Lecture 7 Eye limb coordination Flashcards
Eye limb coordination
Motor act of coordinating the eyes and limb - moving them both toward the same target in unison
Eye movements are ______ with goal directed hand movements
tightly coupled
When reaching or intercepting an object
Humans naturally direct their eyes to the object
How do eye movements improve hand accuracy?
Through a combination of visual with efference-copy information
The information exchange between eye and hand movement system is
Bidirectional.
–> Execution of a concurrent hand movement can result in improvements in eye movements
How long does a saccade take?
20-40ms
When we track something with our eyes how do they move?
They track the target and then jump with a saccade and then track again.
Eye foot coordination
When walking, gaze consistently looks 1.5s ahead to optimise vision of the environment that is traversed so they can walk efficiently and stable.
How do we encode information for eye hand coordination?
With reference frames and coordinates systems
Egocentric reference frames
Representing an object relative to yourself
Allocentric Reference Frames
Representing an object relative to an external object
The hippocampus has more _____ coded information
Allocentrically
Gaze
The direction of your eye. Where you are looking in space. The main purpose of gaze shifts is to redirect the fovea toward a new object of regard
Retinal/Eye fixed/Eye centered
Information is coded relevant to your looking direction
Shoulder-arm geometry
The reference frame for a limb is the torse. The centre of shoulder rotation is significantly shifted from that of the head, which in turn is shifted with respect to that of the eye
Forward Models
A network that predicts the sensory consequences of a given motor command in an environment
The ___ and ___ seem to be more involved in reaching movements
Premotor cortex and M1
How do we make a decision in a sports related context such as do I hit the ball to the left or to the right? Or do I block the ball instead (volleyball)
The brain specifies multiple possible actions in parallel up to the level of motor preparation while a variety of biasing influences cause one specific response program to prevail.
How does continous control work?
So we can still change or update our movements even after they have begun. We change our mind as information is still being collected after the initial decision to move towards a certain thing
How long does it take for a correction to kick in?
About 100ms. It is not reflexive
Looking ahead for forthcoming actions
We need to be able to look ahead at a sequence of movements
