Somatosensation
*the skin sensations: touch/pressure, warmth, cold, and pain.
Pacinian Corpuscle
*The prototype touch receptor; detects sudden displacement or high frequency vibrations on skin.
Pacinian Corpuscle Potential Strength
*When the potential is big enough the receptor reaches threshold and generates and AP
Adaptation
*The progressive loss of response to a maintained stimulus. Key for representing changes in ones Environment*
Tonic receptors
*Show slow or no decline in action potential frequency
Phasic Receptors
*Display adaptation and decrease frequency of AP's
Sensory Adaptations
*Include Tonic Receptors, and Phasic Receptors
2 Mechanisms for Detecting changes in intensity of Stimulation
*Changes in AP frequency in single neurons; Different populations of neurons that respond to different levels of intensity.
4 Tactile Touch Receptors in the skin
Pacinian Corpuscle- Vibration,fast adapting
Meissner's Corpuscle-touch,fast-adapting
Merkel's Discs-Touch,slow-adapting
Ruffini's ending-stretch, slow adapting
Primary somatosensory cortex (S1)
*Receives touch information form the opposite side of the body
Secondary somatosensory cortex (S2)
*Maps both sides of the body
Somatosensory Pathways
*Information from touch receptors in the head enter CNS through Cranial nerves
Information from receptors below head enter spinal cord and travel thru 31 spinal nerves to the brain
Somatosensory information
*Ascends ipsilaterally in the dorsal column system
Dermartome
*Refers to the skin area connected to or innervated by a single sensory spinal nerve
Pain
*Discomfort normally associated with tissue damage. Conveyed by activation of receptors on free nerve endings
Nociceptors
*name of sensory receptors that convey pain-related information
TRPV1
*Conveys Pain information relevant to heat
Cold and Hot
-Found in unmyelinated fibers "C Fibers"
Capsaicin
*molecule in chili peppers that activates this class of receptors
TRPV2
*Detects hotter temperatures than TRPV1
Really Hot
-Found on large myelinated nerve fiber
"A Delta"
SCN9 gene
*Encodes a NA+ on nociceptors, people with a defect in this gene can not feel pain
Pain Pathways
Ascend in the spinothalamic tract
Periaqueductal gray area (PAG)
*Midbrain structure that exerts descending inhibitory control over afferent pain pathways
PAG releases -substance P in afferent pathways
Endorphins
*Group of endogenous peptides that activate opiate receptors. (enkephalin, dynorphin)
Gate Control Theory of Pain
*Melzack and Wall (1965)
Incoming pain information can be blocked at the level of the spinal cord from descending paths from the PAG
Placebo
*Drug or other procedure with no pharmacological effect.
Placebos decrease pain perceptions by activating emotional response systems.
Cannabinoids
*Chemicals related to marijuana that are believed to block pain perceptions
Chemodetection
*Taste and Smell
5 Taste Receptors
*Sweet, Sour, Salty, Bitter, Unami- (Meaty)
Papillae
*On tongue contains 50-150 taste receptor cells per bud. Taste cells constantly replace
3 Types of Papillae
*Foliate, fungiform, vallate
Taste
*Salty-Na+ is transported across cell membrane via channels leading to depolarization
Sour-Acid (H+)sensitive receptors block K+ channels and induce depolarization by preventing K+ outflow
Sweet- Detected by combination of two members of taste receptor family
Supertasters
*Have higher sensitivity to all taste and mouth sensations
Olfaction
*Sense of smell
Olfactory receptors
*Nerve endings that act as the receptors for the sense of smell
Memory
*The retention of information.
Primacy Effect
*The tendency to remember the first items well.
Recency Effect
*The tendency to remember the last items well.
Free Recall
*To produce a response.
ex. essay or short answer tests.
Cued Recall
*Recieving significant hints about the material.
Recognition
*Several choices, and choosing the correct response.
ex. multiple choice tests.
Savings Method
*aka. relearning method.
Detects memory by comparing the speed of original learning to the speed of relearning.
Explicit Memory
*aka. direct memory
Someone who states an answer regards it as a product of his or her memory.
Implicit Memory
*aka. indirect memory
An experience influences what you say or do even though you might not be aware of the influence
ex. The taxidermy/zoo video
Primes
*Reading or hearing a word temporarily primes that word and increases the chance you will use it yourself.
Procedural Memories
*Memories of motor skills.
Declaritive Memories
*Memories we can readily state in words.
Information- Processing Model
*Information that enters the system is processed, coded, and stored.
Sensory Store
*Momentary storage of sensory information.
Short-Term Memory
*Temporary storage of recent events.
Long-Term Memory
*A relatively permanent store.
Semantic Memory
*Memory of general principles and facts.
Episodic Memory
*Memory for specific events in a person's life.
Source Amnesia
*Forgetting where or how you learned something.
Chunking
*Grouping items into meaningful sequences or clusters.
Retrieval Cues
*Associated information that might help you regain the memory.
Consalidate
*Converting a short- term memory into a long- term memory.
Working Memory
*A system for working with current information.
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