Chapter 7 Flashcards
Define secondary sensory cortex
A system comprises the area of the sensory cortex that receives most of their input from the primary sensory cortex of that system or from other areas of the secondary cortex of the same system
Define primary sensory cortex
The area of sensory that receives most of its input directly from the thalamic relay nuclei of that system
Define association cortex
Any area of the cortex that receives input from more than one sensory system. Most input to areas of association cortex comes via area of secondary sensory cortex.
Explain what it means to say that sensory systems are organized by hierarchical organization?
Hierarchical organization- a system whose members can be assigned to specific levels or ranks in relation to one another.
1) sensory info is thought to flow through brain structures in order of their increasing neuroanatomical complexity
2) sensation is thought to be less complex than perception
What are the 3 separate systems composing the somatosensory system?
1) Exteroceptive cutaneous system- which senses external stimuli that are applied to the skin.
2) Proprioception system- (monitors body position) which monitors info about the position of the body that comes from receptors in muscles, joints, and organs of balance
3) Interoceptive system- (monitors conditions within the body such as blood pressure). Which provides general info about conditions within the body.
Free nerve endings are sensitive to _____ and ______
Changes in skin temperature, pain
List the 2 primary pathways for which somatosensory info ascends from the skin to the cortex
1) Dorsal-column medial-lemniscus system: Tends to carry info about touch and proprioception
2) Anterolateral system: Tend to carry info about pain and temperature
________ are cutaneous receptors that adapt rapidly and do not respond to constant pressure
Pacinian corpuscles
_________ are cutaneous receptors that adapt slowly and respond to gradual skin indentation
Merkel’s disks
________ are cutaneous receptors that adapt slowly and respond to skin stretch
Ruffini endings
What is a dermatome?
The area of the body that is innervated by the left and right dorsal roots of a firm segment of the spinal cord
List and define the 2 primary types of somatosensory agnosias
Astereognosia- The inability to recognize objects by touch. (Defects in somatosensation)
Asomatognosia- The failure to recognize parts of one’s own body.
What is the cortical area most frequently associated with pain?
Anterior cingulate cortex
Electrical stimulation of the ________ has analgesic effects
Peri aqueducts gray area
List 2 characteristics of selective attention
1) it improves the perception of the stimuli that are its focus
2) it interferes with perception of the stimuli that are not its focus
