Dr. Abhilasha Joshi
Assistant Professor National Centre for Biological Sciences, India
Postdoctoral fellow University of California, San Francisco
PhD University of Oxford
When Dr. Abhilasha Joshi was a child, she had an active imagination. She was constantly guessing at the inner musings of every creature she encountered, from her pet dog to the birds in the garden to the people in her daily life. Not only did she love imagining what the creatures around her were thinking, but she would create a mental model of how these thoughts were linked to their behavior. Perhaps, then, it is not surprising that Abhilasha was ultimately drawn to the field of neuroscience. Today, she is starting her lab as an Assistant Professor at the National Center for Biological Studies in Bengaluru, India.
Despite her childhood experience in linking the thoughts and behavior of humans and other animals, Abhilasha did not initially consider that this could be the basis of a career. Interested in science more generally but unsure what career path she would pursue, she started a bachelor’s-master’s program at the Indian Institute of Science Education and Research (IISER) in Mohali, India. As she began taking classes, the first concept that stood out to Abhilasha was evolutionary biology; she was struck by the idea that biology was about the organism’s entire life history. Later, as she learned about neuronal physiology in neuroscience classes, Abhilasha began to see the links between animal behavior—which had always fascinated her—and the biological concepts she was learning. Not only did her time at IISER spark a fascination with science, but it was also when Abhilasha fell in love with research. The structure of the program involved mandatory research internships, and Abhilasha chose a different topic each time, studying everything from cancer and mitochondrial dynamics to protein biophysics and developmental neuroscience. While she enjoyed all of it, ultimately she knew that she wanted to dig more deeply into topics surrounding animal behavior and its underlying neural mechanisms.
After graduating from IISER with her master’s degree, Abhilasha started her PhD working with Drs. Peter Somogyi and David Dupret at the University of Oxford. Peter’s lab was interested in temporal firing patterns in the brain. Previous work had already revealed that interneurons in the hippocampus exhibit coordinated, oscillatory firing at 5-12 Hz, known as “theta oscillations.” It was also known that a group of neurons in the medial septum—a region with major projections to hippocampus—exhibits a similar frequency oscillation, and that inactivating the medial septum blocks hippocampal theta oscillations. Abhilasha set out to discover the circuit and cellular basis of this relationship between the medial septum and the hippocampus. Recording from the medial septum, she discovered many subtypes of neurons with diverse firing patterns. She became interested in a neuronal subtype with particularly rhythmic bursting activity. The rhythmic firing of the cell type was so distinct that, after listening to countless cells while exploring the medial septum, Abhilasha could pick out her cells of interest by ear. She was able to record from and label enough of these cells to then further characterize them and trace their projections. She discovered that these bursting cells were a special subset of GABAergic neurons that projected straight to the CA3 region of the hippocampus. Her thesis work thus described a novel cell type driving septal-hippocampal communication.
As she was nearing the end of her PhD, Abhilasha made a surprising discovery. She typically did her neural recordings on mice that were head-fixed and running on a ball. One day, she decided to slow down the video recording of the mouse to examine its movements more closely. She was shocked to realize that the frequency of the animal’s footfalls was the same as that of both the hippocampal theta oscillations and theta rhythm in the medial septum. While initially she and her labmates and colleagues thought this finding was a cute coincidence, Abhilasha quickly began to intuit that this potential synchronization between motor behavior and hippocampal rhythms could be revolutionary to the field. Her advisor, Peter, also took the finding seriously and encouraged her to think more deeply about how she could actively study and quantify this synchronization. Buoyed by his support, Abhilasha began talking to potential postdoctoral advisors about pursuing this question in their laboratories. Ultimately, she chose to work with Dr. Loren Frank at University of California, San Francisco. Not only did she trust him after having worked with him during one of her IISER internships during her master’s, but she also recognized that his lab had the tools and knowledge she would need to follow up on her initial findings.
In the Frank lab, Abhilasha began to expand her understanding of how physical movement was connected to the internal workings of the brain. She began working with freely behaving rats instead of head-fixed mice and recorded firing patterns in the hippocampus—spatial representations of the rat’s environment. Abhilasha discovered that the stepping cycle in freely moving rats peaks at around 8 Hz, matching not only hippocampal theta oscillations but also the spatial representations. Interestingly, she found that, as rats approach a spatial decision, the moment that the rat’s forelimb touches the ground is precisely timed with the hippocampal representation of the rat’s present spatial location. The representation then shifts towards potential future locations in between forelimb footfalls. This critical discovery deepens the field’s understanding of the synchronization between cognition and sensorimotor activity.
Towards the end of Abhilasha’s postdoc, Dr. Megan Carey—who studies how the brain controls coordinated movement— visited UCSF to give a seminar talk. Abhilasha knew Megan’s work and made sure they had a chance to meet during the visit. They clicked immediately and discussed their common research interests as well as some of Abhilasha’s results. After Megan’s talk, a member of the audience asked a question and, in response, Megan pointed out Abhilasha in the crowd and described how Abhilasha’s work would help to answer the question. This was a pivotal moment for Abhilasha—she felt that she and her work had been truly “seen.” Later, while she was applying for faculty positions, she ran into visa issues and had to end her postdoc at UCSF before securing a job. Abhilasha reached out to Megan and ultimately took a position as a Visiting Scientist working with Megan at the Champalimaud Centre for the Unknown in Lisbon, Portugal while she finished her faculty job search.
Today, Abhilasha is an incoming Assistant Professor at the National Center for Biological Sciences in Bengaluru, India. She is excited to continue studying the interactions between internal cognitive processes and motor actions during natural behaviors. Reflecting back on her journey, Abhilasha feels that the most rewarding periods have been those in which she could focus completely on playing detective in the lab, chasing the biological truth wherever it led. As a child, if Abhilasha had seen a mouse running through the garden, she would certainly have wondered what it was thinking as it ran. Today, she has the training and tools to begin to answer this life-long question.
Find out more about Abhilasha and her lab’s research here.
Listen to Meenakshi’s full interview with Abhilasha on June 3, 2024 below!
