Neuro - Block3 - Sensory
Understand the basic qualities of environmental stimuli extracted by the sensory receptor cells.
Know the ways that clinical conditions might be expected to interact with information being transmitted by a sensory system.
Understand mechanisms for slow- and rapid-adapting receptors, and be able to discern the kinds of sensory information that non- , slow- , and rapid-adapting receptors are each able to convey. Be cognizant of how receptor placement and receptive field characteristics coordinate to influence the transmission of sensory information.
Understand the mechanisms of convergence and divergence in neural pathways and how these pathways work to process sensory information.
Understand basic neural information-processing mechanisms: surround-antagonism, inhibition, and disinhibition.
Know the ways that clinical conditions might be expected to interact with information being transmitted by a sensory system.
Understand mechanisms for slow- and rapid-adapting receptors, and be able to discern the kinds of sensory information that non- , slow- , and rapid-adapting receptors are each able to convey. Be cognizant of how receptor placement and receptive field characteristics coordinate to influence the transmission of sensory information.
Understand the mechanisms of convergence and divergence in neural pathways and how these pathways work to process sensory information.
Understand basic neural information-processing mechanisms: surround-antagonism, inhibition, and disinhibition.
Terms
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- Sensory receptors detect energy, which is perceived as
- Modality (pain, taste, temp etc.) Intensity Location Duration
- Submodalities = ?
- ex. sweet, salty Exist because sensors are not all homogenous
- The energy that is specific to a sensory receptor
- The "adequate stimulus"
- Threshold for stimulus at a receptor shares a ________ relationship with sensitivity
- Reciprocal: ie. receptor w/ higher sensitivity --> lower threshold receptor
- Practice, fatigue, stress and context all influence
- Threshold of a sensor
- When stimulus intensity increases, but probability of detection of stimulus (via testing) stays the same, what else has changed
- Ability of sensory system to detect change has decreased
- Intensity of sensation diminishes regardless of persisting stimulus b/c
- Receptor potential amplitude has decreased
- When receptor potential amplitude decreases, this is called
- Adaptation
- Forms of adaptation
- Fast Slow Non-adapting
- Changes in intensity of the stimulus
- Travels on fast adapting receptors
- Steadily changing or static stimulus
- Travels on slow/non-adapting receptors
- Variations in adaptation between cells is dependent upon
- The manipulation of the cell's membrane components (ex. inactivation of Na+, Ca2+ channels or activation of Ca2+ dependent K+ channels)
- Pacinian Corpuscles are what form of adaptors
- Fast Adaptors
- Portion of the body that when stimulated results in sensory neuron activation
- The receptive field
- Dedicated axons for a specific receptive field
- Labeled Lines
- Types of Receptive Fields
- 1 and 2
- Character of a Type 1 field (shallow)
- Small area Clearly defined Uniform response across field
- Character of a Type 2 field (deep)
- Larger area Poorly defined Single point of maximal response within their field
- Receptive fields are not detailed enough though, so what is needed
- Classification of receptors by both Field and Adaptation
- Small, well defined, continuous firing receptors with uniform responsiveness across their field
- SA1 - Slow Adapting Type1 Receptor
- Large, poorly defined, continuously firing receptors with varying responsiveness across their field
- SA2 - Slow Adapting Type2 Receptor
- Small, clearly defined, burst firing (onset and end of stimulus) receptors with uniform response across their field
- FA1 - Fast Adapting Type1 Receptor
- Large, poorly defined, burst firing (onset and end of stimuli), with varying responsiveness across their field
- FA2 - Fast Adapting type2 Receptor
- The subcategories of SA1, SA2, FA1, and FA2 receptors provide what facilitation for the senses
- More detailed information about duration, intensity and location of stimuli
- How sensation with various receptors increases
- Overlap of fields Convergence of pathways Divergence of pathways
- The strongest post synaptic inhibition occurs where on the neuron
- Inhibition which originates just before the first Node of Ranvier
- Descending strength of post synaptic inhibitions
- Prior to first Node of Ranvier On soma of neuron On distant region of neuron (downstream)
- Inhibitory neuron on pre-synaptic axon terminal of neuron being inhibited is what type of neuron
- Pre-synaptic potential
- Presynaptic potential utilizes what mechanism
- Prevents the opening of voltage gated Ca2+ channels needed to release Ca2++ for vesicle fusion and neurotransmitter release
- Some stimulatory pathways are maintained near threshold (but not passing) via what mechanism
- Tonic Inhibition
- Tonically inhibited stimulatory pathways require what
- Disinhibition
- Prominent example of Tonic Inhibition
- Runner's high - endogenous pain modulation via opiod modulators
- Stimulus in the center of a receptive field provides stimulation, but stimulus surrounding it provide inhibition
- Center Surround organization of receptive fields
- Center Surround organization allows for better
- Localization