Search results for "HIPPOCAMPUS"
showing 10 items of 622 documents
Nrg1 haploinsufficiency alters inhibitory cortical circuits
2021
Neuregulin 1 (NRG1) and its receptor ERBB4 are schizophrenia (SZ) risk genes that control the development of both excitatory and inhibitory cortical circuits. Most studies focused on the characterization ErbB4 deficient mice. However, ErbB4 deletion concurrently perturbs the signaling of Nrg1 and Neuregulin 3 (Nrg3), another ligand expressed in the cortex. In addition, NRG1 polymorphisms linked to SZ locate mainly in non-coding regions and they may partially reduce Nrg1 expression. Here, to study the relevance of Nrg1 partial loss-of-function in cortical circuits we characterized a recently developed haploinsufficient mouse model of Nrg1 (Nrg1tm1Lex). These mice display SZ-like behavioral d…
In situ behavior of wild long-snouted seahorse Hippocampus guttulatus Cuvier, 1829
2021
The study of behavior is one of the fundamental aspects of conservation biology. While for animals such as mammals there are well-defined protocols that have been applied for a long time, for marine animals, and fish in particular, studies are available for a limited number of species. The behavior of seahorses, for example, is poorly studied and in this work, we made a first attempt of using video recordings to analyze behavior of these endangered species in Mar Piccolo of Taranto (Southern Italy). The study presents preliminary data on behavioral activities and their comparisons among different life stages of Hippocampus guttulatus, namely females, males, and juveniles. Juveniles and fema…
Theta and gamma oscillations in the rat hippocampus during attentive lever pressing
2018
AbstractThe hippocampus is known to be pivotal for spatial memory but emerging evidence suggests its contribution to temporal memories as well. However, it is not clear how the hippocampus represents time and how it synchronizes spatial and temporal presentations into a coherent memory. We assessed the specific role of hippocampal theta and gamma oscillations and their interaction in short-term timing of motor reactions. Rats were trained to maintain lever pressing for 2.5 s and then to quickly release the lever and retrieve water reward from a nearby water port guided by a cue light. In essence, this task allows observation of hippocampal rhythms during timed anticipation when no overt mov…
Polyphosphoinositide Metabolism and Golgi Complex Morphology in Hippocampal Neurons in Primary Culture is Altered by Chronic Ethanol Exposure
2012
Aims : Ethanol affects not only the cytoskeletal organization and activity, but also intracellular trafficking in neurons in the primary culture. Polyphosphoinositide (PPIn) are essential regulators of many important cell functions, including those mentioned, cytoskeleton integrity and intracellular vesicle trafficking. Since information about the effect of chronic ethanol exposure on PPIn metabolism in neurons is scarce, this study analysed the effect of this treatment on three of these phospholipids. Methods : Phosphatidylinositol (PtdIns) levels as well as the activity and/or levels of enzymes involved in their metabolism were analysed in neurons chronically exposed to ethanol. The level…
Modification of the monoaminergic neurotransmitters in frontal cortex and hippocampus by dietary trans alpha linolenic acid in piglets
2002
International audience; The effect of partial isomerization of dietary α-linolenic acid on the monoaminergic neurotransmitters in piglets was studied. After feeding the animals for 14 days with diets containing or not trans α-linolenic acid, neurotransmitters related to the monoaminergic function were quantified in the frontal cortex and in the hippocampus. The partial isomerization of dietary α-linolenic acid resulted in increasing endogenous monoamine levels in the frontal cortex (+55% for dopamine) and was related to a very low incorporation of trans polyunsaturated fatty acids. However, feeding animals with a diet in which the imbalance generated by the isomerization of α-linolenic acid…
An update to Hippocampome.org by integrating single-cell phenotypes with circuit function in vivo.
2021
Understanding brain operation demands linking basic behavioral traits to cell-type specific dynamics of different brain-wide subcircuits. This requires a system to classify the basic operational modes of neurons and circuits. Single-cell phenotyping of firing behavior during ongoing oscillations in vivo has provided a large body of evidence on entorhinal–hippocampal function, but data are dispersed and diverse. Here, we mined literature to search for information regarding the phase-timing dynamics of over 100 hippocampal/entorhinal neuron types defined in Hippocampome.org. We identified missing and unresolved pieces of knowledge (e.g., the preferred theta phase for a specific neuron type) a…
Nigral influence on focal epilepsy.
1990
The substantia nigra (SN) has been proposed as a structure involved in epileptiform phenomena. Previous investigations demonstrated that SN is able to elicit hippocampal rhythmic slow activity (RSA) as well as to inhibit hippocampal interictal spikes induced by parenteral administration of penicillin. The present series of experiments was carried out in order to characterize the action of SN on a focal model of hippocampal epilepsy. Experiments were performed on encephale isole cats in which steady epileptiform activity was induced by locally applied penicillin. Electrical stimulation of SN pars reticulata (pr) caused a statistically significant decrease of hippocampal spike frequency and a…
A study of caudate inhibition on an epileptic focus in the cat hippocampus
1988
The mechanisms whereby the caudate nucleus modifies hippocampal spiking activity have been studied. Epileptiform activity was induced in the cat hippocampus by topical application of sodium penicillin in different concentrations. The frequency of induced spikes appeared to be directly correlated to the two doses of epileptogenic agent. The inhibitory effect of 10 Hz caudate stimulation on spike frequency was present even when stimulation lasted for 180 s. Likewise 25 Hz caudate stimulation brought about an inhibition which was maintained by stimulus trains lasting up to 90 s, while the degree of inhibition was reduced by trains of longer duration (120, 150 and 180 s); similar results were a…
Negative occurrence between hippocampal rhythmic slow activity and epileptiform spikes: Influence of the striatum
1986
AbstractThe effects of caudate and septal stimulation on hippocampal activity were studied. Sodium penicillin was intravenously injected in order to induce a steady rate of in-terictal epileptic activity. Penicillin injection caused significant reduction of the rate of occurrence and duration of hippocampal rhythmic slow activity (RSA). Spontaneous RSA as well as RSA-eliciting caudate and septal stimulation induced a marked inhibition on frequency of epileptiform complexes. Lesions of the medial septal nucleus made it impossible to record RSA or to observe any sort of influence on hippocampal epileptiform activity by caudate stimulation. This result suggests that the septum is important for…
Grey matter microstructural alterations in schizophrenia patients with treatment-resistant auditory verbal hallucinations.
2021
Treatment-resistant auditory verbal hallucinations (TRAVH) are a relatively prevalent and devastating symptom in patients with schizophrenia (SCZ). Even though their pathological mechanisms are poorly understood, they seem to differ from those underlying non-hallucinating SCZ.& nbsp; In this study, we characterise structural brain changes in SCZ patients with TRAVH. With respect to nonhallucinating patients and healthy controls, we studied macrostructural grey matter changes through cortical thickness and subcortical volumetric data. Additionally, we analysed microstructural differences across groups using intracortical and subcortical mean diffusivity data. This latter imaging metric has b…