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The responsiveness of Clare-Bishop neurons to size cues for motion stereopsis
Insights
Clare-Bishop (CB) cells integrate visual size and motion cues for 3D motion perception. This study reveals how these cells process combined signals for approaching and receding visual stimuli, forming a basis for neuronal circuitry models.
Area of Science:
- Neuroscience
- Visual Perception
- Computational Neuroscience
Background:
- Clare-Bishop (CB) cells are crucial for processing visual motion cues.
- Understanding how CB cells integrate size and motion information is key to deciphering 3D visual perception.
Purpose of the Study:
- To investigate the responsiveness of CB cells to size cues and combined size-motion cues in 3D visual stimuli.
- To determine how different types of CB cells (approaching, receding, frontoparallel) process these integrated signals.
Main Methods:
- Electrophysiological recordings from 118 Clare-Bishop (CB) cells in response to visual stimuli.
- Stimuli varied in size, motion direction (approaching, receding, frontoparallel), and combinations of cues.
- Analysis of cell responses to single versus combined visual cues.
Main Results:
- Cells responsive to approaching (AP) and receding (RC) motion optimally integrated both size and motion cues.
- Cells responsive to frontoparallel (FP) motion were primarily driven by motion cues, with size cues often reducing responses.
- Non-selective (NS) cells showed varied responses to size cues, with many not differentiating between approaching and receding motion.
Conclusions:
- CB cell responsiveness to 3D motion relies on the integration of motion and size signals from both eyes.
- A neuronal circuitry model was proposed to explain the observed integration mechanisms in CB cells.
Abstract:
The responsiveness to the size cue, and a combination of the size and motion cues contained in 3-dimensional motion of a visual stimulus was studied in 118 Clare-Bishop (CB) cells, including 37 and 10 cells selectively responsive to approaching (AP) and to recessive motion along the axis through the center of the receptive area and the nose (RC), 40 cells responsive to the frontoparallel motion in the horizontal direction (FP), 23 cells rather non-selectively responsive to the two types of motion (NS) and 8 cells responsive to the size cue but unresponsive to the 3-dimensional motion (SZ). About three quarters of the AP cells (27/37) were responsive to both an increase in the stimulus size and divergent motion of the retinal images in the two eyes, which represents the size and motion cues for the approaching motion along the axis through the center of the receptive area and the nose, and were optimally excited by a combination of the two visual cues. About the same fraction of the RC cells (6/10) was responsive to the motion (convergent motion) and size cues (a decrease in stimulus size), and optimally excited by a combination of the two visual cues. In contrast, only a small fraction of the FP cells (6/40) were sensitive to the size cue, and all FP cells were optimally excited by the single presentation of the motion cue for the frontoparallel motion (either right- or leftward motion in both eyes). Responses were frequently (18/40) smaller for the combined presentation of the two visual cues than for the single presentation of the motion cue. Similarly, a small fraction of the NS cells (7/23) was sensitive to the size cue, but many of them (16/23) were non-selectively responsive to the size cues for the approaching and recessive motion. A similar study in an additional 108 (78 AP and 30 RC) cells which were responsive to approaching or recessive motion vertically or obliquely deviating from the axis through the center of the receptive area and the nose demonstrated that they were also sensitive to both motion and size cues for that approaching or recessive motion, and were optimally excited by a combination of the two visual cues. These findings indicate that the CB cell responsiveness to 3-dimensional motion is based on the integration of the motion and size signals conveyed through the two eyes. A model of neuronal circuitry was constructed to explain the CB cell responsiveness to the motion and size signals.