The basolateral amygdala (BLA) is a region of the brain that has been studied almost exclusively in the context of fear and emotion. Only recently have researchers begun to question whether BLA can play a more important and general role in memory and behavior. However, almost nothing is known about the neuronal activity of BLA during naturalistic behavior.
To answer these questions, neuroscientists at UCL’s Sainsbury Wellcome Center observed neuronal activity in this region of the brain as rats freely engaged in a variety of different ethological stimuli. Interactions with ethological stimuli are relevant to the survival of the animal and the spread of its genes, and include food, prey, and conspecifics. In a new study, published today in Cell Reports, researchers show strong responses to these kinds of events in the BLA.
The naturalistic stimuli in this study were important to animals in their daily lives, and rats were naturally curious to interact with them. They included complex multisensory stimuli such as male and female rats, food, and a moving toy mouse.
Traditionally, research has focused on studying BLA in rats during trained tasks. Instead, we wanted to observe neural activity as rats behaved freely to see if we could find a global role for BLA during natural behavior that could unite previous lines of research. ”
Cristina Mazuski, researcher at O’Keefe Lab, Sainsbury’s Wellcome Center and lead author of the paper
Using Neuropixels, Mazuski and O’Keefe simultaneously recorded hundreds of neurons in rat BLA and correlated unicellular neuronal activity with complex behavior to identify different classes of cells within BLA that respond to ethological stimuli. They identified and described two new cell categories in the BLA; event-specific neurons, which responded only to one of four classes of stimuli, and panresponsive neurons, which responded equally well to most or all stimuli.
Surprisingly, 1/3 of the cells showed an active memory response: the neuronal response not only lasted throughout the event, but continued after the end of the event for many minutes. The authors speculate that these later responses may be acting as a memory system indicating to the rest of the brain that a major event had just occurred and perhaps alerting other regions of the brain to store information about other aspects of the event and circumstances. that surround him.
Commenting on these aspects of the results, Professor O’Keefe, lead author of the article, said: “These findings place the basolateral amygdala at the center of the social / ethological brain and open a whole research program that investigates which other “The stimuli that occur in the rest of the BLA cells (usually silent) are of interest.
As the researchers were recording many neurons simultaneously using Neuropixels, they were also able to observe the connectivity of the circuit. By delving into the correlated activity between different unique neurons, they could infer the flow of information from more specific neurons, such as those that respond to female rats or feed on less specific panresponsive neurons.
“This initial study opens up many avenues for future research. The next steps are to find out how sensitive the responses are, how robust they are, and to confirm whether they play a role in memory,” Cristina concluded.
This research received funding from the European Union’s Horizon 2020 research and innovation program under the Marie-Sklodowska-Curie grant agreement no. 840562 to Cristina Mazuski, basic grant from the Sainsbury Wellcome Center of the Gatsby Charitable Foundation and Wellcome Trust (090843 / F / 09). / Z) and Wellcome Trust Principal Research Fellowship (Wt203020 / z / 16 / z) to John O’Keefe.
Source:
Sainsbury’s Welcome Center
Magazine reference:
Mazuski, C & O’Keefe, J., (2022) Representation of Ethological Events by Basolateral Amygdala Neurons. Cell reports. doi.org/10.1016/j.celrep.2022.110921.