Does spatial distribution of boutons relate to orientation preference in layer IV spiny neurons

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Does spatial distribution of boutons relate to
orientation preference in layer IV spiny neurons?

• Fuyuki KARUBE and Zoltán F. Kisvárday
• Laboratory for Cortical Systems Neuroscience,
• Medical and Health Science Center (MHSC),
• University of Debrecen, HUNGARY

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Materials and Methods

• Adult cats (2.3 - 3.2 kg) were used.
• Visual stimuli
• Moving luminance gratings (square waves
  frequency, 0.1-0.8 cpd velocity, 2 Hz).
• Imaging
• Cortex (A18) was illuminated at 605 nm light.
  Intrinsic signals were captured with a CCD
  camera.
• Extracellular recordings to identify receptive
  field properties.
• Tracer injections for extracellular staining
• Reconstruction of stained single cells by
  Neurolucida.

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Time course of intrinsic signal
Start visual stimulation
Stop stimulation
From Grinvald and Bonhoeffer
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Optical imaging of intrinsic signal
From Grinvald and Bonhoeffer
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Analysis of map structure for orientation
preference
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Orientation preference patches elongated along
iso-elevation line in visual field
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Reconstructions of layer IV spiny neurons
Dendrites were drawn in black, axons in red.
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Bouton distribution pattern relative to
orientation preference
Local
Within 400mm diameter
Distal
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Bouton distribution in iso-,oblique-, and
cross-orientation patches
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Tentative LM and AP-elongated cells on
orientation preference map
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Quantification of bouton distribution
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Bouton distribution to cortical dimensions and
preferred orientations
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conclusion

• Layer IV spiny neurons showed various bouton
  distribution from cell to cell.
• half of them preferred iso-orientation,
  another half did cross-orientation.
• Orientation patches elongated with LM (or
  iso-elevation) axis. Thus, spatial distribution
  of boutons of single cells can affect
  connectivity between iso- or cross-orientation
  preference patches.

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