Limits...
Motor properties of peripersonal space in humans.

Serino A, Annella L, Avenanti A - PLoS ONE (2009)

Bottom Line: In monkeys, fronto-parietal networks are involved both in integrating multisensory information within a limited space surrounding the body (i.e. peripersonal space, PPS) and in action planning and execution, suggesting an overlap between sensory representations of space and motor representations of action.Such auditory modulation of hand motor representation was specific to a hand-centred, and not a body-centred reference frame.This pattern of corticospinal modulation highlights the relation between space and time in the pps representation: an early facilitation for near stimuli may reflect immediate motor preparation, whereas, at later time intervals, motor preparation relates to distant stimuli potentially approaching the body.

View Article: PubMed Central - PubMed

Affiliation: Dipartimento di Psicologia, Università degli Studi di Bologna, Bologna, Italy. andrea.serino@unibo.it

ABSTRACT

Background: A stimulus approaching the body requires fast processing and appropriate motor reactions. In monkeys, fronto-parietal networks are involved both in integrating multisensory information within a limited space surrounding the body (i.e. peripersonal space, PPS) and in action planning and execution, suggesting an overlap between sensory representations of space and motor representations of action. In the present study we investigate whether these overlapping representations also exist in the human brain.

Methodology/principal findings: We recorded from hand muscles motor-evoked potentials (MEPs) induced by single-pulse of transcranial magnetic stimulation (TMS) after presenting an auditory stimulus either near the hand or in far space. MEPs recorded 50 ms after the near-sound onset were enhanced compared to MEPs evoked after far sounds. This near-far modulation faded at longer inter-stimulus intervals, and reversed completely for MEPs recorded 300 ms after the sound onset. At that time point, higher motor excitability was associated with far sounds. Such auditory modulation of hand motor representation was specific to a hand-centred, and not a body-centred reference frame.

Conclusions/significance: This pattern of corticospinal modulation highlights the relation between space and time in the pps representation: an early facilitation for near stimuli may reflect immediate motor preparation, whereas, at later time intervals, motor preparation relates to distant stimuli potentially approaching the body.

Show MeSH

Related in: MedlinePlus

Mean MEP amplitude with respect to baseline (MEPi) recorded when sounds were presented NEAR (red lines) and FAR (blue lines) from the subjects' body (Experiment 2).(A) MEPi recorded with lower (120% rMT) TMS pulse intensity. (B) MEPi recorded with higher (140% rMT) TMS pulse intensity. Error bars denote s.e.m.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2719059&req=5

pone-0006582-g004: Mean MEP amplitude with respect to baseline (MEPi) recorded when sounds were presented NEAR (red lines) and FAR (blue lines) from the subjects' body (Experiment 2).(A) MEPi recorded with lower (120% rMT) TMS pulse intensity. (B) MEPi recorded with higher (140% rMT) TMS pulse intensity. Error bars denote s.e.m.

Mentions: The Muscle × Space × Intensity ANOVA performed on MEPis recorded in Experiment 2 did not show any significant main effect or interaction (ps>.12). Therefore, as Figure 4 clearly shows, no relevant modulation of MEPs was recorded when participants rotated their arm backwards, thereby placing their hand quite distant from the previously NEAR loudspeaker.


Motor properties of peripersonal space in humans.

Serino A, Annella L, Avenanti A - PLoS ONE (2009)

Mean MEP amplitude with respect to baseline (MEPi) recorded when sounds were presented NEAR (red lines) and FAR (blue lines) from the subjects' body (Experiment 2).(A) MEPi recorded with lower (120% rMT) TMS pulse intensity. (B) MEPi recorded with higher (140% rMT) TMS pulse intensity. Error bars denote s.e.m.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2719059&req=5

pone-0006582-g004: Mean MEP amplitude with respect to baseline (MEPi) recorded when sounds were presented NEAR (red lines) and FAR (blue lines) from the subjects' body (Experiment 2).(A) MEPi recorded with lower (120% rMT) TMS pulse intensity. (B) MEPi recorded with higher (140% rMT) TMS pulse intensity. Error bars denote s.e.m.
Mentions: The Muscle × Space × Intensity ANOVA performed on MEPis recorded in Experiment 2 did not show any significant main effect or interaction (ps>.12). Therefore, as Figure 4 clearly shows, no relevant modulation of MEPs was recorded when participants rotated their arm backwards, thereby placing their hand quite distant from the previously NEAR loudspeaker.

Bottom Line: In monkeys, fronto-parietal networks are involved both in integrating multisensory information within a limited space surrounding the body (i.e. peripersonal space, PPS) and in action planning and execution, suggesting an overlap between sensory representations of space and motor representations of action.Such auditory modulation of hand motor representation was specific to a hand-centred, and not a body-centred reference frame.This pattern of corticospinal modulation highlights the relation between space and time in the pps representation: an early facilitation for near stimuli may reflect immediate motor preparation, whereas, at later time intervals, motor preparation relates to distant stimuli potentially approaching the body.

View Article: PubMed Central - PubMed

Affiliation: Dipartimento di Psicologia, Università degli Studi di Bologna, Bologna, Italy. andrea.serino@unibo.it

ABSTRACT

Background: A stimulus approaching the body requires fast processing and appropriate motor reactions. In monkeys, fronto-parietal networks are involved both in integrating multisensory information within a limited space surrounding the body (i.e. peripersonal space, PPS) and in action planning and execution, suggesting an overlap between sensory representations of space and motor representations of action. In the present study we investigate whether these overlapping representations also exist in the human brain.

Methodology/principal findings: We recorded from hand muscles motor-evoked potentials (MEPs) induced by single-pulse of transcranial magnetic stimulation (TMS) after presenting an auditory stimulus either near the hand or in far space. MEPs recorded 50 ms after the near-sound onset were enhanced compared to MEPs evoked after far sounds. This near-far modulation faded at longer inter-stimulus intervals, and reversed completely for MEPs recorded 300 ms after the sound onset. At that time point, higher motor excitability was associated with far sounds. Such auditory modulation of hand motor representation was specific to a hand-centred, and not a body-centred reference frame.

Conclusions/significance: This pattern of corticospinal modulation highlights the relation between space and time in the pps representation: an early facilitation for near stimuli may reflect immediate motor preparation, whereas, at later time intervals, motor preparation relates to distant stimuli potentially approaching the body.

Show MeSH
Related in: MedlinePlus