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@INPROCEEDINGS{Essink:1007028,
      author       = {Essink, Simon and Ito, Junji and Riehle, Alexa and
                      Brochier, Thomas and Grün, Sonja},
      title        = {{D}oes a bimodal distribution of preferred directions to
                      hand movements in visuo-parietal areas reflect a genuine
                      motor response?},
      reportid     = {FZJ-2023-01947},
      year         = {2022},
      abstract     = {Decades of intense research established that neurons in the
                      monkey motor cortex are tuned to handmovement direction with
                      a cosine-like function that can be characterized by a
                      preferred direction[1]. Although preferred directions were
                      assumed to be uniformly distributed at the population
                      level,more recent analyses showed that these preferred
                      directions are bimodally distributed if hand move-ments are
                      constrained to a horizontal work area [2,3]. In
                      electrophysiological recordings in macaquemonkeys via
                      multiple Utah electrode arrays during a visually guided
                      motor task that is constrainedto the horizontal plane [4],
                      we reproduced this result for the motor cortex and expand
                      the analysisto visual area V2 and parietal areas DP and
                      7A.Macaque monkeys had been trained to perform a visually
                      guided sequential reaching task while theirarm was in a
                      robotic exoskeleton system (KINARM Exoskeleton Laboratory,
                      BKIN Technologies).Both eye movements and hand movements
                      were recorded along with extracellular potentials from224
                      channels across visual (V1, V2), parietal (DP, 7a) and motor
                      (M1/PMd) areas. After spike sorting,we relate spiking
                      activity per single unit with the instantaneous hand
                      movement direction throughreverse correlation [5]. From
                      this, we extract the preferred hand movement direction by
                      fitting avon Mises tuning model [6]. The resulting
                      distributions of preferred directions per area were
                      testedfor bimodality using the Rayleigh r statistic.We
                      confirmed the bimodality of preferred directions of hand
                      movement-related responses (peaksat ~109 and ~309 degrees)
                      for neurons recorded in the motor cortex. Surprisingly, we
                      observedthe same tendencies in visual area V2 and in the
                      parietal areas DP and 7A and checked for thestatistical
                      significance of the results. Subsequently, we investigated
                      whether the observations in ourexperiment are a genuine
                      expression of the hand movement or rather arise in response
                      to the visualstimuli toward which the monkeys moved their
                      hands. The responses to hand movement directionsin area V2
                      can be explained by the receptive field locations of the
                      recorded neurons and the visualstimuli arising during the
                      task. In the parietal areas, however, we tend to exclude
                      visual stimuli asconfounding signals, hinting at the
                      presence of a genuine motor signal in parietal
                      areas.References:[1] Georgopoulos, A., Kalaska, J.,
                      Caminiti, R. $\&$ Massey, J. On the relations between the
                      directionof two-dimensional arm movements and cell discharge
                      in primate motor cortex. J. Neurosci. 2,1527–1537
                      (1982).[2] Scott, S. H., Gribble, P. L., Graham, K. M. $\&$
                      Cabel, D. W. Dissociation between hand motion andpopulation
                      vectors from neural activity in motor cortex. Nature 413,
                      161–165 (2001).[3] Lillicrap, T. P. $\&$ Scott, S. H.
                      Preference Distributions of Primary Motor Cortex Neurons
                      ReflectControl Solutions Optimized for Limb Biomechanics.
                      Neuron 77, 168–179 (2013).[4] de Haan, M. J., Brochier,
                      T., Grün, S., Riehle, A. $\&$ Barthélemy, F. V. Real-time
                      visuomotor be-havior and electrophysiology recording setup
                      for use with humans and monkeys. Journal of Neuro-physiology
                      120, 539–552 (2018).Page 136INM IBI Retreat 2022 / Book of
                      Abstracts[5] Eggermont, J. J., Johannesma, P. M. $\&$
                      Aertsen, A. M. Reverse-correlation methods in
                      auditoryresearch. Q Rev Biophys 16, 341–414 (1983).[6]
                      Amirikian, B. $\&$ Georgopulos, A. P. Directional tuning
                      profiles of motor cortical cells. Neuro-science Research 36,
                      73–79 (2000).},
      month         = {Oct},
      date          = {2022-10-18},
      organization  = {INM-IBI Retreat, Juelich (Germany), 18
                       Oct 2022 - 19 Oct 2022},
      subtyp        = {After Call},
      cin          = {INM-6 / IAS-6 / INM-10},
      cid          = {I:(DE-Juel1)INM-6-20090406 / I:(DE-Juel1)IAS-6-20130828 /
                      I:(DE-Juel1)INM-10-20170113},
      pnm          = {5232 - Computational Principles (POF4-523) / HBP SGA3 -
                      Human Brain Project Specific Grant Agreement 3 (945539)},
      pid          = {G:(DE-HGF)POF4-5232 / G:(EU-Grant)945539},
      typ          = {PUB:(DE-HGF)24},
      doi          = {10.34734/FZJ-2023-01947},
      url          = {https://juser.fz-juelich.de/record/1007028},
}