Lecture 5 - Sensory Systems Flashcards
Whats the organisation of sensory systems ?
Peripheral sensory receptors
Spinal cord
Sensory thalamus
Primary sensory cortex
Unimodal assocaition cortex
Multimodal association cortex
Whats the link between taste and smell?
Smelling food all helps us to taste our food
Whats the gustatory pathway?
Taste buds
Going to either
- taste receptor cells or touch, pain receptors
Goes to brainstem
Goes to thalamus
The tast receptor cells goes to the taste centres of somatosensory cortex
And the touch and pain receptors go to the somatosensory cortex
Whats area V4 for?
Colour processing
Explain more about area V4?
Individual neurons in the V4 response to a variety of wavelengths
What happens when you damage the V4?
Achromatopsia - inability to perceive colour
Patients see the world in black and white
Inability to image or remember colour
Vision otherwise normal
Whats area V5 known for?
Movement perception
Describe area V5?
Neurones respond to movement
What happens when you damage area v5?
UNAFFECTED IN colour, perception, object recognition, etc
- able to judge movement of tactile or auditory stimuli
What does the left visual field project for laterality of vision?
Projects bilaterally to right visual cortex
What does the right visual field project for laterality of vision?
Bilaterally to left visual cortex
Whats area v3?
Building a visual represention of the object
Whats area v2?
Virtual vision
Whats the ventral stream?
Structural information and object recognition
Whats the dorsal stream?
Spatial information
Describe the ear cochlea?
Sound waves converted into vibrations in basilar membrane
Hair cells in organ of corti transduce movement of basilar membrane into electrical signal
Information is transmitted along vestibulo-cochlear nerve
Describe the auditory processing pathway ?
Cochlea - ear
Cochlear nucleas - pons
Superior Oliver’s nucleus - pons
Inferior colliculus - thalamus
Medial eniculate nucleas - thalamus
Auditory cortex - cortex
Where is processing originally thought to be in?
The auditory cortex
When’s auditory discrimination possible in the absence of?
Auditory cortex like direction, pitch and tunes
So
Initial processing occurs in pons and thalamus
What does auditory cortex analyse?
Analyses the complex aspects of sound
What are the two types of analysis in complex aspects of sound?
Dorsal stream in the partial lobe - spatial analysis
Ventral stream in the temporal lobe - component analysis
What is localisation of sound dependent on?
On different characterises of a sound arriving at each ear
Describe intensity difference?
Difference in intensity of sound between the two ear
Whats latency?
- phase shift between the two ears
- due to slightly different distance to reach each ear
Whats duplex theroy?
Sound location depends on a combination of intensity and latency
Where is the semicircular canals found in?
The vestibular organ - inner ear
What does the semicircular canals detect?
Detects head rotation and tilt around three axes
Explain the direction for head movement to information being transmitted to brain?
Head movement
Movement of endolymph
Displacement of capula
Stimulation of hair cells
Activation of CN VIII, vestibulocochlear nerve
Information transmitted to brain
Whats the two things in the vestibular nuclei?
Medial and lateral which are brain stems
Whats in the medial?
Neck muscles
Head orientation
Whats in the lateral ?
Peripheral muscles
Postural muscles balance
What causes motion sickness?
May be caused by a mismatch between visual information and information from the vestibular organ
What maintains the relative position for the head?
As head orates, eyes move to compensate maintain the relative position
When does vestibule-ocular reflex occur and what are they depdent on?
Occurs even with eyes closed
Not dependent on visual input but dependent on vestibular input
Where is auditory receptors contained in?
Cochlea of the ear
Whats the lateral vestibular muscles responsible for?
Maintaining posture and balance
Whats the medial vestibular nucleas responsible for?
Head oriention and ocular reflexes
Maintain gaze during head movement
Whats the flow for somatosensory perception?
Spinal cord - peripheral - sensory receptors
Brainstem - cranial - sensory receptors
Thalamus
Somatosensory cortex - cingualte cortex
Other cortical area
Where is pain and temperature detected for peripheral sensory receptors?
Free nerve endings
Whats the sensory receptor for touch?
Merkels disc
Meissners corpuscle
Whats the sensory receptor for vibrations?
Pacinian corpuscle
What’s thee sensory receptor for stretch?
Ruffinis ending
Whats the sensory receptor for touch and movement?
Hair follicle receptor
What is nociception?
The perception of noxious somatosensory information
Whats the subjective sensation evoked by nocicpetion?
Pain
Whats the modulation of nocicpetion or pain?
Analgesia
Whats the main sense organ for somatosensory perception?
The skin
Whats the main sense organ for somatosensory perception?
The skin
Where does somatosensory (touch) perception occur?
In somatosensory cortex - post central gyrus
