Lecture 7 Review Flashcards
List the principles of the sensory system
- Transduction mechanism
- Receptive Fields
- Topographically arranged
- Relay Centers
- Parallel Pathways
- Hierarchical organization
- Cross midline
What is the transduction mechanism?
It converts environmental energy into biological energy. Transduction is the change in membrane conductance. There are three types, mechanical, chemical, and photic.
Increasing stimulus strength increases the receptor potentials and frequencies of APs
What is the receptive field?
each transducing cell or neuron is receptive to specific sensory information.
It is the area of input for a single cell and where transduction occurs
What is topographical arrangement?
The “shape” of information. Allows for information to be encoded across a population of cells. Defined by an anatomically defined rule.
What are relay centers?
Projection neurons that relay information at specific sites in the brain. Each relay center makes the information more complex.
What do parallel pathways do?
Allow sensory information to be maintained across modalities and quality of message to be maintained
What is lateral inhibition?
When local neurons interact with a pathway. It enhances the differential activation within a population.
Match the relay to the system: VPL Olfaction VPM Visual MGN Somatosensation LGN Auditory MDN Taste
VPL - Somatosensory VMP - Taste MGN - auditory LGN - Visual MDN - olfaction
What is the primary cortex?
The first area of the cortex that receives sensory information
What are secondary and association cortices?
Secondary: receives information from the primary cortices
Association: receives information from multiple sensory pathways or is sensory/motor
What is hierarchical organization?
This increases complexity. Allows highly complex integration and responses by nervous system. Increases in complexity occurs in relays by convergence
Why does information cross the midline?
It just does. Information from one side of the body is projected on CONTRALATERAL side of brain (ex. somatosensory)
What are the chemical senses?
Smell and Taste
What is the olfactory epithelium?
The chemically sensitive part of the brain
How does olfactory transduction work?
G protein coupled receptors. Gs increases cAMP which activates ion channels. This causes high intracellular Cl and depolarization. They have population encoding, which activates multiple neurons differently and allows for differentiation
What part of the olfactory system does the odorant interact with?
the Cilia
Where is the first relay for olfaction?
The olfactory bulb on the cortex
What does the olfactory bulb glomerulus do?
similar neurons converge on the glomeruli and communicate to neural centers. It creates a anatomical map of the type of odorants. they run in parallel to higher areas of the brain
What is the function of the periglomerular granule cell in the olfactory pathway?
It serves as lateral inhibition
What pathway does not run though the thalamus?
the olfactory pathway
What part of the brain has continuous cell birth?
Olfactory bulb
What are taste cells?
sensory cells on the tongue that are chemically sensitive, and have a graded potential. must reach a threshold to taste.
How to gustatory neurons respond?
They are differentially tuned, have population encoding
Describe how the taste transducer works
Though it is different for each taste, it generally increases intracellular Ca
Describe the taste pathways
taste buds respond to chemicals, transduce information. information is projected to the brain stem, then the VPM on the thalamus and to the cortex
