Neural components enabling flexible cognition and behavior are well-established, and depend mostly on proper intercommunication within the prefrontal cortex (PFC) and striatum. However, dense projections from the ventral hippocampus (vHPC) alter the functioning of the medial PFC (mPFC). Dysfunctional hippocampo-prefrontal connectivity negatively affects the integrity of flexible cognition, especially in patients with schizophrenia. In this study, we aimed to test the role of the vHPC and mPFC in a place avoidance task on a rotating arena using two spatial flexibility task variants - reversal learning and set-shifting. To achieve this, we inactivated each of these structures in adult male Long-Evans rats by performing bilateral local muscimol (a GABAA receptor agonist) injections. A significantly disrupted performance was observed in reversal learning in the vHPC-inactivated, but not in the mPFC-inactivated rats. These results confirm the notion that the vHPC participates in some forms of behavioral flexibility, especially when spatial cues are needed. It seems, rather unexpectedly, that the mPFC is not taxed in these flexibility tasks on a rotating arena.
- MeSH
- hipokampus účinky léků fyziologie MeSH
- krysa rodu rattus MeSH
- muscimol farmakologie MeSH
- pozornost účinky léků fyziologie MeSH
- prefrontální mozková kůra účinky léků fyziologie MeSH
- prostorové vidění účinky léků fyziologie MeSH
- receptory GABA-A - agonisté farmakologie MeSH
- reverzní učení účinky léků fyziologie MeSH
- učení vyhýbat se účinky léků fyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Neural components enabling flexible cognition and behavior are well-established, and depend mostly on proper intercommunication within the prefrontal cortex (PFC) and striatum. However, dense projections from the ventral hippocampus (vHPC) alter the functioning of the medial PFC (mPFC). Dysfunctional hippocampo-prefrontal connectivity negatively affects the integrity of flexible cognition, especially in patients with schizophrenia. In this study, we aimed to test the role of the vHPC and mPFC in a place avoidance task on a rotating arena using two spatial flexibility task variants - reversal learning and set-shifting. To achieve this, we inactivated each of these structures in adult male Long-Evans rats by performing bilateral local muscimol (a GABAA receptor agonist) injections. A significantly disrupted performance was observed in reversal learning in the vHPC-inactivated, but not in the mPFC-inactivated rats. These results confirm the notion that the vHPC participates in some forms of behavioral flexibility, especially when spatial cues are needed. It seems, rather unexpectedly, that the mPFC is not taxed in these flexibility tasks on a rotating arena.
- MeSH
- hipokampus účinky léků fyziologie MeSH
- krysa rodu rattus MeSH
- muscimol farmakologie MeSH
- pozornost účinky léků fyziologie MeSH
- prefrontální mozková kůra účinky léků fyziologie MeSH
- prostorové vidění účinky léků fyziologie MeSH
- receptory GABA-A - agonisté farmakologie MeSH
- reverzní učení účinky léků fyziologie MeSH
- učení vyhýbat se účinky léků fyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
It is well known that communication between the medial prefrontal cortex (mPFC) and the ventral hippocampus (vHPC) is critical for various cognitive and behavioral functions. However, the exact role of these structures in spatial coordination remains to be clarified. Here we sought to determine the involvement of the mPFC and the vHPC in the spatial retrieval of a previously learned active place avoidance task in adult male Long-Evans rats, using a combination of unilateral and bilateral local muscimol inactivations. Moreover, we tested the role of the vHPC-mPFC pathway by performing combined ipsilateral and contralateral inactivations. Our results showed not only bilateral inactivations of either structure, but also the combined inactivations impaired the retrieval of spatial memory, whereas unilateral one-structure inactivations did not yield any effect. Remarkably, muscimol injections in combined groups exerted similar deficits, regardless of whether the inactivations were contralateral or ipsilateral. These findings confirm the importance of these structures in spatial cognition and emphasize the importance of the intact functioning of the vHPC-mPFC pathway.
It is well known that communication between the medial prefrontal cortex (mPFC) and the ventral hippocampus (vHPC) is critical for various cognitive and behavioral functions. However, the exact role of these structures in spatial coordination remains to be clarified. Here we sought to determine the involvement of the mPFC and the vHPC in the spatial retrieval of a previously learned active place avoidance task in adult male Long-Evans rats, using a combination of unilateral and bilateral local muscimol inactivations. Moreover, we tested the role of the vHPC-mPFC pathway by performing combined ipsilateral and contralateral inactivations. Our results showed not only bilateral inactivations of either structure, but also the combined inactivations impaired the retrieval of spatial memory, whereas unilateral one-structure inactivations did not yield any effect. Remarkably, muscimol injections in combined groups exerted similar deficits, regardless of whether the inactivations were contralateral or ipsilateral. These findings confirm the importance of these structures in spatial cognition and emphasize the importance of the intact functioning of the vHPC-mPFC pathway.
BACKGROUND: Postictal potentiation presented immediately after cortical seizures in immature rats might be due to imbalance between excitation and inhibition. The aim of the present study was to determine whether augmentation of inhibition mediated by GABAA receptors could also suppress the postictal potentiation. METHODS: Twelve-day old rats with implanted electrodes were used in our study. Five drugs were tested: the agonist muscimol, the positive modulator midazolam and three neurosteroids affecting GABAA receptors-allopregnanolone, pregnanolone sulphate and pregnanolone glutamate. RESULTS: None of the five drugs was able to suppress potentiation appearing immediately after cortical epileptic afterdischarges, but all of them exhibited delayed anticonvulsant action 10 (in the case of midazolam and muscimol) or 20 min (all three steroids) after cortical seizures. CONCLUSION: Our results support a role of GABA in augmentation of cortical after discharges after longer intervals, whereas immediate postictal potentiation is not affected by GABAergic drugs. Due to similar effect with GABAergic drugs, the main mechanism of action of the three steroids tested is potentiation of GABAergic inhibition.
- MeSH
- antikonvulziva farmakologie MeSH
- časové faktory MeSH
- implantované elektrody MeSH
- krysa rodu rattus MeSH
- midazolam farmakologie MeSH
- modely nemocí na zvířatech MeSH
- muscimol farmakologie MeSH
- neurosteroidy farmakologie MeSH
- potkani Wistar MeSH
- receptory GABA-A účinky léků metabolismus MeSH
- záchvaty farmakoterapie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- srovnávací studie MeSH
We studied the effects of GABA receptor agonists microinjections in medullary raphé on the mechanically induced tracheobronchial cough response in anesthetized, unparalyzed, spontaneously breathing cats. The results suggest that GABA-ergic inhibition significantly contributes to the regulation of cough reflex by action of both GABA(A) and GABA(B) receptors. The data are consistent with inhomogeneous occurrence of GABA-ergic neurons in medullary raphé and their different involvement in the cough reflex control. Cells within rostral nucleus raphéobscurus with dominant role of GABA(A) receptors and neurons of rostral nucleus raphépallidus and caudal nucleus raphémagnus with dominant role of GABA(B) receptors participate in regulation of cough expiratory efforts. These cough control elements are distinct from cough gating mechanism. GABA-ergic inhibition in the raphé caudal to obex had insignificant effect on cough. Contradictory findings for GABA, muscimol and baclofen administration in medullary raphé suggest involvement of coordinated activity of GABA on multiple receptors affecting raphé neurons and/or the local neuronal circuits in the raphé modulating cough motor drive.
- MeSH
- baklofen farmakologie terapeutické užití MeSH
- kašel farmakoterapie patofyziologie MeSH
- kočky MeSH
- medulla oblongata účinky léků fyziologie MeSH
- muscimol farmakologie terapeutické užití MeSH
- nuclei raphe účinky léků fyziologie MeSH
- receptory GABA-A - agonisté farmakologie terapeutické užití MeSH
- receptory GABA-A fyziologie MeSH
- receptory GABA-B - agonisté farmakologie terapeutické užití MeSH
- receptory GABA-B fyziologie MeSH
- reflex účinky léků fyziologie MeSH
- zvířata MeSH
- Check Tag
- kočky MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The role of rodent hippocampus has been intensively studied in different cognitive tasks. However, its role in discrimination of objects remains controversial due to conflicting findings. We tested whether the number and type of features available for the identification of objects might affect the strategy (hippocampal-independent vs. hippocampal-dependent) that rats adopt to solve object discrimination tasks. We trained rats to discriminate 2D visual objects presented on a computer screen. The objects were defined either by their shape only or by multiple-features (a combination of filling pattern and brightness in addition to the shape). Our data showed that objects displayed as simple geometric shapes are not discriminated by trained rats after their hippocampi had been bilaterally inactivated by the GABAA-agonist muscimol. On the other hand, objects containing a specific combination of non-geometric features in addition to the shape are discriminated even without the hippocampus. Our results suggest that the involvement of the hippocampus in visual object discrimination depends on the abundance of object's features.
- MeSH
- chování zvířat účinky léků fyziologie MeSH
- diskriminační učení účinky léků fyziologie MeSH
- generalizace (psychologie) účinky léků fyziologie MeSH
- hipokampus účinky léků fyziologie MeSH
- krysa rodu rattus MeSH
- muscimol farmakologie MeSH
- operantní podmiňování účinky léků fyziologie MeSH
- potkani Long-Evans MeSH
- receptory GABA-A - agonisté farmakologie MeSH
- rozpoznávání obrazu účinky léků fyziologie MeSH
- vnímání tvaru účinky léků fyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
x
- Klíčová slova
- muscazone, stizolobic acid,
- MeSH
- Amanita * chemie patogenita MeSH
- aminokyseliny dikarboxylové MeSH
- betalainy MeSH
- biologické toxiny MeSH
- halucinace chemicky indukované MeSH
- isoxazoly MeSH
- kyselina ibotenová MeSH
- lidé MeSH
- muscimol MeSH
- muskarin MeSH
- otrava houbami patofyziologie MeSH
- oxazoly MeSH
- polysacharidy MeSH
- vanad MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
- přehledy MeSH
Although animals often learn and monitor the spatial properties of relevant moving objects such as conspecifics and predators to properly organize their own spatial behavior, the underlying brain substrate has received little attention and hence remains elusive. Because the anterior cingulate cortex (ACC) participates in conflict monitoring and effort-based decision making, and ACC neurons respond to objects in the environment, it may also play a role in the monitoring of moving cues and exerting the appropriate spatial response. We used a robot avoidance task in which a rat had to maintain at least a 25cm distance from a small programmable robot to avoid a foot shock. In successive sessions, we trained ten Long Evans male rats to avoid a fast-moving robot (4cm/s), a stationary robot, and a slow-moving robot (1cm/s). In each condition, the ACC was transiently inactivated by bilateral injections of muscimol in the penultimate session and a control saline injection was given in the last session. Compared to the corresponding saline session, ACC-inactivated rats received more shocks when tested in the fast-moving condition, but not in the stationary or slow robot conditions. Furthermore, ACC-inactivated rats less frequently responded to an approaching robot with appropriate escape responses although their response to shock stimuli remained preserved. Since we observed no effect on slow or stationary robot avoidance, we conclude that the ACC may exert cognitive efforts for monitoring dynamic updating of the position of an object, a role complementary to the dorsal hippocampus.
- MeSH
- cingulární gyrus účinky léků fyziologie MeSH
- krysa rodu rattus MeSH
- muscimol farmakologie MeSH
- neurony účinky léků fyziologie MeSH
- podněty MeSH
- potkani Long-Evans MeSH
- pozornost účinky léků fyziologie MeSH
- prostorové chování účinky léků fyziologie MeSH
- reakční čas fyziologie MeSH
- receptory GABA-A - agonisté farmakologie MeSH
- učení vyhýbat se účinky léků fyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
