Neural Mechanisms of Negative Symptoms

1989 ◽  
Vol 155 (S7) ◽  
pp. 93-98 ◽  
Author(s):  
Nancy C. Andreasen

When Kraepelin originally defined and described dementia praecox, he assumed that it was due to some type of neural mechanism. He hypothesised that abnormalities could occur in a variety of brain regions, including the prefrontal, auditory, and language regions of the cortex. Many members of his department, including Alzheimer and Nissl, were actively involved in the search for the neuropathological lesions that would characterise schizophrenia. Although Kraepelin did not use the term ‘negative symptoms', he describes them comprehensively and states explicitly that he believes the symptoms of schizophrenia can be explained in terms of brain dysfunction:“If it should be confirmed that the disease attacks by preference the frontal areas of the brain, the central convolutions and central lobes, this distribution would in a certain measure agree with our present views about the site of the psychic mechanisms which are principally injured by the disease. On various grounds, it is easy to believe that the frontal cortex, which is specially well developed in man, stands in closer relation to his higher intellectual abilities, and these are the faculties which in our patients invariably suffer profound loss in contrast to memory and acquired ability.” Kraepelin (1919, p. 219)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Florian Bitsch ◽  
Philipp Berger ◽  
Andreas Fink ◽  
Arne Nagels ◽  
Benjamin Straube ◽  
...  

AbstractThe ability to generate humor gives rise to positive emotions and thus facilitate the successful resolution of adversity. Although there is consensus that inhibitory processes might be related to broaden the way of thinking, the neural underpinnings of these mechanisms are largely unknown. Here, we use functional Magnetic Resonance Imaging, a humorous alternative uses task and a stroop task, to investigate the brain mechanisms underlying the emergence of humorous ideas in 24 subjects. Neuroimaging results indicate that greater cognitive control abilities are associated with increased activation in the amygdala, the hippocampus and the superior and medial frontal gyrus during the generation of humorous ideas. Examining the neural mechanisms more closely shows that the hypoactivation of frontal brain regions is associated with an hyperactivation in the amygdala and vice versa. This antagonistic connectivity is concurrently linked with an increased number of humorous ideas and enhanced amygdala responses during the task. Our data therefore suggests that a neural antagonism previously related to the emergence and regulation of negative affective responses, is linked with the generation of emotionally positive ideas and may represent an important neural pathway supporting mental health.


2009 ◽  
Vol 24 (S1) ◽  
pp. 1-1
Author(s):  
D. Marinescu ◽  
L. Mogoanta ◽  
T. Udristoiu

Background:The alteration of hippocampal and prefrontal structures is linked with schizophrenia cognitive impairment and negative symptoms. the antipsychotics can induced apoptotic mechanisms correlated with the psychopharmacological mechanism of excesive blocking of the D2 receptors. Distress determined increase of the glucocorticoid aggression wich drive to the decrease of neuroprotective capacity at the brain level.Methods:We formed 5 study lots (5 adults rats) and a control lot. the substancies were administrated intraperitoneal, daily, saline solution equivalent to: ziprasidone (1.25mg/kg/day) and haloperidole (0.20mg/kg/day), dexametasone (0.20mg/kg/day):N1 - Haloperidole; N2 - Dexametasone; N3 - Ziprasidone; N4 - Dexametasone and Haloperidole; N5 - Dexametasone and Ziprasidone; N6 -control lot.We monitorised the cardiovascular function, respiration and EPS, without signaling any serious deadly adverse event. the rats were sacrificed during the 10th day and 21th day.Results:Frontal cortex and hippocamp were the most intensely affected even since the 10-th day to the N4 (haloperidole and dexametasone) lot with massive neuronal loss at the VI, V, and IV frontal cerebral layers.The lots treated with ziprasidone presented significant lesser structural changes in frontal cortex and hippocamp, comparative to haloperidole. the lots treated with dexametasone and ziprasidone (N5) are lesser affected at the cerebral structure level.Conclusions:Haloperidole has a significant decrease in neuroprotection. Ziprasidone demonstrated an neuroprotective effect.


2020 ◽  
Vol 20 (26) ◽  
pp. 2404-2421
Author(s):  
Mayasah Y. Al-Nema ◽  
Anand Gaurav

Schizophrenia is a severe mental disorder that affects more than 1% of the population worldwide. Dopamine system dysfunction and alterations in glutamatergic neurotransmission are strongly implicated in the aetiology of schizophrenia. To date, antipsychotic drugs are the only available treatment for the symptoms of schizophrenia. These medications, which act as D2-receptor antagonist, adequately address the positive symptoms of the disease, but they fail to improve the negative symptoms and cognitive impairment. In schizophrenia, cognitive impairment is a core feature of the disorder. Therefore, the treatment of cognitive impairment and the other symptoms related to schizophrenia remains a significant unmet medical need. Currently, phosphodiesterases (PDEs) are considered the best drug target for the treatment of schizophrenia since many PDE subfamilies are abundant in the brain regions that are relevant to cognition. Thus, this review aims to illustrate the mechanism of PDEs in treating the symptoms of schizophrenia and summarises the encouraging results of PDE inhibitors as anti-schizophrenic drugs in preclinical and clinical studies.


2020 ◽  
Vol 32 (9) ◽  
pp. 1749-1763
Author(s):  
Sachio Otsuka ◽  
Jun Saiki

Prior research has reported that the medial temporal, parietal, and frontal brain regions are associated with visual statistical learning (VSL). However, the neural mechanisms involved in both memory enhancement and impairment induced by VSL remain unknown. In this study, we examined this issue using event-related fMRI. fMRI data from the familiarization scan showed a difference in the activation level of the superior frontal gyrus (SFG) between structured triplets, where three objects appeared in the same order, and pseudorandom triplets. More importantly, the precentral gyrus and paracentral lobule responded more strongly to Old Turkic letters inserted into the structured triplets than to those inserted into the random triplets, at the end of the familiarization scan. Furthermore, fMRI data from the recognition memory test scan, where participants were asked to decide whether the objects or letters shown were old (presented during familiarization scan) or new, indicated that the middle frontal gyrus and SFG responded more strongly to objects from the structured triplets than to those from the random triplets, which overlapped with the brain regions associated with VSL. In contrast, the response of the lingual gyrus, superior temporal gyrus, and cuneus was weaker to letters inserted into the structured triplets than to those inserted into the random triplets, which did not overlap with the brain regions associated with observing the letters during the familiarization scan. These findings suggest that different brain regions are involved in memory enhancement and impairment induced by VSL.


2010 ◽  
pp. 455-458 ◽  
Author(s):  
D F Avgustinovich ◽  
O V Alekseyenko

The binding of [3H]SCH 23390 has been studied in various brain regions of male mice with the experience of repeated victory (winners) or defeat (losers) gained over 10 (T10) and 20 (T20) days of daily agonistic confrontations. In the frontal cortex, Bmax of [3H]SCH 23390 binding sites was found to be increased in T10 losers and decreased in T20 losers when compared to the control mice. In the striatum, T10 and T20 winners had reduced values of [3H]SCH 23390 binding sites than the ones in the control mice. The Kd was increased in the frontal cortex of T10 losers and T10 winners as well as in the amygdala of T20 losers. Reduced Kd values were found in the striatum of all experimental groups as well as in the amygdala of T20 winners. Thus, both specific changes relating to social behavior patterns and non-specific ones in [3H]SCH 23390 binding were found in the brain regions of mice after 10 and 20 days of intermale confrontations.


2020 ◽  
Author(s):  
Florian Bitsch ◽  
Philipp Berger ◽  
Andreas Fink ◽  
Arne Nagels ◽  
Benjamin Straube ◽  
...  

AbstractThe ability to generate humor gives rise to positive emotions and thus facilitate the successful resolution of adversity. Although there is consensus that inhibitory processes might be related to broaden the way of thinking, the neural underpinnings of these mechanisms are largely unknown. Here, we use functional Magnetic Resonance Imaging, a humorous alternative uses task and a stroop task, to investigate the brain mechanisms underlying the emergence of humorous ideas in 24 subjects. Neuroimaging results indicate that greater cognitive control abilities are associated with increased activation in the amygdala, the hippocampus and the superior and medial frontal gyrus during the generation of humorous ideas. Examining the neural mechanisms more closely shows that the downregulation of frontal brain regions is associated with an upregulation in the amygdala, which is concurrently linked with an increased number of humorous ideas and enhanced amygdala responses during the task. Our data therefore suggests that a neural antagonism previously related to the emergence and regulation of negative affective responses, is linked with the generation of emotionally positive ideas and may represent an important neural pathway supporting mental health.


2007 ◽  
Vol 190 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Harumasa Takano ◽  
Nobutaka Motohashi ◽  
Takeshi Uema ◽  
Kenichi Ogawa ◽  
Takashi Ohnishi ◽  
...  

BackgroundAlthough electroconvulsive therapy (ECT) is widely used to treat psychiatric disorders such as depression, its precise neural mechanisms remain unknown.AimsTo investigate the time course of changes in cerebral blood flow during acute ECT.MethodCerebral blood flow was quantified serially prior to, during and after acute ECT in six patients with depression under anaesthesia using [15O]H2O positron emission tomography (PET).ResultsCerebral blood flow during ECT increased particularly in the basal ganglia, brain-stem, diencephalon, amygdala, vermis and the frontal, temporal and parietal cortices compared with that before ECT. The flow increased in the thalamus and decreased in the anterior cingulate and medial frontal cortex soon after ECT compared with that before ECT.ConclusionsThese results suggest a relationship between the centrencephalic system and seizure generalisation. Further, they suggest that some neural mechanisms of action of ECT are mediated via brain regions including the anterior cingulate and medial frontal cortex and thalamus.


2014 ◽  
Vol 26 (8) ◽  
pp. 1871-1882 ◽  
Author(s):  
Ralph Weidner ◽  
Thorsten Plewan ◽  
Qi Chen ◽  
Axel Buchner ◽  
Peter H. Weiss ◽  
...  

A moon near to the horizon is perceived larger than a moon at the zenith, although—obviously—the moon does not change its size. In this study, the neural mechanisms underlying the “moon illusion” were investigated using a virtual 3-D environment and fMRI. Illusory perception of an increased moon size was associated with increased neural activity in ventral visual pathway areas including the lingual and fusiform gyri. The functional role of these areas was further explored in a second experiment. Left V3v was found to be involved in integrating retinal size and distance information, thus indicating that the brain regions that dynamically integrate retinal size and distance play a key role in generating the moon illusion.


2021 ◽  
Author(s):  
Lorin Friesen

Neurological research has made amazing strides in recent years. Enough is now known about what specific brain areas do to make it possible to start examining how various parts of the brain interact. What is missing is a general theory of cognition to tie all of this information together. Back in the 1980s, a cognitive theory was developed that began with a system of cognitive styles and was expanded through an in-depth study of biographies. It was discovered at that time that this theory mapped in a general way onto the brain. This cognitive theory, known as the theory of mental symmetry, has recently been tested as a meta-theory by using it to analyze a number of fields and theories dealing with human thought and behavior. This paper shows that personality traits that were discovered by mental symmetry correspond in detail to the functioning of brain regions described in current neurological papers. In brief, the cognitive model suggests that there are seven cognitive styles: There are four simple styles, and there are three composite styles that combine the thinking of the simple styles. Two of the simple styles use emotions and emphasize a circuit composed of orbitofrontal cortex, inferior frontal cortex, temporal lobe, and amygdala, with one in the left hemisphere and the other in the right hemisphere. The other two simple styles use confidence and emphasize a circuit consisting of dorsolateral frontal cortex, frontopolar cortex, parietal cortex, and hippocampus, again with one in the left hemisphere and the other in the right hemisphere. The three composite styles form a processing chain. The first composite style combines the two simple emotional styles and emphasizes the ventral striatum, and dopamine. This leads to the second composite style, which combines the two simple confidence styles and emphasizes the anterior cingulate, the dorsal striatum, and serotonin. This is followed by the third composite style which balances the functioning of the mind and emphasizes the thalamus and noradrenaline.


2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Christopher I. Petkov ◽  
Yukiko Kikuchi ◽  
Alice E. Milne ◽  
Mortimer Mishkin ◽  
Josef P. Rauschecker ◽  
...  

Abstract It is generally held that non-primary sensory regions of the brain have a strong impact on frontal cortex. However, the effective connectivity of pathways to frontal cortex is poorly understood. Here we microstimulate sites in the superior temporal and ventral frontal cortex of monkeys and use functional magnetic resonance imaging to evaluate the functional activity resulting from the stimulation of interconnected regions. Surprisingly, we find that, although certain earlier stages of auditory cortical processing can strongly activate frontal cortex, downstream auditory regions, such as voice-sensitive cortex, appear to functionally engage primarily an ipsilateral temporal lobe network. Stimulating other sites within this activated temporal lobe network shows strong activation of frontal cortex. The results indicate that the relative stage of sensory processing does not predict the level of functional access to the frontal lobes. Rather, certain brain regions engage local networks, only parts of which have a strong functional impact on frontal cortex.


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