Schizophrenia, psychosis, and the basal ganglia

Reversal of Basal Ganglia Hypermetabolism Following Surgical Removal of Adrenocorticotropic Hormone-Producing Lung Carcinoid in a Patient of Cushing Syndrome With Unusual Presentation of Acute Psychosis: Proof of Concept

ABSTRACT

A 34-year-old woman who presented with severe psychosis and clinical features of Cushing syndrome underwent 18 F-FDG PET/CT that revealed hypermetabolic lung lesion along with predominantly increased metabolism of bilateral basal ganglia, a scintigraphic correlate of acute psychosis. The lesion was surgically excised and histopathologically proven to be adrenocorticotropic hormone-producing lung carcinoid. Posttreatment 18 F-FDG PET scan showed restoration of normal brain metabolism with complete reversal of psychosis. Even though rare, one should be aware of psychosis as an initial presentation of Cushing syndrome and use of 18 F-FDG PET/CT for mapping brain metabolism as shown in this case.

Validation of behavioral measures of social cognition in individuals diagnosed with schizophrenia

Schizophrenia, a complex neuropsychiatric disorder, manifests severe impairments in social cognition, notably in Theory of Mind (ToM), empathy, and emotion recognition, which significantly influence social competence and overall functioning. These aspects are crucial for prognosis in individuals diagnosed with schizophrenia (SZ). This study validates a comics strip paradigm for ToM and empathy assessment, the Montreal Affective Voices (MAV) for measuring emotion recognition, and a Go-NoGo task for inhibition control estimation in individuals diagnosed with SZ, comparing their performance with healthy controls. SZ participants exhibited diminished abilities in the comics strip task, especially in ToM and empathy conditions, alongside challenges in identifying emotions from vocal cues in MAV. They responded slower and tended to be less accurate in the Go-NoGo task. The validated behavioral battery addresses the limitations of previous measures and emerges as a promising tool for future investigations into the neural systems underlying social cognition in schizophrenia. Such insights can lead to the development of long-needed treatment for negative symptoms and social dysfunctions in schizophrenia.

Understanding tDCS effects in schizophrenia: a systematic review of clinical data and an integrated computation modeling analysis

Although recent clinical studies using transcranial direct current stimulation (tDCS) for schizophrenia showed encouraging results, several tDCS montages were employed and their current flow pattern has not been investigated. We performed a systematic review to identify clinical tDCS studies in schizophrenia. We then applied computer head modeling analysis for prediction of current flow. Out of 41 references, we identified 12 relevant studies. The most employed montage was anode and cathode over the left dorsolateral prefrontal and temporoparietal cortex, respectively. Computational model analysis predicted activation and under-activation under the anode and the cathode, respectively, occurring in areas respectively associated with negative and positive symptoms. We also identified tDCS-induced electrical currents in cortical areas between the electrodes (frontoparietal network) and, to a lesser extent, in deeper structures involved in schizophrenia pathophysiology. Mechanisms of tDCS effects in schizophrenia and the usefulness of computer modeling techniques for planning tDCS trials in schizophrenia are discussed.

Gray matter in first-episode schizophrenia before and after antipsychotic drug treatment. Anatomical likelihood estimation meta-analyses with sample size weighting

BACKGROUND

Cerebral morphological abnormalities in schizophrenia may be modulated by treatment, chronicity, and duration of illness. Comparing brain imaging studies of individuals with first-episode schizophrenia and neuroleptic naive (NN-FES) with that of their neuroleptic-treated counterparts (NT-FES) can help to dissect out the effect of these potential confounders.

METHODS

We used the anatomical likelihood estimation method to compare voxel-based morphometric studies of NN-FES (n = 162 patients) and NT-FES (n = 336 patients) studies. The analysis included a sample size weighting step based on the Liptak-Stouffer method to reflect the greater power of larger studies.

RESULTS

Patient samples were matched for age, gender, and duration of illness. An extensive network of gray matter deficits in frontal, temporal, insular, striatal, posterior cingulate, and cerebellar regions was detected in the NN-FES samples as compared with healthy controls. Major deficits were detected in the frontal, superior temporal, insular, and parahippocampal regions for the NT-FES group compared with the NN-FES group. In addition, the NT-FES group showed minor deficits in the caudate, cingulate, and inferior temporal regions compared with the NN-FES group. There were no regions with gray matter volumetric excess in the NT-FES group.

CONCLUSION

Frontal, striato-limbic, and temporal morphological abnormalities are present in the early stage of schizophrenia and are unrelated to the effects of neuroleptic treatment, chronicity, and duration of illness. There may be dynamic effects of treatment on striato-limbic and temporal, but not frontal, regional gray matter volumes of the brain.

Identification and treatment of a pineal region tumor in an adolescent with prodromal psychotic symptoms

An adolescent male patient originally presented to a prodromal clinical research program with severe obsessive-compulsive behaviors and subthreshold symptoms of psychosis, which eventually developed into first-rank psychotic symptoms. The patient was followed over a 2-year period. His symptoms did not respond to psychotherapy or pharmacotherapy. However, when a pineal region tumor was discovered and treated with chemotherapy and autologous stem cell rescue, both psychotic symptoms and psychosocial functioning reverted toward baseline. Although subcortical brain structures have been implicated in the pathophysiology of idiopathic psychosis, reports of psychiatric sequelae of treatment of subcortical tumors are rare. Etiological pathways that may have played a role in symptom development are of particular interest, as understanding these mechanisms may shed light on the pathophysiology of psychotic disorders more generally.

Predictive eye and hand movements are differentially affected by schizophrenia

BACKGROUND

Schizophrenic patients are known to have problems suppressing reflexive eye movements. This is considered to indicate a dysfunction in prefrontal cortex. As the eye and hand motor systems are tightly coupled, we investigated whether predictive hand movements and eye-hand coordination are unimpaired in schizophrenic patients.

METHODS

Saccades and hand movements of 19 patients during an acute schizophrenic episode and 19 controls were measured in a task in which the predictability of target timing was varied.

RESULTS

Schizophrenic patients generated more anticipatory and less visually triggered saccades than controls with both non-predictable and predictable target timing. Anticipatory saccades in the wrong direction were clearly directed towards previous target positions, indicating that they are indicators of erroneous prediction rather than of fixation instability. In contrast to saccades, the number of anticipatory and visually triggered hand movements was the same in patients as in controls. As a consequence, patients took longer to initiate a hand movement after a saccade than controls.

CONCLUSIONS

Schizophrenic patients show increased predictive saccadic activity, but no qualitative changes in predictive saccades. Since prediction itself was not disturbed, the patients' deficit rather lies in the suppression or gating of anticipatory saccades than in their generation. This may be explained by a selective dysfunction of the basal ganglia oculomotor loop. As predictive hand movements were unimpaired, the problems in eye-hand coordination as expressed by a longer initiation time of hand movements relative to saccades are a direct consequence of impaired predictive saccadic behaviour.

MRI volumetric and 31P MRS metabolic correlates of caudate nucleus in antipsychotic-naïve schizophrenia

OBJECTIVE

To examine the volumetric and metabolic correlates of caudate nucleus in antipsychotic-naïve schizophrenia patients in comparison with healthy controls.

METHOD

Twelve antipsychotic-naïve schizophrenia patients and 13 healthy controls underwent (31)P magnetic resonance spectroscopy of basal ganglia. Magnetic resonance imaging volume of caudate nuclei was measured using scion image software.

RESULTS

Patients had significantly smaller caudate volume than healthy controls. Phosphocreatine (PCr)/total phosphorous and PCr/total adenosine tri-phosphate ratios of both caudate nuclei were significantly lower in patients than controls. Significant negative correlation was found between the left caudate volume and left PCr/total phosphorus ratio in the patients. Age at onset of psychosis had i) significant negative correlation with right and left caudate volumes and ii) significant positive correlation with left PCr/total phosphorus ratio.

CONCLUSION

The metabolic and volumetric abnormalities of caudate nucleus in antipsychotic-naïve schizophrenia patients support neurodevelopmental etiopathogenesis.

Relationship of neuromotor disturbances to psychosis symptoms in first-episode neuroleptic-naive schizophrenia patients

From the very inception of the modern diagnostic scheme for psychotic disorders, abnormalities in motor function have been observed in these conditions. Despite convergence from multiple areas of research supporting the notion that multiple frontal-subcortical circuits regulate motor and limbic behavior, the precise relationship between motor abnormalities and psychopathology has not been elucidated. The goals of this study were to examine the prevalence of extrapyramidal signs (EPS) in first-episode schizophrenia patients and their relationships to three psychopathological dimensions (positive psychosis syndrome, negative syndrome, and disorganization). We assessed EPS using traditional observer-based as well as quantitative instrumental measures in 39 neuroleptic-naive first-episode schizophrenia subjects. Subjects were followed for 6 months after initiating antipsychotic treatment to examine the stability of motor-limbic relationships. Four main findings emerged from this study. First, depending on the measure used the prevalence of dyskinesia prior to treatment ranged from 13% to 20%. The prevalence of parkinsonism ranged from 18% to 28%. Second, severity of dyskinesia was associated with the positive psychotic syndrome; whereas parkinsonism was associated with the positive psychosis, negative syndrome and disorganization. Third, psychopathology improved significantly across all symptom dimensions following antipsychotic treatment, while EPS remained stable. This suggests that some motor abnormalities in schizophrenia may reflect trait characteristics. Fourth, abnormalities on the pre-treatment instrumental measure of parkinsonism predicted greater improvement on positive psychosis symptoms following treatment (p=0.008). Our findings support the notion that neuromotor disturbances may be a core feature of schizophrenia in a substantial proportion of patients and implicate multiple fronto-striatal circuits regulating limbic and neuromotor behavior in schizophrenia.

The basal ganglia: anatomy, physiology, and pharmacology

The basal ganglia are perceived as important nodes in cortico-subcortical networks involved in the transfer, convergence, and processing of information in motor, cognitive, and limbic domains. How this integration might occur remains a matter of some debate, particularly given the consistent finding in anatomic and physiologic studies of functional segregation in cortico-subcortical loops. More recent theories, however, have raised the notion that modality-specific information might be integrated not spatially, but rather temporally, by coincident processing in discrete neuronal populations. Basal ganglia neurotransmitters, given their diverse roles in motor performance, learning, working memory, and reward-related activity are also likely to play an important role in the integration of cerebral activity. Further work will elucidate this to a greater extent, but for now, it is clear that the basal ganglia form an important nexus in the binding of cognitive, limbic, and motor information into thought and action.

Association between cognitive performance and striatal dopamine binding is higher in timing and motor tasks in patients with schizophrenia

The basal ganglia have received increasing attention with regard to their role in time pacing, motor function and other components of cognition. The aim of this study was to test whether the finer the motor activity and/or time perception performance were, the higher the striatal dopamine D(2) binding would be. Single photon emission computed tomography (SPECT) with [(123)I]iodobenzamide (IBZM) was performed to measure striatal D(2) receptor densities. A battery of neuropsychological tests, including the Wisconsin Card Sorting Test (WCST), the finger tapping test (FTT), and an attention test, was performed by patients with schizophrenia. Results indicated a strong correlation between the FTT score and striatal D(2) receptor binding. Neuroleptic dosage plays an important role in the relationship between cognitive tasks and striatal dopamine receptor densities. In addition, the striatal D(2) receptor density is more significantly correlated with attentional tests that consider the time effect than those that do not. Among the three tests performed, the WCST was least significantly correlated with striatal D(2) receptor densities. A decrease in striatal dopamine D(2) receptor density seems to be associated with impaired performance on optimal timing tasks and motor processing in patients with schizophrenia.

The effects of neuroleptic medications on basal ganglia blood flow in schizophreniform disorders: a comparison between the neuroleptic-naïve and medicated states

BACKGROUND

Previous studies indicate that basal ganglia volumes of first-episode neuroleptic-naïve patients with schizophrenia are smaller than those of normal control subjects. Subsequent exposure to neuroleptic medication appears to induce volumetric change. Possible reasons for this include differences in blood flow and metabolism between the neuroleptic-naïve and medicated states.

METHODS

We used positron emission tomography (PET) to measure blood flow to the caudate and putamen, in a sample of 29 neuroleptic-naïve patients with schizophreniform disorders and 29 matched control subjects. We also studied a subset of the patient sample (n = 13), comparing their "before" versus "on" medication PET scans.

RESULTS

We did not find a significant difference in blood flow to the caudate and putamen between neuroleptic-naïve patients and control subjects even after controlling for whole brain blood flow; however, in the subset of 13 patients compared in the "on" versus "off" medication states, there was a statistically significant increase in blood flow to both the caudate and putamen.

CONCLUSIONS

Before treatment, there appears to be no difference in striatal blood flow between first-episode neuroleptic-naïve patients and healthy volunteers, but there appears to be a significant increase in blood flow to the striatum after the treatment is initiated.

Neuropsychiatry of the basal ganglia

This review aims to relate recent findings describing the role and neural connectivity of the basal ganglia to the clinical neuropsychiatry of basal ganglia movement disorders and to the role of basal ganglia disturbances in "psychiatric"' states. Articles relating to the relevant topics were initially collected through MEDLINE and papers relating to the clinical conditions discussed were also reviewed. The anatomy and connections of the basal ganglia indicate that these structures are important links between parts of the brain that have classically been considered to be related to emotional functioning and brain regions previously considered to have largely motor functions. The basal ganglia have a role in the development and integration of psychomotor behaviours, involving motor functions, memory and attentional mechanisms, and reward processes.

Ressonância magnética na esquizofrenia: um estudo morfométrico

Trinta e três pacientes esquizofrênicos crônicos e 21 indivíduos normais foram submetidos a exames de ressonância magnética em aparelho de 1,5 T, sendo realizadas imagens ponderadas em T2 nos planos axial e coronal. Foram analisados, por métodos morfométricos semi-automáticos, os volumes intracraniano, supratentorial, infratentorial, do líquido cefalorraquiano total, ventricular e subaracnóide e do encéfalo. Foram ainda medidos os volumes do complexo amígdala-hipocampo, córtex do giro para-hipocampal, putâmen, globo pálido, lobo temporal e substâncias branca e cinzenta do lobo temporal. Foram calculados os volumes relativos dessas estruturas, corrigidos pelo volume intracraniano. As alterações mais relevantes observadas nos esquizofrênicos, em comparação com os controles, foram de redução do volume relativo do encéfalo, aumento do volume relativo do líquido cefalorraquiano ventricular, subaracnóide e total. Foi ainda observada redução do volume dos complexos amígdala-hipocampo, dos lobos temporais e da substância branca dos lobos temporais, e aumento de volume dos putâmens.

Neural basis of novel and well-learned recognition memory in schizophrenia: a positron emission tomography study

The level of familiarity of a given stimulus plays an important role in memory processing. Indeed, the novelty/familiarity of learned material has been proven to affect the pattern of activations during recognition memory tasks. We used visually presented words to investigate the neural basis of recognition memory for relatively novel and familiar stimuli in schizophrenia. Subjects were 34 healthy volunteers and 19 schizophrenia spectrum patients. Two experimental cognitive conditions were used: 1 week and again 1 day prior to the PET imaging subjects had to thoroughly learn a list of 18 words (well-learned memory). Subjects were also asked to learn another set of 18 words presented 1 min before the PET experiment (novel memory). During the PET session, subjects had to recognize the list of 18 words among 22 new (distractor) words. Subjects also performed a control task (reading words). A nonparametric randomization test and a statistical t-mapping method were used to determine between- and within-group differences. In patients the recognition of novel material produced relatively less flow in several frontal areas, superior temporal gyrus, insular cortex, and parahippocampal areas, and relatively higher activity in parietal areas, visual cortex, and cerebellum, compared to controls. No significant differences in flow were seen when comparing well-learned memory activations between groups. These results suggest that different neural pathways are engaged during novel recognition memory in patients with schizophrenia compared to healthy individuals. During recognition of novel material, patients failed to activate frontal/limbic regions, recruiting a set of posterior perceptual brain regions instead.

Negative symptoms: the 'pathology' of motivation and goal-directed behaviour

In many neurological and psychiatric disorders, including Alzheimer's disease and schizophrenia, symptoms are present that appear to reflect an essential absence of normal movement, cognition and emotional states. These negative symptoms might reflect fundamental impairments in basic brain mechanisms that underlie goal-directed behaviour. Knowledge of the pathology and pathophysiology of these diseases, combined with evidence from basic science, offers opportunities for understanding the neurobiological basis of goal-directed behaviour, particularly the interaction between limbic structures and striato-thalamo-cortical circuits. The study of patients with negative symptoms also provides opportunities for testing cognitive models of goal-directed behaviour, and eventually to map such models onto the neurobiology of both normal and abnormal behaviour.

Case study: suprasellar germinoma presenting with psychotic and obsessive-compulsive symptoms

This case describes a 13-year-old boy who had a suprasellar germinoma involving the bilateral basal ganglia. His presenting symptoms included left-sided weakness, diabetes insipidus, a decline in academic functioning as well as psychotic and obsessive-compulsive symptoms. His neuroradiological findings and clinical symptoms lend support to the potential role of the basal ganglia in psychotic and obsessive-compulsive symptomatology.

Caudate size in first-episode neuroleptic-naive schizophrenic patients measured using an artificial neural network

BACKGROUND

Structural brain imaging studies have demonstrated an increase in caudate volume in schizophrenic patients medicated with typical neuroleptics and a volume decrease following treatment with atypical neuroleptics. The measurement of striatal volume in patients who have never been treated with neuroleptics may indicate whether these changes are superimposed on intrinsic basal ganglia pathology in schizophrenia or are solely neuroleptic-induced.

METHODS

We studied 36 first-episode, neuroleptic-naive schizophrenic patients and 43 control subjects using an artificial neural network (ANN) to identify and measure the caudate nucleus. The resulting volumes were analyzed using an ANCOVA controlling for intracranial volume, age, gender, and socioeconomic status.

RESULTS

The mean volume difference between the caudate nuclei of patients and control subjects was .297 mL, the caudate nuclei of the patients being smaller than those of controls. When we covaried for intracranial volume, this was a statistically significant difference in caudate volume (n = 79; df = 1,75; F = 4.18; p > .04).

CONCLUSIONS

Caudate nuclei of neuroleptic naive schizophrenic patients are significantly smaller than those of controls. This suggests that patients suffering from schizophrenia may have intrinsic pathology of the caudate nucleus, in addition to the pathology observed as a consequence of chronic neuroleptic treatment.

L-Type Ca(2+) channels are essential for glutamate-mediated CREB phosphorylation and c-fos gene expression in striatal neurons

The second messenger pathways linking receptor activation at the membrane to changes in the nucleus are just beginning to be unraveled in neurons. The work presented here attempts to identify in striatal neurons the pathways that mediate cAMP response element-binding protein (CREB) phosphorylation and gene expression in response to NMDA receptor activation. We investigated the phosphorylation of the transcription factor CREB, the expression of the immediate early gene c-fos, and the induction of a transfected reporter gene under the transcriptional control of CREB after stimulation of ionotropic glutamate receptors. We found that neither AMPA/kainate receptors nor NMDA receptors were able to stimulate independently a second messenger pathway that led to CREB phosphorylation or c-fos gene expression. Instead, we saw a consecutive pathway from AMPA/kainate receptors to NMDA receptors and from NMDA receptors to L-type Ca(2+) channels. AMPA/kainate receptors were involved in relieving the Mg(2+) block of NMDA receptors, and NMDA receptors triggered the opening of L-type Ca(2+) channels. The second messenger pathway that activates CREB phosphorylation and c-fos gene expression is likely activated by Ca(2+) entry through L-type Ca(2+) channels. We conclude that in primary striatal neurons glutamate-mediated signal transduction is dependent on functional L-type Ca(2+) channels.

Molecular components of striatal plasticity: the various routes of cyclic AMP pathways

Neuroplasticity serves an important role for normal striatal function and in disease states. One route to neuroplasticity involves activation of the transcription factor cyclic 3', 5'-adenosine monophosphate (cyclic AMP) response element binding protein (CREB) by phosphorylation of the amino acid 133Ser. Dopamine and glutamate, the two predominant neurotransmitters in the striatum, induce CREB phosphorylation in primary cultures of rat striatum through cyclic AMP and Ca2+ pathways. Here we present the role of N-methyl-D-aspartate receptors and Ca2+ in cyclic AMP-mediated CREB phosphorylation.