726 research outputs found
The role of mediodorsal thalamic nucleus in fear extinction
Get PDFUnderstanding the neural mechanism underlying the formation and extinction of fear memory would guide the development of advanced strategies for treatment of post-traumatic stress disorder (PTSD), a generalized anxiety disorder. The mediodorsal thalamic nucleus (MD) is reciprocally connected with limbic circuitry including the prefrontal cortex and amygdala, key structures for fear formation, and extinction. In addition to the distinctive anatomical relationships, the MD participates in learning and memory process in fear extinction through thalamic dual firing modes: tonic and burst. This review will briefly describe neural mechanisms of fear extinction and highlight the role of MD in modulation of fear extinction. We suggest that excitability of the MD neurons may modulate fear circuits and can be a novel target for treatment of anxiety disorders.© 2016 Lee and Shin. Open Access11Nscopu
T-type Ca2+ channels in absence epilepsy
No full textAbsence epilepsy accompanies the paroxysmal oscillations
in the thalamocortical circuit referred as spike and
wave discharges (SWDs). Low-threshold burst firing mediated
by T-type Ca2+ channels highly expressed in both inhibitory
thalamic reticular nuclei (TRN) and excitatory
thalamocortical (TC) neurons has been correlated with the
generation of SWDs. A generally accepted view has been that
rhythmic burst firing mediated by T-type channels in both
TRN and TC neurons are equally critical in the generation
of thalamocortical oscillations during sleep rhythms and
SWDs. This review examined recent studies on the T-type
channels in absence epilepsy which leads to an idea that even
though both TRN and TC nuclei are required for
thalamocortical oscillations, the contributions of T-type channels
to TRN and TC neurons are not equal in the genesis of
sleep spindles and SWDs. Accumulating evidence revealed a
crucial role of TC T-type channels in SWD generation. However,
the role of TRN T-type channels in SWD generation
remains controversial. Therefore, a deeper understanding of
the functional consequences of modulating each T-type channel
subtype could guide the development of therapeutic tools
for absence seizures while minimizing side effects on physiological
thalamocortical oscillations.1771sciescopu
Altruism and social rewards
No full textScheggia et al.1
have established a behavioral
paradigm to explore preferences for ‘altruistic’
or ‘selfsh’ choice behavior in mice. The results
suggest that altruistic behavior develops
through reinforcement learning driven
by social rewards, which is controlled by
interactions between the basolateral amygdala
and prelimbic cortex.11Nsciescopu
Overcoming Depression by Inhibition of Neural Burst Firing
No full textThe N-methyl-D-aspartate receptor (NMDAR) antagonist ketamine has been found to have rapid and long-lasting antidepressive effects. Two elegant studies from Hailan Hu's laboratory (Cui et al., 2018; Yang et al., 2018) showed that ketamine blocks burst firing of neurons in the lateral habenula (LHb), rapidly relieving symptoms of depression. The N-methyl-D-aspartate receptor (NMDAR) antagonist ketamine has been found to have rapid and long-lasting antidepressive effects. Two elegant studies from Hailan Hu's laboratory (Cui et al., 2018; Yang et al., 2018) showed that ketamine blocks burst firing of neurons in the lateral habenula (LHb), rapidly relieving symptoms of depression. © 2018 Elsevier Inc101Nsci
T-type Ca2+ channels in normal and abnormal brain functions.
No full textLow-voltage-
activated T-type Ca2 channels are widely expressed in various types of neurons.
Once deinactivated by hyperpolarization, T-type channels are ready to be activated by a
small depolarization near the resting membrane potential and, therefore, are optimal
for regulating the excitability and electroresponsiveness of neurons under physiological conditions
near resting states. Ca2 influx through T-type channels engenders low-threshold Ca2 spikes,
which in turn trigger a burst of action potentials. Low-threshold burst firing has been implicated in
the synchronization of the thalamocortical circuit during sleep and in absence seizures. It also has
been suggested that T-type channels play an important role in pain signal transmission, based on
their abundant expression in pain-processing pathways in peripheral and central neurons. In this
review, we will describe studies on the role of T-type Ca2 channels in the physiological as well as
pathological generation of brain rhythms in sleep, absence epilepsy, and pain signal transmission.
Recent advances in studies of T-type channels in the control of cognition will also be briefly
discussed.148521sciescopu
Genetic factors associated with empathy in humans and mice
Get PDF© 2019The neurocognitive ability to recognize and share the mental states of others is crucial for our emotional experience and social interaction. Extensive human studies have informed our understanding of the psychobehavioral and neurochemical bases of empathy. Recent evidence shows that simple forms of empathy are conserved from rodents to humans, and rodent models have become particularly useful for understanding the neurobiological correlates of empathy. In this review, we first summarize aspects of empathy at the behavioral and neural circuit levels, and describe recent developments in rodent model behavioral paradigms. We then highlight different neurobiological pathways involved in empathic abilities, with special emphasis on genetic polymorphisms associated with individual differences in empathy. By directly assessing various neurochemical correlates at molecular and neural circuit levels using relevant animal models, we conclude with the suggestion that rodent research can significantly advance our understanding of the neural basis of empathy. This article is part of the Special Issue entitled ‘The neuropharmacology of social behavior: from bench to bedside’.11Nsci
Rodent models for studying empathy
No full textEmpathy is the important capacity to recognize and share emotions with others. Recent evidence shows that rodents possess a remarkable affective sensitivity to the emotional state of others and that primitive forms of empathy exist in social lives of rodents. However, due to the ambiguous definitional boundaries between empathy, emotional contagion and other related terms, distinct components of empathic behaviors in rodents need to be clarified. Hence, we review recent experimental studies demonstrating that rodents are able to share emotions with others. Specifically, we highlight several behavioral models that examine different aspects of rodent empathic behaviors in response to the various distress of con specifics. Experimental approaches using rodent behavioral models will help elucidate the neural circuitry of empathy and its neurochemical association. Integrating these findings with corresponding experiments in humans will ultimately provide novel insights into therapeutic interventions for mental disorders associated with empathy. (C) 2016 Elsevier Inc. All rights reserved.1691sciessciscopu
Neural Basis of Observational Fear Learning: A Potential Model of Affective Empathy
Get PDFCopyright © 2019 Elsevier Inc. All rights reserved.Observational fear learning in rodents is a type of context-dependent fear conditioning in which an unconditioned stimulus (US) is provided vicariously by observing conspecific others receiving foot shocks. This suggests the involvement of affective empathy, with several recent studies showing many similarities between this behavior and human empathy. Neurobiologically, it is important to understand the neural mechanisms by which the vicarious US activates the fear circuit via the affective pain system, obviating the sensory pain pathway and eventually leading to fear memory formation. This paper reviews current studies on the neural mechanisms underlying observational fear learning and provides a perspective on future research on this subject11Nsci
The Corporation and Economics of Growth and Distribution
No full textEconomics and Policies of the Park Chung Hee Perio
Medial septal GABAergic projection neurons promote object exploration behavior and type 2 theta rhythm
No full textContributed by Hee-Sup Shin, April 20, 2016 (sent for review February 16, 2016; reviewed by Jan Born, György Buzsáki, and Alcino J. Silva) Exploratory drive is one of the most fundamental emotions, of all organisms, that are evoked by novelty stimulation. Exploratory behavior plays a fundamental role in motivation, learning, and well-being of organisms. Diverse exploratory behaviors have been described, although their heterogeneity is not certain because of the lack of solid experimental evidence for their distinction. Here we present results demonstrating that different neural mechanisms underlie different exploratory behaviors. Localized Cav3.1 knockdown in the medial septum (MS) selectively enhanced object exploration, whereas the null mutant (KO) mice showed enhancedobject exploration as well as open-field exploration. In MS knockdown mice, only type 2 hippocampal theta rhythm was enhanced, whereas both type 1 and type 2 theta rhythm were enhanced in KO mice. This selective effect was accompanied by markedly increased excitability of septo-hippocampal GABAergic projection neurons in the MS lacking T-type Ca2+ channels. Furthermore, optogenetic activation of the septo-hippocampal GABAergic pathway in WT mice also selectively enhanced object exploration behavior and type 2 theta rhythm, whereas inhibition of the same pathway decreased the behavior and the rhythm. These findings define object exploration distinguished from open-field exploration and reveal a critical role of T-type Ca2+ channels in the medial septal GABAergic projection neurons in this behavior.18101sciescopu
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