Exploring Circuitry for Maternal Aggression
Sumela Basu, Akash Waghade, Roshni Parveen, Ayushi Kushwaha, and Saptarsi Mitra et al.
(see article e2140242025)
A major reason females display aggression is to protect their young from intruders. For rats, previous research suggests that intruders emit odors that activate the hypothalamic ventral premammillary nucleus (PMv) to provoke aggression. Herein, Basu and colleagues explored how PMv activation triggers maternal aggression. Because the neuropeptide cocaine- and amphetamine-regulated transcript (CART) is highly expressed in the PMv and in circuits that drive aggression, the researchers explored its role in maternal versus male-to-male aggression. They discovered that dams displaying aggression toward intruders have increased PMv neuronal activation, which induces CART signaling and leads to elevated levels of CART. Males displaying aggression toward intruders also had PMv CART neuronal activation, but this occurred in different region of the PMv and did not affect CART levels. Silencing CART signaling in the PMv suppressed maternal—but not male-to-male—aggression. Basu et al. also discovered the PMv circuit that may be involved: CART release from the PMv to the ventrolateral part of the ventromedial hypothalamus triggered aggression in dams. This study points to a CART-mediated mechanism that may, at least in part, underlie the distinction between maternal aggression and male-to-male aggression.
This is a coronal section of the hypothalamus of a dam exposed to an intruder. The CART neurons (green) in the ventral premammillary nucleus show profound c-Fos activation (red). See Basu et al. for more information.
Investigating Neural Processes for Tracking Time
Nir Ofir and Ayelet N. Landau
(see article e1675242025)
How mammals track the passage of time involves different neural processes. However, which processes are involved and how they work together to evaluate time passing is unclear. Ofir and Landau advanced understanding of how the brain evaluates the passage of time in this issue. The authors studied the role of mu-beta activity, a neural signal involved in movement preparation, in time-based decisions during a task in which study participants categorized time intervals as “long” or “short.” The researchers discovered that mu-beta activity before “long” intervals was apparent before the offset of the timed interval. However, for “short” intervals, mu-beta activity only occurred after the interval offset. Furthermore, for “long” responses, mu-beta activity was stronger for faster compared to slower responses. In other words, mu-beta activity, reflecting movement preparation, follows the decision rather than track its formation. According to the authors, their work points to motor preparation and evidence accumulation as related but distinct processes in time-based decisions, offering a more integrated view of how the brain tracks time.
Footnotes
This Week in The Journal was written by Paige McKeon
