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The presence of which gene product inside a neuron is a marker for recent neuronal activation?

In class we discussed the paper, “Optogenetics enables functional analysis of human embryonic stem cell-derived grafts in a Parkinson’s disease model”. In this paper, scientists took hESCs growing in culture and differentiated them into cells that looked like this at 30 days: The scientists then tested these cells for function. One thing they tested (that we did not discuss in class) was that the cells released dopamine when they were stimulated. To do this, the scientists puffed either glutamate (GLU) or saline onto the cells and then measured the amount of dopamine that the cells released into the dish in which they were growing. They did this experiment without optogenetic stimulation (no 545 nm light) and with optogenetic stimulation (in the presence of 545 nm light). You can see the results of this experiment below. (The left side shows the results for the cells that are expressing EYFP, and the right side shows the results for the cells that are also expressing halorhodopsin. Bars outlined in black show results without 545 nm light. Bars outlined in green show results with 545 nm light.) If these cells are functioning as the scientists want: What will the bar look like for cells expressing EYFP that are receiving saline and 545 nm light (bar 1)? Choose from the possible answers. [B] What will the bar look like for cells expressing EYFP that are receiving glutamate and 545 nm light (bar 2)? Choose from the possible answers. [C] What will the bar look like for cells expressing halorhodopsin-EYFP that are receiving glutamate and 545 nm light (bar 3) Choose from the possible answers. [A]

The mutant fly that Dr. Young identified in in the question above contained a mutation in a gene that encoded the enzyme, ‘Casein Kinase 1’. Casein Kinase 1 phosphorylates period when it is not bound to timeless. When period is phosphorylated by Casein Kinase 1, it is degraded. Thus, period levels will be lowest [duringtheday]. This means that in the night, clock and cycle [willnot] be bound to E-boxes.

The image below shows the protein inclusion found in the brains of people with Parkinson’s disease. The primary component of Lewy bodies is:

In 2017, scientists expressed an opsin specifically in dopamine neurons in mice. They then used electrophysiology to record from dopamine neurons in brain slices from these mice. Here’s what the recording looked liked with no light stimulation: Here’s what the recording looked liked with tonic light stimulation (1 light pulse every second): Note: The light pulses are represented by a the blue ticks. Here’s what the recording looked liked with phasic light stimulation (50 light pulse in 1 second): Note: the blue line represents the light pulses. What opsin was expressed in the dopamine neurons? [Channelrhodopsin] What kind of recording is this? [wholecell]

For which of the following algorithms the worst case analysis results in a recurrence relation based on the Fibonacci numbers? 

In the DIRECT pathway, some neurons that have cell bodies in the motor cortex send their axons out to synapse onto neurons whose cell bodies and dendrites are in the striatum. These cortical neurons release glutamate onto the striatal neurons. This glutamate release [1] the neurons in the striatum. Ultimately the thalamus is [2]. Thus, in the direct pathway, the release of glutamate from neurons in the motor cortex [3] movement.

Give an example of a type of binary tree for which the height is bound by a constant times log(n), n being the number of nodes. Define the type of tree you chose.

Which of the following sorting algorithms has a complexity of Q(n log(n)) in the best case?

Consider the image to the right: Below are summaries of three recent research papers that have studied neurons in the labeled structures. Based on your knowledge of brain structures, match the research with the most likely relevant brain structure in the image above. Sniffing is a motivated behavior displayed by nearly all terrestrial vertebrates. While sniffing is associated with acquiring and processing odors, sniffing is also intertwined with emotional (affective) and motivated behavior. A 2025 study reported sniffing involves neurons in this structure. [BC]   In 2022, researchers reported that a subset of neurons in this structure express FoxP2. Activating these neurons made male mice more likely to attack another male mouse when it was introduced into their cages. [D]   The intricate organization of circuits that store memory traces remains poorly understood. To address this knowledge gap, researchers used three-dimensional electron microscopy of neurons in this structure to uncover the structural correlates associative memory. They published their results in March of 2025. [A]