L1- Intro Flashcards
What are the 2 systems for rapid actions?
Open & closed loop feedback
Describe open loop control systems
-preprogrammed set of commands to generate the action
-feedforward system - requires internal model
-internal models learnt and calibrated
Describe closed loop control systems
-rapid pick up & processing of information
-sensory feedback signal from ‘noise’ to reference input
-more accurate, but slower
What near and far road information is available in the 2 control model of steering
Near- road edge feedback
Far- prospective info (feedforward) from road ahead
Describe the results from Wallis et al. (2007) on internal models
-Without visual info, ppts steered incorrectly when changing lane; correct with visual info
-We have poor explicit access to internal model
-Normal steering may be a series of closed loop movements
-Internal models are a form of memory
-Navigation requires previously stored info
What are egocentric representations (with examples)?
To do with your location and body position
-hand, eye, head, & trunk-centred
What are allocentric representations (with examples)?
World centred; Independent from you (e.g. map)
What is unilateral neglect? Where is it most common?
Deficits characterised by impaired detection/ reporting of stimuli in space contralateral to a brain lesion
-common with large stroke in one hemisphere
-more common in RH
What parts of the brain are usually damaged with unilateral neglect?
-lesions involving SUPRAMARGINAL GYRUS in the INFERIOR PARIETAL LOBULE, at the tempo-parietal junction.
How does unilateral neglect affect drawing, line bisection, cancellation, & visual search tasks?
Drawing- draws only 1 half of object
Line bisection- only bisect lines towards one side
Cancellation- only 1/2 of items
Visual search- Explores ipsilateral space much more
What is representational neglect?
Inability to process contralesional side of space
Describe Bisiach & Luzzatti’s (1978) Milan square experiment
-asked to imagine standing in square & describe
-could only describe east side
-described other side when asked to imagine facing the other way
-implies viewpoint altered info received
-must intact representation of landmarks and the square
-allocentric info intact; egocentric representations impaired
What brain regions are involved in allocentric representations?
Parahippocampal lesions- topographical amnesia
-> buried under temporal lobe
Patients with pure hippocampal damage also have problems with spatial info, specifically allocentric spatial memory (map drawing, navigation, new routes etc)
