scholarly journals CA2 neuronal activity controls hippocampal low gamma and ripple oscillations

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Georgia M Alexander ◽  
Logan Y Brown ◽  
Shannon Farris ◽  
Daniel Lustberg ◽  
Caroline Pantazis ◽  
...  
Keyword(s):  
Neuronal Activity ◽  
Cognitive Functions ◽  
Social Memory ◽  
Experimental System ◽  
Gamma Oscillations ◽  
Neuronal Populations ◽  
Prefrontal Cortical ◽  
Network Oscillations ◽  
Hippocampal Area

Hippocampal oscillations arise from coordinated activity among distinct populations of neurons and are associated with cognitive functions. Much progress has been made toward identifying the contribution of specific neuronal populations in hippocampal oscillations, but less is known about the role of hippocampal area CA2, which is thought to support social memory. Furthermore, the little evidence on the role of CA2 in oscillations has yielded conflicting conclusions. Therefore, we sought to identify the contribution of CA2 to oscillations using a controlled experimental system. We used excitatory and inhibitory DREADDs to manipulate CA2 neuronal activity and studied resulting hippocampal-prefrontal cortical network oscillations. We found that modification of CA2 activity bidirectionally regulated hippocampal and prefrontal cortical low-gamma oscillations and inversely modulated hippocampal ripple oscillations in mice. These findings support a role for CA2 in low-gamma generation and ripple modulation within the hippocampus and underscore the importance of CA2 in extrahippocampal oscillations.

scholarly journals CA2 Neuronal Activity Controls Hippocampal Oscillations and Social Behavior

2017 ◽  
Author(s):  
Georgia M. Alexander ◽  
Logan Y. Brown ◽  
Shannon Farris ◽  
Daniel Lustberg ◽  
Caroline Pantazis ◽  
...  
Keyword(s):  
Social Behavior ◽  
Neuronal Activity ◽  
Pyramidal Neurons ◽  
Cell Activity ◽  
Experimental System ◽  
Pyramidal Cells ◽  
Gamma Oscillations ◽  
Prefrontal Cortical ◽  
Relative Contribution

AbstractHippocampal oscillations arise from coordinated activity among distinct populations of neurons and are associated with cognitive functions and behaviors. Although much progress has been made toward identifying the relative contribution of specific neuronal populations in hippocampal oscillations, far less is known about the role of hippocampal area CA2, which is thought to support social aspects of episodic memory. Furthermore, the little existing evidence on the role of CA2 in oscillations has led to conflicting conclusions. Therefore, we sought to identify the specific contribution of CA2 pyramidal neurons to brain oscillations using a controlled experimental system. We used excitatory and inhibitory DREADDs in transgenic mice to acutely and reversibly manipulate CA2 pyramidal cell activity. Here, we report on the role of CA2 in hippocampal-prefrontal cortical network oscillations and social behavior. We found that excitation or inhibition of CA2 pyramidal cells bidirectionally regulated hippocampal and prefrontal cortical low gamma oscillations and inversely modulated hippocampal ripple oscillations. Further, CA2 inhibition impaired social approach behavior. These findings support a role for CA2 in low gamma generation and ripple modulation within the hippocampus and underscore the importance of CA2 neuronal activity in extrahippocampal oscillations and social behavior.

The Origins of Neocortex: Connections and Lamination as Distinct Events in Evolution

1989 ◽  
Vol 1 (4) ◽  
pp. 291-301 ◽  
Author(s):  
Harvey J. Karten ◽  
Toru Shimizu
Keyword(s):  
Cognitive Functions ◽  
Single Unit ◽  
Neural Circuits ◽  
Laminar Organization ◽  
Functional Roles ◽  
Neuronal Populations ◽  
Evolutionary Origins ◽  
Cell Groups ◽  
Chemical Content

In the nonmammalian telencephalon, there are neuronal populations corresponding to cell groups in the neocortex of mammals in terms of connections, single unit-responses, chemical content, and functions. Some of these populations in nonmammals, however, are organized in a nonlaminar, rather than laminar fashion. These observations may prompt a reassessment of the functional roles of lamination and the evolutionary origins of the mammalian neocortex. Thus, the role of neural circuits and laminar organization can be differentiated in order to understand the cognitive functions of the neocortex. Moreover, the origins of neocortex can be separable into the precursors of nonlaminar and laminar regions.

scholarly journals Proximodistal organization of the CA2 hippocampal area

2018 ◽  
Author(s):  
I. Fernandez-Lamo ◽  
D. Gomez-Dominguez ◽  
A. Sanchez-Aguilera ◽  
E. Cid ◽  
M. Valero ◽  
...  
Keyword(s):  
Social Memory ◽  
Single Cells ◽  
Memory Task ◽  
Gamma Oscillations ◽  
Synaptic Activity ◽  
Organizational Principle ◽  
Hippocampal Area ◽  
Surrounding Areas ◽  
And Function ◽  
Membrane Potential Fluctuations

The proximodistal axis is considered a major organizational principle of the hippocampus. Interfacing between the hippocampus and other brain systems, the CA2 region apparently breaks this rule. Apart from its specific role in social memory, CA2 has been involved in temporal and contextual memory but mechanisms remain elusive. Here, we used intracellular and extracellular recordings followed by neurochemical identification of single-cells to evaluate CA2 and surrounding areas in the rat. We found marked proximodistal trends of synaptic activity, as well as in subthreshold membrane potentials and phase-locked firing coupled to theta and gamma oscillations. Opposite proximodistal correlations between membrane potential fluctuations and theta sinks and sources at different layers revealed influences from up to three different generators. CA2 memory engrams established after a social memory task reflected these trends. We suggest that the structure and function of CA2 is segregated along the proximodistal hippocampal axis.

scholarly journals Cortical rhythms are modulated by respiration

2016 ◽  
Author(s):  
Detlef H. Heck ◽  
Samuel S. McAfee ◽  
Yu Liu ◽  
Abbas Babajani-Feremi ◽  
Roozbeh Rezaie ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Cognitive Processing ◽  
Neuronal Activity ◽  
Cognitive Functions ◽  
Barrel Cortex ◽  
Respiratory Rhythm ◽  
Gamma Oscillations ◽  
Cortical Activity ◽  
Cortical Rhythms ◽  
Wide Range

SummaryThe brain generates oscillatory neuronal activity at a broad range of frequencies and the presence and amplitude of certain oscillations at specific times and in specific brain regions are highly correlated with states of arousal, sleep, and with a wide range of cognitive processes. The neuronal mechanisms underlying the generation of brain rhythms are poorly understood, particularly for low-frequency oscillations. We recently reported that respiration-locked olfactory bulb activity causes delta band (0.5-4 Hz) oscillatory neuronal activity in the whisker sensory (barrel) cortex in mice. Furthermore, gamma oscillations (30 – 100Hz), which are widely implicated in cognitive processing, were power-modulated in synchrony with the respiratory rhythm. These findings link afferent sensory activity caused by respiration directly to cortical rhythms associated with cognitive functions. Here we review the related literature and present new evidence to propose that respiration has a direct influence on oscillatory cortical activity, including gamma oscillations, and on transitions between synchronous and asynchronous cortical network states (marked by phase transitions). Oscillatory cortical activity, as well as phase transitions, has been implicated in cognitive functions, potentially linking respiratory phase to cognitive processing. We further argue that respiratory influence on cortical activity is present in most, and possibly in all areas of the neocortex in mice and humans. We furthermore suggest that respiration had a role in modulating cortical rhythms from early mammalian evolution. Early mammals relied strongly on their olfactory sense and had proportionately large olfactory bulbs. We propose that to this day the respiratory rhythm remains an integral element of dynamic cortical activity in mammals. We argue that breathing modulates all cortical functions, including cognitive and emotional processes, which could elucidate the well-documented but largely unexplained effects of respiratory exercises on mood and cognitive function.

scholarly journals Effects of optogenetic stimulation of basal forebrain parvalbumin neurons on Alzheimer’s disease pathology

2020 ◽  
Author(s):  
Caroline A Wilson ◽  
Sarah Fouda ◽  
Shuzo Sakata
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Neuronal Activity ◽  
Cognitive Functions ◽  
Basal Forebrain ◽  
Gamma Oscillations ◽  
Cortical Region ◽  
Amyloid Burden ◽  
Sensory Stimuli ◽  
40 Hz

AbstractNeuronal activity can modify Alzheimer’s disease pathology. Although overexcitation of neurons can facilitate disease progression, the induction of cortical gamma oscillations can reduce amyloid load and improve cognitive functions in mouse models. These beneficial effects of gamma oscillations can be caused by either optogenetic activation of cortical parvalbumin-positive (PV+) neurons or 40 Hz repetitive sensory stimuli. However, given the fact that cortical gamma oscillations can be induced by multiple mechanisms, it is still unclear whether other approaches to induce gamma oscillations can also be beneficial. Here we show that optogenetic activation of PV+ neurons in the basal forebrain (BF) increases amyloid burden, rather than reducing it. We applied 40 Hz optical stimulation in the BF of 5xFAD mice by expressing channelrhodopsin-2 (ChR2) in PV+ neurons. After one-hour induction of cortical gamma oscillations over three days, we observed the increase in the concentration of amyloid-β42 in the frontal cortical region, but not amyloid-β40. The density of amyloid plaques also increased in the medial prefrontal cortex and the septal nuclei, both of which are targets of BF PV+ neurons. These results suggest that effects of cortical gamma oscillations on Alzheimer’s disease pathology can be bidirectional depending on their induction mechanisms.Significance StatementAlzheimer’s disease (AD) is the most common cause of dementia. Although numerous molecular targets have been identified, the development of treatment is still a challenge. Accumulating evidence shows that artificial control of neuronal activity can modify AD pathology. In particular, the induction of cortical gamma (~40 Hz) oscillations can ameliorate AD pathology and improve cognitive functions. Here we show that optogenetic activation of parvalbumin-positive (PV+) neurons in the basal forebrain (BF) has opposite effects. By expressing channelrhodopsin-2 (ChR2) in PV+ neurons of an AD mouse model and optically stimulating BF PV+ neurons, we induced gamma oscillations and found increased amyloid burden. These results imply that AD pathology can be modified bidirectionally depending on induction mechanisms of gamma oscillations.

scholarly journals Parvalbumin interneuron dendrites enhance gamma oscillations

2021 ◽  
Author(s):  
Birgit Kriener ◽  
Hua Hu ◽  
Koen Vervaeke
Keyword(s):  
Network Models ◽  
Gamma Oscillations ◽  
Input Output ◽  
Basket Cells ◽  
Gamma Frequency ◽  
Network Oscillations ◽  
In Silico Modeling ◽  
Parvalbumin Interneuron ◽  
Relationship Of

Dendrites are important determinants of the input-output relationship of single neurons, but their role in network computations is not well understood. Here, we used a combination of dendritic patch-clamp recordings and in silico modeling to determine how dendrites of parvalbumin (PV)- expressing basket cells contribute to network oscillations in the gamma frequency band. Simultaneous soma-dendrite recordings from PV basket cells in the dentate gyrus revealed that the slope, or gain, of the dendritic input-output relationship is exceptionally low, thereby reducing the cell's sensitivity to changes in its input. By simulating gamma oscillations in detailed network models, we demonstrate that the low gain is key to increase spike synchrony in PV neuron assemblies when cells are driven by spatially and temporally heterogeneous synaptic input. These results highlight the role of dendritic computations in synchronized network oscillations.

scholarly journals Cannabinoid receptor 2 deletion influences social memory and synaptic architecture in the hippocampus

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joanna Agnieszka Komorowska-Müller ◽  
Kishore Aravind Ravichandran ◽  
Andreas Zimmer ◽  
Britta Schürmann
Keyword(s):  
Cannabinoid Receptor ◽  
Social Memory ◽  
Particle Density ◽  
Gamma Oscillations ◽  
Expression Levels ◽  
Cannabinoid Receptor 2 ◽  
The Brain ◽  
Deficient Mice ◽  
Insight Into

AbstractAlthough the cannabinoid receptor 2 (CB2R) is often thought to play a role mainly outside the brain several publications unequivocally showed the presence of CB2R on hippocampal principal neurons. Activation of CB2R produced a long-lasting membrane potential hyperpolarization, altered the input/output function of CA2/3 principal neurons and produced alterations in gamma oscillations. However, other cellular, molecular and behavioral consequences of hippocampal CB2R signaling have not been studied in detail. Here we demonstrate that the deletion of CB2 leads to a highly significant increase in hippocampal synapsin-I expression levels and particle density, as well as increased vesicular GABA transporter (vGAT) levels. This phenotype was restricted to females and not observed in males. Furthermore, we demonstrate an impairment of social memory in CB2 deficient mice. Our results thus demonstrate that the lack of CB2R leads to changes in the hippocampal synaptic landscape and reveals an important sex-specific difference in endocannabinoid signaling. This study supports a significant role of the CB2R in modulation of different types of memory despite its low expression levels in the brain and provides more insight into a sex-specific role of CB2R in synaptic architecture.

Role of Nut Consumption in the Management of Cognitive Decline - A Mini-Review

2018 ◽  
Vol 15 (9) ◽  
pp. 877-882 ◽  
Author(s):  
Blanka Klimova ◽  
Kamil Kuca ◽  
Martin Valis ◽  
Jakub Hort
Keyword(s):  
Cognitive Decline ◽  
Cognitive Functions ◽  
Dietary Intervention ◽  
Social Issues ◽  
Older Individuals ◽  
Active Life ◽  
Healthy Nutrition ◽  
Health Aging ◽  
Review Study

Background: Currently, there is a significant increase in the number of older generation groups, which may result in serious economic and social issues. Therefore, there is a need to prolong the active life of these older individuals, especially by focusing on modifying lifestyle factors such as healthy nutrition. In fact, recent research has shown that, for example, nuts are an important part of people’s healthy diet because they have appeared to be neuroprotective compounds which might maintain or in some cases even improve people’s cognitive functions. Objective: The purpose of this review study is to explore the role of the nut nutrition in the maintenance and delay of cognitive decline among older individuals. Results: The findings indicate that the nut consumption may contribute to the delay of cognitive decline in aging. However, this nut diet is just one component of the multi-nutrient dietary intervention for health aging. Conclusion: More longitudinal controlled randomized studies have to be performed in this field to prove the efficacy of the nut nutrition for the delay of cognitive decline.

On the novel mechanisms for social memory and the emerging role of neurogenesis

2021 ◽  
Vol 171 ◽  
pp. 56-66
Author(s):  
Paula Lunardi ◽  
Lara M.Z. Mansk ◽  
Laura F. Jaimes ◽  
Grace S. Pereira
Keyword(s):  
Social Memory ◽  
The Novel

scholarly journals Twin-To-Twin Transfusion Syndrome Donor and Recipient and Their Subsequent Cognitive Functioning in Late Childhood as Juvenile Athletes—A Case Study

2021 ◽  
Vol 18 (5) ◽  
pp. 2545
Author(s):  
Ilona Bidzan-Bluma
Keyword(s):  
Cognitive Functioning ◽  
Motor Skills ◽  
Cognitive Functions ◽  
Late Childhood ◽  
Semantic Fluency ◽  
Motor Functioning ◽  
Gross Motor Skills ◽  
History Of

Objective: It is estimated that twin-to-twin transfusion syndrome (TTTS) occurs in 10–15% of monochorionic twin pregnancies. One of the fetuses takes on the role of donor and the other of recipient. The treatment administered involves serial amnioreduction and laser photocoagulation of the communicating blood vessels. After TTTS, children may have deficiencies in psychomotor functioning, in particular in cognitive functions, expressive language, and motor skills. Few scientific reports indicate that twins after TTTS do not demonstrate significant differences in tests which measure intellectual functioning. Methods: The cognitive functioning of twins in the late childhood period was compared using the following tools: an analysis of their medical history, an interview with their parents, and neuropsychological tests allowing the evaluation of their whole profile of cognitive functions. Case Study: Cognitive functioning in the late childhood period was analyzed in a pair of 11-year-old male twins (juvenile athletes), a donor and a recipient, who had developed TTTS syndrome in the prenatal period. Results: Comparison of the cognitive functioning profile of the donor and recipient revealed that children with a history of TTTS develop normally in terms of cognitive and motor functioning in late childhood. A comparative analysis of the donor and recipient was more favorable for the recipient, who had a higher level of general intelligence, visual–motor memory, and semantic fluency. Conclusions: The fact that both the donor and the recipient chose to pursue athletics suggests that gross motor skills are their strongest suit. Playing sports as a method of rehabilitation of cognitive function of children born prematurely after TTTS could contribute to the improvement of cognitive functioning.

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