BIO 467: Neurobiology Final Exam practice tests questions

It is impossible to reopen developmental windows of plasticity in an adult organism T/F

false

Cortical neurons in Layer 2/3 of your binocular visual cortex are monosynaptically connected to incoming thalamocortical afferents from the LGN. T/F

false - Thalamocortical afferents from the LGN synapse into the visual cortex of layer 4, the "input" layer. Layer 4 then projects to layer 2/3, where information is then spread to other cortical areas. The communication from the LGN to layers 2 and 3 are polysynaptic, involving the layer 4 Most LGN input to layers 2 and 3 are from layer 4 cortical connections, which makes this polysynaptic.

Injection of a transynaptic tracer into the nasal retina of your right eye would label axons in the ______ lateral geniculate nucleus and _____ visual cortex. a. left, right b. right, right c. left, left d. right, left

left, left - Your right eye, nasal side, captures your right monocular visual field. After the optic chiasm, visual fields are represented contralaterally in the optic tract, LGN, optic radiations, and visual cortex. Temporal retinas capture the contralateral binocular visual field. They ascend ipsilaterally, so that visual information is still processed in the contralateral side of the brain.

The technique that lets you measure the RNA from a single cell and mapping the level of expression of thousands of genes is called: a. western blots b. single-cell RNA-seq c. microarrays d. aPCR

single-cell RNA-seq General Feedback In general, transcriptomics is the study of genes in a high-throughput manner. This means extracting genomic information, RNA, from cells or tissue and quantify expression of thousands of genes. Quantitative Polymerase Chain Reaction (qPCR) and Westerns are incorrect because they base their analysis on DNA and protein respectively. Although MicroArrays quantify RNA, it can be utilized for bulk RNA extraction, more than one cell, therefore single-cell RNA sequencing is correct.

If you wanted to study the number of cells that are born in an embryonic structure, which of the following compounds would be most useful? a. BrdU b. NGF c. TTX d. an antibody that detects activated caspase-3

BrdU - Bromodeoxyuridine (BrdU) is a synthetic compound that is very similar in structure to thymidine, one nucleotide base of DNA. Only when DNA is replicated during S-phase is BrdU incorporated into the cells. Subsequent divisions dilute the BrdU, therefore darker cells have undergone fewer divisions than cells that have lighter labeling. Using this approach, we know that the cortex is built in an inside-out pattern. Caspase-3 is involved in the cell cycle, however, is a marker of cell death.

Which of the following is a feature of critical periods that support the proper development of visual systems? a. critical periods persist over an extremely long window of time b. sensory input is not necessary for the adaptive process to occur c. circuitry effects can occur over a period of days d. they result in transient changes in visual circuits

Circuitry effects can occur over a period of days

Which of the following manipulations is most likely to result in the death of nociceptive sensory neurons during development? a. deletion of the TrkA gene b. overexpression of Bcl-2 c. deletion of the NT3 gene overexpression of Bax in cells that express TrkC

deletion of the TrkA gene - Nociceptive and proprioceptive neurons are both sensory neurons within the dorsal root ganglion (DRG). Proprioceptive, encodes spatial information from the muscle about where your limbs are. They respond to NT-3/TrkC signaling. Nociceptive neurons are pain sensing neurons that send information from the skin to the dorsal horn of the spinal cord. They respond to NGF/TrkA signaling. While Bax is a pro-death protein, (and Bcl-2 is pro-life), it will only induce apoptosis in proprioceptive neurons, not nociceptive.

Which of the following terms best describes the underlying process that drives morphological changes within a newly born neuron during development? a. commitment b. gastrulation c. proliferation d. differentiation

differentiation - Stem cells undergo the process of commitment followed by differentiation. Commitment is a fate restricting process that limits what type of cell it will be. Typically, these are subtle changes in gene expression that contribute to cell identity. Afterwards, the cell undergoes differentiation, which results in a highly specialized cell type that exhibits characteristics of the mature cell. This includes functional and morphological features that are irreversible.

Which protein was shown to act as an extracellular chemorepulsive cue for a subset of growing RGC axons in the developing optic tectum? a. ephrins b. neurotrophin-3 c. Wnt1 d. Rho GTPase

ephrins - Roger Sperry won the Nobel Prize for Chemoaffinity Hypothesis. He severed a frog's retina, flipped it upside down, and reattached it to see where the retinal fibers grew into the tectum. From this experiment, he discovered that axon guidance depends on molecular cues from the tectum. Temporal retinal ganglion cells (RGC) express high amounts of Eph receptors, therefore were repressed from growing into the caudal region of the tectum where there is high abundance of ephrin ligands. Similarly, nasal RGC express low Eph receptors and therefore are able to grow into the caudal region.

Adult muscle is primarily mononeuronally innervated because a lower motor neuron will typically form a 1:1 relationship with a muscle fiber when it first makes contact during embryogenesis. T/F

false - First, lower motor neurons polyneuronal innervate, meaning they will innervate multiple muscle fibers. During development, neurons then undergo patterned activity-dependent pruning such that they will choose to innervate one muscle fiber that has the strongest synaptic connection based on activity. Inhibiting or overactivating a chemical synapses at the NMJ will delay or accelerate the polyneuronal to mononeuronal switch, respectively. As a result, each muscle fiber will be innervated by only one neuron.

Maps for orientation selectivity, ocular dominance, and retinotopy are sufficient for reconstructing all aspects of visual experience. T/F

false - These are all critical for the deconstruction of vision in order to process visual information. After this processing, information is then sent to areas of the brain to reconstruct and form a complete perception. For example, some features that are also necessary are curves and movement.

Glial cells are only present in the CNS to provide structure for the brain and hold neurons together. T/F

false Initially, glia were discovered as 'neuroglia' serving as the glue holding neurons together. We now know that glia have many more functions that provide structural support. Glia are cells that do not conduct electrical signals, but are found in both the CNS and PNS. Oligodendrocytes myelinate multiple axons in the CNS, while Schwann cells myelinate a single axon in the PNS, both functionally contributing to the fast propagation of action potentials. Astrocytes regulate synaptic signaling and they make connections via their endfeet. Microglia mediate immune responses and clear debris. Ependymal cells line the ventricular system and facilitate movement of the cerebral spinal fluid (CSF). Endothelial cells and pericytes seal the blood brain barrier (BBB).

Axonal guidance is only regulated by diffusible cues. true/false

false There are a lot of components that regulate axonal guidance. First, there are many molecular cues that govern axonal direction, either classified as a chemoattractant, or chemorepellent. Secondly, in order for those cues to translate into movement, the growth cone must express receptors that respond to said cues. Lastly, the molecular machinery within the growth cone relies on the rapid polymerization and depolymerization of actin and microtubules. The guidance cues bind to their receptors and initiate intracellular signaling that converge onto Rho GTPase family of proteins that modulate actin dynamics.

All neurons behave the same electrically. All action potentials fire at similar rates and the amplitude is the same across all neurons. T/F

false Various properties of postsynaptic neurons lead to diverse firing characteristics such as genetic variability and synaptic connections onto a cell. Much like genetic and morphology differences, electrophysiological properties of a cell is another classification used to categorize neurons.

The highest density of cones in the retina can be found in the _____, a small depression in a region near the center of the macula.

fovea In the center of the macula is the fovea, which is composed entirely of cones making it a region of extremely sharp visual acuity.

Connexins are proteins that make _______ junctions which are pores that allow small molecules (typically ions) to pass between the cytoplasm of two cells. a. gap b. canyon c. cleft d. voltage-gated

gap Connexins are proteins that are embedded between the pre- and post- synaptic membranes. There is a pore allowing small molecules to pass through freely. Voltage-gated channels only span the plasma membrane of one cell and depend on the cell's membrane potential of whether it is open or closed.

Genetic labeling allows you to target specific cell subtypes based on.... a. gene expression b. electrical activity c. morphology (shape) d. anatomical location

gene expression Genetic labeling allows you to focus on differences in gene expression.

What is the order of anatomical planes in these images from left to right. a. horizontal, sagittal, coronal b. sagittal, horizontal, coronal c. coronal, sagittal, horizontal d. horizontal, coronal, sagittal

horizontal, coronal, sagittal Horizontal is a top down view, coronal is a front to back, anterior to posterior, sagittal is a side view (left to right). Please refer back to Figure A1 in your textbook or "Anatomical Coordinates and Planes" slide from the lecture

A good example of a non-declarative memory would be_____. a. your fathers middle name b. your gmail password c. how to ride a bike d. the room number for your next class

how to ride a bike - Declarative memory is explicit meaning you "know that". These are things like facts, or things that you can tell definitively. Non-declarative memory is implicit meaning you "know how". A classic example of non-declarative is riding a bike. No one can explain how to do it, you just do it.

Which of the following techniques would be most useful for identifying the location of a synapse that contains protein for a neurotransmitter enzyme in an anatomical section of a human brain? a. in situ hybridizaiton b. immunohistochemistry c. RNAseq/ Microarray d. qPCR

immunohistochemistry RNAseq/microarray and qPCR require lysing or homogenizing the tissue, therefore spatial and anatomical location is lost. In situ hybridization and immunohistochemistry is able to resolve the anatomical location of where mRNA and protein is expressed in a slice of a brain, respectively.

A lab technique that allows you to directly look at colocalization of PROTEINS in cells within an anatomical cross section of a brain a. western blotting b. qPCR c. immunohistochemistry (IHC) d. single cell RNA-seq

immunohistochemistry (IHC) General Feedback qPCR and single cell RNA-sequencing quantify DNA and RNA, respectively. Both western blotting and IHC quantify protein, however, western bott uses tissue samples that have been homogenized. IHC can probe for multiple proteins of intact tissue, which gives the researcher information if two proteins are expressed in the same cell, thus spatial information.

Vesicles that hold neurotransmitters are found...... a. in the pre-synaptic neuron b. in the post-synaptic neuron c. in the synaptic cleft d. in the nuclei of surrounding astrocytes

in the pre-synaptic neuron Neurotransmitters are loaded into vesicles in the presynaptic neuron. Vesicles then fuse with the plasma membrane at the synapse, releasing neurotransmitters into the synaptic cleft. There, they bind to receptors on the postsynaptic neuron. In general, vesicles are located within the cytoplasm of cells and not in the nucleus.

Axonal growth cones are highly dynamic structures that extend wave like extensions known as __ and finger like extensions known as___.

lamellipodia, filopodia - The cytoskeleton of a cell is made up of microtubules and actin. Microtubules are the main component of the neurite shaft and actin sits just beneath the neurite tips. Growth cones are constantly probing their environment and responding to chemocues to direct them where to go. Their rapid polarization and depolarization result in wave-like extensions known as lamellipodia and finger-like projections called filopodia.

Neurons in which of the following cortical layers are born last during development? a. layer 2/3 b. layer 4 c. layer 5 d. layer 6

layer 2/3 - The cortex is built from an inside-out fashion, meaning that deeper layers are born first and superficial layers are born last. Please see the slide entitled "Inside-out pattern of cortical morphogenesis" from the Forebrain Development and Patterning lecture.

The right nucleus gracilis relays mechanosensory information via axon collaterals that synapse in the ____________. a. left cortex b. right thalamus c. left thalamus d. right cortex

left thalamus - The right nucleus gracilis relays mechanosensory information from the lower right side of the body. Afferents from the periphery collect this information and synapse with the dorsal column in the caudal medulla, specifically on the nucleus gracilis. Then the second order neurons here will decussate and ascend contralaterally to the thalamus. A third order thalamocortical neuron would be required to reach the cortex.

Light induced activation of a type of ______ in the photoreceptor leads to ________ cGMP levels, which ultimately triggers changes in cGMP dependent ion channels that result in ______? a. transducin, increased, depolarization b. opsin, increased, depolarization c. arrestin, increased, hyperpolarizaiton d. opsin, decreased, hyperpolarization

opsin, decreased, hyperpolarization - At rest, K+ channels and cGMP-dependent Na+/Ca2+ channels are open in rods and codes. When light then hits the photoreceptors, retinal complexed with opsins absorb the photons, causing it to change shape. This then leads to the activation of g-protein phosphodiesterase (PDE) cascades, which cleaves cGMP. This cleavage and removal of cGMP from the Na+/Ca2+ channels, closes them, stopping the influx of Na+/Ca2+, resulting in hyperpolarization.

The part of the retina that is responsible for our "blind spot" is the __________, which is occupied by blood vessels and axons. a. optic disk b. fundus c. macula lutea d. fovea

optic disk - Blood vessels and axons from retina ganglion cells all travel through at one spot, called the optic dick. This region doesn't contain photoreceptors, hence why it was given the name "blind spot." The fundus is the inside, back surface of the eye. It is made up of the retina, macula, optic disc, fovea and blood vessels. The macula lutea is comprised of the the fovea and its surrounding area, and has a high density of photoreceptors, resulting in the opposite of a blind spot.

What number best indicates the location of the hippocampus?

5 General Feedback The hippocampus is a ventral structure important for learning and memory. For further anatomical structures, please refer to Figure A16 and A20 in the appendix.

___ is the location of the lobe where the primary sensory cortex is located.

B General Feedback The primary sensory cortex is located within the parietal lobe, which is caudal to the frontal lobe. The central sulcus is the boundary between these two lobes. Refer back to the lecture slide titled "Functional Organization of the Telencephalon".

Match the terms - protein - transcription - mRNA - translation - DNA

- performs cellular function - DNA to RNA - signal for protein production in ribosomes -RNA to protein - encodes genetic info DNA is the genetic code in all of our cells. DNA is transcribed (transcription) into messenger RNA (mRNA). mRNA is then translated (translation) into protein. Protein is the molecule that carries out cellular functions.

Somatosensory neurons with a cell body in the DRG normally transmit information from the _________ to the _________. a. skin, cerebellum b. muscle, thalamus c. skin, spinal cord d. muscle striatum

Skin, Spinal cord

Visual information traveling along axons that enter the visual cortex, primarily terminate on neurons that reside in cortical Layer ____? a. 2/3 b. 4 c. 5 d. 6

4 - Retinal ganglion cells synapse into the LGN, and then visual cortex. In general, all sensory information or 'input' into the cortex synapses onto cortical layer 4.

Which of the following was observed in studies of cortical map plasticity? a. loss of a limb can lead ot reorganizaiton of the cortical somatosensory map b. repeated using a digit to a skilled task can alter its cortical representaiton c. if a cortical region is derived of input, the region begins to respond to informatino normally encoded by surroundin cortical regions

- Loss of a limb can lead to reorganization of the cortical somatosensory map. -Repeatedly using a digit in a skilled task can alter its cortical representation -If a cortical region is deprived of input, the region begins to respond to information normally encoded by surrounding cortical regions. - Studying the topography of the barrel cortex of rodents is a useful model for studying cortical map plasticity and remapping. This area of the cortex contains topographical organization of columns corresponding to roughly 24 whiskers used to map space in the environment. Using two-photon calcium imaging of layer 2 during active whiskering, specific neurons lit up when a cue (i.e. pin) was placed in a specific part of the sensory field. After clipping the whiskers, the barrel cortex neurons rearranged their receptive fields because of experience dependent plasticity. This suggests that the brain undergoes reorganization to compensate for the loss of sensory input from the clipped whiskers. Jon Kaas and Michael Merzenich were the first to explore the idea of functional cortical remapping in adults by examining the impact of peripheral lesions on the topographic maps in somatosensory cortex. Immediately after the lesion, the corresponding region of the cortex was found to be unresponsive. After a few weeks, however, the unresponsive area became responsive to stimulation of neighboring regions of the skin. For example, if digit 3 was amputated, cortical neurons that formerly responded to stimulation of digit 3 now responded to stimulation of digits 2 or 4. Such "functional remapping" also occurs in the somatosensory nuclei in the thalamus and brainstem, visual, auditory, and motor cortices- suggesting that some ability to reorganize after peripheral deprivation or injury is a substantial property of the mature brain. Changes changes in cortical representation also can occur in response to physiological changes in sensory or motor experience input to the cortex. For instance, if a monkey is trained to use a specific digit for a particular task that is repeated many times, the functional representation of that digit can expand at the expense of the other digits used less. Reference lecture 4.6 Somatosensory Systems or

_______ could plausibly serve as a molecular mechanism that contributes to learning and/or memory in the nervous system. a. LTP b. post-tentanic potentiation c. synaptic depression d. spike-timing dependent plasticity

-LTP -post-tetanic potentiation -synaptic depression spike-timing dependent plasticity - All of these molecular mechanisms can contribute to learning and memory in the nervous system. Each of them either strengthens or reduces synaptic transmission.

Astrocytes..... (select all that apply) -can have endfeet on blood vessels -can contribute to inflammatory responses -regulate ion homeostasis -releasing NT - produce myelination

-can have endfeet on blood vessels -can contribute to inflammatory responses -regulate ion homeostasis Astrocytes are star shaped glial cells that serve many functions. They make connections with other cells via their "end feet". As a support cell, they regulate ion homeostasis, metabolic support, and blood flow. After injury, astrocytes become phagocytically active, meaning they engulf their surroundings to clear debris. When reactive, they proliferate and promote an inflammatory response resulting in a glial scar. Astrocytes do not release neurotransmitters, however, they do regulate synaptic transmission at the synaptic cleft. Oligodendrocytes produce myelination in the CNS and Schwann cells produce myelin in the PNS.

Differential Gene Expression is critical for... (select all that apply) a. base metabolic processes b. the machinery necessary for the central dogma of biology c. cellular diversity d. maintaining cell-specific functions

-cellular diversity -maintaining cell-specific functions General Feedback Cells express different genes which make up their cellular identity. This gives rise to different cell types. Their gene expression contributes to their specific cellular functions. Regardless of gene expression, all cells need fundamental metabolic processing and machinery for Central Dogma, thus differential gene expression (DGE) is not critical for those processes.

A plausible mechanism for the decline in plasticity that signals the end of a critical period is... a. modification of histone proteins in ways that hinder future transriptional events b. expression of molecules that inhibit axonal remodeling c. structural changes related to myelination and/or glial modifications of the extracellular enviornment

-modification of histone proteins in ways that hinder future transcriptional events -expression of molecules that inhibit axonal remodeling -structural changes related to myelination and/or glial modifications of the extracellular environment

Match the terms -myelination -oligodendrocytes -myelinating schwann cells -non-myelinating schwann cells

-white matter -myelinate multiple axons -myelinate a single axon -ensheath multiple axons (remak bundle) Myelin is a lipid rich coating around the axons, and is opaque, thus terming it "white matter". Oligodendrocytes and Schwann cells myelinate axons in the CNS and PNS respectively. Oligodendrocytes are able to myelinate multiple axons, whereas myelinating Schwann cells only myelinate a single axon. Non-myelinating Schwann cells ensheath multiple axons called Remak bundle after Robert Remak. The purpose of myelination is to facilitate fast action potentials via saltatory conduction. Since Ramak bundles are non-myelinating, those fibers are considered slow.

What number best indicates the location of the corpus callosum?

1 General Feedback Corpus callosum is the dorsal white matter tract that connects both hemispheres of the brain. For further anatomical structures, please refer to Figure A16 and A20 in the appendix.

Assuming the top of the image is rostral to the bottom, what number is located the furthest to the patients right? 3 18 10 14

3 General Feedback The top plane is rostral and the bottom plane (which you can't see) is caudal. That means if you draw the entire person, they are standing up right. Dorsal root ganglia (DRG - 6) cells sends afferents and synapses in the dorsal horn. This means the person has their back (dorsal fin) to the screen and is facing (ventral). Since you are looking at the person from the front, anatomical left and right are opposite of yours, so any number on the left side of the image is the person's right and anything on the right side of the image is the person's left. 18 and 10 are incorrect since they are both located medially. For further anatomical annotation, please refer to Figure A6 in the appendix or watch the supplemental YouTube video entitled "Directional Terms".

What number best indicates the location of white matter? 17 3 6 15

3 In general, looking at a coronal view of the spinal cord, grey matter, where cell bodies are located, are in the middle whereas white matter, which contains myelinated axons, are in the surround. Grey matter has "horns" which is where afferents and efferents enter or leave the spinal cord, respectively. The dorsal side receives information from dorsal root ganglia (DRG) cells and ventral motor neurons sends information to the muscle. 3 - some lateral tract like rubiospinal 17 - central canal is where the cerebral spinal fluid is 6 - dorsal root ganglia, the cell body of sensory neurons 15 - dorsal horn which is part of the grey matter

Somatosensory information traveling along thalamocortical axons that enter the sensory cortex, primarily terminate on neurons that reside in cortical Layer ____? a. 2/3 b. 4 c. 5 d. 6

4

Finally, the authors of Bannerman et al., 2012 utilized the Morris Water Maze to analyze behavioral learning and memory in control (circles) and Grin1DGCA1 mutant (black squares) mice. What statement about this data is FALSE? a.Control mice learn the location of the hidden platform after multiple trials, as indicated by the reduction in swim path length over time. b.Grin1DGCA1 mutant mice learn the location of the hidden platform after multiple trials, as indicated by the reduction in swim path length over time. c.Grin1DGCA1 mutants do not show a statistically significant difference in performance during the Morris Water Maze relative to controls. d.NMDAR expression in the hippocampal CA1 region is necessary for learning the Morris Water Maze task.

Correct answer: NMDAR expression in the hippocampal CA1 region is necessary for learning the Morris Water Maze task. - Morris Water Maze is a classic example of assaying learning and memory in rodents. They are put into a pool of water with a hidden platform. To complete the task, they must learn to swim to the platform in order to get out. Over repeated trials and multiple days, mice that learn the task will make a shorter swimming distance, or quicker swim time. Mice that do not learn the task will not improve their distance or time. Since both control (white circles) and mutant (black squares) both improve over the 9 "blocks", that means Grin1 is dispensable for learning the Morris water maze task.

The loss of embryonic BMP (bone morphogenic protein) expression in the developing nervous system is most likely to cause which of the following problems? a. dorsal localization of normally ventral neuronal subtypes in the spinal cord b. absence of myelinating glia c. anterior localizaiton of normally posterior neuronal subtypes int he spinal cord d. enhanced neuronal specification in the DRG

Dorsal localization of normally ventral neuronal subtypes in the spinal cord - Morphogens are cues that direct orientation. In the spinal cord, bone morphogenetic proteins (BMPs) are highly expressed from the roofplate (dorsal) and Sonic hedgehog (Shh) is highly expressed from the floorplate (ventral). Collectively, this gradient orients the dorso-ventral axis and helps specify where cells will populate in the spinal cord. If BMP is absent, ventrally derived motoneurons won't know where the dorsal boundary is and will continue to populate the dorsal side. Alternatively, in the forebrain, BMP is expressed posterior and FGF (fibroblast growth factor) is expressed anterior. Loss of BMP in the forebrain will allow for normally anterior neurons to populate more posterior regions.

___ is the location of the cerebellum.

E The cerebellum is part of the midbrain important for motor learning, coordination and balance. Please refer to Figure A12 in the appendix.

Neurotrophic factors do NOT directly regulate _____? a. the number of surviving neurons b. synapse formation c. axonal outgrowth d. GPCR activity

GPCR activity - Viktor Hamburger ablated chick limb buds, the target domain of where motor and dorsal root ganglion (DRG) cells synapse to. He found that there were less cells on the side he ablated. When an additional limb bub was added, there were more neurons compared to the normal hemi-spinal cord. This suggested that cues (neurotrophins) in the target domain regulate cell number. Moreover, since cells are overproduced, there is a wave of apoptosis that occurs, resulting in the correct amount of cells. Later, two of his students, Rita Levi-Montalcini and Stanley Cohen, isolated DRG explant and applied nerve growth factor (NGF). The explants survived and had robust axonal outgrowth. Collectively, this is known as the Neurotrophic Hypothesis. It was discovered that tropomyosin related kinase A (TrkA) was the receptor for NGF, signaling that is important for nociceptive neurons. The family of Trk receptors are tyrosine receptor kinases that modulate intracellular signaling. In the CNS, TrkB and brain derived growth factor (BDNF) help facilitate synaptogenesis. TrkC is expressed on proprioceptive neurons, and responds to high levels of NT-3 in developing muscle.

A neurobiological explanation for the fast nature of the knee jerk reflex relies upon ________ fibers that exhibit a ________ conduction velocity due to increased levels of ________. a. adelta, fast, TRPs b. C, slow, myelin c. 1A, fast, myelination d. C, fast, saltatory conduction

IA, fast, myelination - Type IA (and Type II) fibers are important for proprioception and in the knee jerk reflex. These axons have a noticeably thicker diameter due to having more myelin. This increases the velocity of potentials traveling down it, making transmission fast in this reflex. Type A-Delta fibers are for sensing pain and temperature via free nerve endings. These fibers are extremely thin and have a slow conduction velocity due to having less myelin. Additionally, type C fibers are also for pain and temperature, but also itch. These are free nerve endings that lack myelination all together.

Which of the following techniques would be most useful for identifying the location of a cell body that expresses mRNA for a neurotransmitter enzyme in an anatomical section of a human brain? a. in situ hybridization b. immunohistochemistry c. RNAseq/Microarray d. qPCR

In situ Hybridization RNAseq/microarray and qPCR require lysing or homogenizing the tissue, therefore spatial and anatomical location is lost. In situ hybridization and immunohistochemistry is able to resolve the anatomical location of where mRNA and protein is expressed in a slice of a brain, respectively.

You would like to make your sea slug "smarter" by increasing the efficacy of heterosynaptic facilitation. What manipulation is most likely to enhance 'behavioral sensitization' in aplysia? a. injection of nimodipine, a voltage dependent calcium channela ntagonists into the facilitatory interneuron b. injection of rolipram, a phosphodiestrase (PDE) inhibitor into the motor neuron, phosphodiesterases normally degrade cAMP c. injection of TEA into the facilitatory interneuron d. injection of TTX into the sensory neuron

Injection of Tetraethylammonium (TEA) into the facilitatory interneuron. - Heterosnaptic facilitation is the enhancement of synaptic strength brought about by stimulation to the tail. The route would be stimulation of the sensory neuron, to activate serotonin release from the facilitatory interneuron, to activate the motor neuron. Rolipram will decrease cAMP, therefore decrease the cholinergic release of the motor neuron and reduce the gill response. TTX into the sensory neuron would inhibit activation because it blocks voltage gated Na channels. Calcium is important for neurotransmitter release, thus nimodipine will reduce the release of serotonin. TEA into the facilitatory interneuron will inhibit voltage gated K+ channels and prolong the response, thereby increasing the strength of the gill response.

Which of the following correctly describes a critical period? a. dendritic branchinga nd synaptogenesis accelerate on a massive scale throughout the CNS b. latent, adaptive neural plasticity requires sensory input for its utilizaiton c. failure to respond typically results in the immediate death of the animals d. sensory inputs are are first connected to regions controlling motor outputs

Latent, adaptive neural plasticity requires sensory input for its utilization

Which of the following statements about long-term synaptic plasticity in Aplysia is FALSE? a. gill withdrawl behavior in aplysia can be altered for days or weeks by means of repeated pairings of shocks and touches b. the efficay of transmission at many synapses depends upon their history of synaptic activity c. tracking long-term changes in syanptic efficacy is straightforward due to the simple nervous system relative to mammilian brains d. learning in the aplysia gill withdrawal reflex is relativley independent of the timing or the amplitude of sitmuli

Learning in the Aplysia gill withdrawal reflex is relatively independent of the timing or the amplitude of stimuli. - Long term plasticity can last for hours, days or weeks. Short term is on the order of milliseconds to a few minutes. Aplysia was chosen as the model because of its relatively simple nervous system and reactions made it easy for observation. Pairing tactile stimuli over a period of time results in sensitization and habituation of the sensory and motor neurons. Repeated stimulation affects the transmission of synapses, which leads to habituation over time.

Which of the following visual field deficits (black indicates loss of vison) is consistent with left homonymous hemianopsia? A B C D

Left homonymous hemianopsia can be caused by damage to the right optic tract, LGN, optic radiations, or V1 and results in complete loss of one side of the visual field. B would be caused by homonymous hemianopsia with macular sparing which is usually caused by injury to the cortex, but can be anywhere along the visual pathway. C would be caused by damage to the right optic nerve. D would be caused by damage to the optic chiasm.

Which of the following statements regarding retinal ganglion cells is true? a. RGCs primarily encode information about the absolute intensity of light b. the firing rate of an RGC always increases when a stimulus varies signficantly from background illuminaton c. many RGCs encode relative differences in lumanance contrast d. The frequence of action potentials generated by an RGC provides a direct measure of the absolute number of photons captured by a photoreceptor

Many RGCs encode relative differences in luminance contrast. - RCGs primarily encode relative differences in luminance contrast which is necessary for detecting contrast and edges. The firing rate of RGCs can either increase or decrease when a stimulus varies from its background. This is determined by the type, whether they are on-center or off-center, and whether the stimulus is brighter or darker than its surroundings.

Which of the following pathological conditions would be LEAST likely to cause night blindness, known clinically as nyctalopia, where visual acuity in dim lighting is impaired due to deficits in the retina? OPN1LW is a gene on the X chromosome that encodes for long wave sensitive opsin, or red cone photopigment. It is responsible for perception of visible light in the yellow-green range on the visible spectrum. mGluR6 is necessary for receiving glutamate from on-center bipolar cells Vitamin A is needed in rods to make photopigments.

Mutations in the OPN1LW gene - Night blindness would be caused by something that affects the retina's rods. OPN1LW is important for color vision, and would be most expressed in cones. A mutation within mGluR6 would cause deficits in downstream edge detection, which is already more difficult in dim situations.

Which cell types contribute to edge detection during visual processing in the retina? a. on-center retinal ganglion cell b. horizontal cells c. off-center bipolar cell d. all of the above

On-center retinal ganglion cell Horizontal cells Off-center bipolar cell - Center and surround cones within a receptive field are responsible for the initial detection of contrast needed for detection. They then pass information to horizontal cells which then mediates center surround antagonism. They do this by providing inhibitory GABAergic input from the surround cells to the center cells, or from the center cells to the surround cells. This happens before they synapse onto either on- or off-center bipolar cells, and then onto on- or off-center retinal ganglion cells.

Which of the following statements about the treatment of amblyopia is correct? a. treatment should begin after the child has reached age 10-11 b. pathing the stronger eye for prolonged periods has been an effective treatment since the 1800s c. adults respond as well as children to many therapeutic strategies d. LGN projections to the cortex from the weaker eye are more complex

Patching the stronger eye for prolonged periods has been an effective treatment since the 1800s.

Which of the following mechanisms contributes to long term changes in the gill withdrawal reflex in Aplysia but is not important for short-term changes in the reflex? a. activation of GPCRs by serotonin b. phosphorylation of CREB c. decreased opening of presynaptic potassium channels d. acitvation of protein kinase A

Phosphorylation of CREB - Short term changes in synaptic plasticity of the aplasia gill response is governed by changes in cAMP signaling. Serotonin (5-HT) binds and activates GPCRs, which activates the secondary messenger cAMP. cAMP associates with protein kinase a (PKA). When PKA catalytic subunits are released, they phosphorylate potassium channels. This prevents potassium channels from opening, increasing the influx of calcium and facilitating the release of more neurotransmitters. Long-term changes are the result of protein synthesis and changes in gene expression which is regulated by activation of the transcription factor CREB. See figure 8.5 for further details.

A stab wound to the right dorsalmost portion of the spinal cord at Lumbar Segment 2 is most consistent with which of the following outcomes? a. problems sensing touch to the left shin b. problems sensing pain in the right foot c. problems sensing the position of the right knee d. problems sensing temperature to the right belly region

Problems sensing the position of the right knee

Which of the following neuronal subtypes would be most likely to respond to a small spot of light? a. layer 4 pyramidal neuron in V1 b. RGC c. Layer 2/3 pyramidal neuron in V2 d. layer 5 GABAergic neuron in V1

RGC - Neurons in the visual cortex process higher order visual information, like the orientation of contrast and selectivity/tuning of cortical columns, by using the combination of input from many retinal ganglion cells (RGCs). RGCs themselves have a much smaller and refined receptive field which may be activated by a small spot of light.

Which of the following morphogens is derived from the notochord? a. Shh-sonic hedgehog b. BMP4- bone morphogenic protein 4 c. Wnt1- Wnt family member 1 d. FGF8- fibroblast growth factor 8

Shh- sonic hedgehog -The notochord is located just ventral to the neural tube. Shh is a ventrally derived cue. BMP4 is a dorsally derived morphogen cue from the roofplate. Wnt1 and FGF8 are important cues for patterning the forebrain (anterior and posterior axis).

You are working on an in vitro co-culture model to study neuromuscular degeneration in ALS by growing lower motor neurons and nascent muscle cells together in a dish. The neurons appear to be having problems forming actual cholinergic synapses in your cultures. Which of the following genes would most likely help promote neuromuscular junction (NMJ) formation? a. robo b. NGF c. acetylcholine d. agrin

agrin - In your co-culture system of motor neurons and nascent muscle cells, you will need the appropriate neurotrophins to facilitate their survival and growth. While NGF is a neurotrophin, it doesn't directly facilitate the formation of synapses on the muscle. When the growth cone makes contact with the muscle, it will secrete agrin, resulting in clustering of acetylcholine receptors (AChR) on the muscle. Because lower motor neurons are cholinergic, they will release acetylcholine as their neurotransmitter, which binds to the cluster of AChR at the NMJ and induce muscle contractions.

A picture is presented to your right monocular superior visual field. This would result in neurons being activated in________? a. anterior-most region of the right occipital lobe, dorsal to the calcarine sulcus b. posterior-most region of the left occipital lobe, ventral to the calcarine sulcus c. anterior-most region of the left occipital lobe, ventral to the calcarine sulcus d. posterior-most region of the right occipital lobe, dorsal to the calcarine sulcus

anterior-most region of the left occipital lobe, ventral to the calcarine sulcus - The visual field is represented contralaterally in the visual cortex, so a picture in the right visual field will result in activation of the left occipital lobe. Additionally, the superior visual field is represented inferiorly in the anterior most region of the occipital lobe, while the inferior is represented superiorally in the posterior region of the occipital lobe.

Following a surgery that was meant to mitigate his severe epilepsy, patient HM developed a profound case of ________ amnesia, due to damage in his hippocampus. a. retrograde b. anterograde c. reductionist d. parallelograde

anterograde - Patient HM (Henry Gustav) is a famous clinical example in neuroscience. Due to damage to his hippocampus, he was unable to form new declarative memories, but his implicit memory and IQ were intact. This means that he can remember things from his past (retro-), but is unable to form new ones moving forward (antero-). This implies that the hippocampus is important for making new declarative memories.

Recently, a competing lab has shown that Kctd13 is a key regulator of neural progenitor proliferation. Loss of Kctd13 would be most likely to directly alter which of the following processes? a. axonal pathfinding b. apoptosis c. brain growth d. spina bifida

brain growth - In developmental biology, when a gene is said to be a regulator of a process, it means when the gene is deleted or knocked out (KO), that process is disrupted or doesn't occur. If Kctd13 is a regulator for neuronal progenitor proliferation, it means that Kcd13 must be functional in order for there to be neuron progenitor cells. In the timeline of development, progenitors occur first, which gives rise to specific cell types via differentiation, followed by axonal pathfinding and apoptosis. Since progenitor proliferation determines how many cells there will be, it sets the stage for how large the brain will grow.

Damage to the higher order visual processing area, the middle temporal area (MT), is most closely linked with which of the following conditions? a. cerebral akinetopsia, deficit in perceiving movement b. cerebral achromatopsia, color vision deficit c. amblyopia, lazy eye d. scotoma, blind spot

cerebral akinetopsia, deficit in perceiving movement - The MT is a core component of the dorsal pathway necessary for information about movement and position. Damage here may cause cerebral akinetopsia, a deficit in perceiving movement. Cerebral achromatopsia is the loss in the perception of color, usually caused by damage to the extrastriate cortex. Amblyopia is a permanent lazy eye and can be caused by disruptions between oculomotor reflexes and the visual cortex. Scotoma is a visual field defect, usually caused by damage to the eye.

Which neuroanatomical structure does not contain derivatives of the neural crest? a. peipheral nerve b. dorsal root ganglion c. sympathetic ganglion d. cerebral cortex

cerebral cortex - Neural crest cells are derived from the most dorsal lip of the neural tube through a process called epithelial to mesenchymal transition (EMT). These migratory neural crest cells give rise to the peripheral sensory neurons by generating dorsal root ganglia and sympathetic neurons via neurogenesis. Later they transition to gliogenesis and make peripheral glia like Schwann cells. The central nervous system comprises the cerebral cortex (brain) and spinal cord.

Synapses in the CNS and junctions in the PNS are usually ______ synapses, meaning there's actually a small gap between the cells forming the synapse where neurotransmission occurs. a. chemical b. electrical c. reticular d. voltage-gated

chemical Named by Sir Charles Sherriton while studying spinal reflexes.These "synapses" is the site of chemical neurotransmission. Electron microscopy imaging reveals a physical space between neurons, which we call the synaptic cleft.

In 1949 Donald Hebb proposed a theory of learning that required... a. coincident presynaptic and post synaptic activity b. nonspecific inputs from inactive synapses c. weak presynaptic input in varying temporal sequences d. potassium flow into the neuron e. PKA activation of IP3 receptors in the nucleus

coincident presynaptic and post synaptic activity

Your ability to perceive a standard simultaneous brightness contrast illusion in bright lighting conditions relies primarily on the _______ in your retina. a. rods b. scotoma c. cones d. optic disk

cones - Cones are responsible for high visual acuity in bright lighting conditions, as they are mainly responsible for contrast detection and have good spatial sensitivity. Rods on the other hand, are extremely sensitive to light making them more attuned for darker situations. It takes less light energy to hyperpolarize them than it would a cone. The optic disk won't have any perception of this illusion as it lacks photoreceptors, and thus perception. Scotomas are also blind spots.

Which of the following are ways that we can categorize neurons? a. connectivity b. neurochemical properties c. electrophysiological properties d. gene expression e. morphology f. anatomical location

connectivity, neurochemical properties, electrophysiological properties, gene expression, morphology, anatomical location (all of the above)

The cross section below was taken in which anatomical plane?

coronal (aka frontal) General Feedback Coronal is anterior to posterior, front to back. Sagittal sections would be a side view and horizontal sections would top down view at different depths. For reference of anatomical planes and axes, please refer to Figure 1A in the appendix.

Here is a figure in Bannerman et al., 2012 based on data from electrophysiological recordings of the hippocampus. The red arrows at the bottom indicate when a 100Hz stimulation of Shaffer collaterals was administered. The fEPSPs are derived from recordings of CA1 neurons. In this experiment they are testing ______. These data clearly show _____________. a.long term depression, LTP is relatively inhibited when NMDAR are upregulated in CA3 neurons within the Grin1DGCA1 mutant hippocampus. b.long term potentiation, LTP in CA1 neurons is completely blocked when NMDAR expression is selectively downregulated in the Grin1DGCA1 mutant hippocampus. c.short term potentiation, the loss of NMDAR in the Grin1DGCA1 mutant hippocampus had no effect on synaptic plasticity. d. ong term potentiation, the loss of AMPAR in the DG of the Grin1DGCA1 mutant hippocampus significantly disrupted synaptic plasticity between mossy fibers and CA3 neurons.

long term potentiation, LTP in CA1 neurons is completely blocked when NMDAR expression is selectively downregulated in the Grin1DGCA1 mutant hippocampus. - The experimenters deleted Grin1, a NMDA receptor, in the DG and CA1 of the hippocampus. They then asked whether Grin1 was required for LTP by stimulating CA3 and recording from CA1. After 4 stimulations of 100Hz, the control, white circles, shows enhanced fEPSP (above baseline of 1) for upwards of an hour, which is LTP. The mutants however, did not show LTP, therefore the data concludes that NMDA is required for LTP.

The response to glutamate in on-center bipolar cells is mediated through _______ whereas off-center bipolar cell responses rely on _______. a. mGluR6, AMPA, and kainate b. TrkA, NMDA c. NMDA and AMPA, kainate d. AMPA, mGLuR6

mGluR6, AMPA and kainate - Glutamate release from cones causing graded potentials is received at post-synaptic mGluR6 receptors on sign-inverting, on-center bipolar cells. However in off-center, sign-conserving bipolar cells, glutamate activates AMPA receptors and kainate receptors.

In the CNS each cell typically receives input via about _________ synapses. a. only 1 b. 5-10 c. about 100 d. many thousands

many thousands A single excitatory neuron has thousands of synapses all along their dendrite and on their soma bodies. Collectively, the neuron must sum up all of those connections and determine if it is enough for an action potential or not.

[___________] have a small receptive field, are slowly adapting, and critical for processing static sensory features like shape; while [________] have a large receptive field, are rapidly adapting, and important for dynamic sensory stimulus features like the sense of dropping an object. a. free nerve endings, merkel cells b. pacinian corpuscle, ruffini corpuscles c. meissner corpuscles, free nerve endings d. merkel cells, pacinian corpuscles

merkel cells, pacinian corpuscles

the__ provides information about muscle__ and maintains its length via__ motor neurons while the __ provide info about the __ on/of a muscle and tendon

muscle spindle, length, gamma y, golgi tendon organs, tension - Muscle spindles are found in striated (skeletal) muscles. Muscle spindles consist of four to eight specialized intrafusal muscle fibers surrounded by a capsule of connective tissue. Sensory afferents are coiled around the intrafusal spindles, and when the muscle is stretched, the tension on the intrafusal fibers activates mechanically gated ion channels, triggering action potentials conveying information about the muscle length/stretch. Innervation of the muscle spindle arises from two classes of fibers, Type IA and Type II. Additionally, the intrafusal fibers are themselves contractile muscle fibers and are controlled by a separate set of motor neurons, γ motor neurons, which measure changes in the tension of intrafusal fibers. Whereas muscle spindles are specialized to signal changes in muscle length, Golgi Tendon Organs found in tendons respond to changes in tension. These mechanoreceptors are formed by branches of Type IB afferents distributed among the extrafusal collagen fibers.

According to surveys conducted by the March of Dimes foundation, only 34% of women report taking prenatal vitamins before they knew they were pregnant. Evidence suggests that ingestion of 400mg/kg folate, which is typically included in prenatal vitamins, significantly reduced the risk of which of the following developmental defects? a. lissencephaly b. gestational diabetes c. congenital insensitivity to pain d. neural tube closure defects

neural tube closure defects - Folic acid/folate is indicated to significantly reduce the risk of neural tube defects (NTD), however the mechanism is still under investigation. In-situ hybridization of folate-binding protein is high on the dorsal lip of the neural tube. Lissencephaly, or "smooth-brain" is a condition in which neuronal migration is disrupted and results in lack of sulci and gyri, or grooves in the cerebral cortex.

Which of the following is not a process that would likely contribute to changes in neural circuitry that occur during experience dependent refinement? a. neurotransmitter receptor activation b. synapse elimination c. activation of second messenger systems d. neuronal migration

neuronal migration

The transformation of embryonic ectoderm into the neural plate is known as _______? a. mesodermal specification b. neurulation c. gasturlation d. blastulation

neurulation - Once fertilization occurs, the zygote undergoes rapid cell division (cleavage), resulting in a hollow ball of cells. The blastula is the result of blastulation. Gastrulation is the process of invagination of the blastula, resulting in the three germ layers - endoderm, mesoderm and ectoderm. Neurulation is the process where the ectoderm folds in on itself, forming the neural plate/ neural tube.

The maturation of which of the following cell types continues in your prefrontal cortex well into your 20s? a. oligodendrocytes b. lower motor neurons c. radial glia d. DRG sensory neuron

oligodendrocytes - The prefrontal cortex is part of the CNS, therefore lower motor neurons and DRG sensory neurons are incorrect. Radial glia is the stem cell population that gives rise to neurons (neurogenesis), followed by glia (gliogenesis). The prefrontal cortex is a region involved in cognitive and executive processes, personality, and other higher order processes. These domains of cognition undergo significant neural plasticity and concomitant myelination.

Which of the following forefathers of neuroscience was a major proponent of "neurone" theory a. camillo golgi b. santiago ramon y cajal c. rudolph virchow d. theodor schwann

santiago ramon y cajal Camillo Golgi popularized the Reticular theory, that the nervous system is one large, continuous unit. Theodor Schwann proposed the Cell Theory, which states that cells originate from pre-existing cells. He was also named after the discovery of Schwann cells. Rudolph Virchow expanded the cell theory, that any variation from the pre-existing cell is due to disease. He is considered the forefather of cellular pathology.

The migration of immature neurons along which cell type is critical in generating a progenitor domain in the developing nervous system? a. neuroepithelial progenitor b. ependymal cell c. radial glia d. oligodendrocyte

radial glia - Once the neural tube closes, neuroepithelial progenitors (NEP) line the surface closest to what will be the central canal or ventricles. NEP undergoes interkinetic nuclear migration, and then mitosis when the soma returns back to the ventricular surface. This mitosis event gives rise to radial glia (RG) cells, which is only present in the CNS. RG are neuronal stem cells that send a projection to the pial surface which provides support for migrating neuroblasts. RG stay within the VZ and asymmetrically divide to give rise to a single immature neuron. This neuroblast will undergo radial migration along the RG projection to the mantle zone. This cluster of cells is the progenitor domain. Early born neurons will populate the deeper layers of the cortex (L6), and later born neurons will populate the superficial layers (L2/3). After neurogenesis, the RG will undergo gliogenesis and give rise to glia cells, like oligodendrocytes and astrocytes.

The spatial representation of the visual field in the brain is called.... a. tonotopy b. retinotopy c. somatotopy d. visuotopy

retinotopy - Retinotopy is the spatial arrangement of visual input from the retina (visual field) to areas of the brain. Tonotopy is the representation of the spatial arrangement for processing of different sounds frequencies or tones. Somatotopy is the spatial arrangement of somatosensation processing in the cortex arranged by body area.

In the investigation of visual circuitry, retinal injections of a transsynaptic label were used to... a. label the corticothalamic tract b. show which LGN neurons synapse onto different types of cerebellar neurons c. reveal an alternating pattern of cortical innervation related to input from the left or right eye

reveal an alternating pattern of cortical innervation related to input from the left or right eye - In general, tracer dyes are used to label neurons and their axons. They are useful in knowing where specific neurons project to in studying brain connectivity. Radioactive injections into one eye of cats and Macaques were used to look at ocular dominance columns. In the primary visual cortex, the tracer from the injected eye appears white on the radiograph. These alternating strips are axons from the labeled retinal ganglion cells (RGC) innervating from the labeled eye (white) and the non-labeled eye (black).

Damage to which of the following structures would cause the largest deficit in your perception of the left monocular visual field? a. left optic tract b. right optic tract c. temporal retina of your left eye d. right optic nerve

right optic tract - Damaging an optic tract will lead to deficits for an entire half of one's visual field because the optic nerves have already crossed at the chiasm and the tracts now represent the contralateral visual field. Damage to the right optic tract will cause deficits in the left monocular visual field. Damage to the left optic tract will cause deficits in the left monocular visual field and right binocular vision. Damage to an optic nerve will lead to vision loss of an entire eye including the monocular vision for that eye. The other eye will still capture both sides of the visual field, but not the monocular visual field from that eye. Damage to the right optic nerve disrupts left binocular vision and right monocular vision. Damage to the temporal retina of the left eye will cause less acuity of the right visual field.

An injury that resulted in a clean hemisection of the _____ side of the spinal cord at thoracic segment _____ would likely lead to an inability to sense touch on the right side at any site below the level of the nipple. a. left, 3 b. right 1 c. left 7 d. right 5

right, 5 - Somatosensory first-order neurons in the DRG receive information and transmit it to the CNS by synapsing onto neurons in the spinal cord. Fine touch and proprioception information travels through second-order axons travel ipsilaterally up the spinal cord, until they decussate at the medulla and travel via third order neurons to the contralateral side of the brain. The pain pathway decussates at the spinal cord level before ascending up to the medulla and contralateral hemisphere. Since the damage is before the medulla, the ipsilateral (right) side of the body would be affected for fine touch and proprioception information, and the left side of the body's pain would be affected. The first segment of the thoracic segment would correspond to areas on the arms and truck above the armpit, and segment 5 corresponds to the areas just below the nipple.

Where in the retina does "Phototransduction" specifically takes place? a. bipolar cell b. retinal ganglion cell c. outer nuclear layer d. rod/cone outer segment

rod/cone outer segment - Phototransduction occurs in the photoreceptor (rods and cones) outer segments. K+ and Na+/Ca2+ channels in rods and cones are controlled by light-sensitive proteins that cause hyperpolarization when activated by light. Rods and cones transmit information to bipolar and horizontal cells, which transmit information to the retinal ganglion cells which transmit information via action potentials to the optic nerve.

Which type of photoreceptor shows the most convergence onto bipolar cells? a. cones b. amacrine cells c. rods d. horizontal cell

rods - Rods and cones both transmit information to bipolar cells. In the human eye there are many more rods than cones. 15-30 rods converge onto one bipolar cell, while a single code transmits information to a one bipolar cell. This gives cones a much higher spatial resolution compared to rods.

Franz Nissl, a German neuropathologist, invented this immunohistochemical stain. Nissl staining primarily labels which of the following cellular structures? a. mitochondria b. rough endoplasmic reticulum c. synapses d. cell membrane

rough endoplasmic reticulum General Feedback Nissl stains genetic material, DNA and RNA, with cresyl violet giving it that dark purple appearance.

Myelin is a lipid rich coating around cells that help increase the speed of electrical signals. This increased transmission speed is caused by ___________ conduction. a. saltatory b. intracellular fluid c. pepperatory d. schwann

saltatory In both CNS and PNS, myelin insulates the axons and helps propagate the action potential. Nodes of ranvier are gaps in between the myelin contain ion channels to further propagate the action potential. Schwann is specific to the PNS, however, saltatory conduction is fundamental to any myelinated axons.

A pediatric patient presents with a delay in their ability to learn to walk and an unusual hairy patch on the lower back. Which of the following conditions is most likely? a. spina bifida b. caudal agenesis c. anecephaly d. holoprosencephaly

spina bifida - All four answers are different types of defects of neural development. Spina bifida is a birth defect caused by an incomplete closing of the caudal region of the neural tube, occuring in the lower back. In some cases, the vertebrae are not fully closed, which may result in a lesion on the skin accompanied by a hairy patch. Anencephaly is a condition in which the rostral end of the neural tube fails to close properly, resulting in incomplete formation of the cerebral cortex. Holoprosencephaly, also known as cyclopia, results in the failure of the craniofacial structures to segment into bilateral hemispheres. This is due to disrupted Shh signaling. Caudal agenesis, also known as sacral agenesis, is also a defect that occurs during development affecting the lower spine (i.e., caudal portion). This condition results in the absence or severe growth abnormalities of the lower spine and surrounding structures. While it affects the sacrum, it does not typically include skin lesions/openings as in spina bifida.

___________ plays a prominent role in regulating synaptic plasticity in the nervous system. a. spontaneous activity b. quantal release size c. patterned activity d. calcium concentration

spontaneous activity quantal release size patterned activity calcium concentration -all of the above - Synaptic plasticity is the ability of a neuronal connection to adapt to activity-dependent changes. Over time, synapses are strengthened or weakened depending on the activity of the presynaptic neurons signaling to the postsynaptic neuron. Changes in spontaneous and patterned activity are important to first establish (spontaneous) connections during development, and maintain (patterned) connections throughout. If there is little to no activity between two neurons, then over time the synapse is weakened and pruned away. The amount of neurotransmitter release is also important for synaptic plasticity. The larger the quantal size, or release of a neurotransmitter from a single vesicle, the stronger the connection. Vesicles require calcium and snare proteins to fuse with the presynaptic membrane, therefore, all events play an important role in regulating synaptic plasticity.

In regard to the shift in ocular dominance following the suturing of an eyelid, it was found that... a. neuronal cell death occurred specifically in the areas of the animals cortex innervated by the sutured eye b. suturing resulted in a cortical lamination inversion whereby layer 4 was moved above layers 2 and 3 c. the consequences of suturing were similar in kittens and adult cats

suturing had dramatic effects on kittens but very little effect on adult cats

Which of the following best characterizes the function of neurexins? a. synaptic adhesion b. pro-apoptotic protein c. transcription factor d. ligand gated ion channel

synaptic adhesion - Neurexin is a cell adhesion molecule on the presynaptic side that interacts with neuroligin on the postsynaptic neuron to facilitate synaptogenesis. There are many other cell adhesion molecules like cadherins. Because neurexins are membrane bound and involved in the structural formation of synapses, it is not a ligand gated ion channel.

Which of the following mechanisms of plasticity is least likely to assist in the long-term reorganization of synaptic strength in the sensory cortex following training or injury? a. spike-timing dependent plasticity b. long-term potentiation dependent CREB activation c. AMPAR insertion into the synaptic membrane

synaptic facilitation - Synaptic facilitation is a short term plasticity mechanism, and thereby won't be able to elicit any long term changes needed for the reorganization of the cortex. Spike-timing dependent plasticity. LTP dependent CREB activation, and AMPAR insertion into the synaptic membrane are all long term plasticity changes that may be utilized in this reorganization.

After stimulating the aplysia siphon multiple times, you notice the gill withdrawal response is greatly diminished. Which of the following statements regarding changes in synaptic machinery following behavioral habituation is most accurate? a. the number of cholinergic-containing vesicles available for release from the motor neuron is reduced b. the number of serotoning-containing vesicles available for release from the sensory neuron is reduced c. the number of serotonin- containing vesicles available for release from the modulatory interneuron are reduced d. then number of glutamate-containing vesicles available for release from the sensory neurons is reduced

the number of glutamate-containing vesicles available for release from the sensory neurons is reduced. - The glutamatergic sensory neuron from the siphon synapses onto the cholinergic motor neuron controls the gill withdrawal response. When there is a stimulus applied to the siphon, the sensory neuron releases glutamate, an excitatory neurotransmitter to activate the motor neuron and retract, inducing the gill withdrawal reflex. After repeated stimulation, the reserve pool is depleted, less neurotransmitter release, therefore reduction in the gill withdrawal response.

The neuron is very specialized to be able to..... a. be continuous with all other neurons b. transmit electrical signals c. transport nutrients d. produce hormonal signals

transmit electrical signals General Feedback Camillo Golgi supported the Reticular theory, which states that everything in the nervous system is a continuous network. Ramon y Cajal observed that the nervous system is made up of many discrete cells with space inbetween, called the neuron theory or neuron doctrine. The brain uses electrical signals to communicate and process information.

Cortical columns in the cortex tend to have neurons that will synapse with other neurons in the same column. T/F

true Neurons in the same cortical column will synapse with each other. In general, this is called the local microcircuit. As you will learn in later modules, these microcircuits will connect with other brain regions via long-range projection neurons.

Layers across the neocortex tend to have similar cell types and contribute to the organization of information processing. T/F

true Cortical layer is another classification used to categorize the diversity of neurons. It organizes cells and streamlines information processing to be efficient.

A technique that can be used to measure the level of protein in a homogenized tissue is called... a. qPCR b. immunohistochemistry (IHC) c. in-situ hybridization (ISH) d. western blotting

western blotting General Feedback qPCR and ISH quantify DNA and RNA, respectively. Both western blotting and IHC quantify protein, however, western blott uses tissue samples that have been homogenized. IHC probes for proteins of intact tissue, giving spatial information.