A needle is inserted into the right LGN nucleus in the centr

A needle is inserted into the right LGN nucleus in the central nervous system and the area is injected with glycine.

A. Where is this nucleus located? (1)

B. What is glycine and what effect would glycine have on the membrane potentials of neurons in this area? (2)

C. If glycine binds to an inotropic receptor on a post-synaptic neuron, explain how the coupling mechanism associated with this receptor changes the membrane potential of the post-synaptic neuron? (3)

D. What specific sensory pathway would be affected by this injection? (1)

E. Where would the information from the LGN be sent to once it leaves the LGN? Provide the specific location and indicate what happens at this next location. (2)

F. What are the names of the two types primary sensory neurons associated with this pathway? (1)

G. These neurons are activated by photon energy. List two differences between these two receptors and identify what those differences consist of for each cell type. (4)

H. What neurotransmitter is released by these primary sensory neurons? (1)

I. Does it excite or inhibit the next neuron in the sensory pathway? (1)

J. Name all the cells and structures that relay this sensory information from the primary sensory neurons to the LGN. Note: a well labelled diagram can be used to explain the relay of information in this pathway. (8)

K. Describe what (e.g. side, location) information and how the perception of that sensory information would be affected by glycine injected in the right LGN. (2)

Solution

A) Thalamus

B) Glycine is an amino acid neurotransmitter, This senses the membrane potential.

C) Ionotropic receptors of glycine are selectively permeable to Cl- , when these receptors open they cause the neuron to hyperpolarize and therefore they drive the membrane potential away from the threshold for firing an action potential.

D) Visual Pathway

E)  There is connection which is main central connection for the optic nerve to the occipital lobe

F) Unipolar neuron and bipolar neuron

H) amino-acid neurotransmitters

I) Yes

J) Magnocellular cells,  Parvocellular cells and  Koniocellular cells

K) right hemisphere of the brain