exam 3

The mammalian neocortex is typically comprised of _______ layers.

6

What is the best description of the "connectome"?

A comprehensive structural description of the network of elements and connections forming a brain

Which of the following therapeutic approaches would be the most effective combination to promote recovery after spinal cord injury?

AAV-GDNF injections, injection of Schwann cell progenitors, Inhibition of Nogo receptor

In exploring therapeutic approaches to Parkinsons disease, you would like to test injecting a dopamine modulating drug directly into the brain of a patient. What type of dopamine drug (i.e. agonist, antagonist) would you use and where in the basal ganglia would you directly inject it?

Agonist, striatum

What are you DIRECTLY measuring in a typical fMRI experiment that shows increased "signal" in a specific brain voxel?

Blood oxygenation level dependent changes indirectly related to neural activity

The activity of ________ motor neurons is a critical factor that regulates the sensitivity or gain of the muscle spindle system.

gamma

Regrowth of sensory and motor axons to peripheral muscle completely restores the previous pattern of connectivity.

False

Which of the following genes appear to be highly expressed in large motor neurons located in the mature spinal cord ventral horn (hint... http://mousespinal.brain-map.org/ )?

Chat

Dopamine binding to ____ receptors on a subclass of medium spiny neurons in the basal ganglia result in activation of cAMP, while ___ receptors lead to a decrease in cAMP.

D1, D2

A patient in the hospital where you work displays uncontrollable jerking leg and arm movements. Based on the image below and your knowledge of the basal ganglia, which of the following describes the most likely change responsible for the patient's abnormal movement?

Decreased expression of D2-receptors in the putamen

Which of the following genetic changes would be most likely to drive the evolution of the human cerebral cortex?

Duplication of a genomic regions containing ARHGAP11B, a gene that promotes neuroepithelial progenitor self-renewal

Spinal cord injury often leads to loss of descending systems that contribute to CPG function. Which of these treatments is particularly well-suited for restoring CPG activity?

Electrical Epidural Stimulator, EES, implants in the spinal cord below the site of injury.

What is the most likely molecular event that underlies Long-Term Depression (LTD) at parallel fiber-Purkinje cell synapses?

Endocytosis of AMPA Receptors

Which of the following contributes to the failure of axonal regeneration in the CNS?

Expression of myelin-associated growth inhibitors

Both the cerebellum and the motor cortex usually control contralateral muscle function

False

Locomotion is associated with a rhythmic pattern of limb movements controlled by central pattern generators (CPGs). CPGs must have descending input from the cerebral cortex in order to operate at all.

False

A mutation in which of the following genes would be most likely to disrupt cortical connectivity with pontine nuclei? (Try searching Allen Brain Atlas to see if any of these genes are enriched in a specific layer of interest?)

Fezf2

Which of the following functions are least likely to be altered following damage to association cortices?

Generating a motor response elicited by a sensory reflex pathway

You are studying Parkinson's disease using a mouse model and want to use a new treatment that targets dopamine D2 receptors in the dorsal striatum. However, you are concerned that the treatment may affect D2 receptors that are expressed in other regions of the brain. Using the RNA expression information and fluorescent immunohistological sections from the Human Protein Atlas - https://www.proteinatlas.org/ENSG00000149295-DRD2/brain what other regions in the human brain are most likely to be effected by this treatment?

Hypothalamus

Which of the following mechanisms is LEAST likely to provide a therapeutic benefit in regenerating the PNS?

Inhibition of macrophage activity immediately after injury

Damage specifically to the Purkinje neurons in the cerebellum lead to motor execution and motor learning defects through...

Loss of output from the cerebellar cortex that normally inhibits neuron in the deep cerebellar nuclei

Which of the following statements regarding lower motor neurons is false?

Lower motor neurons that innervate the muscles in your hand are located in the medial ventral horn.

Damage to the right lateral portion of the motor cortex in the precentral gyrus would most likely lead to which of the following outcomes?

Problems with left face movements

In the cerebellum, an extremely large GABAergic neuron with a distinctive, highly branched dendritic arbor is known as a ________ cell, while a very small neuron that is one of the most numerous neuronal subtypes in the nervous system is called a ________ cell.

Purkinje, granule

Neuroimaging and functional studies suggest the RIGHT parietal cortex processes information from...

Right and left hemispace

Administration of which of the following agents would most likely block the effects of dopamine on the firing rate of direct pathway MSNs?

Rp-adenosine cyclic phosphorothioate, a cAMP signaling antagonist

Which of the following cell types plays a crucial role in helping promote peripheral nerve regeneration?

Schwann cells

Which of the following statements about neurons in the primary motor cortex is false?

Stimulation of one neuron typically leads to flexion of a single muscle

The pathology of Huntington's disease is characterized by a loss in ______cells that overall lead to _____ of the thalamo-cortical pathway.

Striatal, excitation

The globus pallidus internal segment primarily targets which structure?

VA/VL nuclei in the thalamus

The process of removal of the distal stump of severed axons is known as __________ degeneration.

Wallerian

Which of the following statements about the basal ganglia is NOT correct?

The net effect of excitation of the direct pathway is to inhibit the cortex.

An inability to perform skilled, complex motor movements, even though basic sensorimotor function is intact, is known as ________.

apraxia

Deletion of the PTEN gene assists in effective axonal regrowth through modification of which of the following processes? Correct answer:

enhancement of intrinsic neuronal growth capacity

The indirect pathway in the basal ganglia involves medium spiny neuron projections to the _______ segment of the globus pallidus.

external

Climbing fibers arise from neuronal cell bodies in the _________ that recieve indirect and direct input from the cerebral cortex. Climbing fibers ascend through the ________ cerebellar peduncle to synapse directly onto __________ cells.

inferior olive, inferior, purkinje

The globus pallidus and the substantia nigra pars reticulata provide the primary source of basal ganglia ______. These two nuclei regulate motor commands by forming synapses on neurons in the ______ and _______.

input, thalamus, primary motor cortex

In the direct pathway, medium spiny neurons send a projection to the _______ segment of the globus pallidus.

internal

Which of the following mechanisms provides the best explanation for the effects of dopamine agonists in Parkinson's disease?

l-dopa treatment restores the firing rate of direct pathway MSNs

Upper motor neurons that control axial muscles mostly project to which of the following areas?

medial grey matter over many spinal segments

Corticostriatal axons primarily synapse on __________ neurons in the caudate and the putamen.

medium spiny

What neuroanatomical region of the nervous system is an important component of the "Default Mode Network"?

prefrontal cortex

Thalamocortical efferents that are part of the basal ganglia body movement loop, synapse in the ___________ and __________ cortices.

premotor, primary motor

The medium spiny neurons of the basal ganglia...

produce inhibition by release of GABA

Neurons with cell bodies in the spinal cord that projects intersegmentally to other spinal levels are called __________ neurons.

propriospinal

Which of the following structures is MOST capable of robust axonal regeneration following injury.

sciatic nerve

As descending neural activity to a motor pool increases, slow motor units are recruited first, followed by fast fatigue-resistant, and then fast-fatiguable, a sequential process is known as the ______ principle.

size

The only part of your cerebellum that recieves input directly from your spinal cord is the...

spinocerebellum

Most of the time, corticospinal axons...

synapse onto local circuit neurons in the spinal cord

The ______ association cortex primarily provides information on "what" an object is, while the ______ association cortex, mainly provides information on "where" an object is.

temporal, parietal

Some of the efferent projections that arise from neuronal bodies in the cerebellum project to...

thalamus

The indirect pathway inhibits the direct pathway.

true

Weakness and spasticity are a classic sign of ______ motor neuron syndrome.

upper