Exam 3 Flashcards
(137 cards)
How do we detect stimuli?
receptors convert detection of stimulus into electrical signals, and brain integrates the info
What categories of stimuli can we detect?
mechanical, visual, thermal, chemical, electrical
What are some themes of sensory processing?
Sensory neurons are specialized to translate specific stimuli into electrical signals, and spatial information about the source of stimulus is preserved in the organization of the CNS
How is the nervous system set up for difference detection?
Amplification of new signals and edge detection
Bottom-up modification
As information travels up to the brain, it is processed and integrated, allowing for more complex perception
Top-down modification
Brain inhibits and prevents some signals from occurring- inhibition of pain is one such example
true or false: receptors only respond to a specific type of stimulus at a specific intensity
true
How is intensity of a stimulus encoded?
Frequency of action potentials
How do we distinguish different stimuli?
Labeled lines organization- in which sensory neurons only respond to a specific input and the brain then interprets the signal based on the wiring/source
What are receptor potentials?
Local changes in membrane potential
what are the steps of sensory detection?
sensory stimulus detected, receptor potentials, cell reaches threshold, sensory neurons fire action potentials
Which is sensory, the dorsal or ventral root ganglia?
Dorsal
What is a pacinian corpuscle and how is it innervated?
Pacinian corpuscles are what respond to vibration because their ion channels are stretch sensitive, so when stretched, the sodium enters and depolarizes the cell. They are innervated by dorsal root ganglia
Range fractionation
the term that refers to the idea that different receptors have different thresholds of firing over a range of stimulus intensities, so some receptors require a higher intensity stimulus to fire which also allows for us to determine the intensity of the stimulus- high intensity inputs cause combined responses of all three neurons
Sensory adaptation
The process by which frequency of action potentials decreases with prolonged exposure to stimuli- this is what allows for emphasis of new stimuli
Phasic receptors
Display adaptation
Tonic receptors
Little to no adaptation
How do we control attention to information?
sensory adaptation, accessory structures like eyelids, top-down processing where higher brain centers suppress some inputs and amplify others
Receptive field
The part of the body surface in which a stimulus will trigger firing of that neuron- location and size of receptive field can give information about where a stimulus came from
Surround inhibition
stimulus on outside radius of receptive field provides inhibition/prevents cell firing
True or false: body is mapped onto somatosensory cortex
true
pathway of sensory info
dorsal root ganglia to spinal cord to thalamus to primary somatosensory cortex (S1)
How does sensory information arrive to the brain?
each sensory system has its own pathway, and passes through stations during processing; most sensory pathways pass through the thalamus
Where do sensory pathways terminate
cerebral cortex