Ch 7 Sensory Systems Flashcards
the pathway of perception from the senses/levels of analysis
the sensory receptors to the thalamus
then the to primary sensory cortex
then to secondary sensory cortex
then to the association cortex
current model of the senses
5 levels of analysis
functional segregation
parallel pathways (info flows on many pathways)
hierarchal organization (more complex and specific as you go up)
physical dimensions (list the perceptual) for
amplitude
frequency
complexity
amplitude: loudness
frequency: pitch
complexity: timbre
primary auditory cortex is organized ___
tonotopically (by frequency in functional columns)
what is fourier analysis
breaking down of a sound into its component sine waves
when added together the waves form the complex sound
pitch is related to ____, meaning
fundamental frequency: the frequency that is the highest common divisor for various component frequencies
pitch may not be directly related to the frequency of any of the sounds components
when the basilar membrane vibrates and moves the hair cells, what is the responding nerve
auditory vestibular nerve
The cochlea is highly sensitive to different frequencies:
Higher frequencies stimulate hair cells near the ___
Lower frequencies stimulate hair cells at the tip of the ____
oval window
tip of basilar membrane
what are the receptive organs of the vestibular system
semicircular canals
fluid filled
balance/head position
how is the pathway from the ear to primary auditory cortex different than that of the visual system
it is more of a network than a direct path
where is the primary auditory cortex, where does it get most of its input from, what are its regions
temporal lobe
input from medial geniculate nucleus (MGN)
Core region: Contains primary auditory cortex.
Belt region: Surrounding area — secondary auditory cortex.
Parabelt areas: Secondary regions outside the belt.
Organization of Auditory Cortex
Functional Columns: Columns within the auditory cortex respond optimally to sounds in the same frequency range.
Frequency Gradients: Areas of the cortex are arranged with a gradient of frequency (from low to high frequencies) along its length.
Periodotopy: Organization based on temporal components of sound — variations in amplitude of sound frequencies over time.
two streams of auditory cortex
what/identify: anterior auditory pathways
where/location: posterior auditory pathway
bilateral lesion auditory cortex damage
total loss of hearing (may return after a few weeks)
Permanent Effects:
Loss of the ability to process structural aspects of sound, which is necessary for speech comprehension.
May lead to word deafness — inability to understand speech sounds.
Damage can affect both What and Where auditory pathways.
types of deafness
Conductive deafness
Damage to ossicles
Nerve deafness
Damage to cochlea or auditory nerve
□ If only part of cochlea damaged, some frequencies but not others may be affected
what are the 3 systems that make up the somatosensory system
Exteroceptive: External stimuli, such as touch, pain, and temperature, detected by receptors in the skin.
Proprioceptive: Monitors the position and movement of the body through receptors in muscles, joints, and balance organs.
Interoceptive: Detects internal body conditions (e.g., hunger, internal temperature).
exteroceptive system has three main types of sensory stimuli:
Mechanical stimuli (touch)
Thermal stimuli (temperature)
Nociceptive stimuli (pain)
cutaneous receptors are where, simplest are __ and more complex are ___
in the skin
simple: free nerve endings
complex: largest and deepest (Pacinian)
what adapt slowly and respond generally to skin indentation/ skin stretch
Merkel’s Disks: Slowly adapt and detect gradual skin indentation.
Ruffini Endings: Slowly adapt and detect skin stretch.
Two Major Somatosensory Pathways
Dorsal-column medial-lemniscus system:
Carries information about touch and proprioception (sensing position and motion of body)
Anterolateral system:
Carries information about pain and temperature.
Dorsal-column medial-lemniscus pathway
Neurons enter the spinal cord via the dorsal root and ascend ipsilaterally (on the same side) in the dorsal columns.
They synapse in the dorsal column nuclei of the medulla and then decussate (cross over) to the other side of the brain.
After crossing, they travel through the medial lemniscus to the ventral posterior nucleus of the thalamus and project to the primary somatosensory cortex (SI) and secondary somatosensory cortex (SII).
Anterolateral system pathway
Neurons synapse in the spinal cord immediately upon entry.
The information then decussates and ascends in the contralateral (opposite side) anterolateral portion of the spinal cord.
The three branches of the trigeminal nerve carry pain and temperature information from the face to the thalamus.
The anterolateral system includes three major tracts:
Spinothalamic tract: Pain and temperature to the thalamus.
Spinoreticular tract: Involves arousal and emotional aspects of pain.
Spinotectal tract: Involved in orienting responses to pain.
SI (primary somatosensory cortex) is organized ___
somatotopicaly: according to a map of the bodies surface
