final: sensory integration Flashcards
Give examples of multimodal integration:
Movement: Balance: To stay upright we use information from vestibular, somatosensory, and visual systems.
unimodal, bimodal, trimodal, multimodal:
Unimodal: one modality. Bimodal: two modalities. Trimodal: three modalities.
Multimodal: more than one modality
Explain the McGurk effect:
Communication: Perception of sound can be strongly influenced by visual cues from the moving lips. What you see affects what you hear
How could you test for multimodal integration in a neuron or groups of neurons?
Record from a single neuron in the deep layers of the superior colliculus while playing a visual stimulus, an auditory stimulus, or both at the same time
Superadditive:
The response to the bimodal stimulus is larger than the sum of the responses to the auditory and visual stimuli presented by themselves
Can sensory feedback improve prosthetic control? Case study:
patient had a prosthetic device for 2-years with only visual-feedback
Then added neurostimulation to simulate sensory feedback
Brain has bimodal (visual+somatosensory) feedback!
Explain how you could adapt a prosthetic to provide somatosensory feedback
Neural activity in the motor cortex controls the prosthetic limb. Prosthetic limb movement stimulates somatosensory cortex
Stimulating different electrodes evokes somatosensory percepts at different knuckles
What are the object-transfer task
Object transfer task: pickup cylinder in the grey region, set it down in the green region. Repeat as many times as possible in 2 minutes
What are the ARAT tasks?
ARAT (Action Research Arm Test) -a standard test for measuring motor skills. Time how long it takes to transfer all the objects onto the green platform
How did the patient’s performance change on these tasks after somatosensory feedback? Effects of ICMS (Intracranial microstimulation)
Grasp time decreased, Transport time does not change, Release time decreased, Hand moved around less in grasp zone, Decreased amount of time spent right over the object
Why are owls an excellent model system in which to study multimodal integration?
Owls have excellent auditory localization –photos from a completely dark room.
Owls have excellent night vision –they have a densely packed all-rod retina. Mice are very quiet, and some nights it is very darkàowls rely on coordinated audiovisual input
what are ITD and ILD? How are they used by owls to hunt prey?
ITD (interaural timing difference) used for azimuth
LD (interaural loudness difference) mainly used for elevation (vertical axis)
Explain the contribution of each of the following brain areas to audiovisual integration in the owl: ICC, ICX, Optic Tectum
Brain uses ITD to guide orientation of head toward the sound source. Two positive outcomes:–Gaze reveals visual confirmation of prey. Direction of head orientation then instinctively guides the direction of talon strike.
Successful hunts usually rely on both audition and vision.
Explain the immediate effect of placing prisms on an owl – visuomotor learning
After only tens of minutes, owl makes visuomotor adjustment: learns to reach 20oto the right.Talon strike has now become locked to the direction of gaze, not to the direction of head orientation.This is an improvement since owl can now accurately strike a visually identified target.
Owl relies on ITD information that has not changed.Orients its head toward the sound. Optically displaced gaze falls off target, preventing visual assessment. Owl may not strike to an unknown target without visual identification, thus, talon strike may not occur.
Explain the longer-term effect of placing prisms on an owl—auditory learning
After this learning period, when owl hears a sound at 40o, it moves the head 20o. Successfully aligns the optically displaced gaze to the auditory target.Vision confirms target and corrected talon strike will be accurate Talon accuracy is restored. The underlying basis of this learning is plasticity within the auditory space map (external nucleus of the inferior colliculus = ICX).
