ResearchPad - cognition-and-behavior https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[Induction of LTM following an Insulin Injection]]> https://www.researchpad.co/article/elastic_article_8071 The pond snail Lymnaea stagnalis learns conditioned taste aversion (CTA) and consolidates it into long-term memory (LTM). One-day food-deprived snails (day 1 snails) show the best CTA learning and memory, whereas more severely food-deprived snails (5 d) do not express good memory. However, previous studies showed that CTA-LTM was indeed formed in 5-d food-deprived snails (day 5 snails), but its recall was prevented by the effects of food deprivation. CTA-LTM recall in day 5 snails was expressed following 7 d of feeding and then 1 d of food deprivation (day 13 snails). In the present study, we thus hypothesized that memory recall occurs because day 13 snails are in an optimal internal state. One day of food deprivation before the memory test in day 13 snails increased the mRNA level of molluscan insulin-related peptide (MIP) in the CNS. Thus, we further hypothesized that an injection of insulin into day 5 snails following seven additional days with access to food (day 12 snails) activates CTA neurons and mimics the food deprivation state before the memory test in day 13 snails. Day 12 snails injected with insulin could recall the memory. In addition, the simultaneous injection of an anti-insulin receptor antibody and insulin into day 12 snails did not allow memory recall. Insulin injection also decreased the hemolymph glucose concentration. Together, the results suggest that an optimal internal state (i.e., a spike in insulin release and specific glucose levels) are necessary for LTM recall following CTA training in snails.

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<![CDATA[Off-Target Effects in Transgenic Mice: Characterization of Dopamine Transporter (DAT)-Cre Transgenic Mouse Lines Exposes Multiple Non-Dopaminergic Neuronal Clusters Available for Selective Targeting within Limbic Neurocircuitry]]> https://www.researchpad.co/article/Na879a15f-f0a9-4244-b017-a71c67eff096

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<![CDATA[Zona Incerta GABAergic Output Controls a Signaled Locomotor Action in the Midbrain Tegmentum]]> https://www.researchpad.co/article/Nd948430f-4158-4075-a037-146b558e6bcc

Abstract

The zona incerta is a subthalamic nucleus proposed to link sensory stimuli with motor responses to guide behavior, but its functional role is not well established. Using mice of either sex, we studied the effect of manipulating zona incerta GABAergic cells on the expression of a signaled locomotor action, known as signaled active avoidance. We found that modulation of GABAergic zona incerta cells, but not of cells in the adjacent thalamic reticular nucleus (NRT), fully controls the expression of signaled active avoidance responses. Inhibition of zona incerta GABAergic cells drives active avoidance responses, while excitation of these cells blocks signaled active avoidance mainly by inhibiting cells in the midbrain pedunculopontine tegmental nucleus (PPT). The zona incerta regulates signaled locomotion in the midbrain.

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<![CDATA[Response to the Commentary from Bevelacqua et al.]]> https://www.researchpad.co/article/Ncc565a65-1ad9-4232-be21-dc317a06bc2c ]]> <![CDATA[The Effects of a TMS Double Perturbation to a Cortical Network]]> https://www.researchpad.co/article/N92342763-471b-47cb-ab66-ab6b2f4997c4

Transcranial magnetic stimulation (TMS) is often used to understand the function of individual brain regions, but this ignores the fact that TMS may affect network-level rather than nodal-level processes. We examine the effects of a double perturbation to two frontoparietal network nodes, compared with the effects of single lesions to either node.

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<![CDATA[Multiscale Imaging Reveals Aberrant Functional Connectome Organization and Elevated Dorsal Striatal Arc Expression in Advanced Age]]> https://www.researchpad.co/article/N08d5ffa7-4213-470e-9d63-939484a52ad8

The functional connectome reflects a network architecture enabling adaptive behavior that becomes vulnerable in advanced age. The cellular mechanisms that contribute to altered functional connectivity in old age, however, are not known.

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<![CDATA[RNA from Trained Aplysia Can Induce an Epigenetic Engram for Long-Term Sensitization in Untrained Aplysia]]> https://www.researchpad.co/article/5c00e10bd5eed0c484ea70d7

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<![CDATA[Spatial Mnemonic Encoding: Theta Power Decreases and Medial Temporal Lobe BOLD Increases Co-Occur during the Usage of the Method of Loci]]> https://www.researchpad.co/article/5b2b2ea4463d7e415574c1fb

Abstract

The method of loci is one, if not the most, efficient mnemonic encoding strategy. This spatial mnemonic combines the core cognitive processes commonly linked to medial temporal lobe (MTL) activity: spatial and associative memory processes. During such processes, fMRI studies consistently demonstrate MTL activity, while electrophysiological studies have emphasized the important role of theta oscillations (3–8 Hz) in the MTL. However, it is still unknown whether increases or decreases in theta power co-occur with increased BOLD signal in the MTL during memory encoding. To investigate this question, we recorded EEG and fMRI separately, while human participants used the spatial method of loci or the pegword method, a similarly associative but nonspatial mnemonic. The more effective spatial mnemonic induced a pronounced theta power decrease source localized to the left MTL compared with the nonspatial associative mnemonic strategy. This effect was mirrored by BOLD signal increases in the MTL. Successful encoding, irrespective of the strategy used, elicited decreases in left temporal theta power and increases in MTL BOLD activity. This pattern of results suggests a negative relationship between theta power and BOLD signal changes in the MTL during memory encoding and spatial processing. The findings extend the well known negative relation of alpha/beta oscillations and BOLD signals in the cortex to theta oscillations in the MTL.

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<![CDATA[Activation of Both CB1 and CB2 Endocannabinoid Receptors Is Critical for Masculinization of the Developing Medial Amygdala and Juvenile Social Play Behavior]]> https://www.researchpad.co/article/5bd41462d5eed0c4847ccbc8

Abstract

Juvenile social play behavior is a shared trait across a wide variety of mammalian species. When play is characterized by the frequency or duration of physical contact, males usually display more play relative to females. The endocannabinoid system contributes to the development of the sex difference in social play behavior in rats. Treating newborn pups with a nonspecific endocannabinoid agonist, WIN55,212-2, masculinizes subsequent juvenile rough-and-tumble play behavior by females. Here we use specific drugs to target signaling through either the CB1 or CB2 endocannabinoid receptor (CB1R or CB2R) to determine which modulates the development of sex differences in play. Our data reveal that signaling through both CB1R and CB2R must be altered neonatally to modify development of neural circuitry regulating sex differences in play. Neonatal co-agonism of CB1R and CB2R masculinized play by females, whereas co-antagonism of these receptors feminized rates of male play. Because of a known role for the medial amygdala in the sexual differentiation of play, we reconstructed Golgi-impregnated neurons in the juvenile medial amygdala and used factor analysis to identify morphological parameters that were sexually differentiated and responsive to dual agonism of CB1R and CB2R during the early postnatal period. Our results suggest that sex differences in the medial amygdala are modulated by the endocannabinoid system during early development. Sex differences in play behavior are loosely correlated with differences in neuronal morphology.

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