Amygdala

The human medial temporal lobe contains neurons that respond selectively to the semantic contents of a presented stimulus. These "concept cells" may respond to very different pictures of a given person and even to their written or spoken name. Their response latency is far longer than necessary for object recognition, they follow subjective, conscious perception, and they are found in brain regions that are crucial for declarative memory formation. It has thus been hypothesized that they may represent the semantic "building blocks" of episodic memories. In this talk I will present data from

Fear learning induces synaptic potentiation between engram neurons in the rat lateral amygdala. This study by Marios Abatis et al. demonstrates how fear conditioning strengthens synaptic connections between engram cells in the lateral amygdala, revealed through optogenetic identification of neuronal ensembles and electrophysiological measurements. The work provides crucial insights into memory formation mechanisms at the synaptic level, with implications for understanding anxiety disorders and developing targeted interventions. Presented by Dr. Kenneth Hayworth, this journal club will explore

Aggression can be a fundamental social behavior in many species and is importantly modulated by prior aggressive experience. However, how this experience shapes neural activity and whether it predicts behaviors in novel, more challenging aggression contexts are unknown. Moreover, imitation learning theories of aggression suggest that this behavior can be transferred through observation alone1, but whether this learning leverages the same neural mechanisms as experience is unclear. To address these two questions, here we combine novel behavioral mapping strategies with cell-type-specific and mu

…Although the amygdala and the lateral horn (LH) in mammalian and insect brains are implicated in driving innate olfactory behavior (Heimbeck et al., 2001; Root et al., 2014), whether and how these areas compute innate value of odors remain largely unknown, let alone the underlying circuit mechanism. Here we recorded the activity of virtually all the neurons in t

…indicates that interaction between amygdala, frontal cortex, and striatum is critical for this type of learning. Here, we conducted neurophysiology recordings and applied computational approaches to understand how activity in this circuit varies when choice and reward are separated in time, intentionally decreasing animals’ ability to associate the two together. We trained 3 rhesus macaques to perform a probabilistic reward-learning task. In each session, animals learn the probabi

The sleeping brain is in a constant tradeoff between maintaining its quiescent state, thought to support homeostatic processes, and interrupting it to deal with external contingencies such as threat. While evidence suggests that sleep interruption is an associative contextual process, little is known about its underlying neural substrates. Here, inspired by evidence that sleep interruption in humans relies on associative and contextual components, we develop a paradigm in mice to identify its circuit mechanisms. By training mice on an active avoidance task variant, we discover that auditory co

The interaction of the hippocampus and amygdala, crucial for the formation of emotional memories, may play a central role in the pathophysiology of posttraumatic stress disorder (PTSD). However, with amygdala hyperactivity regarded as a hallmark of PTSD, it is still not clear whether amygdala hyperresponsiveness before a traumatic event is a predisposing factor for the development of PTSD or is an acquired condition upon trauma. To address this question, in the current study, we explore the effect of heightened amygdala activity on anxiety and fear memory in the formation of hippocampal fear m

The ability to form associations is one of the fundamental features of the brain. Pavlov's original work on classical conditioning employed CS that immediately preceded reinforcement. Here, using the model of context preexposure (Rudy, O'Reilly, 2001; Vorobieva et al., 2017), we studied how an engram of a distant past context can become a CS. Mice explored a new context, and then with different delays (from 30 minutes up to 30 days) received an immediate shock in the same environment. We showed that contextual memory engram can be conditioned at all tested intervals. We then used c-Fos express

…prefrontal cortex (DLPFC), amygdala (AMY), and hippocampus (HC), which has mostly been observed in samples of 12–50-year-old individuals. We hypothesize that these anomalies persist in middle- to old-age and brain structure (ROIs: HC, AMY, DLPFC) mediates the association of ACE with anxiety and depression symptoms. Methods The study uses data from the Hamburg City Health Study, which randomly sampled adults between 45–74 years (N=2,525) and tested them for a

…targeting nucleus accumbens (NAc) and amygdala (AMg) nuclei. NAc-projecting DA neurons are activated by nicotine and their optogenetic activation is reinforcin

…the function of target circuits.The amygdala plays an essential role in the processing of emotional stimuli. Salience and synaptic alterations in this region are critical for emotional processing and learning. The amygdala is innervated by all major neuromodulators, yet we know little about the dynamics of n

To understand circuit mechanisms underlying naturalistic behavior, it is essential to simultaneously record neural activity in multiple brain regions and correlate it with behavior. We report a multi-region miniscope that uses four highly flexible and light-weight imaging fiber bundles (IFB) and enables imaging of up to 4 brain areas in freely behaving subjects. Transgenic animals or virus expression is used to express a cell-type specific green fluorescence tag. Up to four GRIN Lens-Connectors (GLCs) can be surgically implanted into the brain regions of interest. The GLCs are designed with th

Background: The corticolimbic tract (CLT), encompassing subcortical and neocortical areas, is linked to socioemotional skills such as emotion processing and regulation. Alterations in CLT structure, function, and connectivity are associated with socioemotional deficits and are reported for different psychopathologies. An increased knowledge of the mechanisms supporting healthy CLT development, including biological and environmental factors, may further our understanding of socioemotional disorders in childhood and adolescence, ultimately impacting early identification and treatment. Here, we a

Dietary restriction (DR), has been shown to improve brain health and function, partly by enhancing GABAergic function and improving the excitation-inhibition balance. However, very few neuro-behavioral studies have explored the beneficial effects of DR outside models of age-related neuropathologies. Therefore, here, we set out to explore DR's-therapeutic potential for stress-induced psychopathologies, by utilizing the "Individual behavioral profiling" approach. Towards that end, after exposing the animals to stress, an “individual Behavioral Profiling” analysis was used to identify, prior to t

Over the course of evolution, the amygdala (AMG) and medial frontal cortex (mPFC) network, involved in behavioral adaptation, underwent structural changes in the old-world monkey and human lineages. Yet, whether and how the functional organization of this network differs remains poorly understood. Using resting-state functional magnetic resonance imagery, we show that the functional connectivity (FC) between AMG nuclei and mPFC regions differs between humans and awake macaques. In humans, the AMG-mPFC FC displays U-shaped pattern along the corpus callosum: a positive FC with the ventromedial p

Prenatal alcohol exposure (PAE) leads to immune system dysfunction and increased susceptibility to autoimmune diseases. To explore potential mechanisms by which PAE induces neuroimmune dysfunction, the current study examined the impact of PAE on toll-like receptor 4 (TLR4) and TLR7/8 activation. Pregnant rats were divided into two groups: PAE - liquid ethanol diet ad libitum, and CON - pelleted control diet ad libitum. Male and female offspring were challenged in adulthood with LPS (40 µg/kg; activates TLR4), R848 (1 mg/kg; activates TLR7/8), or DMSO (vehicle), followed by brain sample collect

In primates, the amygdala forms projections that target large expanses of the ipsilateral cerebral cortex, from the frontal to the occipital lobe. However, it has remained unknown to what extent the amygdala complex also forms monosynaptic connections with the contralateral visual cortex, other than inferior temporal areas. Here we report on the results of 8 retrograde tracer injections (Fast Blue, and CTB conjugated with Alexa fluorophores) placed in the caudal extrastriate visual cortex of 6 marmoset monkeys (Callithrix jacchus), under Alfaxan anaesthesia, followed by 2 weeks transport time.

…(like the preoptic area, POA), and amygdala. AR gene is located in the X chromosome; therefore, it is present in a single copy in men. Males lacking or expressing mutant AR display female-like external sexual organs and infertility, which are recapitulated in

Variable and intricate dynamics are core to cortical communication in the human brain. Electrical stimulations in intracranial EEG (iEEG) can help probe effective connectivity over time and brain states through the measurement of cortico-cortical evoked potentials (CCEPs).In 15 epilepsy patients undergoing iEEG for diagnostic reasons, we probed effective connectivity with single-pulse electrical stimulations (1ms, 3mA). For any given pair of iEEG contacts at shorter (<20mm) or longer (≥20mm) range, effective connectivity was expressed as a probability of observing a single-trial CCEP in one

…associative cortex, alongside various amygdala nuclei

Bipolar disorder (BD) is a chronic mood disorder characterized by recurrent episodes of depression and (hypo-) mania. The gut microbiome is a potential avenue through which metabolic signaling, inflammatory pathways and environmental factors influence mood disorders via the gut-brain axis. Fecal microbiota transplantation (FMT) is a translational tool for investigating the connections between the gut microbiome and the brain, and there is evidence that FMT from humans to mice can induce changes in affective behavior. In this study, we compared the behavior, gut-brain metabolomic profiles, and

In this study, our objective was to explore the role of GABAA receptors within the amygdala region in modulating anxiety-like behavior in response to voluntary physical activity. We employed a stereotaxic instrument to implant two cannulae in the amygdala area, through which we administered the GABAA receptor antagonist, bicuculline. Subsequently, we exposed the animals to a running wheel for a duration of three hours over four weeks. Following this exercise regimen, we conducted behavioral tests, including the open field and elevated plus maze tests, to assess anxiety-like behavior. The findi

Dopamine (DA) is a crucial monoamine neurotransmitter involved in many physiological and pathological processes through a complex network of dopaminergic projections, and the ability to directly monitor DA dynamics is essential for understanding its physiological functions. Despite the widespread use of genetically-encoded dopamine fluorescent sensors in vivo, the detection of DA is often limited to highly innervated regions. Consequently, cortical DA detection has received comparatively little attention due to a lake of sensitivity of current generations of sensors. To address this gap, we ha

The field of developmental neuroscience is expanding rapidly, yet neuroimaging studies in children remain less common than in adults. Movie-watching paradigms may overcome this and further reduce head motion while increasing compliance when working with younger children. Here we characterize neural responses associated with emotion processing and regulation, utilizing a newly developed fMRI movie-watching paradigm. 55 children (6-14 years, 30 female) and 63 young adults (18-30 years, 31 female) watched a 12-minute montage of clips from the movie "Inside Out" (Docter & Del Carmen, 2015) dur