Sensory Systems, Perceptions and Attention Flashcards
How is the sensory system organized?
A hierarchical organization
Flows through brain structures in order of increasing anatomical complexity
Apparent from a comparison of the effects of damage to various levels
What is functional segregation in the sensory system organization?
Different parts specialize in different kinds of analysis
Each of the 3 levels: primary, secondary, association
What is parallel processing in the sensory system organization?
Organization so that information flows between structures, simultaneously along multiple pathways
What is the function of the auditory system?
The function of the auditory system is the perception of sound
Sounds are vibrations of air molecules that stimulate the auditory system - your ears perceive someone talking as a vibrations
What parts of the ears are apart of outer ear?
Tympanic membrane (ear drum)
What parts of the ears are apart of the middle ear?
Ossicles (3 small bones)
What part of the ears are apart of the inner ear?
-Oval window
-Organ of Corti
-Hair cells of basilar membrane
-Tectorial membrane
What is the tonotopic organization?
The organization of the organ of Corti is tonotopic
Different frequencies produce maximal stimulation of hair cells at different points along the basilar membrane
Higher frequencies excite receptors closer to the oval window
Lower frequencies producing greater activation ay the tip of the basilar membrane
What is the order of the pathway from the inner ear to the primary auditory cortex?
- Hair cells synapse on neurons
- Axons enter metencephalon
- Synapse in ipsilateral cochlear nucleus
- Travel to superior olives
- Travel to the inferior colliculus via the lateral lemniscus
- Signals from each ear are combined at a low level (in the superior olives)
- Fibers ascend to the medial geniculate nucleus of the thalamus
- Fibers ascend to the primary auditory cortex in the lateral fissure
- Projections from each ear are bialateral
What is the auditory cortex?
Recieves input from medial geniculate nucleus (thalamus)
Core region (primary auditory cortex and 2 adjacent areas)
Belt surrounds the core
Parabelt areas - areas of the secondary auditory cortex but just on the outside of the belt
What is the organization of primate auditory cortex?
Tonotopically organization - responds to similar frequencies are close together
Contains functional columns - responds to similar frequencies
Poorly understood compared to vision
How does the auditory cortex integrates information?
Auditory signals are processed by two large areas of association cortex: prefrontal cortex and posterior parietal cortex
What are the two streams of the auditory cortex?
Anterior auditory pathway: identifies sound
Posterior auditory pathway: identifies where sound is
What is involved within the auditory-visual interactions
Integral part of sensory processing
Occurs in associations areas but also in primary areas (recent fMRI studies)
Some posterior parietal neurons have visual receptive fields and auditory receptive fields (work in monkeys)
What is the auditory cortex damage
Bilateral lesions do not cause deafness
Loss of the ability to process the structural aspects of sound
What occurs when their is damage to the anterior (“what”) pathway?
Difficultly identifying sounds
What occurs when their is damage to the posterior (“where”) pathway?
Difficulty localization sounds
What are some facts towards deafness in humans
Hearing impairment can lead to social isolation
Total deafness is rare (1% of hearing-impaired individuals)
What are two types of deafness within humans
Conductive deafness: damage to ossicles
Nerve deafness: damage to cochlea or nerve, loss of hair cell receptors
What is age-related hearing loss?
Part of the cochlea is damaged, results in a deficit in percieving high frequencies
High frequencies helped by hearing aids or cochlear implant
What is apart of the exteroceptive cutaneous system made up of
Mechanical stimulation: touch
Thermal stimulation: temperature
Nociceptive stimuli: surface pain
What is the proprioceptive system?
Body position