Reduced Primacy Bias in Autism during Early Sensory Processing.

Recent theories of autism propose that a core deficit in autism would be a less context-sensitive weighting of prediction errors. There is also first support for this hypothesis on an early sensory level. However, an open question is whether this decreased context sensitivity is caused by faster updating of one's model of the world (i.e., higher weighting of new information), proposed by predictive coding theories, or slower model updating. Here, we differentiated between these two hypotheses by investigating how first impressions shape the mismatch negativity (MMN), reflecting early sensory prediction error processing. An autism and matched control group of human adults (both n = 27, 8 female) were compared on the multi-timescale MMN paradigm, in which tones were presented that were either standard (frequently occurring) or deviant (rare), and these roles reversed every block. A well-replicated observation is that the initial model (i.e., the standard and deviant sound in the first block) influences MMN amplitudes in later blocks. If autism is characterized by faster model updating, and thus a smaller primacy bias, we hypothesized (and demonstrate using a simple reinforcement learning model) that their MMN amplitudes should be less influenced by the initial context. In line with this hypothesis, we found that MMN responses in the autism group did not differ between the initial deviant and initial standard sounds as they did in the control group. These findings are consistent with the idea that autism is characterized by faster model updating during early sensory processing, as proposed by predictive coding accounts of autism.SIGNIFICANCE STATEMENT Recent theories of autism propose that a core deficit in autism is that they are faster to update their models of the world based on new sensory information. Here, we tested this hypothesis by investigating how first impressions shape brain responses during early sensory processing, and hypothesized that individuals with autism would be less influenced by these first impressions. In line with earlier studies, our results show that early sensory processing was influenced by first impressions in a control group. However, this was not the case in an autism group. This suggests that individuals with autism are faster to abandon their initial model, and is consistent with the proposal that they are faster to update their models of the world.

Functional re-organization of hippocampal-cortical gradients during naturalistic memory processes.

The functional organization of the hippocampus mirrors that of the cortex, changing smoothly along connectivity gradients and abruptly at inter-areal boundaries. Hippocampal-dependent cognitive processes require flexible integration of these hippocampal gradients into functionally related cortical networks. To understand the cognitive relevance of this functional embedding, we acquired fMRI data while participants viewed brief news clips, either containing or lacking recently familiarized cues. Participants were 188 healthy mid-life adults and 31 adults with mild cognitive impairment (MCI) or Alzheimer's disease (AD). We employed a recently developed technique - connectivity gradientography - to study gradually changing patterns of voxel to whole brain functional connectivity and their sudden transitions. We observed that functional connectivity gradients of the anterior hippocampus map onto connectivity gradients across the default mode network during these naturalistic stimuli. The presence of familiar cues in the news clips accentuates a stepwise transition across the boundary from the anterior to the posterior hippocampus. This functional transition is shifted in the posterior direction in the left hippocampus of individuals with MCI or AD. These findings shed new light on the functional integration of hippocampal connectivity gradients into large-scale cortical networks, how these adapt with memory context and how these change in the presence of neurodegenerative disease.

Shorter Contextual Timescale Rather Than Memory Deficit in Aging.

Many aspects of cognitive ability and brain function that change as we age look like deficits on account of measurable differences in comparison to younger adult groups. One such difference occurs in auditory sensory responses that index perceptual learning. Meta-analytic findings show reliable age-related differences in auditory responses to repetitive patterns of sound and to rare violations of those patterns, variously attributed to deficits in auditory sensory memory and inhibition. Here, we determine whether proposed deficits would render older adults less prone to primacy effects, robustly observed in young adults, which present as a tendency for first learning to have a disproportionate influence over later perceptual inference. The results confirm this reduced sensitivity to primacy effects but do not support impairment in auditory sensory memory as the origin of this difference. Instead, the aging brain produces data consistent with shorter timescales of contextual reference. In conclusion, age-related differences observed previously for perceptual inference appear highly context-specific necessitating reconsideration of whether and to what function the notion of deficit should be attributed, and even whether the notion of deficit is appropriate at all.

Combining novel trait and neurocognitive frameworks to parse heterogeneity in borderline personality disorder.

OBJECTIVE: Borderline Personality Disorder (BPD) diagnosis comprises several constellations of trait, neurocognitive, and psychosocial alterations. Dimensional models of psychopathology provide new opportunities to parse heterogeneity and create a stronger interface between individual characterization and psychosocial outcomes. However, dimensional models have focused on either traits or neurocognitive features, lacking integration to capture the multifaceted nature of BPD. METHOD: We assessed 100 participants with BPD using a combination of tools stemming from trait (Alternative Model for Personality Disorders) and neurocognitive models (Research Domain Criteria; RDoC) to examine if trait-derived subgroups display distinctive social-processing and psychosocial profiles. We used two complementary analytical approaches: person-centered (k-means clustering) and construct-based (multiple factor analysis). RESULTS: Our person-centered approach identified four subgroups with separable internalizing, detached, externalizing, and low psychopathology trait profiles. These profiles revealed distinctive patterns of affiliation, emotion recognition and mentalization performance in RDoC tasks, and psychosocial measures of quality of life and social connectedness. RDoC-based measures showed close construct proximity with negative affectivity, disinhibition, and antagonism trait domains, relative to the detachment domain, which had close proximity with self-knowledge. CONCLUSIONS: Altogether, findings support consilience between trait-based and neurobiological frameworks and suggest that trait models are useful to parse BPD heterogeneity leading to unique social functioning profiles.

Hierarchical Learning of Statistical Regularities over Multiple Timescales of Sound Sequence Processing: A Dynamic Causal Modeling Study.

Our understanding of the sensory environment is contextualized on the basis of prior experience. Measurement of auditory ERPs provides insight into automatic processes that contextualize the relevance of sound as a function of how sequences change over time. However, task-independent exposure to sound has revealed that strong first impressions exert a lasting impact on how the relevance of sound is contextualized. Dynamic causal modeling was applied to auditory ERPs collected during presentation of alternating pattern sequences. A local regularity (a rare p = .125 vs. common p = .875 sound) alternated to create a longer timescale regularity (sound probabilities alternated regularly creating a predictable block length), and the longer timescale regularity changed halfway through the sequence (the regular block length became shorter or longer). Predictions should be revised for local patterns when blocks alternated and for longer patterning when the block length changed. Dynamic causal modeling revealed an overall higher precision for the error signal to the rare sound in the first block type, consistent with the first impression. The connectivity changes in response to errors within the underlying neural network were also different for the two blocks with significantly more revision of predictions in the arrangement that violated the first impression. Furthermore, the effects of block length change suggested errors within the first block type exerted more influence on the updating of longer timescale predictions. These observations support the hypothesis that automatic sequential learning creates a high-precision context (first impression) that impacts learning rates and updates to those learning rates when predictions arising from that context are violated. The results further evidence automatic pattern learning over multiple timescales simultaneously, even during task-independent passive exposure to sound.

Transdiagnostic variations in impulsivity and compulsivity in obsessive-compulsive disorder and gambling disorder correlate with effective connectivity in cortical-striatal-thalamic-cortical circuits.

Individual differences in impulsivity and compulsivity is thought to underlie vulnerability to a broad range of disorders and are closely tied to cortical-striatal-thalamic-cortical function. However, whether impulsivity and compulsivity in clinical disorders is continuous with the healthy population and explains cortical-striatal-thalamic-cortical dysfunction across different disorders remains unclear. Here, we characterized the relationship between cortical-striatal-thalamic-cortical effective connectivity, estimated using dynamic causal modelling of resting-state functional magnetic resonance imaging data, and dimensional phenotypes of impulsivity and compulsivity in two symptomatically distinct but phenotypically related disorders, obsessive-compulsive disorder and gambling disorder. 487 online participants provided data for modelling of dimensional phenotypes. These data were combined with 34 obsessive-compulsive disorder patients, 22 gambling disorder patients, and 39 healthy controls, who underwent functional magnetic resonance imaging. Three core dimensions were identified: disinhibition, impulsivity, and compulsivity. Patients' scores on these dimensions were continuously distributed with the healthy participants, supporting a continuum model of psychopathology. Across all participants, higher disinhibition correlated with lower bottom-up connectivity in the dorsal circuit and greater bottom-up connectivity in the ventral circuit, and higher compulsivity correlated with lower bottom-up connectivity in the dorsal circuit. In patients, higher clinical severity was also linked to lower bottom-up connectivity in the dorsal circuit, but these findings were independent of phenotypic variation, demonstrating convergence towards behaviourally and clinically relevant changes in brain dynamics. Effective connectivity did not differ as a function of traditional diagnostic labels and only weak associations were observed for functional connectivity measures. Together, our results demonstrate that cortical-striatal-thalamic-cortical dysfunction across obsessive-compulsive disorder and gambling disorder may be better characterized by dimensional phenotypes than diagnostic comparisons, supporting investigation of quantitative liability phenotypes.

Context sensitivity in action decreases along the autism spectrum: a predictive processing perspective.

Recent predictive processing accounts of perception and action point towards a key challenge for the nervous system in dynamically optimizing the balance between incoming sensory information and existing expectations regarding the state of the environment. Here, we report differences in the influence of the preceding sensory context on motor function, varying with respect to both clinical and subclinical features of autism spectrum disorder (ASD). Reach-to-grasp movements were recorded subsequent to an inactive period in which illusory ownership of a prosthetic limb was induced. We analysed the sub-components of reach trajectories derived using a minimum-jerk fitting procedure. Non-clinical adults low in autistic features showed disrupted movement execution following the illusion compared to a control condition. By contrast, individuals higher in autistic features (both those with ASD and non-clinical individuals high in autistic traits) showed reduced sensitivity to the presence of the illusion in their reaching movements while still exhibiting the typical perceptual effects of the illusion. Clinical individuals were distinct from non-clinical individuals scoring high in autistic features, however, in the early stages of movement. These results suggest that the influence of high-level representations of the environment differs between individuals, contributing to clinical and subclinical differences in motor performance that manifest in a contextual manner. As high-level representations of context help to explain fluctuations in sensory input over relatively longer time scales, more circumscribed sensitivity to prior or contextual information in autistic sensory processing could contribute more generally to reduced social comprehension, sensory impairments and a stronger desire for predictability and routine.

Attenuated self-tickle sensation even under trajectory perturbation.

The efference copy account of the tickle effect (i.e., our inability to tickle ourselves) predicts no tickle effect (i.e., an ability to tickle ourselves) when the trajectory of a tactile stimulus is perturbed relative to the associated movement, and there is evidence in support of this. The active inference account, however, predicts the tickle effect should survive trajectory perturbation. We test these accounts of the tickle effect under the hypothesis that previous findings are due to attentional modulation, and that the tickle effect will be found in a paradigm with no conscious attention directed to the trajectory perturbation. We thus expected to find support for active inference. Our first experiment confirms this hypothesis, while our second seeks to explain previous findings in terms of the modulation of the tickle sensation when there is awareness of, and different degrees of attention to, the spatial tactile and kinesthetic trajectories.

Order effects in task-free learning: Tuning to information-carrying sound features.

Event-related potentials (ERPs) acquired during task-free passive listening can be used to study how sensitivity to common pattern repetitions and rare deviations changes over time. These changes are purported to represent the formation and accumulation of precision in internal models that anticipate future states based on probabilistic and/or statistical learning. This study features an unexpected finding; a strong order-dependence in the speed with which deviant responses are elicited that anchors to first learning. Participants heard four repetitions of a sequence in which an equal number of short (30 msec) and long (60 msec) pure tones were arranged into four blocks in which one was common (the standard, p = .875) and the other rare (the deviant, p = .125) with probabilities alternating across blocks. Some participants always heard the sequences commencing with the 30 msec deviant block, and others always with the 60 msec deviant block first. A deviance-detection component known as mismatch negativity (MMN) was extracted from responses and the point in time at which MMN reached maximum amplitude was used as the dependent variable. The results show that if participants heard sequences commencing with the 60 msec deviant block first, the MMN to the 60 msec and 30 msec deviant peaked at an equivalent latency. However, if participants heard sequences commencing with the 30 msec deviant first, the MMN peaked earlier to the 60 msec deviant. Furthermore, while the 30 msec MMN latency did not differ as a function of sequence composition, the 60 msec MMN latency did and was earlier when the sequences began with a 30 msec deviant first. By examining MMN latency effects as a function of age and hearing level it was apparent that the differentiation in 30 msec and 60 msec MMN latency expands with older age and raised hearing threshold due to prolongation of the time taken for the 30 msec MMN to peak. The observations are discussed with reference to how the initial sound composition may tune the auditory system to be more sensitive to different cues (i.e., offset responses vs perceived loudness). The order-effect demonstrates a remarkably powerful anchoring to first learning that might reflect initial tuning to the most valuable discriminating feature within a given listening environment, an effect that defies explanation based on statistical information alone.

Pilot study with randomised control of dual site theta burst transcranial magnetic stimulation (TMS) for methamphetamine use disorder: a protocol for the TARTAN study.

BACKGROUND: Transcranial magnetic stimulation (TMS) (including the theta burst stimulation (TBS) form of TMS used in this study) is a non-invasive means to stimulate nerve cells in superficial areas of the brain. In recent years, there has been a growth in the application of TMS to investigate the modulation of neural networks involved in substance use disorders. This study examines the feasibility of novel TMS protocols for the treatment of methamphetamine (MA) use disorder in an ambulatory drug and alcohol treatment setting. METHODS: Thirty participants meeting the criteria for moderate to severe MA use disorder will be recruited in community drug and alcohol treatment settings and randomised to receive active TMS or sham (control) intervention. The treatment is intermittent TBS (iTBS) applied to the left dorsolateral prefrontal cortex (DLPFC), then continuous TBS (cTBS) to the left orbitofrontal cortex (OFC). Twelve sessions are administered over 4 weeks with opt-in weekly standardized cognitive behaviour therapy (CBT) counselling and a neuroimaging sub-study offered to participants. Primary outcomes are feasibility measures including recruitment, retention and acceptability of the intervention. Secondary outcomes include monitoring of safety and preliminary efficacy data including changes in substance use, cravings (cue reactivity) and cognition (response inhibition). DISCUSSION: This study examines shorter TBS protocols of TMS for MA use disorder in real-world drug and alcohol outpatient settings where withdrawal and abstinence from MA, or other substances, are not eligibility requirements. TMS is a relatively affordable treatment and staff of ambulatory health settings can be trained to administer TMS. It is a potentially scalable and translatable treatment for existing drug and alcohol clinical settings. TMS has the potential to provide a much-needed adjuvant treatment to existing psychosocial interventions for MA use disorder. A limitation of this protocol is that the feasibility of follow-up is only examined at the end of treatment (4 weeks). TRIAL REGISTRATION: Australia New Zealand Clinical Trial Registry ACTRN12622000762752. Registered on May 27, 2022, and retrospectively registered (first participant enrolled) on May 23, 2022, with protocol version 7 on February 24, 2023.

Dichoptic viewing methods for binocular rivalry research: prospects for large-scale clinical and genetic studies.

Binocular rivalry (BR) is an intriguing phenomenon that occurs when two different images are presented, one to each eye, resulting in alternation or rivalry between the percepts. The phenomenon has been studied for nearly 200 years, with renewed and intensive investigation over recent decades. The rate of perceptual switching has long been known to vary widely between individuals but to be relatively stable within individuals. A recent twin study demonstrated that individual variation in BR rate is under substantial genetic control, a finding that also represented the first report, using a large study, of genetic contribution for any post-retinal visual processing phenomenon. The twin study had been prompted by earlier work showing BR rate was slow in the heritable psychiatric condition, bipolar disorder (BD). Together, these studies suggested that slow BR may represent an endophenotype for BD, and heralded the advent of modern clinical and genetic studies of rivalry. This new focus has coincided with rapid advances in 3D display technology, but despite such progress, specific development of technology for rivalry research has been lacking. This review therefore compares different display methods for BR research across several factors, including viewing parameters, image quality, equipment cost, compatibility with other investigative methods, subject group, and sample size, with a focus on requirements specific to large-scale clinical and genetic studies. It is intended to be a resource for investigators new to BR research, such as clinicians and geneticists, and to stimulate the development of 3D display technology for advancing interdisciplinary studies of rivalry.

Skull-bound perception and precision optimization through culture.

Clark acknowledges but resists the indirect mind-world relation inherent in prediction error minimization (PEM). But directness should also be resisted. This creates a puzzle, which calls for reconceptualization of the relation. We suggest that a causal conception captures both aspects. With this conception, aspects of situated cognition, social interaction and culture can be understood as emerging through precision optimization.

The impact of spatial variance on precision estimates in an auditory oddball paradigm.

Predictive processing theories suggest that a principal function of the brain is to reduce the surprise of incoming sensory information by creating accurate and precise models of the environment. These models are commonly explored by looking at the prediction errors elicited when experience departs from predictions. One such prediction error is the mismatch negativity (MMN). Using this component, it is possible to examine the effect of external noise on the precision of the developed model. Recent studies have shown that the brain may not update its model every time there is a change in the environment, rather it will only update it when doing so will increase precision and or accuracy of the model. The current study examined this process using oddball sound sequences with high and low spatial variability and examining how this affected the elicited MMN to a duration deviant sound. The results showed a strong null effect of spatial variance both at a local and sequence levels. These results indicate that variability in the sound sequence will not invariably affect model precision estimates and thus the amplitude of the MMN component.

Primacy biases endure the addition of frequency variability.

The primacy bias (PB) is a phenomenon that indicates the brain does not always process sensory information as an 'ideal Bayesian observer', but rather is disproportionately influenced by first impressions. This study was designed to establish whether a PB observed in auditory event-related potentials (ERPs) to a sequence of sound remained evident in the presence of increased levels of tone frequency variation. Two groups of participants were presented with a novel oddball paradigm, while simultaneously having cortical activity recorded with an EEG. In the control group, participants heard a two-tone sequence where the probability of the two tones of different duration switched after 480 sounds/2.4 min block, so that the tone initially encountered as rare became common and vice versa. The key manipulation introduced in the test group was a change of frequency in each block, removing a key element of regularity. The additional frequency variation resulted in no significant difference in the PB between the groups. The data suggest powerful first learning effects are not disrupted by frequency changes, indicating the robustness of learning heuristics.

Characterising activity and diet compositions for dementia prevention: protocol for the ACTIVate prospective longitudinal cohort study.

INTRODUCTION: Approximately 40% of late-life dementia may be prevented by addressing modifiable risk factors, including physical activity and diet. Yet, it is currently unknown how multiple lifestyle factors interact to influence cognition. The ACTIVate Study aims to (1) explore associations between 24-hour time-use and diet compositions with changes in cognition and brain function; and (2) identify duration of time-use behaviours and the dietary compositions to optimise cognition and brain function. METHODS AND ANALYSIS: This 3-year prospective longitudinal cohort study will recruit 448 adults aged 60-70 years across Adelaide and Newcastle, Australia. Time-use data will be collected through wrist-worn activity monitors and the Multimedia Activity Recall for Children and Adults. Dietary intake will be assessed using the Australian Eating Survey food frequency questionnaire. The primary outcome will be cognitive function, assessed using the Addenbrooke's Cognitive Examination-III. Secondary outcomes include structural and functional brain measures using MRI, cerebral arterial pulse measured with diffuse optical tomography, neuroplasticity using simultaneous transcranial magnetic stimulation and electroencephalography, and electrophysiological markers of cognitive control using event-related potential and time frequency analyses. Compositional data analysis, testing for interactions between time point and compositions, will assess longitudinal associations between dependent (cognition, brain function) and independent (time-use and diet compositions) variables. CONCLUSIONS: The ACTIVate Study will be the first to examine associations between time-use and diet compositions, cognition and brain function. Our findings will inform new avenues for multidomain interventions that may more effectively account for the co-dependence between activity and diet behaviours for dementia prevention. ETHICS AND DISSEMINATION: Ethics approval has been obtained from the University of South Australia's Human Research Ethics committee (202639). Findings will be disseminated through peer-reviewed manuscripts, conference presentations, targeted media releases and community engagement events. TRIAL REGISTRATION NUMBER: Australia New Zealand Clinical Trials Registry (ACTRN12619001659190).

The influence of variability on mismatch negativity amplitude.

Mismatch Negativity (MMN) to pattern deviations reveals exquisite pattern detection ability in the brain. MMN amplitude is proposed to be precision-weighted, being inversely proportional to variability within a patterned sound sequence. Two experiments were conducted to determine whether pattern variability, shown to influence MMN to simple pattern deviance, also extends to MMN elicited to abstract pattern deviants. Participants were presented with 3-tone triplet sequences that were defined by regular frequency ascendance with adjacent (A C deviants for adjacent and non-adjacent dependencies, was smaller for the latter, was impervious to variance in tone loudness, but showed prolonged sensitivity to the level of variability at sequence onset.

Context is everything: How context shapes modulations of responses to unattended sound.

The concept of perceptual inferences taking place over multiple timescales simultaneously raises questions about how the brain can balance the demands of remaining sensitive to local rarity while utilising more global longer-term predictability to modulate cortical responses. In the present study auditory evoked potentials to four presentations of the same sound sequence containing predictable structure on a local (milliseconds to seconds) and more global (many minutes) timescales were recorded. The results from 33 participants are used to demonstrate that predictions about both local (internal predictive models) and global (meta-models that define expected precisions associated with familiar internal model states) regularities are formed. The study exposes more local context-based modulations of the P1 but more global order-based modulations of the auditory evoked N2 components. The results are discussed in terms of theoretical links advocating that uncertainty at multiple timescales could lead to differential component modulations, and the importance of considering the broader learning context in auditory evoked potential studies.

How are attention, learning, and social cognition related on the non-clinical autistic spectrum?

Autism spectrum disorder (ASD) - and autistic traits more generally - are associated with a heterogeneous pattern of differences in cognitive function. These include differences in associative learning, attention, and processing of social information. All three cognitive functions have importance in clinical, educational, and research contexts. The present study investigates the relationships between these functions in the context of autistic traits in the neurotypical population. In an online study, we asked a group of over 400 people to complete the Autism Spectrum Quotient questionnaire. We also asked participants to complete one of two standard attentional learning paradigms - either a Kamin blocking or an attentional highlighting task. To investigate the relation of attention and learning to social information processing, we incorporated social cues in one of each kind of paradigm. We found Kamin blocking increased with increasing number of autistic traits, in particular the sub-trait attention switching, but only for non-social cues. We found that highlighting decreased with increasing number of traits, in particular the sub-trait communication, but only for social cues. We interpret these findings as evidence of a crucial role for attention in other characteristics of the broader autistic phenotype, and discuss the relevance of these results for cognitive explanations of autistic traits and symptoms.

Motion-induced blindness as a tool to measure attentional biases and the link to attention-deficit/hyperactivity traits.

Typically, individuals have an attentional bias toward the left visual field. This is often absent in individuals with attention-deficit/hyperactivity (ADH) disorder (ADHD). We used a motion-induced blindness task with targets in 4 quadrants to assess left/right as well as upper/lower spatial biases in perceptual disappearances and also measured changes in the disappearances with time-on-task. Fifty-eight university students (41 female) completed the Conners Adult ADHD self-report short-form to assess the number of ADH traits, and 48 trials of a 1-min motion-induced blindness (MIB) task. Through a hybrid hypothesis-driven and data-driven analysis approach, we found that the MIB illusion increased with more ADH traits, decreased with time-on-task, and was stronger for left and lower quadrants. The time-on-task likely contributed to the strength of the illusion through changes in arousal, as pupil size decreased with time-on-trial in a subset of participants (n = 11) for whom we measure eye movements. In addition, although participants were biased toward the lower left visual field, this was, unexpectedly, most prominent with those with higher ADH traits. This novel result suggests an additive effect of left/right and upper/lower spatial biases. Taken together, this study supports an association between spatial attention, arousal and ADH traits in MIB. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Sexual Dimorphism of Resting-State Network Connectivity in Healthy Ageing.

OBJECTIVES: The onset of many illnesses is confounded with age and sex. Increasing age is a risk factor for the development of many illnesses, and sexual dimorphism influences brain anatomy, function, and cognition. Here, we examine frequency-specific connectivity in resting-state networks in a large sample (n = 406) of healthy aged adults. METHOD: We quantify frequency-specific connectivity in three resting-state networks known to be implicated in age-related decline: the default mode, dorsal attention, and salience networks, using multiband functional magnetic resonance imaging. Frequency-specific connectivity was quantified in four bands: low (0.015-0.027 Hz), moderately low (0.027-0.073 Hz), moderately high (0.073-0.198 Hz), and high (0.198-0.5 Hz) frequency bands, using mean intensity and spatial extent. Differences in connectivity between the sexes in each of the three networks were examined. RESULTS: Each network showed the largest intensity and spatial extent at low frequencies and smallest extent at high frequencies. Males showed greater connectivity than females in the salience network. Females showed greater connectivity than males in the default mode network. DISCUSSION: Results in this healthy aged cohort are compatible with those obtained in young samples, suggesting that frequency-specific connectivity, and differences between the sexes, are maintained into older age. Our results indicate that sex should be considered as an influencing factor in studies of resting-state connectivity.