scholarly journals Is bigger always better? A critical appraisal of the use of volumetric analysis in the study of the hippocampus

2010 ◽  
Vol 365 (1542) ◽  
pp. 915-931 ◽  
Author(s):  
Timothy C. Roth ◽  
Anders Brodin ◽  
Tom V. Smulders ◽  
Lara D. LaDage ◽  
Vladimir V. Pravosudov
Keyword(s):  
Spatial Memory ◽  
Brain Area ◽  
Volumetric Analysis ◽  
Theoretical Background ◽  
Physiological Adaptation ◽  
Scatter Hoarding ◽  
Axonal Arborization ◽  
Adaptive Specialization ◽  
Mechanisms Of Memory ◽  
The Brain

A well-developed spatial memory is important for many animals, but appears especially important for scatter-hoarding species. Consequently, the scatter-hoarding system provides an excellent paradigm in which to study the integrative aspects of memory use within an ecological and evolutionary framework. One of the main tenets of this paradigm is that selection for enhanced spatial memory for cache locations should specialize the brain areas involved in memory. One such brain area is the hippocampus (Hp). Many studies have examined this adaptive specialization hypothesis, typically relating spatial memory to Hp volume. However, it is unclear how the volume of the Hp is related to its function for spatial memory. Thus, the goal of this article is to evaluate volume as a main measurement of the degree of morphological and physiological adaptation of the Hp as it relates to memory. We will briefly review the evidence for the specialization of memory in food-hoarding animals and discuss the philosophy behind volume as the main currency. We will then examine the problems associated with this approach, attempting to understand the advantages and limitations of using volume and discuss alternatives that might yield more specific hypotheses. Overall, there is strong evidence that the Hp is involved in the specialization of spatial memory in scatter-hoarding animals. However, volume may be only a coarse proxy for more relevant and subtle changes in the structure of the brain underlying changes in behaviour. To better understand the nature of this brain/memory relationship, we suggest focusing on more specific and relevant features of the Hp, such as the number or size of neurons, variation in connectivity depending on dendritic and axonal arborization and the number of synapses. These should generate more specific hypotheses derived from a solid theoretical background and should provide a better understanding of both neural mechanisms of memory and their evolution.

scholarly journals Influencing of Spatial Memory in Rats by DSP-4 and Mescaline

1999 ◽  
Vol 42 (2) ◽  
pp. 69-72 ◽  
Author(s):  
Marie Koupilová ◽  
Josef Herink ◽  
Otakar Krs
Keyword(s):  
Spatial Memory ◽  
Spatial Orientation ◽  
Time Course ◽  
Brain Area ◽  
Brain Structures ◽  
Neurotoxic Effect ◽  
Behavioural Effects ◽  
The Brain

Behavioural effects of two experimental neurotoxins, mescaline and DSP-4 (N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine), on retention of spatial orientation were studied in the T - maze. The stereotaxic administration of both neurotoxins into the selected brain structures was chosen to reveal this effect. The intensity and time course of the neurotoxic effect were dependent on the brain area administered. Nevertheless, the lengthening of the latencies in reaching the goal was generally more marked after mescaline in comparison with DSP-4.

scholarly journals A Simple Method to Avoid Brain Shift during Neuronavigation: Technical Note

2020 ◽  
Author(s):  
Jair Leopoldo Raso
Keyword(s):  
Dura Mater ◽  
Brain Area ◽  
Conventional Technique ◽  
Technical Note ◽  
Cortical Surface ◽  
Brain Shift ◽  
Simple Method ◽  
Cortex Area ◽  
Neuronavigation System ◽  
The Brain

Abstract Introduction The precise identification of anatomical structures and lesions in the brain is the main objective of neuronavigation systems. Brain shift, displacement of the brain after opening the cisterns and draining cerebrospinal fluid, is one of the limitations of such systems. Objective To describe a simple method to avoid brain shift in craniotomies for subcortical lesions. Method We used the surgical technique hereby described in five patients with subcortical neoplasms. We performed the neuronavigation-guided craniotomies with the conventional technique. After opening the dura and exposing the cortical surface, we placed two or three arachnoid anchoring sutures to the dura mater, close to the edges of the exposed cortical surface. We placed these anchoring sutures under microscopy, using a 6–0 mononylon wire. With this technique, the cortex surface was kept close to the dura mater, minimizing its displacement during the approach to the subcortical lesion. In these five cases we operated, the cortical surface remained close to the dura, anchored by the arachnoid sutures. All the lesions were located with a good correlation between the handpiece tip inserted in the desired brain area and the display on the navigation system. Conclusion Arachnoid anchoring sutures to the dura mater on the edges of the cortex area exposed by craniotomy constitute a simple method to minimize brain displacement (brain-shift) in craniotomies for subcortical injuries, optimizing the use of the neuronavigation system.

scholarly journals Polyphenols and IUGR Pregnancies: Effects of the Antioxidant Hydroxytyrosol on Brain Neurochemistry and Development in a Porcine Model

Antioxidants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 884
Author(s):  
Natalia Yeste ◽  
Daniel Valent ◽  
Laura Arroyo ◽  
Marta Vázquez-Gómez ◽  
Consolación García-Contreras ◽  
...  
Keyword(s):  
Intrauterine Growth Restriction ◽  
Porcine Model ◽  
Immunohistochemical Study ◽  
Brain Area ◽  
Fetal Period ◽  
Intrauterine Growth ◽  
Gestational Period ◽  
Hippocampal Ca1 ◽  
Maternal Supplementation ◽  
The Brain

Supplementation of a mother’s diet with antioxidants, such as hydroxytyrosol (HTX), has been proposed to ameliorate the adverse phenotypes of fetuses at risk of intrauterine growth restriction. In the present study, sows were treated daily with or without 1.5 mg of HTX per kilogram of feed from day 35 of pregnancy (at 30% of total gestational period), and individuals were sampled at three different ages: 100-day-old fetuses and 1-month- and 6-month-old piglets. After euthanasia, the brain was removed and the hippocampus, amygdala, and prefrontal cortex were dissected. The profile of the catecholaminergic and serotoninergic neurotransmitters (NTs) was characterized and an immunohistochemical study of the hippocampus was performed. The results indicated that maternal supplementation with HTX during pregnancy affected the NT profile in a brain-area-dependant mode and it modified the process of neuron differentiation in the hippocampal CA1 and GD areas, indicating that cell differentiation occurred more rapidly in the HTX group. These effects were specific to the fetal period, concomitantly with HTX maternal supplementation, since no major differences remained between the control and treated groups in 1-month- and 6-month-old pigs.

scholarly journals Vision and the representation of the surroundings in spatial memory

2011 ◽  
Vol 366 (1564) ◽  
pp. 596-610 ◽  
Author(s):  
Benjamin W. Tatler ◽  
Michael F. Land
Keyword(s):  
Spatial Memory ◽  
Visual Environment ◽  
Coding Scheme ◽  
Perceptual Stability ◽  
The World ◽  
Scene Viewing ◽  
Memory Representations ◽  
The Brain ◽  
Allocentric Representations ◽  
And Task

One of the paradoxes of vision is that the world as it appears to us and the image on the retina at any moment are not much like each other. The visual world seems to be extensive and continuous across time. However, the manner in which we sample the visual environment is neither extensive nor continuous. How does the brain reconcile these differences? Here, we consider existing evidence from both static and dynamic viewing paradigms together with the logical requirements of any representational scheme that would be able to support active behaviour. While static scene viewing paradigms favour extensive, but perhaps abstracted, memory representations, dynamic settings suggest sparser and task-selective representation. We suggest that in dynamic settings where movement within extended environments is required to complete a task, the combination of visual input, egocentric and allocentric representations work together to allow efficient behaviour. The egocentric model serves as a coding scheme in which actions can be planned, but also offers a potential means of providing the perceptual stability that we experience.

scholarly journals Brain stimulation used as biofeedback in neuronal activation of the temporal lobe area in autistic children

2016 ◽  
Vol 74 (8) ◽  
pp. 632-637 ◽  
Author(s):  
Vernon Furtado da Silva ◽  
Mauricio Rocha Calomeni ◽  
Rodolfo Alkmim Moreira Nunes ◽  
Carlos Elias Pimentel ◽  
Gabriela Paes Martins ◽  
...  
Keyword(s):  
Data Collection ◽  
Brain Stimulation ◽  
Mirror Neurons ◽  
Brain Area ◽  
Control Group ◽  
Autistic Children ◽  
Emotional Stimuli ◽  
The One ◽  
The Brain ◽  
Data Collection Procedure

ABSTRACT This study focused upon the functional capacity of mirror neurons in autistic children. 30 individuals, 10 carriers of the autistic syndrome (GCA), 10 with intellectual impairments (GDI), and 10 non-autistics (GCN) had registered eletroencephalogram from the brain area theoretically related to mirror neurons. Data collection procedure occurred prior to brain stimulation and after the stimulation session. During the second session, participants had to alternately process figures evoking neutral, happy, and/or sorrowful feelings. Results proved that, for all groups, the stimulation process in fact produced additional activation in the neural area under study. The level of activation was related to the format of emotional stimuli and the likelihood of boosting such stimuli. Since the increase of activation occurred in a model similar to the one observed for the control group, we may suggest that the difficulty people with autism have at expressing emotions is not due to nonexistence of mirror neurons.

Intranasal administration of mitochondria improves spatial memory in olfactory bulbectomized mice

2021 ◽  
pp. 153537022110568
Author(s):  
Natalia V Bobkova ◽  
Daria Y Zhdanova ◽  
Natalia V Belosludtseva ◽  
Nikita V Penkov ◽  
Galina D Mironova
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Spatial Memory ◽  
Intranasal Administration ◽  
Brain Structures ◽  
Brain Regions ◽  
Dependent Manner ◽  
Behavioral Experiments ◽  
Hippocampal Cell Culture ◽  
The Brain

Here, we found that functionally active mitochondria isolated from the brain of NMRI donor mice and administrated intranasally to recipient mice penetrated the brain structures in a dose-dependent manner. The injected mitochondria labeled with the MitoTracker Red localized in different brain regions, including the neocortex and hippocampus, which are responsible for memory and affected by degeneration in patients with Alzheimer's disease. In behavioral experiments, intranasal microinjections of brain mitochondria of native NMRI mice improved spatial memory in the olfactory bulbectomized (OBX) mice with Alzheimer’s type degeneration. Control OBX mice demonstrated loss of spatial memory tested in the Morris water maze. Immunocytochemical analysis revealed that allogeneic mitochondria colocalized with the markers of astrocytes and neurons in hippocampal cell culture. The results suggest that a non-invasive route intranasal administration of mitochondria may be a promising approach to the treatment of neurodegenerative diseases characterized, like Alzheimer's disease, by mitochondrial dysfunction.

scholarly journals Muscular Movements in Man, and their Evolution in the Infant: a Study of Movement in Man, and its Evolution, together with Inferences as to the Properties of Nerve-Centres and their Modes of Action in expressing Thought

1889 ◽  
Vol 35 (149) ◽  
pp. 23-44 ◽  
Author(s):  
Francis Warner
Keyword(s):  
Brain Area ◽  
Muscular Contraction ◽  
The Body ◽  
Brain Areas ◽  
Modes Of Action ◽  
Central Nerve System ◽  
Nerve System ◽  
The Brain ◽  
Compound Series ◽  
Stimulation Of

(1) Movement in mau has long been a subject of profitable study. Visible movement in the body is produced by muscular contraction following upon stimulation of the muscles by efferent currents passing from the central nerve-system. Modern physiological experiments have demonstrated that when a special brain-area discharges nerve-currents, these are followed by certain visible movements or contraction of certain muscles corresponding. So exact are such reactions, as obtained by experiment upon the brain-areas, that movements similar to those produced by experimental excitation of a certain brain-area may be taken as evidence of action in that area, or as commencing in discharge from that area (see Reinforcement of Movements, 35; Compound Series of Movements, 34).

scholarly journals Chronic social stress-induced hyperglycemia in mice couples individual stress susceptibility to impaired spatial memory

2018 ◽  
Vol 115 (43) ◽  
pp. E10187-E10196 ◽  
Author(s):  
Michael A. van der Kooij ◽  
Tanja Jene ◽  
Giulia Treccani ◽  
Isabelle Miederer ◽  
Annika Hasch ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Spatial Memory ◽  
Chronic Stress ◽  
High Glucose ◽  
Social Stress ◽  
Cognitive Impairments ◽  
Memory Performance ◽  
Dietary Treatment ◽  
Metabolic Phenotype ◽  
The Brain

Stringent glucose demands render the brain susceptible to disturbances in the supply of this main source of energy, and chronic stress may constitute such a disruption. However, whether stress-associated cognitive impairments may arise from disturbed glucose regulation remains unclear. Here we show that chronic social defeat (CSD) stress in adult male mice induces hyperglycemia and directly affects spatial memory performance. Stressed mice developed hyperglycemia and impaired glucose metabolism peripherally as well as in the brain (demonstrated by PET and induced metabolic bioluminescence imaging), which was accompanied by hippocampus-related spatial memory impairments. Importantly, the cognitive and metabolic phenotype pertained to a subset of stressed mice and could be linked to early hyperglycemia 2 days post-CSD. Based on this criterion, ∼40% of the stressed mice had a high-glucose (glucose >150 mg/dL), stress-susceptible phenotype. The relevance of this biomarker emerges from the effects of the glucose-lowering sodium glucose cotransporter 2 inhibitor empagliflozin, because upon dietary treatment, mice identified as having high glucose demonstrated restored spatial memory and normalized glucose metabolism. Conversely, reducing glucose levels by empagliflozin in mice that did not display stress-induced hyperglycemia (resilient mice) impaired their default-intact spatial memory performance. We conclude that hyperglycemia developing early after chronic stress threatens long-term glucose homeostasis and causes spatial memory dysfunction. Our findings may explain the comorbidity between stress-related and metabolic disorders, such as depression and diabetes, and suggest that cognitive impairments in both types of disorders could originate from excessive cerebral glucose accumulation.

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