Isabella Catalano - March 2025

Isabella Catalano on聽Early auditory and adult mating experiences interact with singer identity to shape neural responses to song in female zebra finches

Read the article in J. Neurophysiology .

Coming into grad school, I heard all the usual platitudes: 鈥榓 PhD is a marathon, not a sprint鈥�, 鈥榶ou have to pace yourself鈥�, 鈥榙on鈥檛 give up鈥�, et cetera, et cetera. Unfortunately, I鈥檓 not much of a runner, so I didn鈥檛 take that as much to heart as I might have; nonetheless, it was important advice that ended up being very relevant towards putting out my first first-author paper, 鈥淓arly auditory and adult mating experiences interact with singer identity to shape neural responses to song in female zebra finches鈥�, which recently came out in J. Neurophysiology.

My graduate school journey started pretty early鈥擨 joined a research lab during my first semester of undergraduate studies, and I was hooked. I loved research, from designing experiments to troubleshooting them, and even the pesky 鈥榬epeating the same task n amount of times鈥� part. I stayed in that lab for my four years of undergrad, studying the effects of smoking cessation drugs such as varenicline on drug-seeking behavior in rats. At the same time, I later conducted an independent research project for my Bachelor thesis, this time on multilingualism and executive function, as well as getting hired in my last year to work as an RA for another lab that studied classroom interventions for teaching about climate and climate change. These were all great experiences that made me certain I wanted to pursue a PhD, but as you might be able to tell, I had fairly wide-ranging interests, and for the longest time I didn鈥檛 know what to pursue at the graduate level.

Naturally, when I found out that some programs (such as 91黑料网) offered an option to rotate through different labs before deciding on a final PhD option, I knew I had to take the chance. I鈥檓 very glad I did, because I ended up accepted to the IPN鈥檚 Rotation Program, and started in the fall of 2019. My first rotation was with the Rajah Lab, where I learned how to use EEG to study older adults and working memory. My second rotation was with the Woolley Lab, working with zebra finches to study a range of things, from dopamine鈥檚 effects on pair-bonding and preference to early life experience and perception.

Pause for a moment here to look at this adorable picture of a pair of zebra finches:

Fig. 1: an adorable zebra finch couple. Picture from Tiluria on Pixabay. The male is the one on the left with brighter plumage鈥攐ur lab focuses on the females, who are more drab in colour but no less adorable.

Okay. Now that you鈥檝e seen the picture, hopefully you can understand how the finches won me over.

The project that eventually became the paper was one I started working on during my rotation, in Winter of 2020. Barely two months in, with not even a full immunocytochemical batch processed, COVID hit, and we were shut down for months. (My final rotation, which I had planned to do with human subjects again, quite understandably didn鈥檛 pan out.) Once we got clearance to start experimental work again, I immediately faced another hurdle鈥攈aving only been in the lab for two months, part of which was just getting used to handling birds in the first place (you would never guess this, but capturing an animal that can move in three dimensions is much harder than catching, say, a lab rat), there were some huge gaps in my knowledge base. Luckily, with some ingenuity, we managed to overcome the worst of it: a lab mate in on a different day than me managed to record a video of her using a microtome by way of a GoPro strapped to her forehead, so I was able to slowly learn the necessary skills.

The project progressed a bit faster once we were allowed to go to lab in pairs, so I could learn directly from another person; but between needing birds reared in certain experimental conditions and having to record other birds to create stimuli, I didn鈥檛 finish the initial phase of data collection until almost the end of 2021. This phase provided the setup for everything else: we paired female birds from two different rearing conditions together with males and allowed them to form a pair bond, then we played back a male鈥檚 song before perfusing the females and preserving the brains, which then had to be sliced, stained for an activity marker, and mounted on slides.

And then came phase two: imaging and cell counting. Luckily, by this point, we were able to bring in help (read: undergraduates), so I was able to offload some of the work. Since this project was somewhat exploratory in nature, we ended up taking a lot of images covering twelve distinct brain regions. With 39 birds in the study, it also ended up being a lot of cells counted, and I kept coming across brain regions not in our original plan but that would nonetheless be interesting to look like. All told (and because I was also juggling two other projects, TAing, and taking my candidacy exam), we ended up finishing the data collection in early 2023鈥攐nly to realize as I was taking pictures to turn into a figure that actually, one of my main regions of interest, a secondary auditory processing region called the caudomedial nidopallium (NCM), had quite a bit of variation within it that our original sampling method wasn鈥檛 catching, and it would actually be best split up into multiple regions. This resulted in an entirely new round of imaging and counting.

In the end, this was a good catch, because we were able to show differences across rearing conditions鈥攊n normally-reared females, for example, our activity response was highest to the mate song across the NCM, but in song-na茂ve females (females who were not exposed to conspecific song as juveniles), unfamiliar song actually elicited greater response in the more dorsal NCM subregions. This is exciting for several reasons; for one, it helps us birdsong researchers have a better idea of what different parts of NCM (which is largely featureless on a neuroanatomical level) do, and for another, it really goes to show how much of an impact early life experiences can have even into adulthood!

Fig. 2: a subset from the paper鈥檚 figure 3a, showing that NCM is pretty big and also has lots of activity! NCM here is the area of the brain under the broad light-coloured stripe, which is Field L, part of the avian primary auditory processing system. White dots are cells expressing phosphorylated S6 ribosomal protein (pS6), which is a marker of activity. Columns represent rearing conditions, rows represent two (of four) stimulus conditions: here you can see that unfamiliar song in general elicits more activity than a silence condition, and that the unfamiliar condition in normally-reared birds has less pS6 than the song-na茂ve birds. We had to adjust our methodology to try and account for the variation we saw while taking large images.

Finally armed with this data, all that was left was pushing through the motivational doldrums to actually finish writing (and then submitting, and then revising鈥�) the paper. Now that Catalano & Woolley, 2025 is out in the world, I will be focusing on finishing up my other two papers in the works, as well as my thesis, and thus grad school in general. I am still not a runner, but the experience of working on this paper had definitely made me understand where the marathon metaphor for grad school comes from, as well as having taught me important lessons about patience, persistence, and pausing for stretch breaks.

Fig. 3: Me, definitely not running for the finish line.