For decades, memory research has centered on the role of neurons, which do not function in isolation. However, astrocytes play important roles in regulating neuronal recruitment and function at the local and network levels, forming the basis for information processing as well as memory formation and storage. In this review, we discuss the role of astrocytes in memory functions and their cellular underpinnings at multiple time points. We summarize important breakthroughs and controversies in the field as well as potential avenues to further illuminate the role of astrocytes in memory processes.
Astrocytes ; Neuronal Plasticity/physiology* ; Memory/physiology* ; Neurons/physiology* ; Cognition/physiology*

Neural oscillatory phenomenon generally exists in the nervous system through a dynamic form. It plays a very important role in the brain, especially in the higher cognitive activities, such as information processing, transfer and integration, consolidating memory and so on. Furthermore, the specific activity pattern of neural oscillations is often associated with cognitive functions and their alterations. Accordingly, how to quantitatively analyze the pattern of neural oscillations becomes one of the fundamental issues in the computational neuroscience. In this review, we addressed a variety of analytic algorithms, which are commonly employed in our recent studies to investigate the issues of neurobiology and cognitive science. In addition, we tried to classify these analytic algorithms by distinguishing their different metrics, synchronization and coupling modes. Finally, multidimensional analytic algorithms for potential application have also been discussed.
Brain ; physiology ; Cognition ; Humans ; Memory ; Nerve Net ; physiology

Visual memory, mainly composed of visual long-term memory (VLTM) and visual working memory (VWM), is an important mechanism of human information storage. Since Baddeley proposed the multicomponent working memory model, the idea that VWM is independent of the VLTM system has been widely accepted. However, the new theoretical evidence suggested a close connection between VLTM and VWM. For instance, the three embedded components model describes the VLTM and VWM in the same framework, which suggests that VWM is only a distinct state of VLTM. On the one hand, the operating function of VWM is supported by the persistence of VLTM. On the other hand, the evidence from neuroimaging studies shows that VWM and VLTM tasks activate some same brain areas. In addition, the whole visual memory system shows a trend of processing from early visual cortex to prefrontal cortex. The present article not only reviews the current studies about the relationship between VLTM and VWM but also gives some forecasts for future studies.
Brain ; physiology ; Humans ; Memory, Long-Term ; Memory, Short-Term ; Visual Cortex ; physiology ; Visual Perception

Adolescent ; Adult ; Altitude ; Extremities ; physiology ; Humans ; Male ; Memory ; physiology ; Motor Activity ; physiology ; Movement ; physiology ; Young Adult

As a rhythmic neural activity, neural oscillation exists all over the nervous system, in structures as diverse as the cerebral cortex, hippocampus, subcortical nuclei and sense organs. This review firstly presents some evidence that synchronous neural oscillations in theta and gamma bands reveal much about the origin and nature of cognitive processes such as learning and memory. And then it introduces the novel analyzing algorithms of neural oscillations, which is a directionality index of neural information flow (NIF) as a measure of synaptic plasticity. An example of application used such an analyzing algorithms of neural oscillations has been provided.
Animals ; Biological Clocks ; Brain ; physiology ; Cognition ; physiology ; Humans ; Learning ; physiology ; Memory ; physiology ; Nervous System Physiological Phenomena ; physiology ; Neural Pathways ; physiology ; Neuronal Plasticity ; physiology ; Synapses ; physiology ; Theta Rhythm ; physiology

Astrocytes are increasingly recognized to play an active role in learning and memory, but whether neural inputs can trigger event-specific astrocytic Ca²⁺ dynamics in real time to participate in working memory remains unclear due to the difficulties in directly monitoring astrocytic Ca²⁺ dynamics in animals performing tasks. Here, using fiber photometry, we showed that population astrocytic Ca²⁺ dynamics in the hippocampus were gated by sensory inputs (centered at the turning point of the T-maze) and modified by the reward delivery during the encoding and retrieval phases. Notably, there was a strong inter-locked and antagonistic relationship between the astrocytic and neuronal Ca²⁺ dynamics with a 3-s phase difference. Furthermore, there was a robust synchronization of astrocytic Ca²⁺ at the population level among the hippocampus, medial prefrontal cortex, and striatum. The inter-locked, bidirectional communication between astrocytes and neurons at the population level may contribute to the modulation of information processing in working memory.
Animals ; Astrocytes ; Hippocampus/physiology* ; Humans ; Memory, Short-Term/physiology* ; Mice ; Neurons/physiology* ; Population Dynamics

Olfactory processing involves a large number of central olfactory structures, interconnected with each other in complex fashion, and incorporating both feed forward and feed back interaction. Thus understanding how these structures in odor acquisition, perception, and memory perform functional roles is a central question in olfactory disorders that can only be addressed using a combination of approaches, including neuroimaging, neurophysiology and behavioral analyses. Recent whole-brain imaging studies have shown that multiple diverse neural structures become activated during tasks involving olfactory stimulation. This article reviews the current understanding of anatomy, sensory physiology of central olfactory structures. Especially the sensory physiology of main olfactory bulb, pyriform cortex, and orbitofrontal cortex will be emphasized here.
Memory ; Neuroimaging ; Neurophysiology ; Odors ; Olfactory Bulb ; Olfactory Pathways* ; Physiology ; Smell

OBJECTIVETo observe the effects of repeated subconvulsive electrical stimuli to the hippocampus on the emotional behavior and spatial learning and memory ability in rats.

METHODSOne hundred and eight male Wistar rats were randomized into 3 groups. Animals in group SE (n = 42) were given subconvulsive electrical stimulation to the hippocampus through a constant pulsating current of 100 mu A with an intratrain frequency of 25 Hz, pulse duration of 1 millisecond, train duration of 10 seconds and interstimulus interval of 7 minutes, 8 times a day, for 5 days. In the electrode control group or CE group (n = 33), animals were implanted with an electrode in the hippocampus, but were not stimulated. Group NC (n = 33) animals received no electrode or any stimulation. The emotional behavior of experimental rats was examined by activity in an unfamiliar open field and resistance to capture from the open field, while the spatial learning and memory ability was measured during training in a Morris water maze.

RESULTSThe stimulated rats tested 1 month after the last round of stimulation displayed substantial decreases in open field activity (scale: 10.4 +/- 2.3, P < 0.05) and increases in resistance to capture (scale: 2.85 +/- 0.56, P < 0.01). The amount of time for rats in group SE to find the platform (latency) as a measurement for spatial bias was prolonged (29 +/- 7) seconds after 15 trials in the water maze, P < 0.05). The experimental rats swam aimlessly in all four pool quadrants during the probe trial in the Morris water maze.

CONCLUSIONSFollowing repeated subconvulsive electrical stimuli to the hippocampus, rats displayed long-lasting significant abnormalities in emotional behavior, increased anxiety and defensiveness, enhanced ease to and delayed habituation to startlement, transitory spatial learning and memory disorder, which parallels many of the symptoms in posttraumatic stress disorder patients.

Animals ; Electric Stimulation ; adverse effects ; Emotions ; physiology ; Hippocampus ; physiology ; Learning ; physiology ; Male ; Memory ; physiology ; Rats ; Rats, Wistar ; Space Perception ; physiology

OBJECTIVETo compare the spatiotemporal pattern of event-related potentials (ERPs) of relational memory retention between color-location binding and semantics-location binding.

METHODSThe ERPs of 19 channels were recorded from 14 healthy subjects while performing the two binding delayed-match-to-sample tasks. A paired-sample t test was used for analysis of both the behavioral performance and ERPs, and statistical parametric mapping (SPM) of the t values was applied to ERPs.

RESULTSBehavioral performances (reaction time and accuracy) in color-location binding were significant better than those of semantics-location binding. The SPM(t) of the ERPs showed significant effects in the middle frontal region and most areas of the parietal lobe (about 200 ms), the bilateral prefrontal and frontal regions (260 approximately 320 ms), and the left occipital region (500 approximately 580 ms).

CONCLUSIONRetention of semantics-location relation involves more brain regions than that of color-location relation, and the largest effect occurs in the frontal region.

Electroencephalography ; Event-Related Potentials, P300 ; physiology ; Frontal Lobe ; physiology ; Humans ; Memory ; physiology ; Retention (Psychology) ; physiology ; Task Performance and Analysis

BACKGROUNDAs the widespread use of electric devices in modern life, human are exposed to extremely low frequency magnetic fields (ELF MF) much more frequently than ever. Over the past decades, a substantial number of epidemiological and experimental studies have demonstrated that ELF MF (50 Hz) exposure is associated with increased risk of various health effects. The present study examined the effects of chronic exposure to ELF MF on anxiety level and spatial memory of adult rats.

METHODSThe 50-Hz ELF MF was used during the whole experimental procedures and the value of magnetic field (MF) was set to 2 mT. Adult rats were divided randomly to control, MF 1 hour and MF 4 hours group. Anxiety-related behaviors were examined in the open field test and the elevated plus maze; changes in spatial learning and memory were determined in Morris water maze after 4 weeks of daily exposure.

RESULTSRats in MF 4 hours group had increased anxiety-like behaviors with unaltered locomotor activity. In the Morris water maze test, rats had reduced latency to find the hidden platform and improved long-term memory of former location of platform without changes in short-term memory and locomotor activity.

CONCLUSIONChronic ELF MF exposure has anxiogenic effect on rats, and the promoting effects on spatial learning and long-term retention of spatial memory.

Animals ; Anxiety ; physiopathology ; Electromagnetic Fields ; Male ; Maze Learning ; physiology ; Memory ; physiology ; Rats ; Rats, Sprague-Dawley