Comparative Neuroscience
What is a model organism, and why do scientists use them?
A model organism is a species studied to understand biological processes that may apply to other species, including humans.
What is neurogenesis?
The production of new neurons from neural precursor cells.
Which two structures of the eye primarily bend and focus incoming light onto the retina?
The cornea and lens.
What imaging technique is commonly used to examine the anatomical structure of the brain?
Structural MRI.
Humans typically have three cone types. How many do dogs generally have?
Two cone types.
What is homology?
Homology refers to structures that evolved from a shared ancestor, even if they have different functions.
What developmental process eliminates unnecessary or weak synapses?
Synaptic pruning.
Which photoreceptors are primarily responsible for color vision, and which are more sensitive in dim light?
Cones are responsible for color vision, while rods are more sensitive in dim lighting.
What imaging technique can identify patterns of brain activation while someone performs a task?
Functional MRI (fMRI).
A student recognizes a blurry image more easily after being told what object to expect. Is this top-down or bottom-up processing?
Top-down processing because prior knowledge and expectations influence visual perception.
Name two reasons why researchers commonly choose mice as model organisms.
Short lifespan, easy breeding, relatively low cost, and biological similarities to humans. (Any two.)
What are growth cones, and how do attractive and repulsive signals affect them?
Growth cones are structures at the ends of developing axons. Attractive signals guide them toward targets, while repulsive signals guide them away.
What is the difference between ON-center and OFF-center retinal ganglion cells?
ON-center cells increase firing when light illuminates the center of their receptive field. OFF-center cells increase firing when the center becomes darker.
Which neuroimaging method uses water movement to estimate the direction of white matter pathways?
Diffusion tensor imaging (DTI).
What is a retinotopic map, and where is one found?
A retinotopic map preserves the spatial arrangement of visual information from the retina. Retinotopic maps are found in the lateral geniculate nucleus (LGN) and primary visual cortex (V1).
Why might a particular brain region be proportionally larger in one species than in another?
Brain regions can vary in size due to overall brain size, evolutionary adaptations, and species-specific sensory or behavioral specializations.
What are the three major steps of synaptogenesis?
Recognizing the postsynaptic target and separating from bundled axons (defasciculation).
Establishing contact through cell adhesion.
Developing functional neurotransmitter and receptor signaling.
What type of visual stimuli can strongly activate face-selective neurons in the inferotemporal cortex?
Images of faces.
What is the difference between anterograde and retrograde neural tract tracers?
Anterograde tracers follow projections from cell bodies toward axon terminals. Retrograde tracers identify neurons projecting to the tracer injection site.
A child experiences reduced visual input during a critical developmental period. Explain how this could affect later visual processing.
Reduced visual input during a critical period may disrupt normal visual circuit development, potentially causing lasting visual impairments.
What does "inside-out" cortical development mean?
Earlier-born neurons settle in deeper cortical layers, while later-born neurons migrate past them to form more superficial layers.
What is the difference between anencephaly and spina bifida in terms of neural tube development?
Anencephaly results from failed closure of the rostral neural tube, severely affecting brain development. Spina bifida results from incomplete closure in the caudal spinal region.
Explain what happens to cGMP, sodium channels, and membrane potential when light hits a photoreceptor.
Light activates rhodopsin, which activates transducin and phosphodiesterase. This decreases cGMP, closes cGMP-gated sodium channels, and causes the photoreceptor to hyperpolarize.
A researcher wants to determine which cortical layers form first. Describe how they could use birthdating tracers in pregnant mice.
Researchers inject birthdating tracers at different embryonic time points and later examine the offspring's cortex. Earlier-labeled neurons are found in deeper layers, while later-labeled neurons are found in more superficial layers.
A developing brain does not eliminate weak synapses normally. What process is disrupted, and how might this affect connectivity?
Synaptic pruning is disrupted. This can allow excess weak or unnecessary connections to remain, potentially altering neural circuit organization.