Bipolar disorder (BD) is a recurrent chronic disorder characterised by fluctuations in mood and energy disposition. Diseases could lead to degenerative alterations in brain structures such as corpus callosum (CC). Studies demonstrated that abnormalities in CC are associated with BD symptoms. The present study aims to analyse the CC of the patients with statistical shape analysis (SSA) and compare the findings with healthy controls.

Forty-one BD patients and 41 healthy individuals in similar age groups, which included 23 female and 18 male subjects, participated in the study. CC was marked with landmarks on the mid-sagittal images of each individual. The mean ‘Procrustes’ point was calculated, and shape deformations were analysed with thin-plate spline analysis.

Significant differences were observed in the shape of CC between the two groups, where maximum CC deformation was observed in posterior region marks in BD patients. There was no significant difference between the CC area of the BD patients and controls.

CC analysis conducted with SSA revealed significant differences between patients and healthy controls. The study findings emphasised the abnormal distribution of white matter in CC and the variable subregional nature of CC in BD patients. This study may enable the development of more targeted and effective treatment strategies by taking into account biological factors and understanding the differences in the brain regions of individuals with BD.

Previous studies have found deficits in imaginative elaboration and social inference to be associated with agenesis of the corpus callosum (ACC; Renteria-Vasquez et al., 2022; Turk et al., 2009). In the current study, Thematic Apperception Test (TAT) responses from a neurotypical control group and a group of individuals with ACC were used to further study the capacity for imaginative elaboration and story coherence.

Topic modeling was employed utilizing Latent Diritchlet Allocation to characterize the narrative responses to the pictures used in the TAT. A measure of the difference between models (perplexity) was used to compare the topics of the responses of individual participants to the common core model derived from the responses of the control group. Story coherence was tested using sentence-to-sentence Latent Semantic Analysis.

Group differences in perplexity were statistically significant overall, and for each card individually (p < .001). There were no differences between the groups in story coherence.

TAT narratives from persons with ACC were normally coherent, but more conventional (i.e., more similar to the core text) compared to those of neurotypical controls. Individuals with ACC can make conventional social inferences about socially ambiguous stimuli, but are restricted in their imaginative elaborations, resulting in less topical variability (lower perplexity values) compared to neurotypical controls.

Accumulating evidence suggests that corpus callosum development is critically involved in the emergence of behavioral and cognitive skills during the first two years of life and that structural abnormalities of the corpus callosum are associated with a variety of neurodevelopmental disorders. Indeed by adulthood ∼30% of individuals with agenesis of the corpus callosum (ACC), a congenital condition resulting in a partial or fully absent corpus callosum, exhibit phenotypic features consistent with autism spectrum disorder (ASD). However, very little is known about developmental similarities and/or differences among infants with ACC and infants who develop ASD. This study describes temperament in infants with ACC during the first year of life in comparison with a neurotypical control group. Additionally, it examines the potential contribution of disrupted callosal connectivity to early expression of temperament in ASD through comparison to children with high familial likelihood of ASD.

Longitudinal ratings of positive and negative emotionality were acquired at 6 and 12 months on the Infant Behavior Questionnaire-Revised across four groups of infants: isolated complete and partial ACC (n=104), high familial likelihood of ASD who do and do not have a confirmed ASD diagnosis (HL+ n=81, HL- n=282), and low-likelihood controls (LL- n=152).

Overall, the ACC group demonstrated blunted affect, with significantly lower positive and negative emotionality than LL controls at both timepoints. Specifically, the ACC group exhibited lower activity and approach dimensions of positive emotionality at both timepoints, with lower high-intensity pleasure at 6 months and lower vocal reactivity at 12 months. On negative emotionality subscales, the ACC group exhibited lower distress to limitations and sadness at both timepoints, as well as lower falling reactivity at 6 months. The ACC and HL groups did not differ significantly on positive emotionality at either timepoint. However, negative emotionality was lower in the ACC group than the HL- group at both timepoints and lower than the HL+ group at 12 months, with lower distress to limitations and sadness ratings than both HL groups at both timepoints.

These findings highlight the importance of interhemispheric connections in facilitating active engagement and pursuit of pleasurable activities during the first year of life, as well as expression of sadness and distress to limitations. Notably, similarities between infants with ACC and infants at elevated familial risk of ASD suggest that disrupted callosal connectivity may specifically contribute to reductions in positive emotionality.

It is unclear how agenesis of the corpus callosum (ACC), a congenital brain malformation defined by complete or partial absence of the corpus callosum, impacts language development. fMRI studies of middle childhood suggest that the corpus callosum plays a role in the interhemispheric language network (Bartha-Doering et al., 2020), and that reduced interhemispheric functional connectivity is correlated with worse language abilities in children with ACC (Bartha-Doering et al., 2021). Additionally, accumulating evidence suggests structural abnormalities of the corpus callosum play a role in neurodevelopmental disorders. While children who go on to receive an autism spectrum disorder (ASD) diagnosis may show early signs of altered word and gesture acquisition (Iverson et al., 2018), the same is not known about ACC. This study examined language development during the second year of life in children with ACC in comparison to neurotypical control participants, as well as other children at elevated risk of ASD.

The MacArthur-Bates Communicative Development Inventories (MCDI): Words and Gestures scales were administered to parents of 74 children with isolated ACC at 12, 18 and 24 months of age. Children whose first language was not English and children who were bilingual were excluded. Comparison groups consisted of individuals with a low familial likelihood of ASD (LL- n=140) and individuals with high familial likelihood of ASD who do and do not have a confirmed ASD diagnosis (HL+ n=68, HL- n=256).

Compared to LL controls, the ACC group produced fewer words at 18 and 24 months of age, and demonstrated fewer words understood at all three timepoints. Similarly, compared to the HL- group, the ACC group demonstrated fewer words produced and understood at 18 months of age, and fewer words produced at 24 months of age. The ACC and HL+ groups did not differ in words produced or words understood at any timepoint.

Overall, infants with ACC demonstrated delayed vocabulary expansion from 12 to 24 months of age. These findings illustrate the role of callosal connectivity in the development of language across the first 2 years of life, and highlight the need for support and interventions that target vocabulary production and comprehension.

Fetal alcohol spectrum disorder (FASD) is a life-long condition, and few interventions have been developed to improve the neurodevelopmental course in this population. Early interventions targeting core neurocognitive deficits have the potential to confer long-term neurodevelopmental benefits. Time-targeted choline supplementation is one such intervention that has been shown to provide neurodevelopmental benefits that emerge with age during childhood. We present a long-term follow-up study evaluating the neurodevelopmental effects of early choline supplementation in children with FASD approximately 7 years on average after an initial efficacy trial. In this study, we examine treatment group differences in executive function (EF) outcomes and diffusion MRI of the corpus callosum using the Neurite Orientation Dispersion and Density Index (NODDI) biophysical model.

The initial study was a randomized, double-blind, placebo-controlled trial of choline vs. placebo in 2.5- to 5-year-olds with FASD. Participants in this long-term follow-up study included 18 children (9 placebo; 9 choline) seen 7 years on average following initial trial completion. The mean age at follow-up was 11 years old. Diagnoses were 28% fetal alcohol syndrome (FAS), 28% partial FAS, and 44% alcohol-related neurodevelopmental disorder. The follow-up evaluation included measures of executive functioning (WISC-V Picture Span and Digit Span; DKEFS subtests) and diffusion MRI (NODDI).

Children who received choline early in development outperformed those in the placebo group across a majority of EF tasks at long-term follow-up (effect sizes ranged from -0.09 to 1.27). Children in the choline group demonstrated significantly better performance on several tasks of lower-order executive function skills (i.e., DKEFS Color Naming [Cohen's d = 1.27], DKEFS Word Reading [Cohen's d = 1.13]) and showed potentially better white matter microstructure organization (as indicated by lower orientation dispersion; Cohen's d = -1.26) in the splenium of the corpus callosum compared to the placebo group. In addition, when collapsing across treatment groups, higher white matter microstructural organization was associated with better performance on several EF tasks (WISC-V Digit Span; DKEFS Number Sequencing and DKEFS Word Reading).

These findings highlight long-term benefits of choline as a neurodevelopmental intervention for FASD and suggest that changes in white matter organization may represent an important target of choline in this population. Unique to this study is the use of contemporary biophysical modeling of diffusion MRI data in youth with FASD. Findings suggest this neuroimaging approach may be particularly useful for identifying subtle white matter differences in FASD as well as neurobiological responses to early intervention associated with important cognitive functions.

Previous research suggests that individuals with isolated Agenesis of the Corpus Callosum (AgCC) have cognitive and psychosocial deficiencies that include impaired recognition of the emotions of others (Symington et al., 2010) and a diminished ability to infer and describe the emotions of others (Paul et al., 2021; Turk et al., 2010). In addition, galvanic skin responses effectively discriminated between emotional images despite atypical emotion ratings (Paul et al, 2006), supporting a dissociation between cognitive and affective empathy in AgCC. Likewise, atypical patterns of visual attention to faces corresponded with impaired emotion recognition in AgCC (Bridgman et al, 2014), suggesting that atypical visual attention in AgCC negatively impacts the ability to identify others’ emotions. This study used the Multifaceted Empathy Test [MET] (Foell et al., 2018) to examine the impact of visual aesthetics (photo composition) on empathetic feelings (affective empathy) and situational emotion recognition (cognitive empathy) in persons with AgCC. Both cognitive and affective empathy scores are typically higher on MET stimuli composed according to the “Golden Spiral” (Callaway, 2022).

Results from 50 control participants recruited from Cloud Research were compared to responses from 19 participants with AgCC and normal-range FSIQ (>80). Data was gathered through an online version of the MET, which uses a series of photographs of individuals displaying an emotion, half of which adhere to the compositional technique known as “The Golden Spiral.” To measure cognitive empathy, the participants are asked to pick the correct emotion being displayed with three distractors for each item. To measure affective empathy, they are then asked on a sliding scale, “how much do you empathize with the person shown” (1 = Not at all, 7 = Very much).

Repeated measures mixed ANOVAs revealed no difference between AgCC and control groups on affective empathy, and as expected on the MET, both groups had significantly higher ratings for photos composed according to the Golden Spiral (AgCC, np2 = .071; control, np2 = .136). In contrast, the AgCC group scored significantly lower than controls overall on cognitive empathy, np2 =.065. Exploratory post-hoc found a significant group difference in cognitive empathy only on photos composed according to the Golden Spiral, np2 = .090, with the scores in the AgCC group unimpacted by composition type while the control group exhibiting significantly higher scores Golden Spiral images, np2 = .254.

Empathic deficits in AgCC were restricted to the cognitive component, while affective empathy was not impaired. Visual aesthetics of photo composition influenced affective empathy ratings in both AgCC and control groups. However, adults with AgCC had diminished ability to give cognitive labels to the emotional states of others, which was not enhanced by the formal aesthetics of stimuli. Thus the corpus callosum seems to facilitate the ability to cognitively label emotions by facilitating visual attention. It also suggests that the corpus callosum does not facilitate affective empathy, in part because it does not appear to determine whether formal aesthetics influences the processing of visual stimuli in AgCC or neurotypical controls.

Agenesis of the Corpus Callosum (AgCC) is the congenital absence of all or part of the corpus callosum. Previous research has demonstrated that isolated AgCC results in a pattern of cognitive and psychosocial deficiencies, even when FSIQ is in the normal range (FSIQ > 80; Brown & Paul, 2019). Importantly, individuals with AgCC have been shown to provide narratives containing fewer emotional words, social interactions, and mental inferences on the Thematic Apperception Test (TAT; Turk et al., 2009). Similarly, research has suggested deficits in the elaborative imagination of persons with AgCC when they are providing narrative descriptions of simple animations (Renteria-Vasquez et al., 2021). Such findings raise questions about aesthetic perception in AgCC. While previous research has demonstrated differences in aesthetic perception among other neuropsychological populations (e.g. Parkinson's Disease; Lauring et al., 2019), there is no research reported regarding aesthetic appreciations in AgCC. The present study employed the Assessment of Art Attributes (AAA; Chatterjee et al., 2010) to compare the conceptual and perceptual aspects of aesthetic perception of persons with AgCC to neurotypical control participants. Prior investigation by Bromberger and colleagues (2011) utilized the AAA to examine the aesthetic perception of persons with right hemisphere lesions, finding deviations in judgements of abstractness, symbolism, realism, and animacy– all classified as “conceptual attributes.” Based on these findings, it was predicted that individuals with AgCC would rate paintings differently than neurotypical controls on conceptual attributes, but not on perceptual attributes.

Thirteen persons with AgCC and 49 neurotypical individuals completed the AAA. After completing measures of artistic experience and colorblindness, participants rated 24 paintings on 14 attributes. Balance, color saturation, color temperature, depth, simplicity, and stroke made up the “perceptual scales,” while abstractness, animacy, emotion, objective accuracy, realism, interest, and preference made up the “conceptual scales.”

Following Bromberger and colleagues (2011), average ratings from all control participants were used to rank the 24 paintings for each scale. Spearman's rank-order correlations were then conducted between the rankings of each participant and the average of the controls for each scale. Spearman's rho coefficients were then compared between AgCC and control groups using t-tests, controlling for multiple comparisons. As hypothesized, the AgCC group had significant deviations from the average of the controls (lower rho values) on several conceptual attributes: Abstractness (p = .004, d = .11), emotion (p < .001, d = .12), and interest (p < .001, d = .18), whereas individuals with AgCC deviated on only one perceptual attribute: Simplicity (p = .003, d = .12).

While generally unremarkable in the sensory aspects, persons with AgCC demonstrated greatest differences in three important conceptual aspects of aesthetic perception. This outcome suggests that such higher-order aesthetic appreciations require interhemispheric interactivity. These results further support the hypothesis that decreased elaborative imagination is a fundamental component of AgCC.

Agenesis of the Corpus Callosum (ACC), a congenital disorder in which the corpus callosum partially or completely fails to develop properly, occurs in ∼1 in 4,000 live births. ACC has been identified as a major risk factor for receiving an Autism Spectrum Disorder (ASD) diagnosis (∼10% diagnosis rate, as compared to 2.3% in the general population), but little is currently known about behavioral and social development during infancy and early childhood in this disorder. In this study we aim to 1) characterize the manifestation of autistic features in 24-month-old children (a common age for early diagnosis of ASD) with ACC and a convenience sample of age matched comparison children from the community, and 2) determine if parent reports of autistic features during the first year of life are associated with reciprocal social behavior and autistic traits at 24-months of age in children with ACC.

Parents of infants who had received a diagnosis of ACC completed the Parent Rating of Communication, Emotion, and Social Skills (PROCESS) for their child at 6, 12, and 24-months of age, and the video-referenced rating of reciprocal social behavior (vrRSB) at 24-months of age. Comparison data were obtained from a convenience community sample in Minnesota. Aim 1). The distributions of PROCESS total scores at 24-months were compared between the ACC group (n=43) and control group (n=1058) via a 2-tailed t-test. Likewise, distributions of reciprocal social behavior (RSB) scores at 24 months were compared between ACC (n=72) and controls (n=1438) via a 2-tailed t-test. Aim 2). A partial Pearson Correlation was conducted between ACC participants’ 6-month PROCESS scores and 24-month RSB (n=18) scores, as well as between their 12-month PROCESS and 24-month vrRSB (n=37) scores, controlling for child sex.

Aim 1). At 24 months of age, children with ACC are reported to have significantly higher PROCESS scores (t = 3.73, df = 42.67, p < .001), and RSB (t = 4.89, df = 88.38, p < .001) scores than comparison toddlers, indicating an elevated presentation of behaviors associated with autistic features. Aim 2). No correlation was found between participants’ 6-month PROCESS and 24-month RSB scores (r(16) = .39, p = .12). A relatively strong correlation (r(35) = .60, p < .001) was found between participants’ 12-month PROCESS and 24-month RSB scores.

As early as two years of age, children with ACC display a heightened presentation of autistic features compared to typically developing controls. Additionally, reports of social behaviors related to ASD at 24-months are correlated with reports of autistic features at 12-months of age. This evidence indicates that children with ACC who are at a higher likelihood for being diagnosed with ASD may be identified as early as 12-months old. Formulating and leveraging an early identification methodology is imperative for this population with an already elevated risk for ASD, as providing early interventions leads to improved outcomes later in life.

Differences in adaptive functioning present early in development for many children with monogenic (Down Syndrome, Fragile X) and neurodevelopmental disorders. At this time, it is unclear whether children with ACC present with early adaptive delays, or if difficulties emerge later as functional tasks become more complex. While potential delays in motor development are frequently reported, other domains such as communication, social and daily living skills are rarely described. We used a prospective, longitudinal design to examine adaptive behavior from 6-24 months in children with ACC and compared their trajectories to those with monogenic and neurodevelopmental conditions.

Our sample included children with primary ACC (n= 27-47 depending on time point) whose caregivers completed the Vineland Adaptive Behavior Scales-Interview 3rd Edition, via phone at 6, 12, 18 and 24 months. Comparison samples (using the Vineland-2) included children with Down Syndrome (DS; n = 15-56), Fragile X (FX; n = 15-20), children at high familial likelihood for autism (HL-; n=192-280), and low likelihood (LL; no family history of autism and no developmental/behavioral diagnosis; n = 111196). A subset of the HL children received an autism diagnosis (HL+; n = 48-74). The DS group did not have an 18-month Vineland.

A series of linear mixed model analyses (using maximum likelihood) for repeated measures was used to compare groups on three Vineland domains at 6, 12, 18 and 24 month timepoints). All fixed factors (diagnostic group, timepoint, and group X timepoint interaction) accounted for significant variance on all Vineland domains (p < .001). Post hoc comparisons with Bonferroni-correction examined ACC Vineland scores compared to the other diagnostic groups at each timepoint. At 6 months, parent-ratings indicated the ACC group had significantly weaker skills than the LL group in Communication and Motor domains. At 12, 18 and 24 months, ratings revealed weaker Communication, Daily Living and Motor skills in the ACC group compared to both the LL and HL- groups. Compared to the other clinical groups, the ACC group had stronger Socialization and Motor skills than Fragile X at 6 months, and at 24 months had stronger Communication and Socialization skills than both the DS and FX groups, as well as stronger Socialization than the HL+ group.

Compared to children with low likelihood of ASD, children with primary ACC reportedly have weaker Communication and Motor skills from 6 to 24 months, with weakness in Daily Living Skills appearing at 12 months and all differences increase with age. Compared to Fragile X, the ACC exhibited relative strengths in socialization and motor skills starting at 6 months. By 24 months, the ACC group was outperforming the monogenic groups on Socialization and Communication. In general, the ACC scores were consistent with the HL+ sample, except the ACC group had stronger Social skills at 18 and 24 months. The results clearly inform the need for early intervention in the domains of motor and language skills. Additionally, as we know that children with ACC are at increased risk for social difficulties, research is needed both using more fine-grained social-communication tools, and following children from infancy through middle childhood.

Agenesis of the corpus callosum(AgCC) is a disorder in which the connection between the two brain hemispheres is congenitally absent. Previous research has suggested that the auditory system can be affected in individuals with AgCC (Demopoulos et al., 2015). However, the nature of AgCC’s effect on musical perception skills is unclear. This study investigated the impact of AgCC on the music perception skills in high-functioining adults using a brief version of the Profile of Music Perception Skills (PROMS; Zentner, M. & Strauß, H. 2017). It was hypothesized that individuals with AgCC would have diminished music perception abilities when compared to a neurotypical control group.

Participants included 10 high-functioning adults with AgCC that had an intelligence quotation within the normal range (FSIQ>80) and 63 neurotypical controls who were recruited via Cloud Research. During the PROMS the participants were asked to listen to two different sound excerpts after which they were asked whether the second sound was the same or different from the first (correct answers= 2 points, uncertain answers= 1 point, and remaining answers not coded). The participants answered questions in four different areas of musical perception: Melody, Tuning, Accent, and Tempo.

Results indicated that there was not a significant difference between the control group and the AgCC participants on music perception skills on the overall PROMS scores F(1,72)= .365, P-value= .548. Tested individually, none of the 4 individual domains showed a significant difference: Melody F(1,72)=2.67, P-value= .107; Tuning F(1,72)= .271, P-value= .606; Accent F(1,72)= .017, P-value= .897; or Tempo F(1,72)=.106, P-value= .746.

Contrary to the hypothesis of this study, the results showed that the participants with AgCC did not perform significantly differently in the PROMS total score when compared to neurotypical controls, nor were there significant differences in any of the four of the subtests (Melody, Tuning, Accent, and Tempo). Thus these high-functioning individuals with AgCC did not have deficient music perception abilities. These findings demonstrate that although the auditory system may be affected in some individuals with AgCC, we do not see differences in musical perception skills in high-functioning individuals with AgCC.

A previous review of the syndrome of Agenesis of the Corpus Callosum (ACC) identified three primary deficits: reduced interhemispheric transfer of sensory motor information, slowed cognitive processing, and deficits in complex problem solving (Brown & Paul, 2019). Interaction of these three deficits contributes to a variety of secondary cognitive and psychosocial deficiencies across domains. Recent research has also identified a possible fourth core deficit in ACC: restricted capacity for elaborative thought and creativity (Renteria et al., 2022; Bogen & Bogen 1988). We examined the syndrome of ACC using an exploratory factor analysis of neuropsychological test data (not including data regarding interhemispheric transfer) and hypothesized it would organize into factors of (1) reduced cognitive processing speed, (2) difficulty with complex problem solving, and (3) difficulty with creative tasks.

The present study analyzed archival data from individuals with ACC (N=60) acquired from common neuropsychological instruments: D-KEFS, WAIS-III, and WRAT-2. Among the participants, 13 had partial ACC, 1 was unspecified, and the remainder had complete ACC. The participants’ ages ranged from 7 to 55 years (M = 21.55, SD = 12.36), with an education level that ranged from 2 to 19 years (M = 11.59, SD = 3.77). All participants had complete data for at least one assessment and all available data was included. Missing values (49.85%) were excluded from analysis. Factor analysis (principal factor solution with promax rotation) was conducted with 33 commonly derived summary (standard) scores. Horn’s Parallel Analysis recommended a 4-factor solution, but we elected to generate a 3-factor model that would more closely follow previous literature.

Factor one involved processing speed and was comprised primarily of D-KEFS Color Word Interference Word Reading (1.02) and Color Naming (.78), D-KEFS Trail Making Test Visual Scanning (.86) and Number Sequencing (.74), and WAIS-III Processing Speed Index (.68). The second factor included several problem solving measures [e.g. D-KEFS Sorting Test Free Sorting (.90) and Sort Recognition (.90), and WAIS-III Perceptual Organization Index (.72)], as well as several additional measures including WAIS-III Working Memory Index (.84), WRAT-2 Arithmetic (.83), and WAIS-III Verbal Comprehension Index (.80). Finally, the third factor involved several measures requiring mental flexibility and cognitive control [e.g. D-KEFS Twenty Questions Test Achievement Score (.70), D-KEFS Design Fluency Switching Condition (.56), and D-KEFS Trail Making Test Number-Letter Switching Condition (.44)], as well as a measure of single word reading [WRAT-2 Reading (.66)].

The findings support inclusion of slowed cognitive processing speed as a core feature of the neurocognitive syndrome in ACC described by Brown and Paul (2019). The second factor is partially consistent with a deficit in complex problem solving, but is not restricted to that cognitive domain. Likewise, the third factor is largely related to mental flexibility and control (one aspect of creativity), but is not restricted to that domain. Future attempts to model the neurocognitive syndrome of ACC may provide greater clarity by including a wider range of cognitive and psychosocial indices and excluding individuals with comorbid neuropathology.

Partial agenesis of the corpus callosum (PACC) is a rare brain birth defect characterized by incomplete development of the corpus callosum, the primary white matter bundle that connects the right and left hemispheres. PACC can be associated with other congenital abnormalities, including malformation of the brain’s ventricular system, such as colpocephaly or ventriculomegaly, and it is typically considered a pediatric diagnosis. Clinically, this condition may present with a broad continuum of cognitive and socioemotional difficulties ranging from significant day-to-day impairment to relative independence. Newly diagnosed PACC with ventriculomegaly in adults is very rare (0.0200.025%) and little is known about neuropsychological functioning in adults with this condition. The aim of this case study is to add to the literature base for better PACC neuropsychological conceptualization.

This case study involves neuropsychological evaluation of cognitive and behavioral health functioning of a 37-year-old active duty service member (ADSM) with recently identified PACC and ventriculomegaly (via incidental imaging finding). The ADSM reported a history of learning difficulty, though she was able to earn rank of sergeant first class in a low density military occupation specialty (i.e., Mortuary Affairs) over an 18.5 year active duty career.

Cognitive testing was notable for consistently low to exceptionally low attention and processing speed scores. Mild executive dysfunction was also noted in the areas of planning and inhibition. Emotionally, she endorsed mild somatic and depression symptoms. Interpersonally, she was shy and avoidant with longstanding characterological traits characterized by worry, insecurity, and general tendency to catastrophize.

This case adds to the broad clinical presentation of PACC with ventriculomegaly, and highlights that even in the context of a significant congenital brain deformity and longstanding cognitive deficits, independent functioning can be achieved.

Previous research suggests that individuals with isolated Agenesis of the Corpus Callosum (AgCC) have cognitive and psychosocial deficits including that of complex processing of emotions (Anderson et al., 2017) and their ability to verbally express emotional experiences (Paul et al., 2021). Additionally, research suggests individuals with AgCC show impaired recognition of the emotions of others (Symington et al., 2010), as well as diminished ability to infer and describe the emotions of others (Renteria-Vazquez et al., 2022; Turk et al., 2010). However, the nature of the empathic abilities of individuals with AgCC remains unclear in empirical research. Capacity for empathetic feelings and situational recognition in persons with AgCC were tested using the Multifaceted Empathy Test [MET] (Foell et al., 2018). We hypothesized that individuals with AgCC would have lower abilities for both cognitive and affective empathy than neurotypical controls.

Results from 50 neurotypical control participants recruited from MTurk Cloud were compared to responses from 19 AgCC participants with normal-range FSIQ (>80) drawn from the individuals with AgCC involved with the Human Brain and Cognition Lab at the Travis Research Institute. The research was completed through an online version of the MET. The MET uses a series of photographs of individuals displaying an emotion. To measure cognitive empathy, the participants are asked to pick the correct emotion being displayed with three distractors for each item. To measure affective empathy, they are then asked on a sliding scale, “how much do you empathize with the person shown” (1 = Not at all, 7 = Very much).

Results of a MANOVA showed a trend for a significant overall difference between individuals with AgCC and controls for empathic abilities F(1, 67) = 2.59, p-value = .082, with persons with AgCC showing less empathy overall. Follow-up one-way ANOVAs showed that individuals with AgCC scored significantly lower in cognitive empathy F(1, 67) = 4.63, p-value = .035, ηp2 = .065; however, affective empathy was not significantly different between groups F(1, 67) = .537, p-value = .466, ηp2 = .008.

Results suggest that adults with AgCC have a diminished ability to give cognitive labels to the emotional states of others compared to neurotypical controls. However, contrary to our hypothesis, participants with AgCC had affective responses to the pictures of the emotional states of others which were similar to neurotypical controls. Recent research has shown that individuals with AgCC have difficulty inferring and elaborating on the more complex cognitive, social, and emotional aspects of simple animations (Renteria-Vazquez et al., 2022; Turk et al., 2010). Cognitive empathy would require this form of elaborative thinking, even when affective empathy is normal. Similarly, Paul et al. (2021) described alexithymia in persons with AgCC as difficulty in expressing emotions linguistically, but found similar endorsements of emotional experience when compared to neurotypical controls. This study provides further evidence to suggest the corpus callosum facilitates the ability to cognitively label emotions but not necessarily the ability to experience emotions affectively.

Previous research has demonstrated that individuals with Agenesis of the Corpus Callosum (AgCC), the congenital absence of all or part of the corpus callosum, exhibit a pattern of cognitive and psychosocial deficits, even with a FSIQ in the normal range (FSIQ > 80; Brown & Paul, 2019). This includes a core deficit in their complex reasoning and novel problem-solving (Brown & Paul, 2019), with secondary deficits in capacity to imagine complex emotional/cognitive consequences of potential actions involving others (Young et al, 2019), deficits in emotion

perception (Symington et at., 2010, Bridgman et al 2014), and difficulty with cognitively processing emotions within the context of social interactions (Anderson et al., 2017). This constellation of deficits is likely to also impact moral reasoning. While previous research has demonstrated differences in moral reasoning among other neuropsychological populations such as those with ventromedial prefrontal damage (Moretto et al., 2010) and frontotemporal dementia (Gleichgerrcht et al., 2011), there is no research reported regarding moral judgements in AgCC. This study employed the Moral Dilemmas Scale (Greene, 2001) to compare the moral judgements of persons with AgCC to neurotypical controls. It was predicted that individuals with AgCC would be less contextually nuanced than neurotypical controls in responding to moral dilemmas.

Results consist of data derived from 57 neurotypical control participants (ages 23 to 64 years) recruited from MTurk Cloud and 19 AgCC participants (ages 23 to 77 years) with normal-range FSIQ (>80) drawn from the individuals with AgCC involved with the Human Brain and Cognition Lab at the Travis Research Institute. All participants completed an online version of the Moral Dilemmas Scale (Greene, 2001). The scale consists of 25 dilemmas, of which 11 are considered high-conflict, 7 low-conflict and 7 impersonal. Participants were instructed to read each dilemma and rate whether they found the action to be “appropriate” or not. The high-conflict dilemmas share a similar structure in which responses reflect either a utilitarian or deontological judgement.

“Approve” responses to each of the 3 categories of dilemma were separately tallied for each individual and subjected to a 2group ANOVA. Results revealed the control group produced a significantly higher rate of “appropriate” responses to high-conflict dilemmas than did the individuals with AgCC (F=8.17, p = .006, n2 =.113). However, no significant differences were found among the two groups for results on low (n2 = .013) and impersonal (n2 = .003) dilemmas alone. Furthermore, a X2 analysis of responses to each high conflict dilemma revealed a significant difference in 5 out of the 11 such that more persons with AgCC gave a deontological judgement.

Results suggested that adults with AgCC respond similarly to neurotypical controls with respect to the low conflict or

impersonal dilemmas. However, with respect to high conflict dilemmas, compared to controls they tend to respond in a more deontological than utilitarian basis - that is, based on general principles without contextual nuance. These findings are consistent with the conclusion of Renteria-Vasquez et al. (2021) that persons with AgCC have difficulty imagining the wider implications of present information.

The corpus callosum (CC) is a brain structure with a high heritability and potential role in psychiatric disorders. However, the genetic architecture of the CC and the genetic link with psychiatric disorders remain largely unclear. We investigated the genetic architectures of the volume of the CC and its subregions and the genetic overlap with psychiatric disorders.

We applied multivariate genome-wide association study (GWAS) to genetic and T1-weighted magnetic resonance imaging (MRI) data of 40,894 individuals from the UK Biobank, aiming to boost genetic discovery and to assess the pleiotropic effects across volumes of the five subregions of the CC (posterior, mid-posterior, central, mid-anterior and anterior) obtained by FreeSurfer 7.1. Multivariate GWAS was run combining all subregions, co-varying for relevant variables. Gene-set enrichment analyses were performed using MAGMA. Linkage disequilibrium score regression (LDSC) was used to determine Single nucleotide polymorphism (SNP)-based heritability of total CC volume and volumes of its subregions as well as their genetic correlations with relevant psychiatric traits.

We identified 70 independent loci with distributed effects across the five subregions of the CC (p < 5 × 10−8). Additionally, we identified 33 significant loci in the anterior subregion, 23 in the mid-anterior, 29 in the central, 7 in the mid-posterior and 56 in the posterior subregion. Gene-set analysis revealed 156 significant genes contributing to volume of the CC subregions (p < 2.6 × 10−6). LDSC estimated the heritability of CC to (h2SNP = 0.38, SE = 0.03) and subregions ranging from 0.22 (SE = 0.02) to 0.37 (SE = 0.03). We found significant genetic correlations of total CC volume with bipolar disorder (BD, rg = −0.09, SE = 0.03; p = 5.9 × 10−3) and drinks consumed per week (rg = −0.09, SE = 0.02; p = 4.8 × 10−4), and volume of the mid-anterior subregion with BD (rg = −0.12, SE = 0.02; p = 2.5 × 10−4), major depressive disorder (MDD) (rg = −0.12, SE = 0.04; p = 3.6 × 10−3), drinks consumed per week (rg = −0.13, SE = 0.04; p = 1.8 × 10−3) and cannabis use (rg = −0.09, SE = 0.03; p = 8.4 × 10−3).

Our results demonstrate that the CC has a polygenic architecture implicating multiple genes and show that CC subregion volumes are heritable. We found that distinct genetic factors are involved in the development of anterior and posterior subregions, consistent with their divergent functional specialisation. Significant genetic correlation between volumes of the CC and BD, drinks per week, MDD and cannabis consumption subregion volumes with psychiatric traits is noteworthy and deserving of further investigation.

Cynical hostility (CH), a specific dimension of hostility that consists of a mistrust of others, has been suggested as a high-risk trait for dementia. However, the influence of CH on the incidence of Alzheimer's disease (AD) remains poorly understood. This study investigated whether late-life CH is associated with AD risk and structural neuroimaging markers of AD.

In community-dwelling older adults from the French ESPRIT cohort (n = 1388), incident dementia rate according to CH level was monitored during an 8-year follow-up and analyzed using Cox proportional hazards regression models. Brain magnetic resonance imaging volumes were measured at baseline (n = 508). Using automated segmentation procedures (Freesurfer 6.0), the authors assessed brain grey and white volumes on all magnetic resonance imaging scans. They also measured white matter hyperintensities volumes using semi-automated procedures. Mean volumes according to the level of CH were compared using ANOVA.

Eighty-four participants developed dementia (32 with AD). After controlling for potential confounders, high CH was predictive of AD (HR 2.74; 95% CI 1.10–6.85; p = 0.030) and all dementia types are taken together (HR 2.30; 95% CI 1.10–4.80; p = 0.027). High CH was associated with white matter alterations, particularly smaller anterior corpus callosum volume (p < 0.01) after False Discovery Rate correction, but not with grey matter volumes.

High CH in late life is associated with cerebral white matter alterations, designated as early markers of dementia, and higher AD risk. Identifying lifestyle and biological determinants related to CH could provide clues on AD physiopathology and avenues for prevention strategies.