FENS Forum 2010 - Amsterdam
- Posters: to be on display from 8:00 to 13:15 in the morning and from 13:30 to 18:45 in the afternoon.
Poster sessions run from 09:30 to 13:15 in the morning and from 13:30 to 17:30 in the afternoon.
A one hour time block is dedicated to discussion with the authors (authors should be in attendance at
their posters as from the time indicated.)
- For other sessions, time indicates the beginning and end of the sessions.
First author
Heba, Stefanie (poster)
Poster board D61 - Tue 06/07/2010, 14:30 - Hall 1
Session 171 - Posture and voluntary movements
Abstract n° 171.5
Publication ref.: FENS Abstr., vol.5, 171.5, 2010
Authors
Heba S. (1, 2), Philipp R. (2) & Hoffmann K. P. (1, 2)
Addresses
(1) International Graduate School of Neuroscience, Bochum, Germany; (2) Ruhr-University, Bochum,
Germany
Title
Contribution of a subcortical brain structure to error correction in the skeletomotor system
Text
Cortical areas like the posterior parietal cortex, frontal and prefrontal areas and the cerebellum
compose a substantial, though not exclusive part of the neural correlate for in-flight monitoring and
corrections of arm movements. Here, our experiments reveal neuronal responses during correction of
arm movements in the superior colliculus (SC) of the macaque monkey. Thus, the SC acts also in
response to skeletomotor operations, but neither relevance nor functional correlation of these
neuronal reach-signals were investigated in detail, yet.
Several approaches are used to evaluate the onset of a movement correction (SOC): (1) "sliding
window" t-test, (2) aberrations from confidence intervals, (3) landmarks in the velocity profile and (4)
algorithmic extraction of movement primitives. Neuronal data from three monkeys performing a
"fixation-reach"-task is aligned to these differently attained SOC's. In addition, the time points of
significant changes in neuronal firing rate are analysed with respect to their correlation with SOC's of
type (1) -(4), and cross-correlations test for a presumed functional significance of the primate SC in
skeletomotor actions.
We report an impact of reach correction on the neuronal activity of reach related cells, with a
substantial, though not exclusive, part of the cells responding with increased rates during corrections,
almost 100ms prior to first changes in movement kinetics. The sign of discharge rate change tends
not to be dependent on the directional tuning of the neuron. Further analysis reveals an impact of the
direction of corrective movements on neuronal latency, with shorter latencies for corrections into
preferred (median: 89.5ms) than unpreferred (110.5ms) directions. Additionally, for neuronal latencies
up to 200ms, a positive correlation of increased spikerate and decreased latency can be observed.
The response of collicular reach neurons may exhibit a functional, or at least supporting role in
skeletomotor control. Reach correction might be achieved by an alteration of the population vector
during perturbed movements, followed by passing the refined motor command directly to spinal motor
neurons, or providing an error signal to brain structures involved in motor-error processing.
Theme
D - Sensory and motor systems
Posture and voluntary movements
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