Question

Which of the following statements about the retina’s operation across different levels of ambient light is most accurate?

1. On-center retinal ganglion cells (RGCs) respond to a small spot of light in the center of its receptive field over an extremely small range of ambient intensities.
2. Off-center RGCs respond to a small spot of light in the center of its receptive field over a broad range of ambient intensities.
3. RGCs generally do not report absolute ambient light intensities, but rather encode relative intensity differences between its receptive field center and surround.
4. Interactions within the outer plexiform layer do not play an important role in modulating the photic sensitivity of ganglion cells.
5. Back-propagating action potentials from RGC targets in the ventral posterolateral thalamic nuclei alter light sensitivity.

A student with intractable epilepsy had their corpus callosum surgically severed in an effort to limit the spread of the seizures.  This procedure resulted in a disruption of…

1. Axons arising from glutamatergic neurons in Layer 2/3 of the cortex that project to the thalamus and are born first during embryonic cortical neurogenesis.
2. Axons arising from dopaminergic neurons in Layer 5 of the cortex that project to the striatum and are born during the middle of the period of embryonic cortical neurogenesis.
3. Axons arising from glutamatergic neurons in Layer 2/3 of the cortex that project to other regions of the cortex and are born last during embryonic cortical neurogenesis.
4. Axons arising from glutamatergic neurons in Layer 5 of the cortex that are born first during embryonic cortical neurogenesis.
5. None of the above

A colleague has made a new mouse model that exhibits selectively loss of Vglut2 (a protein involved in loading glutamate into vesicles) in neurons of the subthalamic nucleus. This results in a reduction in indirect pathway glutamatergic output from the basal ganglia. The mouse most likely exhibits... a. Inability to initiate movements b. Hyperlocomotion c. Enhanced visual responsiveness d. Loss of auditory function

During your shift as an emergency room physician, you admit a patient who fell 30 feet while rock climbing onto rocky terrain. Upon examination, the patient has reduced voluntary motor control of his right leg, a loss of pain and temperature sensation in his left side from the hip down, and a loss of fine touch and proprioception in his right side from the hip down. What is the likely location of his spinal cord lesion?

1. A complete spinal cord lesion at L1
2. A partial lesion localized to the left side of the spinal cord six segments rostral to T7
3. A partial lesion localized to the right side of the spinal cord six segments caudal to T7
4. A complete spinal cord lesion three segments caudal to C8
5. A partial lesion localized to the right side of the spinal cord three segments rostral to S5

Answer 1

Which of the following statements about the retina’s operation across different levels of ambient light is most accurate?

The answer is d,Interactions within the outer plexiform layer do not play an important role in modulating the photic sensitivity of ganglion cells.

A student with intractable epilepsy had their corpus callosum surgically severed in an effort to limit the spread of the seizures.  This procedure resulted in a disruption of…

The answer is e,None of the above

A colleague has made a new mouse model that exhibits selectively loss of Vglut2 (a protein involved in loading glutamate into vesicles) in neurons of the subthalamic nucleus. This results in a reduction in indirect pathway glutamatergic output from the basal ganglia. The mouse most likely exhibits..

The answer is . a. Inability to initiate movements

During your shift as an emergency room physician, you admit a patient who fell 30 feet while rock climbing onto rocky terrain. Upon examination, the patient has reduced voluntary motor control of his right leg, a loss of pain and temperature sensation in his left side from the hip down, and a loss of fine touch and proprioception in his right side from the hip down. What is the likely location of his spinal cord lesion?

The answer isa, A complete spinal cord lesion at L1