Ventromedial Hypothalamus and the Generation of Aggression

Abstract

Aggression is a costly behavior, sometimes with severe consequences including death. Yet aggression is prevalent across animal species ranging from insects to humans, demonstrating its essential role in the survival of individuals and groups. The question of how the brain decides when to generate this costly behavior has intrigued neuroscientists for over a century and has led to the identification of relevant neural substrates. Various lesion and electric stimulation experiments have revealed that the hypothalamus, an ancient structure situated deep in the brain, is essential for expressing aggressive behaviors. More recently, studies using precise circuit manipulation tools have identified a small subnucleus in the medial hypothalamus, the ventrolateral part of the ventromedial hypothalamus (VMHvl), as a key structure for driving both aggression and aggression-seeking behaviors. Here, we provide an updated summary of the evidence that supports a role of the VMHvl in aggressive behaviors. We will consider our recent findings detailing the physiological response properties of populations of VMHvl cells during aggressive behaviors and provide new understanding regarding the role of the VMHvl embedded within the larger whole-brain circuit for social sensation and action.

Changes in neuronal activity across the mouse ventromedial nucleus of the hypothalamus in response to low glucose: Evaluation using an extracellular multi‐electrode array approach

“…Indeed, although the relative percentage of VL‐VMN glucose‐sensing neurones is reported to be similar in male and female mice, the proportion of the different subtypes of glucose‐sensing neurones in the VL‐VMN (GE, adapting GI and non‐adapting GI) appears to be sexually dimorphic, which may relate to differential activation of sex steroid hormone receptors impacting neuronal glucose‐sensing . Furthermore, the VL‐VMN is strongly implicated in mediating sexual behaviour and aggression . It is not clear why the GE/PER channels in this region showed higher basal firing rates in response to 2.5 mmol L ‐1 glucose; one possibility could be that, because both sexual behaviour and aggression are energetically expensive, it may make biological sense that a key component in the circuit controlling these behaviours is sensitive to changes in systemic energy availability.…”

“…21,22 Furthermore, the VL-VMN is strongly implicated in mediating sexual behaviour and aggression. 44 ItisnotclearwhytheGE/PERchannelsinthisregionshowedhigher basal firing rates in response to 2.5 mmol L -1 glucose; one possibility could be that, because both sexual behaviour and aggression are energeticallyexpensive,itmaymakebiologicalsensethatakeycomponent in the circuit controlling these behaviours is sensitive to changes insystemicenergyavailability.Althoughpreviousstudieshaveperformed detailed electrophysiological characterisation of VMN neurones, 45 toourknowledge,thisisthefirstreportofobservedregional differences in basal firing frequency in 2.5 mmol L -1 glucose across the VMN, highlighting a strength of simultaneous recording across theslice,whichtheMEAapproachenables.…”

Connectional architecture of a mouse hypothalamic circuit node controlling social behavior

“…This stands in contrast to viralanatomical studies of monoamine neuromodulatory systems: in the Locus Coereleus, neurons collateralize extensively and receive similar input regardless of downstream target (13), while in the Dorsal Raphe, subpopulations collateralize broadly but to distinct combinations of targets, and receive biased inputs depending on their projection target (26). Type 1 estrogen receptor (Esr1)-expressing neurons in the ventromedial hypothalamic nucleus (VMH) control social and defensive behaviors as well as metabolic states (6,7,9,27); reviewed in (28)(29)(30)(31)(32)(33). Unlike the ARC Agrp and the MPOA Gal populations, which are primarily GABAergic (24,34), VMHvl Esr1 neurons are mainly glutamatergic (35).…”

Hypothalamus – Response to early paracetamol exposure in male rats offspring

“…The paraventricular nucleus of the hypothalamus play a role as integration center between the peripheral and central autonomic nervous systems and regulates the endocrine system, fertility and sexual behaviour (Biran et al, 2015;Migaud et al, 2016;Hashikawa et al, 2017). Observed changes in the neurotransmitters level in this brain structure are not only responsible for the desirable beneficial antipyretic effect of pacetamol, but are also likely to affect other health features in the Table 1 Effect of prenatal and early postnatal paracetamol administration on the level of monoamines and their metabolites and neurotransmitters turnover (mean ± SEM) in the hypothalamus of rat pups.…”