MST Neuronal Responses to Heading Direction During Pursuit Eye Movements

Abstract

As you move through the environment, you see a radial pattern of visual motion with a focus of expansion (FOE) that indicates your heading direction. When self-movement is combined with smooth pursuit eye movements, the turning of the eye distorts the retinal image of the FOE but somehow you still can perceive heading. We studied neurons in the medial superior temporal area (MST) of monkey visual cortex, recording responses to FOE stimuli presented during fixation and smooth pursuit eye movements. Almost all neurons showed significant changes in their FOE selective responses during pursuit eye movements. However, the vector average of all the neuronal responses indicated the direction of the FOE during both fixation and pursuit. Furthermore, the amplitude of the net vector increased with increasing FOE eccentricity. We conclude that neuronal population encoding in MST might contribute to pursuit-tolerant heading perception.

Spatial Reference Frames of Visual, Vestibular, and Multimodal Heading Signals in the Dorsal Subdivision of the Medial Superior Temporal Area

“…This ability implies that the neural processing of optic flow must somehow take into account the rotation of the eyes. Indeed, several authors have shown that the heading tuning of some neurons in areas MST (Bradley et al, 1996;Page and Duffy, 1999;Shenoy et al, 1999Shenoy et al, , 2002Ilg et al, 2004) and VIP (Zhang et al, 2004) compensates for smooth pursuit eye movements. It has been argued that pursuit compensation is equivalent to a transformation 2 ] as a function of VVR and EPR.…”

Cortical dynamics of navigation and steering in natural scenes: Motion-based object segmentation, heading, and obstacle avoidance

“…The human homolog of monkey MST is also implicated in human heading detection tasks (Beardsley & Vaina, 2001). Heading appears to be represented as a population code in both primate MSTd and human MT complex (hMT+) (Beardsley & Vaina, 2001;Page & Duffy, 1999). It is the MT -ON-center OFF-surround network that enables it to respond to differential motion.…”

A neural model of how the brain computes heading from optic flow in realistic scenes

“…Eye movement sensitive gain fields have been shown to efficiently deal with real eye rotations in template models (Beintema & van den Berg, 1998;Elder et al, 2008). Consistent with such a mechanism, some primate MSTd cells have responses that are modified during pursuit eye movements (Page & Duffy, 1999). Although these data are consistent with a template model with gain fields, they are hard to explain using models that produce a rotation-free optic flow representation before inputting to MST, such as decomposition or differential models.…”

“…Such a distributed representation of heading has been described in primates and humans (Beardsley & Vaina, 2001;Page & Duffy, 1999). The model is computationally efficient, demonstrating that a small number of adaptive flow filters, or templates, distributed across visual space can produce high levels of accuracy with a wide range of inputs.…”

“…Radial motion occurs when an observer travels along a forward or backward path through the environment, whereas planar motion occurs due to a sideward path through the environment or due to rotation of the head or eyes. Heading appears to be represented as a distributed population code in both primate MSTd and human hMT+ (Beardsley & Vaina, 2001;Page & Duffy, 1999).…”