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Search Results: 1 - 10 of 1276 matches for " infralimbic cortex "
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Confocal analysis of cholinergic and dopaminergic inputs onto pyramidal cells in the prefrontal cortex of rodents
Zi-Wei Zhang,Mark W. Burke,Nicole Calakos,Jean-Martin Beaulieu,Elvire Vaucher
Frontiers in Neuroanatomy , 2010, DOI: 10.3389/fnana.2010.00021
Abstract: Cholinergic and dopaminergic projections to the rat medial prefrontal cortex (mPFC) are both involved in cognitive functions including attention. These neuronal systems modulate mPFC neuronal activity mainly through diffuse transmission. In order to better understand the anatomical level of influence of these systems, confocal microscopy with triple-fluorescent immunolabeling was used in three subregions of the mPFC of rats and Drd1a-tdTomato/Drd2-EGFP transgenic mice. The zone of interaction was defined as a reciprocal microproximity between dopaminergic and cholinergic axonal segments as well as pyramidal neurons. The density of varicosities, along these segments was considered as a possible activity-dependant morphological feature. The percentage of cholinergic and dopaminergic fibers in microproximity ranged from 12 to 40% depending on the layer and mPFC subregion. The cholinergic system appeared to have more influence on dopaminergic fibers since a larger proportion of the dopaminergic fibers were within microproximity to cholinergic fibers. The density of both cholinergic and dopaminergic varicosities was significantly elevated within microproximities. The main results indicate that the cholinergic and dopaminergic systems converge on pyramidal cells in mPFC particularly in the layer V. In transgenic mice 93% of the pyramidal cells expressed the transgenic marker for Drd2 expression, but only 22% expressed the maker for Drd1ar expression. Data presented here suggest that the modulation of mPFC by dopaminergic fibers would be mostly inhibitory and localized at the output level whereas the cholinergic modulation would be exerted at the input and output level both through direct interaction with pyramidal cells and dopaminergic fibers.
The Plasticity of Extinction: Contribution of the Prefrontal Cortex in Treating Addiction through Inhibitory Learning
J. T. Gass,L. J. Chandler
Frontiers in Psychiatry , 2013, DOI: 10.3389/fpsyt.2013.00046
Abstract: Theories of drug addiction that incorporate various concepts from the fields of learning and memory have led to the idea that classical and operant conditioning principles underlie the compulsiveness of addictive behaviors. Relapse often results from exposure to drug-associated cues, and the ability to extinguish these conditioned behaviors through inhibitory learning could serve as a potential therapeutic approach for those who suffer from addiction. This review will examine the evidence that extinction learning alters neuronal plasticity in specific brain regions and pathways. In particular, subregions of the prefrontal cortex (PFC) and their projections to other brain regions have been shown to differentially modulate drug-seeking and extinction behavior. Additionally, there is a growing body of research demonstrating that manipulation of neuronal plasticity can alter extinction learning. Therefore, the ability to alter plasticity within areas of the PFC through pharmacological manipulation could facilitate the acquisition of extinction and provide a novel intervention to aid in the extinction of drug-related memories.
Functional connectivity-based parcellation and connectome of cortical midline structures in the mouse: a perfusion autoradiography study
Daniel P. Holschneider,Zhuo Wang
Frontiers in Neuroinformatics , 2014, DOI: 10.3389/fninf.2014.00061
Abstract: Rodent cortical midline structures (CMS) are involved in emotional, cognitive and attentional processes. Tract tracing has revealed complex patterns of structural connectivity demonstrating connectivity-based integration and segregation for the prelimbic, cingulate area 1, retrosplenial dysgranular cortices dorsally, and infralimbic, cingulate area 2, and retrosplenial granular cortices ventrally. Understanding of CMS functional connectivity (FC) remains more limited. Here we present the first subregion-level FC analysis of the mouse CMS, and assess whether fear results in state-dependent FC changes analogous to what has been reported in humans. Brain mapping using [14C]-iodoantipyrine was performed in mice during auditory-cued fear conditioned recall and in controls. Regional cerebral blood flow (CBF) was analyzed in 3-D images reconstructed from brain autoradiographs. Regions-of-interest were selected along the CMS anterior-posterior and dorsal-ventral axes. In controls, pairwise correlation and graph theoretical analyses showed strong FC within each CMS structure, strong FC along the dorsal-ventral axis, with segregation of anterior from posterior structures. Seed correlation showed FC of anterior regions to limbic/paralimbic areas, and FC of posterior regions to sensory areas–findings consistent with functional segregation noted in humans. Fear recall increased FC between the cingulate and retrosplenial cortices, but decreased FC between dorsal and ventral structures. In agreement with reports in humans, fear recall broadened FC of anterior structures to the amygdala and to somatosensory areas, suggesting integration and processing of both limbic and sensory information. Organizational principles learned from animal models at the mesoscopic level (brain regions and pathways) will not only critically inform future work at the microscopic (single neurons and synapses) level, but also have translational value to advance our understanding of human brain architecture.
Histamine and motivation
Fernando Torrealba,Maria E. Riveros,Jose L. Valdes
Frontiers in Systems Neuroscience , 2012, DOI: 10.3389/fnsys.2012.00051
Abstract: Brain histamine may affect a variety of different behavioral and physiological functions; however, its role in promoting wakefulness has overshadowed its other important functions. Here, we review evidence indicating that brain histamine plays a central role in motivation and emphasize its differential involvement in the appetitive and consummatory phases of motivated behaviors. We discuss the inputs that control histaminergic neurons of the tuberomamillary nucleus (TMN) of the hypothalamus, which determine the distinct role of these neurons in appetitive behavior, sleep/wake cycles, and food anticipatory responses. Moreover, we review evidence supporting the dysfunction of histaminergic neurons and the cortical input of histamine in regulating specific forms of decreased motivation (apathy). In addition, we discuss the relationship between the histamine system and drug addiction in the context of motivation.
The stressed female brain: neuronal activity in the prelimbic but not infralimbic region of the medial prefrontal cortex suppresses learning after acute stress
Lisa Y. Maeng,Tracey J. Shors
Frontiers in Neural Circuits , 2013, DOI: 10.3389/fncir.2013.00198
Abstract: Women are nearly twice as likely as men to suffer from anxiety and post-traumatic stress disorder (PTSD), indicating that many females are especially vulnerable to stressful life experience. A profound sex difference in the response to stress is also observed in laboratory animals. Acute exposure to an uncontrollable stressful event disrupts associative learning during classical eyeblink conditioning in female rats but enhances this same type of learning process in males. These sex differences in response to stress are dependent on neuronal activity in similar but also different brain regions. Neuronal activity in the basolateral nucleus of the amygdala (BLA) is necessary in both males and females. However, neuronal activity in the medial prefrontal cortex (mPFC) during the stressor is necessary to modify learning in females but not in males. The mPFC is often divided into its prelimbic (PL) and infralimbic (IL) subregions, which differ both in structure and function. Through its connections to the BLA, we hypothesized that neuronal activity within the PL, but not IL, during the stressor is necessary to suppress learning in females. To test this hypothesis, either the PL or IL of adult female rats was bilaterally inactivated with GABAA agonist muscimol during acute inescapable swim stress. About 24 h later, all subjects were trained with classical eyeblink conditioning. Though stressed, females without neuronal activity in the PL learned well. In contrast, females with IL inactivation during the stressor did not learn well, behaving similarly to stressed vehicle-treated females. These data suggest that exposure to a stressful event critically engages the PL, but not IL, to disrupt associative learning in females. Together with previous studies, these data indicate that the PL communicates with the BLA to suppress learning after a stressful experience in females. This circuit may be similarly engaged in women who become cognitively impaired after stressful life events.
La corteza prefrontal medial controla el alerta conductual y vegetativo: Implicancias en desórdenes de la conducta
Valdés G,José Luis; Torrealba L,Fernando;
Revista chilena de neuro-psiquiatría , 2006, DOI: 10.4067/S0717-92272006000300005
Abstract: the frontal lobe, the most human part of the brain (goldberg), has been intensely studied, particularly in the last decades. this region is crucial for the control of behavior, cognition, planning, and working memory. both behavior and higher cognitive abilities depend importantly on the arousal level, and on the autonomic responses that anticipate and accompany behaviors. in this review we will discuss the role played by the medial prefrontal cortex in controlling the level of vigilance and the autonomic and endocrine responses that are crucial for normal behavior. we will also discuss how dysfunctions of the medial prefrontal cortex resulting in the loss of the cortical control over arousal (both behavioral and vegetative) can help to explain the behavioral alterations observed in patients with posttraumatic stress, schizophrenia, attentional deficit and hyperactivity disorder and antisocial and aggressive behavior. additionally we will discuss how studies in rats may give us valuable information about of the mechanisms by which the medial prefrontal cortex is capable of controlling the arousal state, autonomic and emotional responses in humans
The prelimbic cortex uses higher-order cues to modulate both the acquisition and expression of conditioned fear.
Melissa J. Sharpe,Simon Killcross
Frontiers in Systems Neuroscience , 2014, DOI: 10.3389/fnsys.2014.00235
Abstract: The prelimbic (PL) cortex allows rodents to adapt their responding under changing experimental circumstances. In line with this, the PL cortex has been implicated in strategy set shifting, attentional set shifting, the resolution of response conflict, and the modulation of attention towards predictive stimuli. One interpretation of this research is that the PL cortex is involved in using information garnered from higher-order cues in the environment to modulate how an animal responds to environmental stimuli. However, data supporting this view of PL function in the aversive domain are lacking. In the following experiments, we attempted to answer two questions. Firstly, we wanted to investigate whether the role of the PL cortex in using higher-order cues to influence responding generalizes across appetitive and aversive domains. Secondly, as much of the research has focused on a role for the PL cortex in performance, we wanted to assess whether this region is also involved in the acquisition of hierarchal associations which facilitate an ability to use higher-order cues to modulate responding. In order to answer these questions, we assessed the impact of PL inactivation during both the acquisition and expression of a contextual bi-conditional discrimination. A contextual bi-conditional discrimination involves presenting two stimuli. In one context, one stimulus is paired with shock while the other is presented without shock. In another context, these contingencies are reversed. Thus, animals have to use the present contextual cues to disambiguate the significance of the stimulus and respond appropriately. We found that PL inactivation disrupted both the encoding and expression of these context-dependent associations. This supports a role for the PL cortex in allowing higher-order cues to modulate both learning about, and responding towards, different cues. We discuss these findings in the broader context of functioning in the medial prefrontal cortex.
Excitotoxic lesions of the infralimbic, but not prelimbic cortex facilitate reversal of appetitive discriminative context conditioning: the role of the infralimbic cortex in context generalization
Rachel Ashwell,Rutsuko Ito
Frontiers in Behavioral Neuroscience , 2014, DOI: 10.3389/fnbeh.2014.00063
Abstract: The prelimbic and infralimbic regions of the rat medial prefrontal cortex (mPFC) are important components of the limbic cortico-striatal circuit, receiving converging projections from the hippocampus (HPC) and amygdala. Mounting evidence points to these regions having opposing roles in the regulation of the expression of contextual fear and context-induced cocaine-seeking. To investigate this functional differentiation in motivated behavior further, this study employed a novel radial maze task previously shown to be dependent on the integrity of the hippocampus and its functional connection to the nucleus accumbens (NAc) shell, to investigate the effects of selective excitotoxic lesions of the prelimbic (PL) and infralimbic (IL) upon the spatial contextual control over reward learning. To this end, rats were trained to develop discriminative responding towards a reward-associated discrete cue presented in three out of six spatial locations (3 arms out of 6 radial maze arms), and to avoid the same discrete cue presented in the other three spatial locations. Once acquired, the reward contingencies of the spatial locations were reversed, such that responding to the cue presented in a previously rewarded location was no longer rewarded. Furthermore, the acquisition of spatial learning was probed separately using conditioned place preference (CPP) and the monitoring of arm selection at the beginning of each training session. Lesions of the PL transiently attenuated the acquisition of the initial cue approach training and spatial learning, while leaving reversal learning intact. In contrast, IL lesions led to a significantly superior performance of spatial context-dependent discriminative cue approach and reversal learning, in the absence of a significant preference for the new reward-associated spatial locations. These results indicate that the PL and IL have functionally dissociative, and potentially opposite roles in the regulation of spatial contextual control over appetitive learning.
Modulation of medial prefrontal cortical activity using in vivo recordings and optogenetics
Ji Guangchen,Neugebauer Volker
Molecular Brain , 2012, DOI: 10.1186/1756-6606-5-36
Abstract: Background The medial prefrontal cortex (mPFC) serves major executive functions. mPFC output to subcortical brain areas such as the amygdala controls emotional processing and plays an important role in fear extinction. Impaired mPFC function correlates with extinction deficits in anxiety disorders such as PTSD and with cognitive decision-making deficits in neuropsychiatric disorders and persistent pain. Controlling mPFC output is a desirable therapeutic goal in neuropsychiatric disorders but functional differences of cell types (pyramidal cells and interneurons) and regions (infralimbic and prelimbic) represent a challenge. This electrophysiological study used optogenetics for the cell- and region-specific modulation of mPFC pyramidal output in the intact anesthetized animal. Results Extracellular single-unit recordings were made from infralimbic (IL) pyramidal cells, IL interneurons and prelimbic (PL) pyramidal cells 2–3 weeks after intra-IL injection of a viral vector encoding channel rhodopsin 2 (ChR2) under the control of the CaMKII promoter (rAAV5/CaMKIIa-ChR2(H134R)-EYFP) or a control vector that lacked the ChR2 sequence (rAAV5/CaMKIIa-EYFP). Optical stimulation with laser-generated blue light pulses delivered through an optical fiber to the IL increased spontaneous and evoked action potential firing of ChR2 expressing IL pyramidal cells but had no effect on IL interneurons that were distinguished from pyramidal cells based on their higher firing rate and shorter spike duration. Optical activation of IL pyramidal cells also inhibited PL pyramidal cells, suggesting that IL output controls PL output. The effects were light intensity-dependent and reversible. Confocal microscopy confirmed ChR2-EYFP or control vector expression in mPFC pyramidal cells but not in GABAergic cells. Conclusions The novelty of our study is the analysis of optogenetic effects on background and evoked activity of defined cell types in different mPFC regions. The electrophysiological in vivo results directly demonstrate the optogenetic modulation of mPFC activity in a region- and cell type-specific manner, which is significant in conditions of impaired mPFC output.
Characterization of excitatory and inhibitory neuron activation in the mouse medial prefrontal cortex following palatable food ingestion and food driven exploratory behavior
Ronald P. Gaykema,Xuan-Mai Nguyen,Jonathan Joy-gaba,Michael M. Scott
Frontiers in Neuroanatomy , 2014, DOI: 10.3389/fnana.2014.00060
Abstract: The medial prefrontal cortex (mPFC) is implicated in aspects of executive function, that include the modulation of attentional and memory processes involved in goal selection. Food-seeking behavior has been shown to involve activation of the mPFC, both during the execution of strategies designed to obtain food and during the consumption of food itself. As these behaviors likely require differential engagement of the prefrontal cortex, we hypothesized that the pattern of neuronal activation would also be behavior dependent. In this study we describe, for the first time, the expression of Fos in different layers and cell types of the infralimbic/dorsal peduncular (IL/DP) and prelimbic/anterior cingulate (PL/AC) subdivisions of mouse mPFC following both the consumption of palatable food and following exploratory activity of the animal directed at obtaining food reward. While both manipulations led to increases of Fos expression in principal excitatory neurons relative to control, food-directed exploratory activity produced a significantly greater increase in Fos expression than observed in the food intake condition. Consequently, we hypothesized that mPFC interneuron activation would also be differentially engaged by these manipulations. Interestingly, Fos expression patterns differed substantially between treatments and interneuron subtype, illustrating how the differential engagement of subsets of mPFC interneurons depends on the behavioral state. In our experiments, both vasoactive intestinal peptide- and parvalbumin-expressing neurons showed enhanced Fos expression only during the food-dependent exploratory task and not during food intake. Conversely, elevations in arcuate and paraventricular hypothalamic fos expression were only observed following food intake and not following food driven exploration. Our data suggest that activation of select mPFC interneurons may be required to support high cognitive demand states while being dispensable during food intake.
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