In an innovative new publication from the Anderson lab at Caltech, ‘An approximate line
attractor in the hypothalamus encodes an aggressive state,’ Nair et al. use the Inscopix
miniscope to investigate the population dynamics of the ventromedial hypothalamus
(VMHvl) during aggressive behavior.
This brain region was previously shown to cause attack behavior when optogenetically
stimulated, although, in apparent contradiction, very few neurons from the region
exhibited time-locked activity with aggressive episodes. To address this seeming
inconsistency, Nair et al. showed computational prowess by analyzing previously
recorded in vivo calcium imaging data from over 300 neurons in this deep brain region
of the hypothalamus during aggressive, social behaviors using the nVista system from
three previous studies in the Anderson lab (Remedios et al., (2017) Nature; Karigo et
al., (2021) Nature; Yang et al., (2022) Nature).
They demonstrated that in a manner more often reported for higher-order cortical and
hippocampal regions, the VMHvl encodes the phases of attack through a specific type
of population activity pattern–an ‘approximate line attractor.’ Using dimensionality
reduction strategies, they were able to differentiate specific behaviors like sniffing, from
attack or dominance mounting behaviors using only the recorded neural activity. To
emphasize the novelty of this finding, they further showed that a neighboring
hypothalamic region, the medial preoptic nucleus (MPOA), exhibits entirely different
action-specific coding for related social behaviors.
Thus, the activity of the VMHvl subverts expectations by representing attack behavior
as an emergent property of the neuronal population, rather than through action-specific
cell populations. We congratulate Nair et al. on changing our conceptions of neural
representations in the hypothalamus, and look forward to other cool, miniscope
Dr. Peter Schuette, is a Field Scientific Consultant for the US, West Coast region and a Neuroscience PhD with expertise in neuromodulation and memory from Dr. Nanthia Suthana’s lab at UCLA. As a post-doctoral fellow, under the joint mentorship of Drs. Avishek Adhikari and Jonathan Kao at UCLA, Peter extensively researched threat-induced behaviors using computational and systems neuroscience approaches. We are thrilled to have Peter contribute to the successes of the Inscopix miniscope community!