The Neural Correlates of Narcissism: Is There a Connection with Desire for Fame and Celebrity Worship?

(1) Objective: Narcissism is characterized by emotional regulation deficits, a lack of empathy for others, and extreme self-focus. Narcissism has also been linked to an increased desire for fame and celebrity worship. Here, the neuroscience underlying narcissism is examined in order to determine what regions and networks of the brain are altered when non-narcissistic individuals are compared to participants with both grandiose and vulnerable narcissism. (2) Methods: The behavioral relationships between grandiose narcissism and desire for fame and vulnerable narcissism and celebrity worship are explored, along with a possible relationship at the neural level between these constructs. In this paper, we review research demonstrating that increased levels of grandiose narcissism are associated with an increase in obsession with fame, while vulnerable narcissism is associated with celebrity worship. (3) Results: Based on current data, the frontal regions underlie narcissism and also likely underlie celebrity worship and desire for fame. This tenuous conclusion is based on a limited number of studies. (4) Conclusions: The brain areas associated with grandiose narcissism may be associated with an intense desire for fame as well, while brain regions associated with vulnerable narcissism may be similar in celebrity worshipers. Future research studies on the brain that are specifically designed to test these relationships at a neurological level are needed.

Laterality Hotspots in the Striatum

Striatal loci are connected to both the ipsilateral and contralateral frontal cortex. Normative quantitation of the dissimilarity between striatal loci's hemispheric connection profiles and its spatial variance across the striatum, and assessment of how interindividual differences relate to function, stands to further the understanding of the role of corticostriatal circuits in lateralized functions and the role of abnormal corticostriatal laterality in neurodevelopmental and other neuropsychiatric disorders. A resting-state functional connectivity fingerprinting approach (n = 261) identified "laterality hotspots"-loci whose profiles of connectivity with ipsilateral and contralateral frontal cortex were disproportionately dissimilar-in the right rostral ventral putamen, left rostral central caudate, and bilateral caudal ventral caudate. Findings were replicated in an independent sample and were robust to both preprocessing choices and the choice of cortical atlas used for parcellation definitions. Across subjects, greater rightward connectional laterality at the right ventral putamen hotspot and greater leftward connectional laterality at the left rostral caudate hotspot were associated with higher performance on tasks engaging lateralized functions (i.e., response inhibition and language, respectively). In sum, we find robust and reproducible evidence for striatal loci with disproportionately lateralized connectivity profiles where interindividual differences in laterality magnitude are associated with behavioral capacities on lateralized functions.

Bipolar spectrum disorders are associated with increased gray matter volume in the medial orbitofrontal cortex and nucleus accumbens

Objective

Elevated sensitivity to rewards prospectively predicts Bipolar Spectrum Disorder (BSD) onset; however, it is unclear whether volumetric abnormalities also reflect BSD risk. BSDs emerge when critical neurodevelopment in frontal and striatal regions occurs in sex-specific ways. The current paper examined the volume of frontal and striatal brain regions in both individuals with and at risk for a BSD with exploratory analyses examining sex-specificity.

Methods

One hundred fourteen medication-free individuals ages 18-27 at low-risk for BSD (moderate-reward sensitivity; N = 37), at high-risk without a BSD (high-reward sensitivity; N = 47), or with a BSD (N = 30) completed a structural MRI scan of the brain. We examined group differences in gray matter volume in a priori medial orbitofrontal cortex (mOFC) and nucleus accumbens (NAcc) regions-of-interest.

Results

The BSD group had enlarged frontostriatal volumes (mOFC, NAcc) compared to low individuals (d = 1.01). The mOFC volume in BSD was larger than low-risk (d = 1.01) and the high-risk groups (d = 0.74). This effect was driven by males with a BSD, who showed an enlarged mOFC compared to low (d = 1.01) and high-risk males (d = 0.74). Males with a BSD also showed a greater NAcc volume compared to males at low-risk (d = 0.49), but not high-risk males.

Conclusions

An enlarged frontostriatal volume (averaged mOFC, NAcc) is associated with the presence of a BSD, while subvolumes (mOFC vs. NAcc) showed unique patterning in relation to risk. We report preliminary evidence that sex moderates frontostriatal volume in BSD, highlighting the need for larger longitudinal risk studies examining the role of sex-specific neurodevelopmental trajectories in emerging BSDs.

Frontostriatothalamic effective connectivity and dopaminergic function in the psychosis continuum

Dysfunction of fronto-striato-thalamic (FST) circuits is thought to contribute to dopaminergic dysfunction and symptom onset in psychosis, but it remains unclear whether this dysfunction is driven by aberrant bottom-up subcortical signalling or impaired top-down cortical regulation. We used spectral dynamic causal modelling of resting-state functional MRI to characterize the effective connectivity of dorsal and ventral FST circuits in a sample of 46 antipsychotic-naïve first-episode psychosis patients and 23 controls and an independent sample of 36 patients with established schizophrenia and 100 controls. We also investigated the association between FST effective connectivity and striatal 18F-DOPA uptake in an independent healthy cohort of 33 individuals who underwent concurrent functional MRI and PET. Using a posterior probability threshold of 0.95, we found that midbrain and thalamic connectivity were implicated as dysfunctional across both patient groups. Dysconnectivity in first-episode psychosis patients was mainly restricted to the subcortex, with positive symptom severity being associated with midbrain connectivity. Dysconnectivity between the cortex and subcortical systems was only apparent in established schizophrenia patients. In the healthy 18F-DOPA cohort, we found that striatal dopamine synthesis capacity was associated with the effective connectivity of nigrostriatal and striatothalamic pathways, implicating similar circuits to those associated with psychotic symptom severity in patients. Overall, our findings indicate that subcortical dysconnectivity is evident in the early stages of psychosis, that cortical dysfunction may emerge later in the illness, and that nigrostriatal and striatothalamic signalling are closely related to striatal dopamine synthesis capacity, which is a robust marker for psychosis.

Set-shifting-related basal ganglia deformation as a novel familial marker of obsessive-compulsive disorder

The symptoms of obsessive-compulsive disorder (OCD) are suggestive of cognitive rigidity, and previous work identified impaired flexible responding on set-shifting tasks in such patients. The basal ganglia are central to habit learning and are thought to be abnormal in OCD, contributing to inflexible, rigid habitual patterns of behaviour. Here, we demonstrate that increased cognitive inflexibility, indexed by poor performance on the set-shifting task, correlated with putamen morphology, and that patients and their asymptomatic relatives had common curvature abnormalities within this same structure. The association between the structure of the putamen and the extradimensional errors was found to be significantly familial in OCD proband-relative pairs. The data implicate changes in basal ganglia structure linked to cognitive inflexibility as a familial marker of OCD. This may reflect a predisposing heightened propensity toward habitual response patterns and deficits in goal-directed planning.

Deciphering the frontostriatal circuitry through the fiber dissection technique: direct structural evidence on the morphology and axonal connectivity of the fronto-caudate tract

OBJECTIVE

The authors sought to investigate the very existence and map the topography, morphology, and axonal connectivity of a thus far ill-defined subcortical pathway known as the fronto-caudate tract (FCT) since there is a paucity of direct structural evidence regarding this pathway in the relevant literature.

METHODS

Twenty normal adult cadaveric formalin-fixed cerebral hemispheres (10 left and 10 right) were explored through the fiber microdissection technique. Lateral to medial and medial to lateral dissections were carried out in a tandem manner in all hemispheres. Attention was focused on the prefrontal area and central core since previous diffusion tensor imaging studies have recorded the tract to reside in this territory.

RESULTS

In all cases, the authors readily identified the FCT as a fan-shaped pathway lying in the most medial layer of the corona radiata and traveling across the subependymal plane before terminating on the superolateral margin of the head and anterior part of the body of the caudate nucleus. The FCT could be adequately differentiated from adjacent fiber tracts and was consistently recorded to terminate in Brodmann areas 8, 9, 10, and 11 (anterior pre-supplementary motor area and the dorsolateral, frontopolar, and fronto-orbital prefrontal cortices). The authors were also able to divide the tract into a ventral and a dorsal segment according to the respective topography and connectivity observed. Hemispheric asymmetries were not observed, but instead the authors disclosed asymmetry within the FCT, with the ventral segment always being thicker and bulkier than the dorsal one.

CONCLUSIONS

By using the fiber microdissection technique, the authors provide sound structural evidence on the topography, morphology, and connectional anatomy of the FCT as a distinct part of a wider frontostriatal circuitry. The findings are in line with the tract's putative functional implications in high-order motor and behavioral processes and can potentially inform current surgical practice in the fields of neuro-oncology and functional neurosurgery.

Corticostriatal Projections of Macaque Area 44

Ventrolateral frontal area 44 is implicated in inhibitory motor functions and facilitating prefrontal control over vocalization. The contribution of corticostriatal circuits to area 44 functions is unclear, as prior investigation of area 44 projections to the striatum—a central structure in motor circuits—is limited. Here, we used anterograde and retrograde tracing in macaques to map the innervation zone of area 44 corticostriatal projections, quantify their strengths, and evaluate their convergence with corticostriatal projections from other frontal cortical regions. First, whereas terminal fields from a rostral area 44 injection site were found primarily in the central caudate nucleus, those from a caudal area 44 injection site were found primarily in the ventrolateral putamen. Second, amongst sampled injection sites, area 44 input as a percentage of total frontal cortical input was highest in the ventral putamen at the level of the anterior commissure. Third, area 44 projections converged with orofacial premotor area 6VR and other motor-related projections (in the putamen), and with nonmotor prefrontal projections (in the caudate nucleus). Findings support the role of area 44 as an interface between motor and nonmotor functional domains, possibly facilitated by rostral and caudal area 44 subregions with distinct corticostriatal connectivity profiles.

Frontostriatal White Matter Integrity Relations with "Cool" and "Hot" Self-Regulation after Pediatric Traumatic Brain Injury

Traumatic brain injury (TBI) produces microstructural damage to white matter pathways connecting neural structures in pre-frontal and striatal regions involved in self-regulation (SR). Dorsal and ventral frontostriatal pathways have been linked to cognitive ("cool") and emotional ("hot") SR, respectively. We evaluated the relation of frontostriatal pathway fractional anisotropy (FA) 2 months post-TBI on cool and hot SR assessed 7 months post-TBI. Participants were 8-15 years of age, including children with uncomplicated mild TBI (mTBI; n = 24), more severe TBI (complicated-mild, moderate, severe [cms]TBI; n = 60), and typically developing (TD) children (n = 55). Diffusion tensor tractography was used to map frontostriatal pathways. Cool SR included focused and sustained attention performance, and parent-reported attention, whereas hot SR included risk-taking performance and parent-reported emotional control. Multivariate general linear models showed that children with cmsTBI had greater parent-reported cool and hot SR difficulties and lower dorsal and ventral FA than TD children. Focused attention, risk taking, and emotional control correlated with FA of specific dorsal and ventral pathways; however, only the effect of TBI on focused attention was mediated by integrity of dorsal pathways. Results suggest that frontostriatal FA may serve as a biomarker of risk for SR difficulties or to assess response to interventions targeting SR in pediatric TBI and in broader neurodevelopmental populations.

Frontal atrophy as a marker for dementia conversion in Parkinson's disease with mild cognitive impairment

This study aimed to investigate the cortical neural correlates of dementia conversion in Parkinson's disease with mild cognitive impairment (PD-MCI). We classified 112 patients with drug-naïve early stage PD meeting criteria for PD-MCI into either PD with dementia (PDD) converters (n = 34) or nonconverters (n = 78), depending on whether they developed dementia within 4 years of PD diagnosis. Cortical thickness analyses were performed in 34 PDD converters and 34 matched nonconverters. Additionally, a linear discriminant analysis was performed to distinguish PDD converters from nonconverters using cortical thickness of the regions that differed between the two groups. The PDD converters had higher frequencies of multiple domain MCI and amnestic MCI with storage failure, and poorer cognitive performances on frontal/executive, memory, and language function domains than did the nonconverters. Cortical thinning extending from the posterior cortical area into the frontal region was observed in PDD converters relative to nonconverters. The discriminant analysis showed that the prediction model with two cortical thickness variables in the right medial superior frontal and left olfactory cortices optimally distinguished PDD converters from nonconverters. Our data suggest that cortical thinning in the frontal areas including the olfactory cortex is a marker for early dementia conversion in PD-MCI.

Increased glia density in the caudate nucleus in williams syndrome: Implications for frontostriatal dysfunction in autism

Williams syndrome (WS) is a rare neurodevelopmental disorder with a well-described, known genetic etiology. In contrast to Autism Spectrum Disorders (ASD), WS has a unique phenotype characterized by global reductions in IQ and visuospatial ability, with relatively preserved language function, enhanced reactivity to social stimuli and music, and an unusual eagerness to interact socially with strangers. A duplication of the deleted region in WS has been implicated in a subset of ASD cases, defining a spectrum of genetic and behavioral variation at this locus defined by these opposite extremes in social behavior. The hypersociability characteristic of WS may be linked to abnormalities of frontostriatal circuitry that manifest as deficits in inhibitory control of behavior. Here, we examined the density of neurons and glia in associative and limbic territories of the striatum including the caudate, putamen, and nucleus accumbens regions in Nissl stained sections in five pairs of age, sex, and hemisphere-matched WS and typically-developing control (TD) subjects. In contrast to what is reported in ASD, no significant increase in overall neuron density was observed in this study. However, we found a significant increase in the density of glia in the dorsal caudate nucleus, and in the ratio of glia to neurons in the dorsal and medial caudate nucleus in WS, accompanied by a significant increase in density of oligodendrocytes in the medial caudate nucleus. These cellular abnormalities may underlie reduced frontostriatal activity observed in WS, with implications for understanding altered connectivity and function in ASD. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 531-545, 2018.

Impaired planning in Parkinson's disease is reflected by reduced brain activation and connectivity

Objective

Parkinson's disease (PD) often entails impairments of executive functions, such as planning. Although widely held that these impairments arise from dopaminergic denervation of the striatum, not all executive functions are affected early on, and the underlying neural dynamics are not fully understood. In a combined longitudinal and cross‐sectional study, we investigated how planning deficits progress over time in the early stages of PD compared to matched healthy controls. We used functional magnetic resonance imaging (fMRI) to identify accompanying neural dynamics.

Methods

Seventeen PD patients and 20 healthy controls performed a parametric Tower of London task at two time points separated by ∼3 years (baseline and follow‐up). We assessed task performance longitudinally in both groups; at follow‐up, a subset of participants (14 patients, 19 controls) performed a parallel version of the task during fMRI. We performed meta‐analyses to localize regions‐of‐interest (ROIs), that is, the bilateral dorsolateral prefrontal cortex (DLPFC), inferior parietal cortex, and caudate nucleus, and performed group‐by‐task analyses and within‐group regression analyses of planning‐related neural activation. We studied task‐related functional connectivity of seeds in the DLPFC and caudate nucleus.

Results

PD patients, compared with controls, showed impaired task performance at both time‐points, while both groups showed similar performance reductions from baseline to follow‐up. Compared to controls, patients showed lower planning‐related brain activation together with decreased functional connectivity.

Conclusion

These findings support the notion that planning is affected early in the PD disease course, and that this impairment in planning is accompanied by decreases in both task‐related brain activity and connectivity. Hum Brain Mapp 36:3703–3715, 2015. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

Alexithymia and apathy in Parkinson's disease: neurocognitive correlates

Non-motor symptoms such as neuropsychiatric and cognitive dysfunction have been found to be common in Parkinson’s disease (PD) but the relation between such symptoms is poorly understood. We focused on alexithymia, an impairment of affective and cognitive emotional processing, as there is evidence for its interaction with cognition in other disorders. Twenty-two non-demented PD patients and 22 matched normal control adults (NC) were administered rating scales assessing neuropsychiatric status, including alexithymia, apathy, and depression, and a series of neuropsychological tests. As expected, PD patients showed more alexithymia than NC, and there was a significant association between alexithymia and disease stage. Alexithymia was associated with performance on non-verbally mediated measures of executive and visuospatial function, but not on verbally mediated tasks. By contrast, there was no correlation between cognition and ratings of either depression or apathy. Our findings demonstrate a distinct association of alexithymia with non-verbal cognition in PD, implicating right hemisphere processes, and differentiate between alexithymia and other neuropsychiatric symptoms in regard to PD cognition.

The neuropsychiatry of hyperkinetic movement disorders: insights from neuroimaging into the neural circuit bases of dysfunction

BACKGROUND

Movement disorders, particularly those associated with basal ganglia disease, have a high rate of comorbid neuropsychiatric illness.

METHODS

We consider the pathophysiological basis of the comorbidity between movement disorders and neuropsychiatric illness by 1) reviewing the epidemiology of neuropsychiatric illness in a range of hyperkinetic movement disorders, and 2) correlating findings to evidence from studies that have utilized modern neuroimaging techniques to investigate these disorders. In addition to diseases classically associated with basal ganglia pathology, such as Huntington disease, Wilson disease, the neuroacanthocytoses, and diseases of brain iron accumulation, we include diseases associated with pathology of subcortical white matter tracts, brain stem nuclei, and the cerebellum, such as metachromatic leukodystrophy, dentatorubropallidoluysian atrophy, and the spinocerebellar ataxias.

CONCLUSIONS

Neuropsychiatric symptoms are integral to a thorough phenomenological account of hyperkinetic movement disorders. Drawing on modern theories of cortico-subcortical circuits, we argue that these disorders can be conceptualized as disorders of complex subcortical networks with distinct functional architectures. Damage to any component of these complex information-processing networks can have variable and often profound consequences for the function of more remote neural structures, creating a diverse but nonetheless rational pattern of clinical symptomatology.

Functional and structural connectivity of frontostriatal circuitry in Autism Spectrum Disorder

Abnormalities in frontostriatal circuitry potentially underlie the two core deficits in Autism Spectrum Disorder (ASD); social interaction and communication difficulties and restricted interests and repetitive behaviors. Whilst a few studies have examined connectivity within this circuitry in ASD, no previous study has examined both functional and structural connectivity within the same population. The present study provides the first exploration of both functional and structural frontostriatal connectivity in ASD. Twenty-eight right-handed Caucasian male ASD (17.28 ± 3.57 years) and 27 right-handed male, age and IQ matched controls (17.15 ± 3.64 years) took part in the study. Resting state functional connectivity was carried out on 21 ASD and control participants, and tractography was carried out on 22 ASD and 24 control participants, after excluding subjects for excessive motion and poor data quality. Functional connectivity analysis was carried out between the frontal cortex and striatum after which tractography was performed between regions that showed significant group differences in functional connectivity. The ASD group showed increased functional connectivity between regions in the frontal cortex [anterior cingulate cortex (ACC), middle frontal gyrus (MFG), paracingulate gyrus (Pcg) and orbitofrontal cortex (OFC)], and striatum [nucleus accumbens (NAcc) and caudate]. Increased functional connectivity between ACC and caudate was associated with deactivation to social rewards in the caudate, as previously reported in the same participants. Greater connectivity between the right MFG and caudate was associated with higher restricted interests and repetitive behaviors and connectivity between the bilateral Pcg and NAcc, and the right OFC and NAcc, was negatively associated with social and communicative deficits. Although tracts were reliably constructed for each subject, there were no group differences in structural connectivity. Results are in keeping with previously reported increased corticostriatal functional connectivity in ASD.

Size and shape of the caudate nucleus in individuals with bipolar affective disorder

OBJECTIVE

The caudate nucleus (CN) is a crucial component of the ventral striatum, which is part of a prefrontal-striatal-thalamic circuit that is modulated by limbic structures to subserve emotional processing. Bipolar disorder is thought to be underpinned by dysfunctional anterior limbic networks, although MRI studies examining the CN have shown equivocal results. As gross volumetric analyses may not detect subtle regional change, we aimed to clarify the role of the CN in bipolar disorder by undertaking shape analysis to detect regional reductions.

METHODS

The CN was manually traced on MRI scans from 27 patients with bipolar-I disorder and 24 matched controls. A non-parametric spherical harmonic shape analysis was undertaken using the SPHARM toolkit.

RESULTS

Whilst the left CN volume was consistently larger in the sample, there was no effect of group or gender or significant interactions between these variables. Volume did not correlate with illness duration or lithium dosage, but was larger in those with a history of psychosis at trend level. However, left caudate shape differed significantly between groups, with deflation in an area along the ventromedial surface (connecting to dorsolateral prefrontal regions) in bipolar patients. Psychotic patients showed increases in the dorsal head and body at trend level overall, in regions connecting to medial and orbitofrontal regions.

CONCLUSIONS

These findings suggest that subtle rather than gross structural changes occur in the CN, which may not be detectable by volumetric analysis alone, and reflect alterations in specific frontostriatal circuitry in the disorder.

Caudate atrophy and impaired frontostriatal connections are linked to executive dysfunction in temporal lobe epilepsy

This study tested the hypothesis that executive dysfunction, common in temporal lobe epilepsy (TLE), is associated with an abnormal frontostriatal network. Structural and diffusion tensor MR scans, the Wisconsin Card Sorting Test (WCST) targeting cognitive flexibility, and the Trail Making Test B examining parallel sequencing were obtained from 9 patients with left TLE and 17 healthy controls. The five major findings were: (1) Caudate volume is reduced on the left side in TLE. (2) The atrophy involves the dorsal and ventral head of the caudate. (3) These atrophic caudate regions have a corresponding high probability of connections to dorsal prefrontal, anterior cingulate, and orbitofrontal cortex. (4) Smaller caudate volumes are linked to greater numbers of WCST perseverative errors. (5) Reduced connections between caudate and dorsal prefrontal cortex correlated with poorer scores on the Trail Making Test B. The results suggest that atrophy in the dorsal head of the caudate might disrupt frontostriatal networks that are critical for executive functioning in TLE.

Neurocognitive correlates of alexithymia in asymptomatic individuals with HIV

Alexithymia, an impairment of affective and cognitive emotional processing, is often associated with human immunodeficiency virus (HIV) and may reflect effects of the virus on brain areas that are also important for multiple cognitive functions, such as the prefrontal and anterior cingulate cortices. We hypothesized that there would be a correlation between extent of alexithymia and cognitive performance associated with these brain areas, including attention, executive function, and visuospatial processing. Thirty-four asymptomatic HIV+ participants and 34 matched healthy HIV- volunteers were administered the Toronto Alexithymia Scale, a series of neuropsychological tests, and measures of apathy, depression, and quality of life (QoL). The HIV+ participants had significantly higher levels of alexithymia, depression and apathy than the HIV- group. The extent of alexithymia and two of its processing components (Difficulty Describing Feelings [DDF] and Externally Oriented Thinking), but not depression, correlated with performance on measures of executive and visuospatial abilities, consistent with dysfunction of the frontostriatal circuits and their cortical projections. Apathy was related to alexithymia and two processing components (Difficulty Identifying Feelings and DDF) but to only one cognitive measure. The higher rate of alexithymia, as well as cognitive dysfunction, in HIV may be a consequence of the infection on the frontostriatal system and its cortical connections. Our findings also demonstrated a dissociation of apathy and alexithymia in HIV, pointing to overlapping but distinct neural substrates within frontostriatal circuits. Alexithymia correlated strongly with QoL ratings, underscoring the importance of assessment and treatment of HIV-associated emotional and cognitive processing deficits.

A voxel-based morphometry comparison of regional gray matter between fragile X syndrome and autism

The phenotypic association between fragile X syndrome (FXS) and autism is well established, but no studies have directly compared whole-brain anatomy between the two disorders. We performed voxel-based morphometry analyses of magnetic resonance imaging (MRI) scans on 10 individuals with FXS, 10 individuals with autism, and 10 healthy comparison subjects to identify volumetric changes in each disorder. Regional gray matter volumes within frontal, parietal, temporal, and cingulate gyri, as well as in the caudate nuclei and cerebellum, were larger in the FXS group relative to the autism group. In addition, volume increases in FXS were observed in frontal gyri and caudate nuclei compared to controls. The autism group exhibited volume increases in frontal and temporal gyri relative to the FXS group, and no volume increases relative to controls. Volumetric deficits relative to controls were observed in regions of the cerebellum for both groups, with additional deficits in parietal and temporal gyri for the FXS group. Our caudate nuclei and frontal gyri results may implicate dysfunction of frontostriatal circuitry in FXS. Cerebellar deficits suggest atypical development of the cerebellum contributing to the phenotype of both disorders, but further imply that unique cerebellar regions contribute to the phenotype of each disorder.

Mapping mental number line in physical space: vertical and horizontal visual number line orientation in asymptomatic individuals with HIV

Multiple studies have implicated frontostriatal dysfunction in human immunodeficiency virus (HIV) and described cognitive deficits with a focus on executive function and memory. Remarkably little is known about visuospatial and number processing in HIV, though these capacities are also supported by frontostriatal circuits and their parietal connections. We investigated the relation of numerical and spatial cognition in asymptomatic individuals with HIV and explored physical and mental number orientation using several modes of presentation and response: mental number line bisection, physical line bisection, and physical number line orientation on visually-presented horizontal and vertical number lines. The asymptomatic HIV+ group was significantly slower and produced more errors on visuospatial and number processing tasks than the HIV- group (n=37/group). Both groups showed significant correlations between number processing and visuospatial performance. These findings demonstrate that HIV-related brain damage early in the disease course can alter the spatial representation of numerical distance, providing evidence for disruption of frontostriatal circuits and their parietal projections underlying numerical processing in HIV. Besides disease-related effects, this study demonstrates that the physical number line preserves its numerical and spatial integrity in both the vertical and horizontal physical dimensions, as all participants exhibited underestimation of numerical distance, i.e. leftward bias (for horizontal presentation) and downward bias (for vertical). Our results also revealed a dissociation between the processing components of numerical distance and physical space, suggesting differentiation between the neural networks involved in number lines and physical line orientation.