an-automated-t-maze-based-apparatus-protocol-for-analyzing-delay

An Automated T-maze Based Apparatus and Protocol for Analyzing Delay- and Effort-based Decision Making in  Free Moving Rodents

Many neurological and psychiatric patients demonstrate difficulties and/or deficits in decision making. Rodent models are helpful to produce a deeper ...

automated-long-term-behavioral-assay-for-cognitive-functions-multiple

Automated, Long-term Behavioral Assay for Cognitive Functions in Multiple Genetic Models of Alzheimer's Disease, Using IntelliCage

Multiple factors&#8212;such as aging and genes&#8212;are frequently associated with cognitive decline. Genetically modified mouse models of cognitive ...

RIKEN

The habenular complex linking forebrain and midbrain structures is subdivided into the medial (mHb) and the lateral nuclei (lHb). The mHb is characterized by the expression of specific nicotinic acetylcholine receptor isoforms and the release of acetylcholine to the interpeduncular nucleus (IPN), the sole output region of the mHb. The specific function of this circuit, however, is poorly understood. Here we generated transgenic mice in which mHb cells were selectively ablated postnatally. These lesions led to large reductions in acetylcholine levels within the IPN. The mutant mice exhibited abnormalities in a wide range of behavioral domains. They tended to be hyperactive during the early night period and were maladapted when repeatedly exposed to new environments. Mutant mice also showed a high rate of premature responses in the 5-choice serial reaction time task (5-CSRTT), indicating impulsive and compulsive behavior. Additionally, mice also exhibited delay and effort aversion in a decision-making test, deficits in spatial memory, a subtle increase in anxiety levels, and attenuated sensorimotor gating. IntelliCage studies under social housing conditions confirmed hyperactivity, environmental maladaptation, and impulsive/compulsive behavior, delay discounting, deficits in long-term spatial memory, and reduced flexibility in complex learning paradigms. In 5-CSRTT and adaptation tasks, systemic administration of nicotine slowed down nose-poke reaction and enhanced adaptation in control but not mutant mice. These findings demonstrate that the mHb-IPN pathway plays a crucial role in inhibitory control and cognition-dependent executive functions.

Genetic dissection of medial habenula-interpeduncular nucleus pathway function in mice.

A major concern in neuroscience is how cognitive ability in adulthood is affected and regulated by developmental mechanisms. The molecular bases of cognitive development are not well understood. We provide evidence for the involvement of the α2 isoform of Rac-specific guanosine triphosphatase (GTPase)-activating protein (RacGAP) α-chimaerin (chimerin) in this process. We generated and analyzed mice with global and conditional knockouts of α-chimaerin and its isoforms (α1-chimaerin and α2-chimaerin) and found that α-chimaerin plays a wide variety of roles in brain function and that the roles of α1-chimaerin and α2-chimaerin are distinct. Deletion of α2-chimaerin, but not α1-chimaerin, beginning during early development results in an increase in contextual fear learning in adult mice, whereas learning is not altered when α2-chimaerin is deleted only in adulthood. Our findings suggest that α2-chimaerin acts during development to establish normal cognitive ability in adulthood. 

RacGAP α2-chimaerin function in development adjusts cognitive ability in adulthood.

Guanine nucleotide exchange factors (GEFs) activate small GTPases that are involved in several cellular functions. cAMP-guanine nucleotide exchange factor II (cAMP-GEF II) acts as a target for cAMP independently of protein kinase A (PKA) and functions as a GEF for Rap1 and Rap2. Although cAMP-GEF II is expressed abundantly in several brain areas including the cortex, striatum, and hippocampus, its specific function and possible role in hippocampal synaptic plasticity and cognitive processes remain elusive. Here, we investigated how cAMP-GEF II affects synaptic function and animal behavior using cAMP-GEF II knockout mice.

Involvement of cAMP-guanine nucleotide exchange factor II in hippocampal long-term depression and behavioral flexibility.

Transgenic mouse models of Alzheimer's disease (AD) with nonphysiologic overexpression of amyloid precursor protein (APP) exhibit various unnatural symptoms/dysfunctions. To overcome this issue, mice with single humanized App knock-in (KI) carrying Swedish (NL), Beyreuther/Iberian (F), and Arctic (G) mutations in different combinations were recently developed. The validity of these mouse models of AD from a behavioral viewpoint, however, has not been extensively evaluated. Thus, using an automated behavior monitoring system, we analyzed various behavioral domains, including executive function, and learning and memory. The App-KI mice carrying NL-G-F mutations showed clear deficits in spatial memory and flexible learning, enhanced compulsive behavior, and reduced attention performance. Mice carrying NL-F mutations exhibited modest abnormalities. The NL-G-F mice had a greater and more rapid accumulation of Aβ deposits and glial responses. These findings reveal that single pathologic App-KI is sufficient to produce deficits in broad cognitive domains and that App-KI mouse lines with different levels of pathophysiology are useful models of AD.

Cognitive deficits in single App knock-in mouse models.

Further increase in energy density of lithium batteries is needed for zero emission vehicles. However, energy density is restricted by unavoidable theoretical limits for positive electrodes used in commercial applications. One possibility towards energy densities exceeding these limits is to utilize anion (oxide ion) redox, instead of classical transition metal redox. Nevertheless, origin of activation of the oxide ion and its stabilization mechanism are not fully understood. Here we demonstrate that the suppression of formation of superoxide-like species on lithium extraction results in reversible redox for oxide ions, which is stabilized by the presence of relatively less covalent character of Mn with oxide ions without the sacrifice of electronic conductivity. On the basis of these findings, we report an electrode material, whose metallic constituents consist only of 3d transition metal elements. The material delivers a reversible capacity of 300 mAh g based on solid-state redox reaction of oxide ions.

Origin of stabilization and destabilization in solid-state redox reaction of oxide ions for lithium-ion batteries.

Cytoplasmic aggregation of fused in sarcoma (FUS) is detected in brain regions affected by amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), which compose the disease spectrum, FUS proteinopathy. To understand the pathomechanism of ALS-FTD-associated FUS, we examined the behavior and cellular properties of an ALS mouse model overexpressing FUS with nuclear localization signal deletion. Mutant FUS transgenic mice showed hyperactivity, social interactional deficits, and impaired fear memory retrieval, all of which are compatible with FTD phenotypes. Histological analyses showed decreased dendritic spine and synaptic density in the frontal cortex before neuronal loss. Examination of cultured cells confirmed that mutant but not wild-type FUS was associated with decreased dendritic growth, mRNA levels, and protein synthesis in dendrites. These data suggest that cytoplasmic FUS aggregates impair dendritic mRNA trafficking and translation, in turn leading to dendritic homeostasis disruption and the development of FTD phenotypes.

Yuki Kobayashi

Laboratory of Behavioral Genetics,
Center for Brain Science,
Laboratory for Behavioral Genetics,
Laboratory of Behavioral Genetics, Center for Brain Science,
Laboratory for Behavioral Genetics, Center for Brain Science

RIKEN

An Automated T-maze Based Apparatus and Protocol for Analyzing Delay- and Effort-based Decision Making in Free Moving Rodents

Automated, Long-term Behavioral Assay for Cognitive Functions in Multiple Genetic Models of Alzheimer's Disease, Using IntelliCage

Yuki Kobayashi

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Laboratory of Behavioral Genetics,Center for Brain Science,Laboratory for Behavioral Genetics,Laboratory of Behavioral Genetics, Center for Brain Science,Laboratory for Behavioral Genetics, Center for Brain Science

RIKEN

An Automated T-maze Based Apparatus and Protocol for Analyzing Delay- and Effort-based Decision Making in Free Moving Rodents

Automated, Long-term Behavioral Assay for Cognitive Functions in Multiple Genetic Models of Alzheimer's Disease, Using IntelliCage

Laboratory of Behavioral Genetics,
Center for Brain Science,
Laboratory for Behavioral Genetics,
Laboratory of Behavioral Genetics, Center for Brain Science,
Laboratory for Behavioral Genetics, Center for Brain Science