Acta physiologica Scandinavica, ISSN 0302-2994 suppl. 514, 1983
58 s. : il. ; 24 cm
Negativní příznaky jsou považovány za nejvíce perzistující a zneschopňující komponentu schizofrenie. Jejich možnost ovlivnění antipsychotiky zůstává sporná. Repetitivní transkraniální magnetická stimulace (rTMS) představuje novou možnost ovlivnění negativních příznaků schizofrenie. Teoretické zdůvodnění účinnosti rTMS u negativních příznaků schizofrenie lze spatřovat ve skutečnosti, že vysokofrekvenční rTMS má aktivační vliv na neurony mozkové kůry. Negativní korelace mezi aktivitou frontálního kortexu a závažností negativních příznaků byla opakovaně prokázána. Dalším neméně významným faktem je ovlivnění uvolňování dopaminu mezolimbického a mezostriatálního mozkového systému vysokofrekvenční stimulací frontálního kortexu. Konzistentní literární údaje mapující danou tématiku v klinické praxi prakticky neexistují.
Negative symptoms are regarded as the most persistent and disabling component of schizophrenia. The possibility of influencing them by means of antipsychotics remains problematic. Repetitive transcranial magnetic simulation (rTMS) presents a new opportunity for influencing negative schizophrenic symptoms. A theoretical justification of the effect of rTMS on negative schizophrenic symptoms can be seen in the fact that high-frequency rTMS has an activating impact on cortex neurons. The negative correlation between activity of the frontal cortex and severity of negative symptoms has been proved repeatedly. Another important fact is that dopamine can be released in the mesolimbic and mesostriatal brain systems by high-frequency stimulation of the frontal cortex. There are hardly any consistent published data mapping the subject in clinical practice.
- MeSH
- Depressive Disorder therapy MeSH
- Dopamine metabolism MeSH
- Electromagnetic Phenomena methods statistics & numerical data trends MeSH
- Research Support as Topic MeSH
- Humans MeSH
- Prefrontal Cortex physiology physiopathology MeSH
- Signs and Symptoms MeSH
- Schizophrenia complications parasitology therapy MeSH
- Check Tag
- Humans MeSH
- Publication type
- Comparative Study MeSH
222 s. : il.
The prefrontal cortex is deputed to higher functions, such as behavior and personality. It includes three regions: ventromedial, orbitofrontal, and dorsolateral. Each of them has a function. Devising, programming, and planning are all conditions related to the dorsolateral cortex, also responsible for rational content and decision. Damage to this region results in apathetic syndrome, a condition that causes loss of interest, initiative, and attention, and in the most severe cases leads to a lethargic state. It is also known as a form of secondary depression, the so-called pseudo-depression syndrome, according to Karl Kleist or apathetic-abulic-akinetic syndrome, according to Alexander Luria. The prefrontal dorsolateral syndrome is responsible for the reduction or abolition of free will. Free will is an expression of individual freedom. It allows the human being to have and express own opinions as well as to respect those of others. Free will is related to moral sense, a binomial which directs the individual towards a proper social conduct. In this review, we describe the effects of the pseudo-depression syndrome on free will, of which we treat both the anatomical site and the social aspect.
1st ed. viii, 248 s., il.
BACKGROUND: Treating memory and cognitive deficits requires knowledge about anatomical sites and neural activities to be targeted with particular therapies. Emerging technologies for local brain stimulation offer attractive therapeutic options but need to be applied to target specific neural activities, at distinct times, and in specific brain regions that are critical for memory formation. METHODS: The areas that are critical for successful encoding of verbal memory as well as the underlying neural activities were determined directly in the human brain with intracranial electrophysiological recordings in epilepsy patients. We recorded a broad range of spectral activities across the cortex of 135 patients as they memorised word lists for subsequent free recall. FINDINGS: The greatest differences in the spectral power between encoding subsequently recalled and forgotten words were found in low theta frequency (3-5 Hz) activities of the left anterior prefrontal cortex. This subsequent memory effect was proportionally greater in the lower frequency bands and in the more anterior cortical regions. We found the peak of this memory signal in a distinct part of the prefrontal cortex at the junction between the Broca's area and the frontal pole. The memory effect in this confined area was significantly higher (Tukey-Kramer test, p<0.05) than in other anatomically distinct areas. INTERPRETATION: Our results suggest a focal hotspot of human verbal memory encoding located in the higher-order processing region of the prefrontal cortex, which presents a prospective target for modulating cognitive functions in the human patients. The memory effect provides an electrophysiological biomarker of low frequency neural activities, at distinct times of memory encoding, and in one hotspot location in the human brain. FUNDING: Open-access datasets were originally collected as part of a BRAIN Initiative project called Restoring Active Memory (RAM) funded by the Defence Advanced Research Project Agency (DARPA). CT, ML, MTK and this research were supported from the First Team grant of the Foundation for Polish Science co-financed by the European Union under the European Regional Development Fund.
- MeSH
- Humans MeSH
- Magnetic Resonance Imaging MeSH
- Brain Mapping MeSH
- Brain physiology MeSH
- Memory * physiology MeSH
- Prefrontal Cortex * physiology MeSH
- Mental Recall physiology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article 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
- GABA-A Receptor Agonists pharmacology MeSH
- Hippocampus drug effects physiology MeSH
- Rats MeSH
- Muscimol pharmacology MeSH
- Attention drug effects physiology MeSH
- Prefrontal Cortex drug effects physiology MeSH
- Spatial Processing drug effects physiology MeSH
- Reversal Learning drug effects physiology MeSH
- Avoidance Learning drug effects physiology MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't 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
- GABA-A Receptor Agonists pharmacology MeSH
- Hippocampus drug effects physiology MeSH
- Rats MeSH
- Muscimol pharmacology MeSH
- Attention drug effects physiology MeSH
- Prefrontal Cortex drug effects physiology MeSH
- Spatial Processing drug effects physiology MeSH
- Reversal Learning drug effects physiology MeSH
- Avoidance Learning drug effects physiology MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The glia limitans superficialis (GLS) on the rodent cortical surface consists of astrocyte bodies intermingled with their cytoplasmic processes. Many studies have observed astrocyte reactivity in the medial prefrontal cortex (mPFC) parenchyma induced by a peripheral nerve injury, while the response of GLS astrocytes is still not fully understood. The aim of our study was to identify the reactivity of rat GLS astrocytes in response to sciatic nerve compression (SNC) over different time periods. The alteration of GLS astrocyte reactivity was monitored using immunofluorescence (IF) intensities of glial fibrillary acidic protein (GFAP), glutamine synthetase (GS), and NFκBp65. Our results demonstrated that SNC induced GLS astrocyte reactivity seen as increased intensities of GFAP-IF, and longer extensions of cytoplasmic processes into lamina I. First significant increase of GFAP-IF was observed on post-operation day 7 (POD7) after SNC with further increases on POD14 and POD21. In contrast, dynamic alteration of the extension of cytoplasmic processes into lamina I was detected as early as POD1 and continued throughout the monitored survival periods of both sham and SNC operations. The reactivity of GLS astrocytes was not associated with their proliferation. In addition, GLS astrocytes also displayed a significant decrease in GS immunofluorescence (GS-IF) and NFκB immunofluorescence (NFκB-IF) in response to sham and SNC operation compared with naïve control rats. These results suggest that damaged peripheral tissues (following sham operation as well as peripheral nerve lesions) may induce significant changes in GLS astrocyte reactivity. The signaling mechanism from injured peripheral tissue and nerve remains to be elucidated.
- MeSH
- Astrocytes * metabolism pathology MeSH
- Glial Fibrillary Acidic Protein metabolism MeSH
- Rats MeSH
- Sciatic Nerve injuries metabolism MeSH
- Peripheral Nerve Injuries * metabolism MeSH
- Prefrontal Cortex metabolism MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
