Practice Questions Flashcards
A middle aged man presents to the ED with a head injury. During his neuro exam, he has all senses intact except his ability to feel pain. Which of the following parts of the brain was most likely affected?
A. Prefrontal cortex
B. Thalamus
C. Periaqueductal grey
D. Insular cortex
D. Insular cortex
When doing research on parts of the brain, you notice that a part of the brain lights up when the study subject is asked to name numerous objects presented to them. Which of the following areas of the brain is most likely active?
A. Anterior cingulate cortex B. Striatum C. Medial temporal lobe D. Parietal temporal occipital lobe E. Superior temporal sulcus
D. Parietal temporal occipital lobe
[high level interpretation of sensory inputs, names objects, analyzes spatial coordinates of self in environment]
Dr. Pierce is being kept awake one summer night by the sounds of exploding firecrackers coming from one of her neighbor’s houses. Activity of which cochlear nucleus best allows her to identify the disruptive neighbor in question is the one immediately to the north of her house?
A. Association cortex (A2)
B. MGN
C. DCN
D. VCN
C. DCN
The DCN is responsible for localization of sound. The VCN is responsible for identifying the nature of the sound. The MGN is a thalamic relay station in the auditory pathways and allows special processing of sounds rather than localization. The association cortex A2 is thought to respond to more complex types of sounds like speech and music rather than localization.
While working in the rodent lab you realize you no longer notice the smell that you used to notice right away. Which of the following molecular mechanisms involving Golf receptors explains this phenomenon?
A. Odorant receptor binding sites become antagonized by competitive odorants
B. Cyclic nucleotide gated channels (CNGC) become dephosphorylated
C. CNGC sensitivity to cAMP increases and leads to cell hyperpolarization
D. Cation influx in response to cAMP-induced CNGC stimulation decreases
D. Cation influx in response to cAMP-induced CNGC stimulation decreases
Two things contribute to Golf receptor adaptation:
- Sensitivity of CNGC to cAMP decreases, reducing cation influx over time
- CNGC is inactivated by receptor phosphorylation
A glutamatergic metabotropic GPCR that closes cGMP-gated ion channels in the retina occurs in which of the following situations?
A. An ON-center bipolar cell in the presence of light
B. An ON-center bipolar cell in the presence of darkness
C. An OFF-center bipolar cell in the presence of light
D. An OFF-center bipolar cell in the presence of darkness
E. An amacrine cell in the presence of light
B. An ON-center bipolar cell in the presence of darkness
The glutamate receptor in depolarizing bipolars is a GPCR that closes cGMP-gated ion channels similar to light transduction in photoreceptors. This allows a sign change. Channels open when less glutamate is present. Glutamate would activate a metabotropic receptor (mGluR6) on the ON-center bipolar cell. This results in a decrease in cation influx into the bipolar cell. (Closes cGMP-gated Na+ channels) and hyperpolarizes the cell.
While sparring in a taekwondo tournament yesterday, dr. Karius was confronted with a kick to the side of the head, which she blocked by raising her left arm. How did F2 of the premotor cortex contribute to the blocking motion?
A. It relayed the pattern of muscle activation to the alpha motor neurons to raise her left arm
B. It identified the edges of her opponent’s foot and leg to identify the best grasp with which to deflect the kick.
C. It created a rough map of the space in which the incoming kick was located
D. It created the spatial map that allowed her to recognize that her left arm was closest to the incoming kick
E. It positioned her body in space so that she maintained her balance while raising her arm
D. It created the spatial map that allowed her to recognize that her left arm was closest to the incoming kick
[F2 is the part of the premotor cortex that creates a map of space, but the map is about where your body is in relation to the object]
Dr. Karius elected to use a high block (raising her left arm up above her head, elbow bent) to deflect the previously mentioned kick. Which of the following actions would probably activate the exact same neurons in F5?
A. Replicating her opponent’s kick exactly
B. Retaliating with a power left hook punch to opponent’s head
C. Using a grasp block (left arm out, hand extended to grasp) to block the incoming kick)
D. Raising her left arm above her head with the elbow bent to block the sun and allow her to see the incoming kick better
C. Using a grasp block (left arm out, hand extended to grasp) to block the incoming kick)
[neurons in F5 are particularly important in identifying the purpose of the motion, rather than its specifics]
Later in the same sparring match, Dr. Karius is confronted with a front snap kick that she attempts to block using a down block. As the command to execute the block is processed in her brain, the release of EAAs from her subthalamic nucleus is increased. What is the result of this release?
A. Dr. Karius does not execute the block and her opponent scores a point when the kick lands unopposed
B. Dr. Karius corrects the ongoing block slightly to the left to more effectively block the kick
C. Dr. Karius executes the down block and blocks the kick as planned
D. Dr. Karius realizes the last 3 down blocks have not been successful and executes an x block instead
A. Dr. Karius does not execute the block and her opponent scores a point when the kick lands unopposed
[The important detail in the question is that the subthalamic nucleus is releasing EAA.
The subthalamic nucleus is part of the indirect pathway in the basal ganglia. Increased EAA release from the axons of the subthalamic nucleus will cause activation of the SNPR and the GPi, leading to GABA release in the thalamus. Motion is suppressed, so Dr. Karius doesn’t get the block executed and her opponent scored a point]
A patient suffers a severe head injury that damages much of the cortex. Which of the following reflexes are most likely to be impossible to elicit as a direct consequence of that damage. (Subcortical and spinal regions are spared).
A. The righting reflex B. Suckling C. The stretch (myotatic) reflex D. Hopping reaction E. Yawning
D. Hopping reaction
[Of the five options listed, only the hopping reaction (a hop elicited when a person is shoved to one side) is a reflex elicited by cortical activity]
An axon from a pyramidal cell in the primary motor cortex is activated; what is the most likely result?
A. Contraction of a skeletal muscle (e.g., a finger twitches)
B. Activation of the neurons in the substantia nigra
C. Contraction of smooth muscle (e.g., the ciliary muscle of the eye)
D. Activation of the cerebrocerebellum
E. Hyperpolarization of the motor end plate in a skeletal muscle
A. Contraction of a skeletal muscle (e.g., a finger twitches)
[The pyramidal cells in the motor cortex represent the outflow from each column - and since we are in the primary motor cortex, the axons from those pyramidal cells become the corticospinal tract and activate the alpha-motoneurons in the spinal cord. Since each column controls a specific motion (as simple as a twitch), the stimulation will elicit a contraction]
You are participating in a research project organized by a second grade science class attempting to determine how good people are at discriminating between two objects of different weights while blindfolded. Which area of the brain is directly responsible for determining that the first object you held in your hand is heavier than the second object?
A. Somatosensory area 1 B. Somatosensory area 2 C. Insular cortex D. Parieto-temporal-occipital association cortex E. Amygdala
B. Somatosensory area 2
[Somatory sensory area 2 is the area directly responsible for making such comparisons between objects. Although Somatosensory area 1 is necessary to make the initial identifications, it alone cannot make the determination of how two held objects differ - it feeds the information to S2]
What neurotransmitter is used to presynaptically inhibit release of EAA and substance P by C fibers in the spinal cord?
A. GABA B. EAA C. NE D. Opioids E. Substance P
D. Opioids
[This is a simple recall level question regarding the descending inputs that modify pain in the spinal cord. Activation of PAG neurons causes the release of opioids (specifically the enkephalins) from the PAG axons that have traveled to the midline raphe nuclei. The enkephalins activate the raphe neurons, leading to release of serotonin in the spinal cord. This serotonin is released onto an interneuron that presynaptically inhibits the synapse of the C-fiber coming from the skin onto the second order afferent in the spinal cord. The opioids are released to produce the pre-synaptic inhibition]
A patient has suffered a neurological injury that prevents him/her from generating the full autonomic response to pain. In addition, the patient readily admits to feeling pain, but has no emotional response to the pain. What region has most likely been damaged?
A. The periaqueductal gray (PAG) B. The insular cortex C. Somatosensory area 2 D. Somatosensory area 1 E. The amygdala
B. The insular cortex
[The important detail here was recognizing that the patient has lost two major components of the interpretation of pain - the autonomic responses and the emotion responses. In addition to processing information about the internal state of the body in general, the insular cortex is crucial in these two functions and a lesion in this one area explains both observations in the patient.
Although the amygdala is involved in producing the emotional responses to pain, a lesion here would not interfere with the autonomic responses as we saw in the patient]
While being treated for a cat bite that got infected, Dr. Karius notes that even trivial (normal) stimulation of her right hand (where she was bitten) produces the sensation of pain. Being the semi-astute physiologist she is, she recognizes that this pain sensation is being produced by nociceptors that have been sensitized by the on-going (acute) injury/inflammation in her hand. Which of the following chemical mediators are most likely to be responsible for this phenomenon?
a. Excitatory amino acids B. ATP C. Met-Enkephalin D. Anandimide E. Serotonin
B. ATP
[Because the described situation is an acute situation, the increase in pain sensation is due to a decrease in the threshold required to activate the nociceptors. Substance P, ATP, Hydrogen ion, and the kinins (e.g. bradykinin) can sensitize existing nociceptors to other inputs, increasing the perception of pain. Although the EAA are released in the spinal cord as part of the transmission pathway to the brain, they don’t have an affect in the periphery]
A patient develops a demyelinating disease that can affect both afferent and efferent neurons. Which of the following is most likely to be affected by the disorder? Choose all correct answers.
A. Voluntary motor activity B. Slow pain C. Fine touch from the skin D. Fast pain E. Warm perception (warm thermoceptors) F. Reflex activation of skeletal muscle
A. Voluntary motor activity
C. Fine touch from the skin
F. Reflex activation of skeletal muscle
