Chapter 11 - Cingulate role in Tourette syndrome

Imaging of Eating Disorders: Multiple Techniques to Demonstrate the Dynamic Brain

The cingulate gyrus is a major part of the "anatomical limbic system" and, according to classic accounts, is involved in emotion. This view is oversimplified in light of recent clinical and experimental findings that cingulate cortex participates not only in emotion but also in sensory, motor, and cognitive processes. Anterior cingulate cortex, consisting of areas 25 and 24, has been implicated in visceromotor, skeletomotor, and endocrine outflow. These processes include responses to painful stimuli, maternal behavior, vocalization, and attention to action. Since all of these activities have an affective component, it is likely that connections with the amygdala are critical for them. In contrast, posterior cingulate cortex, consisting of areas 29, 30, 23, and 31, contains neurons that monitor eye movements and respond to sensory stimuli. Ablation studies suggest that this region is involved in spatial orientation and memory. It is likely that connections between posterior cingulate and parahippocampal cortices contribute to these processes. We conclude that there is a fundamental dichotomy between the functions of anterior and posterior cingulate cortices. The anterior cortex subserves primarily executive functions related to the emotional control of visceral, skeletal, and endocrine outflow. The posterior cortex subserves evaluative functions such as monitoring sensory events and the organism's own behavior in the service of spatial orientation and memory.

Recent studies have revealed a marked degree of variation in the pyramidal cell phenotype in visual, somatosensory, motor and prefrontal cortical areas in the brain of different primates, which are believed to subserve specialized cortical function. In the present study we carried out comparisons of dendritic structure of layer III pyramidal cells in the anterior and posterior cingulate cortex and compared their structure with those sampled from inferotemporal cortex (IT) and the primary visual area (V1) in macaque monkeys. Cells were injected with Lucifer Yellow in flat-mounted cortical slices, and processed for a light-stable DAB reaction product. Size, branching pattern, and spine density of basal dendritic arbors was determined, and somal areas measured. We found that pyramidal cells in anterior cingulate cortex were more branched and more spinous than those in posterior cingulate cortex, and cells in both anterior and posterior cingulate were considerably larger, more branched, and more spinous than those in area V1. These data show that pyramidal cell structure differs between posterior dysgranular and anterior granular cingulate cortex, and that pyramidal neurons in cingulate cortex have different structure to those in many other cortical areas. These results provide further evidence for a parallel between structural and functional specialization in cortex.

Cytoarchitectonic changes in the anterior cingulate cortex, hippocampus, subiculum, entorhinal cortex, amygdala, mammillary bodies, and septum were reported in a postmortem study of autism. Previously, the authors found smaller cingulate volume and decreased metabolism of the cingulate in seven autistic patients. In this study, they measured the volume and glucose metabolism of the amygdala, hippocampus, and cingulate gyrus in an expanded group of 17 patients with autism spectrum disorders (autism [N=10] or Asperger's disorder [N=7]) and 17 age- and sex-matched healthy volunteers. Subjects performed a serial verbal learning test during (18)F-deoxyglucose uptake. The amygdala, hippocampus, and cingulate gyrus were outlined on magnetic resonance imaging scans, volumes of the structures were applied to matching coregistered positron emission tomography scans, and three-dimensional significance probability mapping was performed. Significant metabolic reductions in both the anterior and posterior cingulate gyri were visualized in the patients with autism spectrum disorders. Both Asperger's and autism patients had relative glucose hypometabolism in the anterior and posterior cingulate as confirmed by analysis of variance; regional differences were also found with three-dimensional significance probability mapping. No group differences were found in either the metabolism or the volume of the amygdala or the hippocampus. However, patients with autism spectrum disorders showed reduced volume of the right anterior cingulate gyrus, specifically in Brodmann's area 24'. Compared with age- and sex-matched healthy volunteers, patients with autism spectrum disorders showed significantly decreased metabolism in both the anterior and posterior cingulate gyri.

To compare the glutamate dehydrogenase (GDH) activity and amounts of GDHI, GDHII, and GDHIII immunoreactive forms in prefrontal, anterior and posterior cingulate cortex and cerebellar cortex of patients with schizophrenia and control subjects. GDH enzymatic activity was measured and levels of GDH immunoreactive forms were determined in extracts of autopsied samples of prefrontal, anterior and posterior cingulate cortex (areas 10, 24, and 23 by Brodmann), and cerebellar cortex of patients with schizophrenia (n=8) and controls (n=9). GDH enzymatic activity was significantly increased in the prefrontal cortex (area 10) (p<0.004), the posterior cingulate cortex (area 23) (p<0.05) and the cerebellar cortex (p<0.002) and was unchanged in the anterior cingulate cortex (area 24) in patients with schizophrenia compared to controls. The levels of immunoreactive GDH I, GDH II and GDH III were significantly higher in the prefrontal cortex of patients with schizophrenia than in controls (p<0.008, p<0.003, and p<0.0001, respectively). Levels of all three immunoreactive GDH forms were unchanged in the anterior cingulate cortex (area 24), but they were increased in the posterior cingulate cortex (area 23) (p<0.004, p<0.001 and p<0.02, respectively). The levels of immunoreactive GDH II and GDH III, but not GDH I, were significantly increased in the cerebellar cortex of patients with schizophrenia compared with the control group (p<0.02 and p<0.001, respectively). The alteration in the levels of GDH immunoreactive forms in the brain of patients with schizophrenia is one of the causes of impaired brain glutamate metabolism and an important aspect of schizophrenia pathogenesis.

Non-invasive brain imaging has identified changes in the prefrontal–limbic network (Fig. 6.1) in patients suffering from major depression disease (MDD), principally in prefrontal cortex, anterior cingulate cortex, orbitofrontal cortex, hippocampus and the amygdala. For example, different regions in the medial prefrontal cortex and orbitofrontal cortex normally exert an inhibitory influence over activity in the amygdala, but fail to do so in depression according to functional magnetic resonance imaging (fMRI) studies (Drevets 2007; Savitz and Drevets 2009). Furthermore the evidence suggests there is a lack of functional connection in depressed patients between the subgenual anterior cingulate cortex (ACC) on the one hand and the rostral (pregenual) ACC and hippocampus on the other, as well as between the rostral ACC and the amygdala (Anand et al. 2009; Savitz and Drevets 2009). In depressed patients there is increased activity in the subgenual ACC accompanied by decreased activity in the dorsolateral prefrontal cortex (Drevets et al. 2008; Mayberg et al. 1999) leading to the conjecture that it is failure of inhibitory control from the dorsal areas over the ventral areas that leads to increased activity in the ventral areas (Taylor and Liberzon 2007). Use of multivariate techniques combined with structural equation modeling, applied to resting-state positron emission tomography (PET) scans of acutely depressed patients, show differences in known anatomical and physiological pathways. An estimate has been made of the strength and direction of ‘effective connections’ between these areas (James et al. 2009). Changes are observed between subgenual ACC, pregenual ACC, orbitofrontal cortex, hippocampus/amygdala, and the prefrontal cortex (Fig. 6.1).

Hypothyroidism is frequently associated with subtle behavioral and psychiatric symptoms. The consequences of inadequate thyroid hormone availability to brain metabolism are poorly understood. This study assessed the relationships between neuropsychiatric symptoms and changes in relative regional cerebral glucose metabolism in hypothyroid patients undergoing thyroid hormone replacement therapy. DESIGN, SETTING, AND OUTCOME MEASURE: Relative regional cerebral glucose metabolism was compared in 13 previously untreated hypothyroid patients and 10 healthy control participants. Effects of thyroid hormone replacement therapy (levothyroxine, 3 months) were assessed using neuropsychiatric measures and positron emission tomography with [(18)F]fluorodeoxyglucose. Before treatment, hypothyroid patients exhibited lower regional activity than control subjects in the bilateral amygdala, hippocampus, and perigenual anterior cingulate cortex (ACC), left subgenual ACC, and right posterior cingulate cortex. Severity of depressive symptoms covaried negatively with pretreatment activity in the bilateral middle frontal gyrus and right subgenual and dorsal ACC. Thyroid hormone replacement therapy abolished pretreatment group differences in regional activity, robustly increased activity in the ventral ACC, and significantly reduced both clinician-rated and self-rated behavioral and psychiatric symptoms. Increased activity within the ventral ACC was associated with reduced somatic complaints, whereas increased activity within the dorsal ACC was associated with reduced depressive symptoms. Reduction of the behavioral complaints during thyroid hormone therapy is associated with a restoration of metabolic activity in brain areas that are integral to the regulation of affect and cognition. The findings suggest that thyroid hormone modulates regional glucose metabolism and psychiatric symptoms in the mature brain.

BackgroundRecent evidence suggests that exercise plays a role in cognition and that the posterior cingulate cortex (PCC) can be divided into dorsal and ventral subregions based on distinct connectivity patterns.AimsTo examine the effect of physical activity and division of the PCC on brain functional connectivity measures in subjective memory complainers (SMC) carrying the epsilon 4 allele of apolipoprotein E (APOE ε4) allele.MethodParticipants were 22 SMC carrying the APOE ε4 allele (ε4+; mean age 72.18 years) and 58 SMC non-carriers (ε4–; mean age 72.79 years). Connectivity of four dorsal and ventral seeds was examined. Relationships between PCC connectivity and physical activity measures were explored.Resultsε4+ individuals showed increased connectivity between the dorsal PCC and dorsolateral prefrontal cortex, and the ventral PCC and supplementary motor area (SMA). Greater levels of physical activity correlated with the magnitude of ventral PCC–SMA connectivity.ConclusionsThe results provide the first evidence that ε4+ individuals at increased risk of cognitive decline show distinct alterations in dorsal and ventral PCC functional connectivity.Declaration of interestD.A. has served on scientific advisory boards for Novartis, Eli Lilly, Janssen, Prana and Pfizer, and as Editor-in-Chief for International Psychogeriatrics; received speaker honoraria from Pfizer and Lundbeck, and research support from Eli Lilly, GlaxoSmithKline, Forest Laboratories, Novartis, and CSIRO. C.L.M. has received consulting fees from Eli Lilly and Prana Biotechnology, and has stock ownership in Prana Biotechnology. C.C.R. has received consultancy payments from Roche and Piramal, and research support from Avid Radiopharmaceuticals, Eli Lilly, GE Healthcare, Piramal and Navidea for amyloid imaging. C.S. has provided clinical consultancy and been on scientific advisory committees for the Australian CSIRO, Alzheimer's Australia, University of Melbourne and other relationships, which are subject to confidentiality clauses; she has been a named Chief Investigator on investigator-driven collaborative research projects in partnership with Pfizer, Merck, Piramal, Bayer and GE Healthcare. Her research programme has received support from the National Health and Medical Research Council Alzheimer's Association, Collier Trust, Scobie and Claire McKinnon Foundation, JO and JR Wicking Trust, Shepherd Foundation, Brain Foundation, Mason Foundation, Ramaciotti Foundation, Alzheimer's Australia and the Royal Australian College of Physicians.Copyright and usage© The Royal College of Psychiatrists 2015. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) licence.

Patients with schizophrenia exhibit impairments in working memory that often appear in attenuated form in persons at high risk for the illness. The authors hypothesized that deviations in task-related brain activation and deactivation would occur in persons with an at-risk mental state performing a working memory task that entailed the maintenance and manipulation of letters. Participants at ultra high risk for developing psychosis (N=60), identified using the Comprehensive Assessment of At-Risk Mental States, and healthy comparison subjects (N=38) 14 to 29 years of age underwent functional MRI while performing a verbal working memory task. Group differences in brain activation were identified using analysis of covariance. The two groups did not show significant differences in speed or accuracy of performance, even after accounting for differences in education. Irrespective of task condition, at-risk participants exhibited significantly less activation than healthy comparison subjects in the left anterior insula. During letter manipulation, at-risk persons exhibited greater task-related deactivation within the default-mode network than comparison subjects. Region-of-interest analysis in the at-risk group revealed significantly greater right dorsolateral prefrontal cortex activation during manipulation of letters. Despite comparable behavioral performance, at-risk participants performing a verbal working memory task exhibited altered brain activation compared with healthy subjects. These findings demonstrate an altered pattern of brain activation in at-risk persons that contains elements of reduced function as well as compensation.

Schizophrenia patients have shown altered resting-state functional connectivity (rsFC) of the cingulate cortex; however, it is unknown whether rsFCs of the cingulate subregions are differentially affected in this disorder. We aimed to clarify the issue by comparing rsFCs of each cingulate subregion between healthy controls and schizophrenia patients. A total of 102 healthy controls and 94 schizophrenia patients underwent resting-state functional magnetic resonance imaging with a sensitivity-encoded spiral-in imaging sequence to reduce susceptibility-induced signal loss and distortion. The cingulate cortex was divided into nine subregions, including the subgenual anterior cingulate cortex (ACC), areas 24 and 32 of the pregenual ACC, areas 24 and 32 of the anterior mid-cingulate cortex (aMCC), posterior MCC (pMCC), dorsal (dPCC) and ventral (vPCC) posterior cingulate cortex (PCC) and retrosplenial cortex (RSC). The rsFCs of each cingulate subregion were compared between the two groups and the atrophy effect was considered. Results with and without global signal regression were reported. Most cingulate subregions exhibited decreased rsFCs in schizophrenia after global signal regression (GSR). Without GSR, only increased rsFC was found in schizophrenia, which primarily restricted to the aMCC, PCC and RSC. Some of these increased rsFCs were also significant after GSR. These findings suggest that GSR can greatly affect between-group differences in rsFCs and the consistently increased rsFCs may challenge the functional disconnection hypothesis of schizophrenia.

The human orbitofrontal cortex, ventromedial prefrontal cortex (vmPFC), and anterior cingulate cortex are involved in reward processing and thereby in emotion but are also implicated in episodic memory. To understand these regions better, the effective connectivity between 360 cortical regions and 24 subcortical regions was measured in 172 humans from the Human Connectome Project and complemented with functional connectivity and diffusion tractography. The orbitofrontal cortex has effective connectivity from gustatory, olfactory, and temporal visual, auditory, and pole cortical areas. The orbitofrontal cortex has connectivity to the pregenual anterior and posterior cingulate cortex and hippocampal system and provides for rewards to be used in memory and navigation to goals. The orbitofrontal and pregenual anterior cortex have connectivity to the supracallosal anterior cingulate cortex, which projects to midcingulate and other premotor cortical areas and provides for action-outcome learning including limb withdrawal or flight or fight to aversive and nonreward stimuli. The lateral orbitofrontal cortex has outputs to language systems in the inferior frontal gyrus. The medial orbitofrontal cortex connects to the nucleus basalis of Meynert and the pregenual cingulate to the septum, and damage to these cortical regions may contribute to memory impairments by disrupting cholinergic influences on the neocortex and hippocampus.

Two pathways differentially linking tau depositions, oxidative stress, and neuronal loss to apathetic phenotypes in progressive supranuclear palsy

Amyloid load, as measured by florbetapir positron emission tomography (PET) standardized uptake value ratio (SUVr), has high specificity in the diagnosis of Alzheimer disease (AD). As the posterior cingulate cortex (PCC) represents densely amyloid-affected regions early in AD, we hypothesized that amyloid load within the key hubs of the default mode networks (DMN) may result in local or distant interconnected gray matter (GM) volume atrophy, thereby affecting cognitive performance. Thirty AD patients with a clinical dementia rating sum of box score ≤2 were enrolled and underwent cognitive evaluation, 3-dimensional T1-weighted imaging and florbetapir PET. Volumes of interest (VOIs) included the hippocampus, lateral temporal region, and key hubs of the DMN [anterior cingulate cortex (ACC), PCC, posterior parietal, and precuneus]. The SUVr was calculated by florbetapir standard uptake value (SUV) within the T1-weighted image segmented GM VOIs divided by the cerebellar GM SUV. Our results suggested inverse correlations between ACC (ρ = −0.444, P = 0.016) and PCC SUVr (ρ = −0.443, P = 0.016) with PCC GM volume. In stepwise regression, the orientation scores were associated with PCC SUVr (β = 2.584, P = 0.02) and posterior parietal volume (β = −0.446, P = 0.04), whereas the word recall score was related to hippocampal volume (β = −0.391, P = 0.04). After removing the patients with a hippocampal VOI below the lowest tertile and adjusting for age, an inverse correlation was found between hippocampal volume and SUVr in the ACC (partial σ = −0.639, P = 0.002), precuneus (partial σ = −0.692, P = 0.002), and lateral temporal SUVr (partial σ = −0.604, P = 0.005). Our results suggest that amyloid burden within the key DMN regions may contribute to local and distant GM atrophy, and that this may explain the cognitive scores.

Major depressive disorder (MDD) is a prevalent mental disorder characterized by impairments in affect, behaviour and cognition. Previous studies have indicated that the anterior cingulate cortex (ACC) may play an essential role in the pathophysiology of depression. In this study, we systematically identified changes in functional connectivity (FC) for ACC subdivisions that manifest in MDD and further investigated the relationship between these changes and the clinical symptoms of depression. Sub-regional ACC FC was estimated in 41 first-episode medication-naïve MDD patients compared to 43 healthy controls. The relationships between depressive symptom severity and aberrant FC of ACC subdivisions were investigated. In addition, we conducted a meta-analysis to generate the distributions of MDD-related abnormal regions from previously reported results and compared them to FC deficits revealed in this study. In MDD patients, the subgenual and perigenual ACC demonstrated decreased FC with the posterior regions of the default network (DN), including the posterior inferior parietal lobule and posterior cingulate cortex. FC of these regions was negatively associated with the Automatic Thoughts Questionnaire scores and largely overlapped with previously reported abnormal regions. In addition, reduced FC between the caudal ACC and precuneus was negatively correlated with the Hamilton Anxiety Scale scores. We also found increased FC between the rostral ACC and dorsal medial prefrontal cortex. Our findings confirmed that functional interaction changes in different ACC sub-regions are specific and associated with distinct symptoms of depression. Our findings provide new insights into the role of ACC sub-regions and DN in the pathophysiology of MDD.

BackgroundWe recently reported evidence that commonly comorbid early onset psychiatric disorders are predicted by a biopsychosocial model composed of adolescent externalizing (EXT) behaviors, early life adversity, and midbrain dopamine autoreceptor availability, as measured with positron emission tomography (PET).Aims & ObjectivesHere, we tested whether two variants of this model could (i) reproduce the transdiagnostic predictions, and (ii) make disorder-specific predictions.MethodIn Study 1, participants were 1338 IMAGEN database members who had Childhood Trauma Questionnaire (CTQ) data, adolescent EXT scores, and functional magnetic resonance imaging (fMRI) measured responses during the monetary incentive delay (MID) task. Regions of interest were the midbrain dopamine cell bodies, ventral striatum, caudate, putamen, and anterior cingulate cortex. DSM-IV diagnoses were made using the Development and Wellbeing Assessment at ages 14, 16, and 19. Binary logistic regression models tested whether a combination of EXT traits, childhood trauma, and MID fMRI contrasts at either 14 or 19 years of age identified participants with a DSM-IV disorder by age 19. In Study 2 (n = 44), EXT behaviors were measured between ages 10 and 16, and both CTQ data and mesocorticolimbic activations to alcohol and juice cues were collected at age 18. Seven years later, participants completed the Alcohol Use Disorders Identification Test (AUDIT). Binomial logistic regression analyses tested whether these three factors predicted high vs low AUDIT scores at the age 25 follow-up.ResultsIn Study 1, all tested three-factor models predicted who had a DSM-IV disorder by age 19 at a high level of statistical significance (p < 1.0 x 10-21). In every model, EXT and CTQ scores were individual predictors (p < 0.001). At age 14, reward anticipation responses were significant predictors in the ventral striatum, caudate, putamen, and anterior cingulate. At age 19, significant predictors were in the ventral striatum. The relation between trauma and diagnoses was partially mediated by higher EXT (indirect path B = 0.0535, 95% CI = 0.0301-0.0835), and moderated by fMRI responses in the cingulate (p = 0.0038) and putamen (p = 0.014) at age 14. Low striatal reward anticipation responses were associated with higher anhedonia. In Study 2, the combination of high mesocorticolimbic responses to Alcohol vs. Juice cues, high EXT scores, and high CTQ scores predicted future alcohol use problems (p < 0.05). fMRI responses were significant contributors to the model in the ventral striatum, associative striatum, anterior and posterior cingulate cortices, and ventromedial prefrontal cortex (p ≤ 0.05).Discussion & ConclusionsThese findings tentatively identify constituents of a hierarchical diathesis-stress model that has (i) transdiagnostic predictive value for commonly comorbid early onset disorders, and (ii) narrower predictive value for future alcohol problems. For the latter, high mesocorticolimbic responses to disease-specific cues might imbue the stimuli with aberrant salience leading to distinct symptoms and disorders – these perturbations might be best identified after controlling for early life adversity and behavioral trajectories.