected toes-up tilt. Postural synergies were triggered in response to the auditory cue even 15 min post-conditioning. Furthermore, conditioned PRs were quickly extinguished as participants became unresponsive by the third trial in extinction. In conclusion, our results reveal that the CNS does not require sensory feedback from postural perturbations in order to trigger PRs.
A D Campbell; C J Dakin; M G Carpenter
Related Documents :
12200616 - Postural dynamics in maximal isometric ramp efforts.
15670656 - Effect of head position and visual condition on balance control in inverted stance.
2809706 - Influence of central set on human postural responses.
16944106 - Representation of dynamic events triggered by motion lines and static human postures.
23658116 - In search of the pitching momentum that enables some lizards to sustain bipedal running...
21534996 - Mammalian tactile hair: divergence from a limited distribution.
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-07-25
Journal Detail:
Title:  Neuroscience     Volume:  164     ISSN:  1873-7544     ISO Abbreviation:  Neuroscience     Publication Date:  2009 Dec 
Date Detail:
Created Date:  2009-11-06     Completed Date:  2010-02-08     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  7605074     Medline TA:  Neuroscience     Country:  United States    
Other Details:
Languages:  eng     Pagination:  986-97     Citation Subset:  IM    
School of Human Kinetics, Osborne Centre Unit II, 6108 Thunderbird Boulevard, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z3.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Acoustic Stimulation
Conditioning (Psychology) / physiology*
Extinction, Psychological / physiology
Feedback, Sensory / physiology*
Muscle Contraction / physiology
Muscle, Skeletal / innervation,  physiology*
Neuropsychological Tests
Postural Balance / physiology*
Posture / physiology*
Reflex / physiology
Startle Reaction / physiology
Young Adult

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

Previous Document:  Catalpol ameliorates beta amyloid-induced degeneration of cholinergic neurons by elevating brain-der...
Next Document:  Critical role of the embryonic mid-hindbrain organizer in the behavioral response to amphetamine and...