The limbic lobe and its output channels: implications for emotional functions and adaptive behavior

Sex-specific neural circuits of emotion regulation in the centromedial amygdala

Sex-related differences in emotion regulation (ER) in the frequency power distribution within the human amygdala, a brain region involved in emotion processing, have been reported. However, how sex differences in ER are manifested in the brain networks which are seeded on the amygdala subregions is unclear. The goal of this study was to investigate this issue from a brain network perspective. Utilizing resting-state functional connectivity (RSFC) analysis, we found that the sex-specific functional connectivity patterns associated with ER trait level were only seeded in the centromedial amygdala (CM). Women with a higher trait-level ER had a stronger negative RSFC between the right CM and the medial superior frontal gyrus (mSFG), and stronger positive RSFC between the right CM and the anterior insula (AI) and the superior temporal gyrus (STG). But men with a higher trait-level ER was associated with weaker negative RSFC of the right CM-mSFG and positive RSFCs of the right CM-left AI, right CM-right AI/STG, and right CM-left STG. These results provide evidence for the sex-related effects in ER based on CM and indicate that men and women may differ in the neural circuits associated with emotion representation and integration.

Neural Signaling of Food Healthiness Associated with Emotion Processing

The ability to differentiate healthy from unhealthy foods is important in order to promote good health. Food, however, may have an emotional connotation, which could be inversely related to healthiness. The neurobiological background of differentiating healthy and unhealthy food and its relations to emotion processing are not yet well understood. We addressed the neural activations, particularly considering the single subject level, when one evaluates a food item to be of a higher, compared to a lower grade of healthiness with a particular view on emotion processing brain regions. Thirty-seven healthy subjects underwent functional magnetic resonance imaging while evaluating the healthiness of food presented as photographs with a subsequent rating on a visual analog scale. We compared individual evaluations of high and low healthiness of food items and also considered gender differences. We found increased activation when food was evaluated to be healthy in the left dorsolateral prefrontal cortex and precuneus in whole brain analyses. In ROI analyses, perceived and rated higher healthiness was associated with lower amygdala activity and higher ventral striatal and orbitofrontal cortex activity. Females exerted a higher activation in midbrain areas when rating food items as being healthy. Our results underline the close relationship between food and emotion processing, which makes sense considering evolutionary aspects. Actively evaluating and deciding whether food is healthy is accompanied by neural signaling associated with reward and self-relevance, which could promote salutary nutrition behavior. The involved brain regions may be amenable to mechanisms of emotion regulation in the context of psychotherapeutic regulation of food intake.

Arborization patterns of amygdalopetal axons from the rat ventral pallidum

We previously analyzed the arborization patterns of rat ventral pallidal (VP) axons that coursed caudally to innervate the thalamus and brainstem (Tripathi et al. in Brain Struct Funct 218:1133-1157, 2013). Here, we have reconstructed 16 previously undetected axons from the same tracer deposits that follow a more lateral trajectory. Virtually all 16 axons emanating from the different VP compartments collateralized in the extended amygdala system (EAS) and amygdaloid complex. The most frequent targets of axons from the lateral and medial (VPm) VP compartments were the rostral sublenticular extended amygdala, the extended amygdala (EA), the central nucleus of the amygdala and the posterior part of the basolateral amygdaloid nucleus. In contrast, axons from the rostral extension of the VP preferentially innervated the anterior amygdaloid area, the magnocellular preoptic nucleus, and the anterior part of the basomedial amygdaloid nucleus. We additionally found and reconstructed a single corticopetal axon arising from the VPm. The new results show that both direct and indirect projections from the basolateral complex and EAS to the ventral striatopallidal system are reciprocated by VP projections, and suggest that the systems can be activated simultaneously. The results additionally suggest that the amygdaloid complex and cortex are innervated separately from the VP. Finally, the combination of new and previous data indicate that approximately 84 % of VP axons (88/105) participate in basal ganglia circuits, 15 % (16/105) target the amygdaloid complex, and less than 1 % innervate the cortex.

Altered functional connectivity of the amygdaloid input nuclei in adolescents and young adults with autism spectrum disorder: a resting state fMRI study

BACKGROUND

Amygdala dysfunction is hypothesized to underlie the social deficits observed in autism spectrum disorders (ASD). However, the neurobiological basis of this hypothesis is underspecified because it is unknown whether ASD relates to abnormalities of the amygdaloid input or output nuclei. Here, we investigated the functional connectivity of the amygdaloid social-perceptual input nuclei and emotion-regulation output nuclei in ASD versus controls.

METHODS

We collected resting state functional magnetic resonance imaging (fMRI) data, tailored to provide optimal sensitivity in the amygdala as well as the neocortex, in 20 adolescents and young adults with ASD and 25 matched controls. We performed a regular correlation analysis between the entire amygdala (EA) and the whole brain and used a partial correlation analysis to investigate whole-brain functional connectivity uniquely related to each of the amygdaloid subregions.

RESULTS

Between-group comparison of regular EA correlations showed significantly reduced connectivity in visuospatial and superior parietal areas in ASD compared to controls. Partial correlation analysis revealed that this effect was driven by the left superficial and right laterobasal input subregions, but not the centromedial output nuclei.

CONCLUSIONS

These results indicate reduced connectivity of specifically the amygdaloid sensory input channels in ASD, suggesting that abnormal amygdalo-cortical connectivity can be traced down to the socio-perceptual pathways.

Current concepts in management of pain in children in the emergency department

Pain is common in children presenting to emergency departments with episodic illnesses, acute injuries, and exacerbation of chronic disorders. We review recognition and assessment of pain in infants and children and discuss the manifestations of pain in children with chronic illness, recurrent pain syndromes, and cognitive impairment, including the difficulties of pain management in these patients. Non-pharmacological interventions, as adjuncts to pharmacological management for acute anxiety and pain, are described by age and development. We discuss the pharmacological management of acute pain and anxiety, reviewing invasive and non-invasive routes of administration, pharmacology, and adverse effects.

Differentially disrupted functional connectivity of the subregions of the amygdala in Alzheimer's disease

The amygdala is an important brain area involved in cognitive procession and emotional regulation. Previous studies have typically considered the amygdala as a single structure, which likely masks contribution of individual amygdala subdivisions. Actually, the amygdala is heterogeneous and composed of structurally and functionally distinct nuclei, which may present different connectivity patterns and predict to relevant cognitive deficits in Alzheimer's disease (AD). However, little is known about functional connectivity of amygdala subregions in the resting state in AD subjects. Here, we employed resting-state functional MRI (fMRI) to examine functional connectivity changes of subregions comparing the AD patients with the age-matched control subjects. Thirty-two AD and 38 control subjects were analyzed. We defined three subregions of the amygdala according to probabilistic cytoarchitectonic atlases and mapped the whole-brain resting-state functional connectivity for each subregion: The central medial nucleus (CM) of amygdala exhibited connections with the lentiform nucleus, parahippocampus and lateral temporal gyrus; the lateral basal nucleus (LB) of amygdala functionally connected with the parahippocampus, lateral temporal gyrus, middle occipital gyrus and medial prefrontal cortex; and the superficial nucleus (SF) of amygdala had connection with the parahippocampus, lentiform nucleus, lateral temporal gyrus, insula, middle occipital gyrus, precentral and postcentral gyrus. Comparing with the controls, the AD patients presented disrupted connectivity patterns in the LB of amygdala, which predicted disconnection with the left uncus, right insula, right precentral gyrus, the left superior temporal gyrus and right claustrum. These findings in a large part supported our hypothesis and provided a new insight in understanding the pathophysiological mechanisms of AD.

Heritability of the limbic networks

Individual differences in cognitive ability and social behaviour are influenced by the variability in the structure and function of the limbic system. A strong heritability of the limbic cortex has been previously reported, but little is known about how genetic factors influence specific limbic networks. We used diffusion tensor imaging tractography to investigate heritability of different limbic tracts in 52 monozygotic and 34 dizygotic healthy adult twins. We explored the connections that contribute to the activity of three distinct functional limbic networks, namely the dorsal cingulum (‘medial default-mode network’), the ventral cingulum and the fornix (‘hippocampal-diencephalic-retrosplenial network’) and the uncinate fasciculus (‘temporo-amygdala-orbitofrontal network’). Genetic and environmental variances were mapped for multiple tract-specific measures that reflect different aspects of the underlying anatomy. We report the highest heritability for the uncinate fasciculus, a tract that underpins emotion processing, semantic cognition, and social behaviour. High to moderate genetic and shared environmental effects were found for pathways important for social behaviour and memory, for example, fornix, dorsal and ventral cingulum. These findings indicate that within the limbic system inheritance of specific traits may rely on the anatomy of distinct networks and is higher for fronto-temporal pathways dedicated to complex social behaviour and emotional processing.

Sources of input to the rostromedial tegmental nucleus, ventral tegmental area, and lateral habenula compared: A study in rat

Profound inhibitory control exerted on midbrain dopaminergic neurons by the lateral habenula (LHb), which has mainly excitatory outputs, is mediated by the GABAergic rostromedial tegmental nucleus (RMTg), which strongly innervates dopaminergic neurons in the ventral midbrain. Early reports indicated that the afferent connections of the RMTg, excepting its very strong LHb inputs, do not differ appreciably from those of the ventral tegmental area (VTA). Presumably, however, the RMTg contributes more to behavioral synthesis than to simply invert the valence of the excitatory signal coming from the LHb. Therefore, the present study was done to directly compare the inputs to the RMTg and VTA and, in deference to its substantial involvement with this circuitry, the LHb was also included in the comparison. Data indicated that, while the afferents of the RMTg, VTA, and LHb do originate within the same large pool of central nervous system (CNS) structures, each is also related to structures that project more strongly to it than to the others. The VTA gets robust input from ventral striatopallidum and extended amygdala, whereas RMTg biased inputs arise in structures with a more direct impact on motor function, such as deep layers of the contralateral superior colliculus, deep cerebellar and several brainstem nuclei, and, via a relay in the LHb, the entopeduncular nucleus. Input from the ventral pallidal-lateral preoptic-lateral hypothalamus continuum is strong in the RMTg and VTA and dominant in the LHb. Axon collateralization was also investigated, providing additional insights into the organization of the circuitry of this important triad of structures.

Heart coherence training combined with back school in patients with chronic non-specific low back pain: first pragmatic clinical results

The aim of this study was to explore on which variables a stress reduction program based on heart coherence can enhance the effects of a back school (BS) in patients with chronic non-specific low back pain and to explore possible moderators for treatment success. A retrospective explorative design was carried out with 170 patients with chronic non-specific low back pain. 89 Patients were admitted to BS and 81 patients were selected for BS and heart coherence training (BS-HCT). Six sessions of heart coherence were provided. At T0 (baseline) and T1 (discharge), the Numeric Rating Scale for pain (NRS pain), Roland Morris Disability Questionnaire (RMDQ), Pain Disability Index (PDI) and Rand-36 were administered in both groups. Both groups improved significantly on NRS pain, RMDQ, PDI and most of the Rand-36 subscales. On physical functioning, the BS-HCT group improved significantly more than the BS group (p = 0.02) but not after Bonferroni correction. Significant moderate correlations (r = 0.39 and r = 0.48) were found between the change of heart coherence and change of PDI and RMDQ respectively, but not with other variables. Baseline characteristics were not related to change on heart coherence. Providing HCT was more effective on physical functioning compared to a BS program. Change in heart coherence was related significantly to 2 out of 12 analyses. Placebo controlled and blinded studies are needed to confirm this. Characteristics of individuals who might benefit remain unknown. Evidence of this study is considered a level C, because of its pragmatic clinical character.

Anhedonia in the psychosis risk syndrome: associations with social impairment and basal orbitofrontal cortical activity

Background/Objectives:

Anhedonia is associated with poor social function in schizophrenia. Here, we examined this association in individuals at clinical high risk (CHR) for schizophrenia and related psychotic disorders, taking into account social anxiety. We then explored correlations between anhedonia and basal metabolic activity in selected forebrain regions implicated in reward processing.

Methods:

In 62 CHR individuals and 37 healthy controls, we measured social adjustment (Social Adjustment Self-Report Scale), social and physical anhedonia (Chapman Revised Anhedonia Scales), and social anxiety (Social Anxiety Scale for Adolescents) in cross-section. In a subgroup of 25 CHR individuals for whom high-spatial-resolution basal-state functional magnetic resonance imaging data were available, we also assessed correlations of these socio-affective constructs with basal cerebral blood volume in orbitofrontal cortex and related regions involved in reward processing.

Results:

Relative to controls, CHR individuals reported social impairment, greater social and physical anhedonia, and more social anxiety, exhibiting impairments comparable to schizophrenia. Regression analyses showed that anhedonia predicted social impairment and correlated negatively with basal cerebral blood volume within the orbitofrontal cortex (all P’s<0.05).

Conclusions:

Anhedonia and social anxiety are prominent in CHR individuals. Trait-like anhedonia may be a core phenotype related to orbitofrontal cortical function that, independent of symptoms, predicts social impairment. These data provide a rationale for interventions that target anhedonia and related activity in orbitofrontal cortical circuits in CHR individuals.

Developmental sex differences in resting state functional connectivity of amygdala sub-regions

During adolescence, considerable social and biological changes occur that interact with functional brain maturation, some of which are sex-specific. The amygdala is one brain area that has displayed sexual dimorphism, specifically in socio-affective (superficial amygdala [SFA]), stress (centromedial amygdala [CMA]), and learning and memory (basolateral amygdala [BLA]) processing. The amygdala has also been implicated in mood and anxiety disorders which display sex-specific features, most prominently observed during adolescence. Using functional magnetic resonance imaging (fMRI), the present study examined the interaction of age and sex on resting state functional connectivity (RSFC) of amygdala sub-regions, BLA and SFA, in a sample of healthy adolescents between the ages 10 and 16 years (n = 122, 71 boys). Whole-brain, voxel-wise partial correlation analyses were conducted to determine RSFC of bilateral BLA and SFA seed regions, created using the Eickhoff-Zilles maximum probability maps based on cytoarchitectonic mapping and FMRIB's Integrated Registration and Segmentation Tool (FIRST). Monte Carlo simulation was implemented to correct for multiple comparisons (threshold of 53 contiguous voxels with a z-value ≥ 2.25). Results indicated that with increasing age, there was a corresponding decrease in RSFC between both amygdala sub-regions and parieto-occipital cortices, with a concurrent increase in RSFC with medial prefrontal cortex (mPFC). Specifically, boys and girls demonstrated increased coupling of mPFC and left and right SFA with age, respectively; however, neither sex showed increased connectivity between mPFC and BLA, which could indicate relative immaturity of fronto-limbic networks that is similar across sex. A dissociation in connectivity between BLA- and SFA-parieto-occipital RSFC emerged, in which girls had weaker negative RSFC between SFA and parieto-occipital regions and boys had weaker negative RSFC of BLA and parieto-occipital regions with increased age, both standing in contrast to adult patterns of amygdala sub-regional RSFC. The present findings suggest relative immaturity of amygdala sub-regional RSFC with parieto-occipital cortices during adolescence, with unique patterns in both sexes that may support memory and socio-affective processing in boys and girls, respectively. Understanding the underlying normative functional architecture of brain networks associated with the amygdala during adolescence may better inform future research of the neural features associated with increased risk for internalizing psychopathology.

Somatic experiencing: using interoception and proprioception as core elements of trauma therapy

Here we present a theory of human trauma and chronic stress, based on the practice of Somatic Experiencing(®) (SE), a form of trauma therapy that emphasizes guiding the client's attention to interoceptive, kinesthetic, and proprioceptive experience. SE™ claims that this style of inner attention, in addition to the use of kinesthetic and interoceptive imagery, can lead to the resolution of symptoms resulting from chronic and traumatic stress. This is accomplished through the completion of thwarted, biologically based, self-protective and defensive responses, and the discharge and regulation of excess autonomic arousal. We present this theory through a composite case study of SE treatment; based on this example, we offer a possible neurophysiological rationale for the mechanisms involved, including a theory of trauma and chronic stress as a functional dysregulation of the complex dynamical system formed by the subcortical autonomic, limbic, motor and arousal systems, which we term the core response network (CRN). We demonstrate how the methods of SE help restore functionality to the CRN, and we emphasize the importance of taking into account the instinctive, bodily based protective reactions when dealing with stress and trauma, as well as the effectiveness of using attention to interoceptive, proprioceptive and kinesthetic sensation as a therapeutic tool. Finally, we point out that SE and similar somatic approaches offer a supplement to cognitive and exposure therapies, and that mechanisms similar to those discussed in the paper may also be involved in the benefits of meditation and other somatic practices.

Brain activation associated with pride and shame

BACKGROUND

Self-referential emotions such as shame/guilt and pride provide evaluative information about persons themselves. In addition to emotional aspects, social and self-referential processes play a role in self-referential emotions. Prior studies have rather focused on comparing self-referential and other-referential processes of one valence, triggered mostly by external stimuli. In the current study, we aimed at investigating the valence-specific neural correlates of shame/guilt and pride, evoked by the remembrance of a corresponding autobiographical event during functional magnetic resonance imaging.

METHOD

A total of 25 healthy volunteers were studied. The task comprised a negative (shame/guilt), a positive (pride) and a neutral condition (expecting the distractor). Each condition was initiated by a simple cue, followed by the remembrance and finished by a distracting picture.

RESULTS

Pride and shame/guilt conditions both activated typical emotion-processing circuits including the amygdala, insula and ventral striatum, as well as self-referential brain regions such as the bilateral dorsomedial prefrontal cortex. Comparing the two emotional conditions, emotion-processing circuits were more activated by pride than by shame, possibly due to either hedonic experiences or stronger involvement of the participants in positive self-referential emotions due to a self-positivity bias. However, the ventral striatum was similarly activated by pride and shame/guilt. In the whole-brain analysis, both self-referential emotion conditions activated medial prefrontal and posterior cingulate regions, corresponding to the self-referential aspect and the autobiographical evocation of the respective emotions.

CONCLUSION

Autobiographically evoked self-referential emotions activated basic emotional as well as self-referential circuits. Except for the ventral striatum, emotional circuits were more active with pride than with shame.

Corticotropin releasing hormone and imaging, rethinking the stress axis

The stress system provides integration of both neurochemical and somatic physiologic functions within organisms as an adaptive mechanism to changing environmental conditions throughout evolution. In mammals and primates the complexity and sophistication of these systems have surpassed other species in triaging neurochemical and physiologic signaling to maximize chances of survival. Corticotropin releasing hormone (CRH) and its related peptides and receptors have been identified over the last three decades and are fundamental molecular initiators of the stress response. They are crucial in the top down regulatory cascade over a myriad of neurochemical, neuroendocrine and sympathetic nervous system events. From neuroscience, we've seen that stress activation impacts behavior, endocrine and somatic physiology and influences neurochemical events that one can capture in real time with current imaging technologies. To delineate these effects one can demonstrate how the CRH neuronal networks infiltrate critical cognitive, emotive and autonomic regions of the central nervous system (CNS) with somatic effects. Abundant preclinical and clinical studies show inter-regulatory actions of CRH with multiple neurotransmitters/peptides. Stress, both acute and chronic has epigenetic effects which magnify genetic susceptibilities to alter neurochemistry; stress system activation can add critical variables in design and interpretation of basic and clinical neuroscience and related research. This review will attempt to provide an overview of the spectrum of known functions and speculative actions of CRH and stress responses in light of imaging technology and its interpretation. Metabolic and neuroreceptor positron emission/single photon tomography (PET/SPECT), functional magnetic resonance imaging (fMRI), anatomic MRI, diffusion tensor imaging (DTI), and proton magnetic resonance spectroscopy (pMRS) are technologies that can delineate basic mechanisms of neurophysiology and pharmacology. Stress modulates the myriad of neurochemical and networks within and controlled through the central and peripheral nervous system and the effects of stress activation on imaging will be highlighted.

Effort responses to suboptimal reward cues are related to striatal dopaminergic functioning

Reward cues have been found to increase the investment of effort in tasks even when cues are presented suboptimally (i.e. very briefly), making them hard to consciously detect. Such effort responses to suboptimal reward cues are assumed to rely mainly on the mesolimbic dopamine system, including the ventral striatum. To provide further support for this assumption, we performed two studies investigating whether these effort responses vary with individual differences in markers of striatal dopaminergic functioning. Study 1 investigated the relation between physical effort responses and resting state eye-blink rate. Study 2 examined cognitive effort responses in relation to individually averaged error-related negativity. In both studies effort responses correlated with the markers only for suboptimal, but not for optimal reward cues. These findings provide further support for the idea that effort responses to suboptimal reward cues are mainly linked to the mesolimbic dopamine system, while responses to optimal reward cues also depend on higher-level cortical functions.

The non-human primate striatum undergoes marked prolonged remodeling during postnatal development

We examined the postnatal ontogeny of the striatum in rhesus monkeys (Macaca mulatta) to identify temporal and spatial patterns of histological and chemical maturation. Our goal was to determine whether this forebrain structure is developmentally static or dynamic in postnatal life. Brains from monkeys at 1 day, 1, 4, 6, 9, and 12 months of age (N = 12) and adult monkeys (N = 4) were analyzed. Nissl staining was used to assess striatal volume, cytoarchitecture, and apoptosis. Immunohistochemistry was used to localize and measure substance P (SP), leucine-enkephalin (LENK), tyrosine hydroxylase (TH), and calbindin D28 (CAL) immunoreactivities. Mature brain to body weight ratio was achieved at 4 months of age, and striatal volume increased from ∼1.2 to ∼1.4 cm(3) during the first postnatal year. Nissl staining identified, prominently in the caudate nucleus, developmentally persistent discrete cell islands with neuronal densities greater than the surrounding striatal parenchyma (matrix). Losses in neuronal density were observed in island and matrix regions during maturation, and differential developmental programmed cell death was observed in islands and matrix regions. Immunohistochemistry revealed striking changes occurring postnatally in striatal chemical neuroanatomy. At birth, the immature dopaminergic nigrostriatal innervation was characterized by islands enriched in TH-immunoreactive puncta (putative terminals) in the neuropil; TH-enriched islands aligned completely with areas enriched in SP immunoreactivity but low in LENK immunoreactivity. These areas enriched in SP immunoreactivity but low in LENK immunoreactivity were identified as striosome and matrix areas, respectively, because CAL immunoreactivity clearly delineated these territories. SP, LENK, and CAL immunoreactivities appeared as positive neuronal cell bodies, processes, and puncta. The matrix compartment at birth contained relatively low TH-immunoreactive processes and few SP-positive neurons but was densely populated with LENK-immunoreactive neurons. The nucleus accumbens part of the ventral striatum also showed prominent differences in SP, LENK, and CAL immunoreactivities in shell and core territories. During 12 months of postnatal maturation salient changes occurred in neurotransmitter marker localization: TH-positive afferents densely innervated the matrix to exceed levels of immunoreactivity in the striosomes; SP immunoreactivity levels increased in the matrix; and LENK-immunoreactivity levels decreased in the matrix and increased in the striosomes. At 12 months of age, striatal chemoarchitecture was similar qualitatively to adult patterns, but quantitatively different in LENK and SP in caudate, putamen, and nucleus accumbens. This study shows for the first time that the rhesus monkey striatum requires more than 12 months after birth to develop an adult-like pattern of chemical neuroanatomy and that principal neurons within striosomes and matrix have different developmental programs for neuropeptide expression. We conclude that postnatal maturation of the striatal mosaic in primates is not static but, rather, is a protracted and dynamic process that requires many synchronous and compartment-selective changes in afferent innervation and in the expression of genes that regulate neuronal phenotypes.

Intra-hippocampal administration of ZIP alleviates depressive and anxiety-like responses in an animal model of posttraumatic stress disorder

Background

Given that impairment of fear extinction has been implicated in the pathogenesis of posttraumatic stress disorder (PTSD), effective pharmacological interventions that facilitate fear extinction may provide alternative strategies to conventional treatment. It is generally accepted that the zeta inhibitory peptide (ZIP), a controversial inhibitor of protein kinase M zeta (PKMζ), could erase certain types of previously established long-term memories. However, it is unclear whether ZIP administration may alleviate PTSD-associated depressive and anxiety-like abnormalities.

Methods

Here we developed a re-stressed single-prolonged stress (SPS) paradigm, a modified prevalent animal model of PTSD, and assayed the expressions of PKMζ in the hippocampus after SPS procedure. Next, Seven days prior to re-stress, ZIP was injected into the hippocampus, and the depressive and anxiety-like behavior was examined by the subsequent forced swim (FS), open-field and elevated plus maze (EPM) test.

Results

Rats given ZIP prior to FS exhibited a reduction of immobility time in FS test, and more open arms (OA) entries and longer OA duration in EPM. They also spent longer time in the center of the open field.

Conclusions

Our results suggested that re-stressed SPS could reproduce behavioral alteration similar to that observed in patients with PTSD, and these behavioral symptoms co-morbid with PTSD could be effectively alleviated by the intro-hippocampal administration of ZIP.

Intersession reliability of fMRI activation for heat pain and motor tasks

As the practice of conducting longitudinal fMRI studies to assess mechanisms of pain-reducing interventions becomes more common, there is a great need to assess the test–retest reliability of the pain-related BOLD fMRI signal across repeated sessions. This study quantitatively evaluated the reliability of heat pain-related BOLD fMRI brain responses in healthy volunteers across 3 sessions conducted on separate days using two measures: (1) intraclass correlation coefficients (ICC) calculated based on signal amplitude and (2) spatial overlap. The ICC analysis of pain-related BOLD fMRI responses showed fair-to-moderate intersession reliability in brain areas regarded as part of the cortical pain network. Areas with the highest intersession reliability based on the ICC analysis included the anterior midcingulate cortex, anterior insula, and second somatosensory cortex. Areas with the lowest intersession reliability based on the ICC analysis also showed low spatial reliability; these regions included pregenual anterior cingulate cortex, primary somatosensory cortex, and posterior insula. Thus, this study found regional differences in pain-related BOLD fMRI response reliability, which may provide useful information to guide longitudinal pain studies. A simple motor task (finger-thumb opposition) was performed by the same subjects in the same sessions as the painful heat stimuli were delivered. Intersession reliability of fMRI activation in cortical motor areas was comparable to previously published findings for both spatial overlap and ICC measures, providing support for the validity of the analytical approach used to assess intersession reliability of pain-related fMRI activation. A secondary finding of this study is that the use of standard ICC alone as a measure of reliability may not be sufficient, as the underlying variance structure of an fMRI dataset can result in inappropriately high ICC values; a method to eliminate these false positive results was used in this study and is recommended for future studies of test–retest reliability.

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Intersession reliability of pain-related fMRI responses was fair-to-moderate

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Intersession reliability of pain-related fMRI responses varied by brain region

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Intersession reliability is comparable for fixed temperature and fixed perception stimuli

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Standard methods of assessing intersession reliability can lead to false positives

Evidence for evolutionary specialization in human limbic structures

Increasingly, functional and evolutionary research has highlighted the important contribution emotion processing makes to complex human social cognition. As such, it may be asked whether neural structures involved in emotion processing, commonly referred to as limbic structures, have been impacted in human brain evolution. To address this question, we performed an extensive evolutionary analysis of multiple limbic structures using modern phylogenetic tools. For this analysis, we combined new volumetric data for the hominoid (human and ape) amygdala and 4 amygdaloid nuclei, hippocampus, and striatum, collected using stereological methods in complete histological series, with previously published datasets on the amygdala, orbital and medial frontal cortex, and insula, as well as a non-limbic structure, the dorsal frontal cortex, for contrast. We performed a parallel analysis using large published datasets including many anthropoid species (human, ape, and monkey), but fewer hominoids, for the amygdala and 2 amygdaloid subdivisions, hippocampus, schizocortex, striatum, and septal nuclei. To address evolutionary change, we compared observed human values to values predicted from regressions run through (a) non-human hominoids and (b) non-human anthropoids, assessing phylogenetic influence using phylogenetic generalized least squares regression. Compared with other hominoids, the volumes of the hippocampus, the lateral nucleus of the amygdala, and the orbital frontal cortex were, respectively, 50, 37, and 11% greater in humans than predicted for an ape of human hemisphere volume, while the medial and dorsal frontal cortex were, respectively, 26 and 29% significantly smaller. Compared with other anthropoids, only human values for the striatum fell significantly below predicted values. Overall, the data present support for the idea that regions involved in emotion processing are not necessarily conserved or regressive, but may even be enhanced in recent human evolution.

An update on the connections of the ventral mesencephalic dopaminergic complex

This review covers the intrinsic organization and afferent and efferent connections of the midbrain dopaminergic complex, comprising the substantia nigra, ventral tegmental area and retrorubral field, which house, respectively, the A9, A10 and A8 groups of nigrostriatal, mesolimbic and mesocortical dopaminergic neurons. In addition, A10dc (dorsal, caudal) and A10rv (rostroventral) extensions into, respectively, the ventrolateral periaqueductal gray and supramammillary nucleus are discussed. Associated intrinsic and extrinsic connections of the midbrain dopaminergic complex that utilize gamma-aminobutyric acid (GABA), glutamate and neuropeptides and various co-expressed combinations of these compounds are considered in conjunction with the dopamine-containing systems. A framework is provided for understanding the organization of massive afferent systems descending and ascending to the midbrain dopaminergic complex from the telencephalon and brainstem, respectively. Within the context of this framework, the basal ganglia direct and indirect output pathways are treated in some detail. Findings from rodent brain are briefly compared with those from primates, including humans. Recent literature is emphasized, including traditional experimental neuroanatomical and modern gene transfer and optogenetic studies. An attempt was made to provide sufficient background and cite a representative sampling of earlier primary papers and reviews so that people new to the field may find this to be a relatively comprehensive treatment of the subject.

Network dysfunction in Alzheimer's disease and frontotemporal dementia: implications for psychiatry

Structural and functional connectivity methods are changing how researchers conceptualize and explore neuropsychiatric disease. Here, we summarize emerging evidence of large-scale network dysfunction in Alzheimer's disease and behavioral variant frontotemporal dementia, focusing on the divergent impact these disorders have on the default mode network and the salience network. We update a working model for understanding the functions of these networks within a broader anatomical context and highlight the relevance of this model for understanding psychiatric illness. Finally, we look ahead to persistent challenges in the application of network-based imaging methods to patients with Alzheimer's disease, behavioral variant frontotemporal dementia, and other neuropsychiatric conditions. Recent advances and persistent needs are discussed, with an eye toward anticipating the hurdles that must be overcome for a network-based framework to clarify the biology of psychiatric illness and aid in the drug discovery process.

Lsamp is implicated in the regulation of emotional and social behavior by use of alternative promoters in the brain

Limbic system-associated membrane protein (LSAMP) is a neural cell adhesion molecule involved in neurite formation and outgrowth. The purpose of the present study was to characterize the distribution of alternatively transcribed Lsamp isoforms in the mouse brain and its implications on the regulation of behavior. Limbic system-associated membrane protein 1b transcript was visualized by using a mouse strain expressing beta-galactosidase under the control of Lsamp 1b promoter. The distribution of Lsamp 1a transcript and summarized expression of the Lsamp transcripts was investigated by non-radioactive in situ RNA hybridization analysis. Cross-validation was performed by using radioactive in situ hybridization with oligonucleotide probes. Quantitative RT-PCR was used to study correlations between the expression of Lsamp isoforms and behavioral parameters. The expression pattern of two promoters differs remarkably from the developmental initiation at embryonic day 12.5. Limbic system-associated membrane protein 1a promoter is active in “classic” limbic structures where the hippocampus and amygdaloid area display the highest expression. Promoter 1b is mostly active in the thalamic sensory nuclei and cortical sensory areas, but also in areas that regulate stress and arousal. Higher levels of Lsamp 1a transcript had significant correlations with all of the measures indicating higher trait anxiety in the elevated plus-maze test. Limbic system-associated membrane protein transcript levels in the hippocampus and ventral striatum correlated with behavioral parameters in the social interaction test. The data are in line with decreased anxiety and alterations in social behavior in Lsamp-deficient mice. We propose that Lsamp is involved in emotional and social operating systems by complex regulation of two alternative promoters.

Relationships between reward sensitivity, risk-taking and family history of alcoholism during an interactive competitive fMRI task

Background

Individuals with a positive family history for alcoholism (FHP) have shown differences from family-history-negative (FHN) individuals in the neural correlates of reward processing. FHP, compared to FHN individuals, demonstrate relatively diminished ventral striatal activation during anticipation of monetary rewards, and the degree of ventral striatal activation shows an inverse correlation with specific impulsivity measures in alcohol-dependent individuals. Rewards in socially interactive contexts relate importantly to addictive propensities, yet have not been examined with respect to how their neural underpinnings relate to impulsivity-related measures. Here we describe impulsivity measures in FHN and FHP individuals as they relate to a socially interactive functional magnetic resonance imaging (fMRI) task.

Methods

Forty FHP and 29 FHN subjects without histories of Axis-I disorders completed a socially interactive Domino task during functional magnetic resonance imaging and completed self-report and behavioral impulsivity-related assessments.

Results

FHP compared to FHN individuals showed higher scores (p = .004) on one impulsivity-related factor relating to both compulsivity (Padua Inventory) and reward/punishment sensitivity (Sensitivity to Punishment/Sensitivity to Reward Questionnaire). Multiple regression analysis within a reward-related network revealed a correlation between risk-taking (involving another impulsivity-related factor, the Balloon Analog Risk Task (BART)) and right ventral striatum activation under reward >punishment contrast (p<0.05 FWE corrected) in the social task.

Conclusions

Behavioral risk-taking scores may be more closely associated with neural correlates of reward responsiveness in socially interactive contexts than are FH status or impulsivity-related self-report measures. These findings suggest that risk-taking assessments be examined further in socially interactive settings relevant to addictive behaviors.

Limbic Tumors of the Temporal Lobe: Radiologic-Pathologic Correlation

PURPOSE

The purpose of this study was to assess imaging and pathologic characteristics of limbic tumors. Our hypothesis was that temporal lobe limbic tumors have distinctive features from extralimbic tumors.

METHODS

This retrospective radiologic-pathologic correlation study of primary temporal lobe tumors (excluding glioblastoma) distinguished limbic from extralimbic tumors based on preoperative magnetic resonance imaging. Limbic tumors were categorized according to Yaşargil's classification into (1) mediobasal temporal (mbT), (2) insular-temporo-opercular (I-TO), and (3) fronto-orbital-insular-temporopolar (FO-I-TP).

RESULTS

A total of 50 cases with a mean age at diagnosis of 38 ± 19.9 years (14 women, 36 men) were included. Pathologic diagnoses were as follows: 20 anaplastic astrocytomas, 11 gangliogliomas, 8 astrocytomas (World Health Organization grade II), 3 pilocytic astrocytomas, 2 dysembryoplastic neuroepithelial tumors, 2 oligodendrogliomas (grade II), 2 anaplastic oligodendrogliomas, 1 low-grade glioneuronal tumor, and 1 atypical extraventricular neurocytoma. In all, 36 tumors were limbic and displayed consistent growth patterns (16 mbT, 11 I-TO, 8 FO-I-TP, and 1 pantemporal) and 14 were extralimbic. There were no differences between limbic and extralimbic tumors with regard to age, sex, pathologic diagnosis, and presentation with seizures. mbT tumors had more frequent neuronal differentiation (50 %) than I-TO (0 %) and FO-I-TP (25 %) tumors (chi-square = 7.8, df = 2, p = 0.02). Neuronal differentiation correlated with lower grade (r = 0.52, p < 0.01) and younger age (r = 0.52, p < 0.01).

CONCLUSIONS

Limbic tumors displayed consistent growth routes. mbT limbic tumors had more frequent neuronal differentiation, which may result from proximity to the neurogenic subgranular zone of the hippocampus. Neuronal differentiation was maximal in mbT and lowest in I-TO and FO-I-TP tumors and correlated with lower tumor grade and younger age at diagnosis.

BDNF serum levels in subjects developing or not post-traumatic stress disorder after trauma exposure

Post-traumatic stress disorder (PTSD) is a syndrome resulting from exposure to a severe traumatic event that poses threatened death or injury and produces intense fear and helplessness. The neural structures implicated in PTSD development belong to the limbic system, an important region for emotional processing. Brain-derived neurotrophic factor (BDNF) is a neurotrophin that serves as survival factor for selected populations of central nervous system (CNS) neurons and plays a role in the limbic system by regulating synaptic plasticity, memory processes and behavior. Impaired BDNF production in the brain can lead to a variety of CNS dysfunctions including symptoms associated with PTSD. However, so far fewer studies have investigated this neurotrophin in patients with PTSD. Furthermore, given the multiple role of BDNF in various CNS disorders, it cannot be excluded that traumatic events per se may influence neurotrophin levels, without a direct association to the PTSD syndrome. To elucidate these issues, in this study we analyzed BDNF serum levels in two groups of subjects: patients with trauma exposure who developed PTSD, and subjects with trauma exposure who did not develop PTSD. We found that BDNF serum levels were lower in PTSD patients as compared to related control subjects. Thus, these data suggest that BDNF might be involved in pathophysiology of PTSD and consequently therapeutic approaches aimed at restoring BDNF serum levels may be beneficial to this pathology.

White matter microstructure alterations: a study of alcoholics with and without post-traumatic stress disorder

Many brain imaging studies have demonstrated reductions in gray and white matter volumes in alcoholism, with fewer investigators using diffusion tensor imaging (DTI) to examine the integrity of white matter pathways. Among various medical conditions, alcoholism and post-traumatic stress disorder (PTSD) are two comorbid diseases that have similar degenerative effects on the white matter integrity. Therefore, understanding and differentiating these effects would be very important in characterizing alcoholism and PTSD. Alcoholics are known to have neurocognitive deficits in decision-making, particularly in decisions related to emotionally-motivated behavior, while individuals with PTSD have deficits in emotional regulation and enhanced fear response. It is widely believed that these types of abnormalities in both alcoholism and PTSD are related to fronto-limbic dysfunction. In addition, previous studies have shown cortico-limbic fiber degradation through fiber tracking in alcoholism. DTI was used to measure white matter fractional anisotropy (FA), which provides information about tissue microstructure, possibly indicating white matter integrity. We quantitatively investigated the microstructure of white matter through whole brain DTI analysis in healthy volunteers (HV) and alcohol dependent subjects without PTSD (ALC) and with PTSD (ALC+PTSD). These data show significant differences in FA between alcoholics and non-alcoholic HVs, with no significant differences in FA between ALC and ALC+PTSD in any white matter structure. We performed a post-hoc region of interest analysis that allowed us to incorporate multiple covariates into the analysis and found similar results. HV had higher FA in several areas implicated in the reward circuit, emotion, and executive functioning, suggesting that there may be microstructural abnormalities in white matter pathways that contribute to neurocognitive and executive functioning deficits observed in alcoholics. Furthermore, our data do not reveal any differences between ALC and ALC+PTSD, suggesting that the effect of alcohol on white matter microstructure may be more significant than any effect caused by PTSD.

Cortico-amygdala-striatal circuits are organized as hierarchical subsystems through the primate amygdala

The prefrontal and insula cortex, amygdala, and striatum are key regions for emotional processing, yet the amygdala's role as an interface between the cortex and striatum is not well understood. In the nonhuman primate (Macaque fascicularis), we analyzed a collection of bidirectional tracer injections in the amygdala to understand how cortical inputs and striatal outputs are organized to form integrated cortico-amygdala-striatal circuits. Overall, diverse prefrontal and insular cortical regions projected to the basal and accessory basal nuclei of the amygdala. In turn, these amygdala regions projected to widespread striatal domains extending well beyond the classic ventral striatum. Analysis of the cases in aggregate revealed a topographic colocalization of cortical inputs and striatal outputs in the amygdala that was additionally distinguished by cortical cytoarchitecture. Specifically, the degree of cortical laminar differentiation of the cortical inputs predicted amygdalostriatal targets, and distinguished three main cortico-amygdala-striatal circuits. These three circuits were categorized as "primitive," "intermediate," and "developed," respectively, to emphasize the relative phylogenetic and ontogenetic features of the cortical inputs. Within the amygdala, these circuits appeared arranged in a pyramidal-like fashion, with the primitive circuit found in all examined subregions, and subsequent circuits hierarchically layered in discrete amygdala subregions. This arrangement suggests a stepwise integration of the functions of these circuits across amygdala subregions, providing a potential mechanism through which internal emotional states are managed with external social and sensory information toward emotionally informed complex behaviors.

The embodied transcendental: a Kantian perspective on neurophenomenology

Neurophenomenology is a research programme aimed at bridging the explanatory gap between first-person subjective experience and neurophysiological third-person data, through an embodied and enactive approach to the biology of consciousness. The present proposal attempts to further characterize the bodily basis of the mind by adopting a naturalistic view of the phenomenological concept of intentionality as the a priori invariant character of any lived experience. Building on the Kantian definition of transcendentality as “what concerns the a priori formal structures of the subject's mind” and as a precondition for the very possibility of human knowledge, we will suggest that this transcendental core may in fact be rooted in biology and can be examined within an extension of the theory of autopoiesis. The argument will be first clarified by examining its application to previously proposed elementary autopoietic models, to the bacterium, and to the immune system; it will be then further substantiated and illustrated by examining the mirror-neuron system and the default mode network as biological instances exemplifying the enactive nature of knowledge, and by discussing the phenomenological aspects of selected neurological conditions (neglect, schizophrenia). In this context, the free-energy principle proposed recently by Karl Friston will be briefly introduced as a rigorous, neurally-plausible framework that seems to accomodate optimally these ideas. While our approach is biologically-inspired, we will maintain that lived first-person experience is still critical for a better understanding of brain function, based on our argument that the former and the latter share the same transcendental structure. Finally, the role that disciplined contemplative practices can play to this aim, and an interpretation of the cognitive processes taking place during meditation under this perspective, will be also discussed.

Discrimination and categorization of emotional facial expressions and faces in Parkinson's disease

Our objective was to compare the ability to discriminate and categorize emotional facial expressions (EFEs) and facial identity characteristics (age and/or gender) in a group of 53 individuals with Parkinson's disease (PD) and another group of 53 healthy subjects. On the one hand, by means of discrimination and identification tasks, we compared two stages in the visual recognition process that could be selectively affected in individuals with PD. On the other hand, facial expression versus gender and age comparison permits us to contrast whether the emotional or non-emotional content influences the configural perception of faces. In Experiment I, we did not find differences between groups, either with facial expression or age, in discrimination tasks. Conversely, in Experiment II, we found differences between the groups, but only in the EFE identification task. Taken together, our results indicate that configural perception of faces does not seem to be globally impaired in PD. However, this ability is selectively altered when the categorization of emotional faces is required. A deeper assessment of the PD group indicated that decline in facial expression categorization is more evident in a subgroup of patients with higher global impairment (motor and cognitive). Taken together, these results suggest that the problems found in facial expression recognition may be associated with the progressive neuronal loss in frontostriatal and mesolimbic circuits, which characterizes PD.

White matter deficits in psychopathic offenders and correlation with factor structure

Psychopathic offenders show a persistent pattern of emotional unresponsivity to the often horrendous crimes they perpetrate. Recent studies have related psychopathy to alterations in white matter. Therefore, diffusion tensor imaging followed by tract-based spatial statistics (TBSS) analysis in 11 psychopathic offenders matched to 11 healthy controls was completed. Fractional anisotropy was calculated within each voxel and comparisons were made between groups using a permutation test. Any clusters of white matter voxels different between groups were submitted to probabilistic tractography. Significant differences in fractional anisotropy were found between psychopathic offenders and healthy controls in three main white matter clusters. These three clusters represented two major networks: an amygdalo-prefrontal network, and a striato-thalamo-frontal network. The interpersonal/affective component of the PCL-R correlated with white matter deficits in the orbitofrontal cortex and frontal pole whereas the antisocial component correlated with deficits in the striato-thalamo-frontal network. In addition to replicating earlier work concerning disruption of an amygdala-prefrontal network, we show for the first time that white matter integrity in a striato-thalamo-frontal network is disrupted in psychopathic offenders. The novelty of our findings lies in the two dissociable white matter networks that map directly onto the two major factors of psychopathy.

Sensorimotor modulation of mood and depression: in search of an optimal mode of stimulation

Depression involves a dysfunction in an affective fronto-limbic circuitry including the prefrontal cortices, several limbic structures including the cingulate cortex, the amygdala, and the hippocampus as well as the basal ganglia. A major emphasis of research on the etiology and treatment of mood disorders has been to assess the impact of centrally generated (top-down) processes impacting the affective fronto-limbic circuitry. The present review shows that peripheral (bottom-up) unipolar stimulation via the visual and the auditory modalities as well as by physical exercise modulates mood and depressive symptoms in humans and animals and activates the same central affective neurocircuitry involved in depression. It is proposed that the amygdala serves as a gateway by articulating the mood regulatory sensorimotor stimulation with the central affective circuitry by emotionally labeling and mediating the storage of such emotional events in long-term memory. Since both amelioration and aggravation of mood is shown to be possible by unipolar stimulation, the review suggests that a psychophysical assessment of mood modulation by multimodal stimulation may uncover mood ameliorative synergisms and serve as adjunctive treatment for depression. Thus, the integrative review not only emphasizes the relevance of investigating the optimal levels of mood regulatory sensorimotor stimulation, but also provides a conceptual springboard for related future research.

Organization of afferents to the striatopallidal systems in the fire-bellied toad Bombina orientalis

The cerebral hemispheres of amphibians display paired dorsal and ventral striatum (commonly referred to as striatum proper and nucleus accumbens, respectively). Each striatal region is proposed to be closely associated with a pallidal structure located caudal to it to form a striatopallidal system. In the present study, afferents to the dorsal and ventral striatopallidal systems of the fire-bellied toad (Bombina orientalis) were investigated using the neuronal tracer biocytin. A quantitative analysis of the topographical distribution of afferent neurons from the thalamus and posterior tubercle/ventral tegmentum was emphasised. The main results show that inputs to the two striatopallidal systems originate from distinct dorsal thalamic nuclei, with dorsal and ventral striatopallidal afferent neurons favouring strongly the lateral/central and anterior thalamic nuclei, respectively. However, afferent neuron distribution in the dorsal thalamus does not differ in the rostrocaudal axis of the brain. Afferent neurons from the posterior tubercle and ventral tegmentum, on the other hand, are organised topographically along the rostrocaudal axis. About 85 % of afferent neurons to the dorsal striatopallidal system are located rostrally in the posterior tubercle, while 75 % of afferent neurons to the ventral striatopallidal system are found more caudally in the ventral tegmentum. This difference is statistically significant and confirms the presence of distinct mesostriatal pathways in an amphibian. These findings demonstrate that an amphibian brain displays striatopallidal systems integrating parallel streams of sensory information potentially under the influence of distinct ascending mesostriatal pathways.

Prevalence and characteristics of depression in mild cognitive impairment: the Sydney Memory and Ageing Study

OBJECTIVE

Depression might be a risk factor for dementia. However, little is known about the prevalence of depressive symptoms in mild cognitive impairment (MCI) and whether mood or motivation-related symptoms are predominant.

METHOD

A total of 767 non-demented community-dwelling adults aged 70-90 years completed a comprehensive assessment, including neuropsychological testing, and a past psychiatric/medical history interview. Depressive symptoms were assessed using the Geriatric Depression Scale (GDS) and Kessler Psychological Distress Scale (K10). Exploratory factor analysis was performed on the GDS and K10 to derive 'mood' and 'motivation' subscales.

RESULTS

A total of 290 participants were classified as having MCI and 468 as cognitively normal (CN). Participants with MCI reported more depressive symptoms, and more MCI participants met the cut-off for clinically significant symptoms, relative to CN participants. Those with amnestic MCI (aMCI), but not non-amnestic MCI, had more depressive symptoms and were more likely to meet the cut-off for clinically significant depressive symptoms, relative to CN participants. Participants with MCI reported more mood-related symptoms than CN participants, while there were no differences between groups on motivation-related symptoms.

CONCLUSION

Individuals with MCI, especially aMCI, endorse more depressive symptoms when compared with cognitively intact individuals. These findings highlight the importance of assessing and treating depressive symptoms in MCI.

Striatal morphology as a biomarker in neurodegenerative disease

The striatum, comprising the caudate nucleus, putamen and nucleus accumbens, occupies a strategic location within cortico-striato-pallido-thalamic-cortical (corticostriatal) re-entrant neural circuits. Striatal neurodevelopment is precisely determined by phylogenetically conserved homeobox genes. Consisting primarily of medium spiny neurons, the striatum is strictly topographically organized based on cortical afferents and efferents. Particular corticostriatal neural circuits are considered to subserve certain domains of cognition, emotion and behaviour. Thus, the striatum may serve as a map of structural change in the cortical afferent pathways owing to deafferentation or neuroplasticity, and conversely, structural change in the striatum per se may structurally disrupt corticostriatal pathways. The morphology of the striatum may be quantified in vivo using advanced magnetic resonance imaging, as may cognitive functioning pertaining to corticostriatal circuits. It is proposed that striatal morphology may be a biomarker in neurodegenerative disease and potentially the basis of an endophenotype.

Persistence of feelings and sentience after bilateral damage of the insula

It has been convincingly established, over the past decade, that the human insular cortices are involved in processing both body feelings (such as pain) and feelings of emotion. Recently, however, an interpretation of this finding has emerged suggesting that the insular cortices are the necessary and sufficient platform for human feelings, in effect, the sole neural source of feeling experiences. In this study, we investigate this proposal in a patient whose insular cortices were destroyed bilaterally as a result of Herpes simplex encephalitis. The fact that all aspects of feeling were intact indicates that the proposal is problematic. The signals used to assemble the neural substrates of feelings hail from different sectors of the body and are conveyed by neural and humoral pathways to complex and topographically organized nuclei of the brain stem, prior to being conveyed again to cerebral cortices in the somatosensory, insular, and cingulate regions. We suggest that the neural substrate of feeling states is to be found first subcortically and then secondarily repeated at cortical level. The subcortical level would ensure basic feeling states while the cortical level would largely relate feeling states to cognitive processes such as decision-making and imagination.

Cooling, pain, and other feelings from the body in relation to the autonomic nervous system

The main sensory input to the autonomic nervous system comes from small-diameter sensory fibers by way of lamina I neurons in the superficial dorsal horn. This pathway supports organotopic homeostatic control of the body's condition, but also human feelings from the body, such as temperature, pain, itch, affective touch, muscle ache, vascular flush, and so on. The anatomical pathways described in this chapter reveal that these feelings are correlates of behavioral homeostatic responses needed to maintain the health of the body. These findings suggest that bodily feelings provide important measures of the body's condition, support emotional well-being and awareness, and can be a significant therapeutic avenue.

Differential putaminal morphology in Huntington's disease, Frontotemporal dementia and Alzheimer's disease

OBJECTIVE

Direct neuronal loss or deafferentation of the putamen, a critical hub in corticostriatal circuits, may result in diverse and distinct cognitive and motoric dysfunction in neurodegenerative disease. Differential putaminal morphology, as a quantitative measure of corticostriatal integrity, may thus be evident in Huntington's disease (HD), Alzheimer's disease (AD) and frontotemporal dementia (FTD), diseases with differential clinical dysfunction.

METHODS

HD (n = 17), FTD (n = 33) and AD (n = 13) patients were diagnosed according to international consensus criteria and, with healthy controls (n = 17), were scanned on the same MRI scanner. Patients underwent brief cognitive testing using the Neuropsychiatry Unit Cognitive Assessment Tool (NUCOG). Ten MRI scans from this dataset were manually segmented as a training set for the Adaboost algorithm, which automatically segmented all remaining scans for the putamen, yielding the following subset of the data: 9 left and 12 right putamen segmentations for AD; 25 left and 26 right putamina for FTD; 16 left and 15 right putamina for HD; 12 left and 12 right putamina for controls. Shape analysis was performed at each point on the surface of each structure using a multiple regression controlling for age and sex to compare radial distance across diagnostic groups.

RESULTS

Age, but not sex and intracranial volume (ICV), were significantly different in the segmentation subgroups by diagnosis. The AD group showed significantly poorer performance on cognitive testing than FTD. Mean putaminal volumes were HD < FTD < AD ≤ controls, controlling for age and ICV. The greatest putaminal shape deflation was evident in HD, followed by FTD, in regions corresponding to the interconnections to motoric cortex.

CONCLUSIONS

Differential patterns of putaminal atrophy in HD, FTD and AD, with relevance to corticostriatal circuits, suggest the putamen may be a suitable clinical biomarker in neurodegenerative disease.

The frontal-anatomic specificity of design fluency repetitions and their diagnostic relevance for behavioral variant frontotemporal dementia

On tests of design fluency, an examinee draws as many different designs as possible in a specified time limit while avoiding repetition. The neuroanatomical substrates and diagnostic group differences of design fluency repetition errors and total correct scores were examined in 110 individuals diagnosed with dementia, 53 with mild cognitive impairment (MCI), and 37 neurologically healthy controls. The errors correlated significantly with volumes in the right and left orbitofrontal cortex (OFC), the right and left superior frontal gyrus, the right inferior frontal gyrus, and the right striatum, but did not correlate with volumes in any parietal or temporal lobe regions. Regression analyses indicated that the lateral OFC may be particularly crucial for preventing these errors, even after excluding patients with behavioral variant frontotemporal dementia (bvFTD) from the analysis. Total correct correlated more diffusely with volumes in the right and left frontal and parietal cortex, the right temporal cortex, and the right striatum and thalamus. Patients diagnosed with bvFTD made significantly more repetition errors than patients diagnosed with MCI, Alzheimer's disease, semantic dementia, progressive supranuclear palsy, or corticobasal syndrome. In contrast, total correct design scores did not differentiate the dementia patients. These results highlight the frontal-anatomic specificity of design fluency repetitions. In addition, the results indicate that the propensity to make these errors supports the diagnosis of bvFTD. (JINS, 2012, 18, 1-11).

Neuronal populations in the basolateral nuclei of the amygdala are differentially increased in humans compared with apes: a stereological study

In human and nonhuman primates, the amygdala is known to play critical roles in emotional and social behavior. Anatomically, individual amygdaloid nuclei are connected with many neural systems that are either differentially expanded or conserved over the course of primate evolution. To address amygdala evolution in humans and our closest living relatives, the apes, we used design-based stereological methods to obtain neuron counts for the amygdala and each of four major amygdaloid nuclei (the lateral, basal, accessory basal, and central nuclei) in humans, all great ape species, lesser apes, and one monkey species. Our goal was to determine whether there were significant differences in the number or percent of neurons distributed to individual nuclei among species. Additionally, regression analyses were performed on independent contrast data to determine whether any individual species deviated from allometric trends. There were two major findings. In humans, the lateral nucleus contained the highest number of neurons in the amygdala, whereas in apes the basal nucleus contained the highest number of neurons. Additionally, the human lateral nucleus contained 59% more neurons than predicted by allometric regressions on nonhuman primate data. Based on the largest sample ever analyzed in a comparative study of the hominoid amygdala, our findings suggest that an emphasis on the lateral nucleus is the main characteristic of amygdala specialization over the course of human evolution.

An investigation of the structural, connectional, and functional subspecialization in the human amygdala

Although the amygdala complex is a brain area critical for human behavior, knowledge of its subspecialization is primarily derived from experiments in animals. We here employed methods for large‐scale data mining to perform a connectivity‐derived parcellation of the human amygdala based on whole‐brain coactivation patterns computed for each seed voxel. Voxels within the histologically defined human amygdala were clustered into distinct groups based on their brain‐wide coactivation maps. Using this approach, connectivity‐based parcellation divided the amygdala into three distinct clusters that are highly consistent with earlier microstructural distinctions. Meta‐analytic connectivity modelling then revealed the derived clusters' brain‐wide connectivity patterns, while meta‐data profiling allowed their functional characterization. These analyses revealed that the amygdala's laterobasal nuclei group was associated with coordinating high‐level sensory input, whereas its centromedial nuclei group was linked to mediating attentional, vegetative, and motor responses. The often‐neglected superficial nuclei group emerged as particularly sensitive to olfactory and probably social information processing. The results of this model‐free approach support the concordance of structural, connectional, and functional organization in the human amygdala and point to the importance of acknowledging the heterogeneity of this region in neuroimaging research. Hum Brain Mapp 34:3247–3266, 2013. © 2012 Wiley Periodicals, Inc.

Evidence for coordinated functional activity within the extended amygdala of non-human and human primates

Neuroanatomists posit that the central nucleus of the amygdala (Ce) and bed nucleus of the stria terminalis (BST) comprise two major nodes of a macrostructural forebrain entity termed the extended amygdala. The extended amygdala is thought to play a critical role in adaptive motivational behavior and is implicated in the pathophysiology of maladaptive fear and anxiety. Resting functional connectivity of the Ce was examined in 107 young anesthetized rhesus monkeys and 105 young humans using standard resting-state functional magnetic resonance imaging (fMRI) methods to assess temporal correlations across the brain. The data expand the neuroanatomical concept of the extended amygdala by finding, in both species, highly significant functional coupling between the Ce and the BST. These results support the use of in vivo functional imaging methods in nonhuman and human primates to probe the functional anatomy of major brain networks such as the extended amygdala.