Activation of sensory cortex by imagined genital stimulation: an fMRI analysis

Affective neuroscience: applications for sexual medicine research and clinical practice

INTRODUCTION

Affective neuroscience is the study of the brain substrates of emotional, embodied experiences. Affective neuroscience theory (ANT) is based on experimental evidence that all mammals are hardwired with 7 primary subcortical emotional operating systems, or "core emotions," that have overlapping but distinct circuits buried in the deep, ancient parts of the brain. Imbalances in the 7 core emotions can affect multiple aspects of the individual's psychosocial well-being (eg, depression, anxiety, substance abuse). Here, we propose that core emotions can also influence sexual function and, specifically, that imbalances in core emotions are the bridge connecting psychiatric symptoms (eg, anhedonia) to sexual dysfunction (eg, anorgasmia).

OBJECTIVES

In this targeted review and commentary, we outline potential connections between ANT and sexual medicine research and clinical practice. We summarize ANT by defining the 3-level BrainMind and core emotions; examining how they relate to personality, behavior, and mental health; and determining the implications for sexual health research and clinical practice.

METHODS

A targeted literature review was conducted. Case studies were adapted from client files and clinician interviews and then anonymized.

RESULTS

We propose a novel organizational schema for implementing affective balance therapies for sexual dysfunction, which integrate psychoeducational, somatic, and cognitive therapeutic approaches under the ANT framework. We provide 3 patient case studies (anorgasmia, hypersexuality, spinal cord injury) outlining the implementation of this approach and patient outcomes.

CONCLUSION

ANT has practical translational applications in sexual health research and clinical practice. By integrating our understanding of the role of core emotions in human sexuality, clinicians can better tailor treatments to address sexual dysfunction.

Sexual incentive motivation, sexual behavior, and general arousal: Do rats and humans tell the same story?

Sexual incentive stimuli activate sexual motivation and heighten the level of general arousal. The sexual motive may induce the individual to approach the incentive, and eventually to initiate sexual acts. Both approach and the ensuing copulatory interaction further enhance general arousal. We present data from rodents and humans in support of these assertions. We then suggest that orgasm is experienced when the combined level of excitation surpasses a threshold. In order to analyze the neurobiological bases of sexual motivation, we employ the concept of a central motive state. We then discuss the mechanisms involved in the long- and short-term control of that state as well as those mediating the momentaneous actions of sexual incentive stimuli. This leads to an analysis of the neurobiology behind the interindividual differences in responsivity of the sexual central motive state. Knowledge is still fragmentary, and many contradictory observations have been made. Nevertheless, we conclude that the basic mechanisms of sexual motivation and the role of general arousal are similar in rodents and humans.

Higher inter-hemispheric homotopic connectivity in lifelong premature ejaculation patients: a pilot resting-state fMRI study

Background

Lifelong premature ejaculation (PE) is one common male sexual dysfunction and is implicated in widespread structural and functional abnormalities of bilateral hemispheres. However, whether the inter-hemisphere functional connectivity (FC) of lifelong PE patients was altered still remain unclear.

Methods

Thirty-four lifelong PE patients and 30 healthy controls (HCs) were enrolled in this study and all underwent T1-weighted and resting-state functional MRI (fMRI) scan. The voxel-mirrored homotopic connectivity (VMHC) measure and independent sample t-test were applied to examine the alterations of VMHC values in the patients relative to HCs with the significant threshold at P<0.05, false discovery rates corrected. Correlation analysis was adopted to calculate the relationships between the imaging results and clinical characteristics of patients (P<0.05, Bonferroni corrected). Receiver operating characteristic (ROC) curve analysis was performed to investigate the possible biomarkers for distinguishing the patients from the HCs using the VMHC values of inter-group differences.

Results

The results revealed that compared with HCs, lifelong PE patients had higher VMHC values in the precentral gyrus (PG), primary somatosensory cortex (S1), supplementary motor area (SMA), precuneus, middle temporal cortex (MTC), superior temporal pole (STP), thalamus, caudate and middle cingulate cortex (MCC). Correlation analysis showed that the mean VMHC values in the S1 negatively correlated with intravaginal ejaculation latency time (IELT) in the patient group. Furthermore, the caudate revealed the well classification power from the ROC analysis.

Conclusions

The present study showed the abnormal inter-hemisphere interaction and integration of information involved in ejaculation inhibitory control, sensorimotor mediation and self-reference processing including the thalamus, caudate, MCC, widespread parietal cortex and temporal cortex in lifelong PE patients compared with HCs. Correlation analysis and ROC analysis revealed the importance of S1 and caudate in lifelong PE. Notably, the ROC result of caudate might show the core roles of caudate played in the pathophysiology of lifelong PE.

International Society for the Study of Women's Sexual Health (ISSWSH) Review of Epidemiology and Pathophysiology, and a Consensus Nomenclature and Process of Care for the Management of Persistent Genital Arousal Disorder/Genito-Pelvic Dysesthesia (PGAD/GPD)

BACKGROUND

Persistent genital arousal disorder (PGAD), a condition of unwanted, unremitting sensations of genital arousal, is associated with a significant, negative psychosocial impact that may include emotional lability, catastrophization, and suicidal ideation. Despite being first reported in 2001, PGAD remains poorly understood.

AIM

To characterize this complex condition more accurately, review the epidemiology and pathophysiology, and provide new nomenclature and guidance for evidence-based management.

METHODS

A panel of experts reviewed pertinent literature, discussed research and clinical experience, and used a modified Delphi method to reach consensus concerning nomenclature, etiology, and associated factors. Levels of evidence and grades of recommendation were assigned for diagnosis and treatment.

OUTCOMES

The nomenclature of PGAD was broadened to include genito-pelvic dysesthesia (GPD), and a new biopsychosocial diagnostic and treatment algorithm for PGAD/GPD was developed.

RESULTS

The panel recognized that the term PGAD does not fully characterize the constellation of GPD symptoms experienced by patients. Therefore, the more inclusive term PGAD/GPD was adopted, which maintains the primacy of the distressing arousal symptoms and acknowledges associated bothersome GPD. While there are diverse biopsychosocial contributors, there is a common underlying neurologic basis attributable to spontaneous intense activity of the genito-pelvic region represented in the somatosensory cortex and its projections. A process of care diagnostic and treatment strategy was developed to guide the clinician, whenever possible, by localizing the symptoms as originating in any of five regions: (i) end organ, (ii) pelvis/perineum, (iii) cauda equina, (iv) spinal cord, and (v) brain. Psychological treatment strategies were considered critical and should be performed in conjunction with medical strategies. Pharmaceutical interventions may be used based on their site and mechanism of action to reduce patients' symptoms and the associated bother and distress.

CLINICAL IMPLICATIONS

The process of care for PGAD/GPD uses a personalized, biopsychosocial approach for diagnosis and treatment.

STRENGTHS AND LIMITATIONS

Strengths and Limitations: Strengths include characterization of the condition by consensus, analysis, and recommendation of a new nomenclature and a rational basis for diagnosis and treatment. Future investigations into etiology and treatment outcomes are recommended. The main limitations are the dearth of knowledge concerning this condition and that the current literature consists primarily of case reports and expert opinion.

CONCLUSION

We provide, for the first time, an expert consensus review of the epidemiology and pathophysiology and the development of a new nomenclature and rational algorithm for management of this extremely distressing sexual health condition that may be more prevalent than previously recognized. Goldstein I, Komisaruk BR, Pukall CF, et al. International Society for the Study of Women's Sexual Health (ISSWSH) Review of Epidemiology and Pathophysiology, and a Consensus Nomenclature and Process of Care for the Management of Persistent Genital Arousal Disorder/Genito-Pelvic Dysesthesia (PGAD/GPD). J Sex Med 2021;18:665-697.

Neural encoding of actual and imagined touch within human posterior parietal cortex

In the human posterior parietal cortex (PPC), single units encode high-dimensional information with partially mixed representations that enable small populations of neurons to encode many variables relevant to movement planning, execution, cognition, and perception. Here, we test whether a PPC neuronal population previously demonstrated to encode visual and motor information is similarly engaged in the somatosensory domain. We recorded neurons within the PPC of a human clinical trial participant during actual touch presentation and during a tactile imagery task. Neurons encoded actual touch at short latency with bilateral receptive fields, organized by body part, and covered all tested regions. The tactile imagery task evoked body part-specific responses that shared a neural substrate with actual touch. Our results are the first neuron-level evidence of touch encoding in human PPC and its cognitive engagement during a tactile imagery task, which may reflect semantic processing, attention, sensory anticipation, or imagined touch.

The Erogenous Mirror: Intersubjective and Multisensory Maps of Sexual Arousal in Men and Women

Erogenous zones of the body are sexually arousing when touched. Previous investigations of erogenous zones were restricted to the effects of touch on one's own body. However, sexual interactions do not just involve being touched, but also involve touching a partner and mutually looking at each other's bodies. We take a novel interpersonal approach to characterize the self-reported intensity and distribution of erogenous zones in two modalities: touch and vision. A large internet sample of 613 participants (407 women) completed a questionnaire, where they rated intensity of sexual arousal related to different body parts, both on one's own body and on an imagined partner's body in response to being touched but also being looked at. We report the presence of a multimodal erogenous mirror between sexual partners, as we observed clear correspondences in topographic distributions of self-reported arousal between individuals' own bodies and their preferences for a partner's body, as well as between those elicited by imagined touch and vision. The erogenous body is therefore organized and represented in an interpersonal and multisensory way.

Recent advances in neuroimaging of bladder, bowel and sexual function

PURPOSE OF REVIEW

In this review, we summarize recent advances in the understanding of the neural control of the bladder, bowel and sexual function, in both men and women.

RECENT FINDINGS

Evidence of supraspinal areas controlling the storage of urine and micturition in animals, such as the pontine micturition centre, emerged in the early 20th century. Neurological stimulation and lesion studies in humans provided additional indirect evidence for additional bladder-related brain areas. Thereafter, functional neuroimaging in humans with PET and fMRI provided more direct evidence of the involvement of these brain areas. The areas involved in the storage and expulsion of urine also seem to be involved in the central control of storage and expulsion of feces. Furthermore, most knowledge on the brain control of sexual function is obtained from dynamic imaging in human volunteers. Relatively little is known about the dysfunctional central circuits in patients with pelvic organ dysfunction.

SUMMARY

fMRI has been the most widely used functional neuroimaging technique in the last decade to study the central control of bladder function, anorectal function and sexual function. The studies described in this review show which sensory and motor areas are involved, including cortical and subcortical areas. We propose the existence of a switch-like phenomenon located in the pons controlling micturition, defecation and orgasm.

Male Urogenital System Mapped Onto the Sensory Cortex: Functional Magnetic Resonance Imaging Evidence

INTRODUCTION

The projection of the human male urogenital system onto the paracentral lobule has not previously been mapped comprehensively.

AIM

To map specific urogenital structures onto the primary somatosensory cortex toward a better understanding of sexual response in men.

METHODS

Using functional magnetic resonance imaging, we mapped primary somatosensory cortical responses to self-stimulation of the penis shaft, glans, testicles, scrotum, rectum, urethra, prostate, perineum, and nipple. We further compared neural response with erotic and prosaic touch of the penile shaft.

MAIN OUTCOME MEASURE

We identified the primary mapping site of urogenital structures on the paracentral lobule and identified networks involved in perceiving touch as erotic.

RESULTS

We mapped sites on the primary somatosensory cortex to which components of the urogenital structures project in men. Evidence is provided that penile cutaneous projection is different from deep penile projection. Similar to a prior report in women, we show that the nipple projects to the same somatosensory cortical region as the genitals. Evidence of differential representation of erotic and nonerotic genital self-stimulation is also provided, the former activating sensory networks other than the primary sensory cortex, indicating a role of "top-down" activity in erotic response.

CLINICAL IMPLICATIONS

We map primary sites of projection of urogenital structures to the primary somatosensory cortex and differentiate cortical sites of erotic from nonerotic genital self-stimulation.

STRENGTH & LIMITATIONS

To our knowledge, this is the first comprehensive mapping onto the primary somatosensory cortex of the projection of the components of the urogenital system in men and the difference in cortical activation in response to erotic vs nonerotic self-stimulation. The nipple was found to project to the same cortical region as the genitals. Evidence is provided that superficial and deep penile stimulation project differentially to the cortex, suggesting that sensory innervation of the penis is provided by more than the (pudendal) dorsal nerve.

CONCLUSION

This study reconciles prior apparently conflicting findings and offers a comprehensive mapping of male genital components to the paracentral lobule. We provide evidence of differential projection of light touch vs pressure applied to the penile shaft, suggesting differential innervation of its superficial, vs deep structure. Similar to the response in women, we found nipple projection to genital areas of the paracentral lobule. We also provide evidence of differential representation of erotic and nonerotic genital self-stimulation, the former activating sensory networks other than the primary sensory cortex, indicating a role of top-down activity in erotic response. Allen K, Wise N, Frangos E, et al. Male Urogenital System Mapped Onto the Sensory Cortex: Functional Magnetic Resonance Imaging Evidence. J Sex Med 2020;17:603-613.

Topographic Somatosensory Imagery for Real-Time fMRI Brain-Computer Interfacing

Real-time functional magnetic resonance imaging (fMRI) is a promising non-invasive method for brain-computer interfaces (BCIs). BCIs translate brain activity into signals that allow communication with the outside world. Visual and motor imagery are often used as information-encoding strategies, but can be challenging if not grounded in recent experience in these modalities, e.g., in patients with locked-in-syndrome (LIS). In contrast, somatosensory imagery might constitute a more suitable information-encoding strategy as the somatosensory function is often very robust. Somatosensory imagery has been shown to activate the somatotopic cortex, but it has been unclear so far whether it can be reliably detected on a single-trial level and successfully classified according to specific somatosensory imagery content. Using ultra-high field 7-T fMRI, we show reliable and high-accuracy single-trial decoding of left-foot (LF) vs. right-hand (RH) somatosensory imagery. Correspondingly, higher decoding accuracies were associated with greater spatial separation of hand and foot decoding-weight patterns in the primary somatosensory cortex (S1). Exploiting these novel neuroscientific insights, we developed-and provide a proof of concept for-basic BCI communication by showing that binary (yes/no) answers encoded by somatosensory imagery can be decoded with high accuracy in simulated real-time (in 7 subjects) as well as in real-time (1 subject). This study demonstrates that body part-specific somatosensory imagery differentially activates somatosensory cortex in a topographically specific manner; evidence which was surprisingly still lacking in the literature. It also offers proof of concept for a novel somatosensory imagery-based fMRI-BCI control strategy, with particularly high potential for visually and motor-impaired patients. The strategy could also be transferred to lower MRI field strengths and to mobile functional near-infrared spectroscopy. Finally, given that communication BCIs provide the BCI user with a form of feedback based on their brain signals and can thus be considered as a specific form of neurofeedback, and that repeated use of a BCI has been shown to enhance underlying representations, we expect that the current BCI could also offer an interesting new approach for somatosensory rehabilitation training in the context of stroke and phantom limb pain.

Neuroanatomy and function of human sexual behavior: A neglected or unknown issue?

INTRODUCTION

Sexual desire, arousal, and orgasm are mediated by complex, yet still not fully understood, interactions of the somatic and autonomic nervous systems operating at the central and peripheral levels. Disruption of endocrine, neural, or vascular response, caused by aging, medical illness, neurological diseases, surgery, or drugs, can lead to sexual dysfunctions, thus significantly affecting patients' quality of life.

PURPOSE

This narrative review aims at characterizing the involvement of the central nervous system in human sexual behavior.

METHODS

A literature search was conducted using PubMed in its entirety up to June 2018, analyzing the studies dealing with the neurobiological and neurophysiological basis of human sexuality.

RESULTS

Sexual behavior is regulated by both subcortical structures, such as the hypothalamus, brainstem, and spinal cord, and several cortical brain areas acting as an orchestra to finely adjust this primitive, complex, and versatile behavior. At the central level, dopaminergic and serotonergic systems appear to play a significant role in various factors of sexual response, although adrenergic, cholinergic, and other neuropeptide transmitter systems may contribute as well.

CONCLUSIONS

Providing healthcare professionals with information concerning sexual behavior may overcome useless and sometimes dangerous barriers and improve patient management, since sexual well-being is considered one of the most important aspects of one's quality of life.

Highly structured, partner-sex- and subject-sex-dependent cortical responses during social facial touch

Touch is a fundamental aspect of social, parental and sexual behavior. In contrast to our detailed knowledge about cortical processing of non-social touch, we still know little about how social touch impacts cortical circuits. We investigated neural activity across five frontal, motor and sensory cortical areas in rats engaging in naturalistic social facial touch. Information about social touch and the sex of the interaction partner (a biologically significant feature) is a major determinant of cortical activity. 25.3% of units were modulated during social touch and 8.3% of units displayed ‘sex-touch’ responses (responded differently, depending on the sex of the interaction partner). Single-unit responses were part of a structured, partner-sex- and, in some cases, subject-sex-dependent population response. Spiking neural network simulations indicate that a change in inhibitory drive might underlie these population dynamics. Our observations suggest that socio-sexual characteristics of touch (subject and partner sex) widely modulate cortical activity and need to be investigated with cellular resolution.

Touch is an important sensory modality during social encounters. Here the authors report that during naturalistic social encounters in rats, the cortical activity in widespread areas at the level of single neurons is modulated by sociosexual characteristics such as the subject and partner sex.

Modeling Human Sexual Motivation in Rodents: Some Caveats

Sexual behavior is activated by motivation. An overwhelming majority of experimental studies of the intricacies of sexual motivation has been performed in rodents, most of them in rats. Sometimes it is desirable to generalize results obtained in this species to other species, particularly the human. It is hoped that studies of the neurobiology of rodent sexual behavior may shed light on the central nervous mechanisms operating in the human, and the search for efficient pharmacological treatments of human sexual dysfunctions relies partly on studies performed in rodents. Then the issue of generalizability of the rodent data to the human becomes crucial. We emphasize the importance of distinguishing between copulatory acts, behavior involving the genitals, and the preceding event, the establishment of physical contact with a potential mate. Comparisons between the structure of copulatory behavior in rats and humans show abysmal differences, but there may be some similarity in the underlying mechanisms. The endocrine control of sex behavior is shortly mentioned, and we also compare the effects of the few drugs known to affect both rodent and human copulatory behavior. The stimuli activating sexual motivation, often called desire in the human literature, are examined, and the sexual approach behaviors in rats and humans are compared. There is a striking similarity between these species in how these behaviors respond to drugs. It is then shown that the intensity of sexual approach is unrelated to the intensity of copulatory behavior. Even though the approach is a requisite for copulation, an activity that requires at least two individuals in close physical contact, these two aspects of sexuality do not covary. This is similar to the role of the testosterone in men and male rats: although the hormone is needed for sex behavior, there is no correlation between serum testosterone concentration and the intensity of copulation. It is also pointed out that human sexual behavior is mostly determined by social conventions, whereas this is not the case in rats and other rodents. It is concluded that some observations in rats can be generalized to the human, but extreme caution must be exercised.

Physiological and Anatomical Outputs of Rat Genital Cortex

Rat somatosensory genital cortex contains a large sexually monomorphic representation of the penis in males and the clitoris in females. Genital cortex microstimulation-evoked movements of legs, trunk and genitals, which showed sex-specific differences related to mating behaviors and included thrusting in males and lordosis-like movements in females. Erections/tumescence of penis or clitoris could not be evoked, however. Anterograde tracer injections into penis/clitoris cortex revealed eleven corticocortical and 10 subcortical projection targets, which were qualitatively similar in both sexes. Corticocortical genital-cortex-projections innervated about 3% of the cortical surface and most were analog to other somatosensory projections targeting motor cortex, secondary somatosensory cortex, parietal cortex and perirhinal cortex. Corticocortical projections that differed from other parts of somatosensory cortex targeted male scrotum cortex, female vulva cortex, the somatosensory–ear–auditory-cortex-region and the caudal parietal area. Aligning cytoarchitectonic borders with motor topography, sensory genital responses and corticocortical projections identified a candidate region for genital motor cortex. Most subcortical genital-cortex-projections were analog to other thalamic, tectal or pontine projections of somatosensory cortex. Genital-cortex-specific subcortical projections targeted amygdala and nucleus submedius and accumbens. Microstimulation-effects and projections support a sexual function of genital cortex and suggest that genital cortex is a major hub of sexual sensorimotor processing in rodents.

How Hot Are They? Neural Correlates of Genital Arousal: An Infrared Thermographic and Functional Magnetic Resonance Imaging Study of Sexual Arousal in Men and Women

BACKGROUND

The few studies that have examined the neural correlates of genital arousal have focused on men and are methodologically hard to compare.

AIM

To investigate the neural correlates of peripheral physiologic sexual arousal using identical methodology for men and women.

METHODS

2 groups (20 men, 20 women) viewed movie clips (erotic, humor) while genital temperature was continuously measured using infrared thermal imaging. Participants also continuously evaluated changes in their subjective arousal and answered discrete questions about liking the movies and wanting sexual stimulation. Brain activity, indicated by blood oxygen level-dependent (BOLD) response, was measured using functional magnetic resonance imaging.

OUTCOMES

BOLD responses, genital temperature, and subjective sexual arousal.

RESULTS

BOLD activity in a number of brain regions was correlated with changes in genital temperature in men and women; however, activation in women appeared to be more extensive than in men, including the anterior and posterior cingulate cortex, right cerebellum, insula, frontal operculum, and paracingulate gyrus. Examination of the strength of the correlation between BOLD response and genital temperature showed that women had a stronger brain-genital relation compared with men in a number of regions. There were no brain regions in men with stronger brain-genital correlations than in women.

CLINICAL TRANSLATION

Our findings shed light on the neurophysiologic processes involved in genital arousal for men and women. Further research examining the specific brain regions that mediate our findings is necessary to pave the way for clinical application.

STRENGTHS AND LIMITATIONS

A strength of the study is the use of thermography, which allows for a direct comparison of the neural correlates of genital arousal in men and women. This study has the common limitations of most laboratory-based sexual arousal research, including sampling bias, lack of ecologic validity, and equipment limitations, and those common to neuroimaging research, including BOLD signal interpretation and neuroimaging analysis issues.

CONCLUSIONS

Our findings provide direct sex comparisons of the neural correlates of genital arousal in men and women and suggest that brain-genital correlations could be stronger in women. Parada M, Gérard M, Larcher K, et al. How Hot Are They? Neural Correlates of Genital Arousal: An Infrared Thermographic and Functional Magnetic Resonance Imaging Study of Sexual Arousal in Men and Women. J Sex Med 2018;15:217-229.

Brain Imaging of Human Sexual Response: Recent Developments and Future Directions

PURPOSE OF REVIEW

The purpose of this study is to provide a comprehensive summary of the latest developments in the experimental brain study of human sexuality, focusing on brain connectivity during the sexual response.

RECENT FINDINGS

Stable patterns of brain activation have been established for different phases of the sexual response, especially with regard to the wanting phase, and changes in these patterns can be linked to sexual response variations, including sexual dysfunctions. From this solid basis, connectivity studies of the human sexual response have begun to add a deeper understanding of the brain network function and structure involved.

SUMMARY

The study of "sexual" brain connectivity is still very young. Yet, by approaching the brain as a connected organ, the essence of brain function is captured much more accurately, increasing the likelihood of finding useful biomarkers and targets for intervention in sexual dysfunction.

The Role of Ovarian Hormones and the Medial Amygdala in Sexual Motivation

Purpose

Although research into the neurobiology of sexual desire in women is active, relatively little is understood about the origins of sexual motivation in women. The purpose of our review is to discuss factors that influence a central sexual motivate state and generalized arousal as potential drivers of sexual motivation in women and female rats.

Recent Findings

Sexual motivation is the product of interactions of the central motive state and salient sexually-relevant cues. Ovarian hormones and generalized arousal influence the central motive state, and endogenous levels of estradiol and progesterone correlate with sexual motivation and behavior in women. The amygdala is a key integratory site for generalized arousal and sexual sensory stimulation, which could then increase sexual motivation through its downstream projections.

Summary

Our model of enhanced female sexual motivation suggests that the combined effects of dopamine and progesterone receptor activation in the medial amygdala increases the incentive properties of a sexual stimulus. Further study into the interactions of ovarian hormones and mediators of generalized arousal on the processing of sexually-relevant cues informs our understanding of the neurobiology of female sexual motivation and could lead to the development of therapeutics to treat the dysfunctions of sexual desire in women.

Aerobic exercise promotes executive functions and impacts functional neural activity among older adults with vascular cognitive impairment

BACKGROUND

Vascular cognitive impairment (VCI) results from cerebrovascular disease, and worldwide, it is the second most common type of cognitive dysfunction. While targeted aerobic training is a promising approach to delay the progression of VCI by reducing cardiometabolic risk factors, few randomised controlled trials to date have specifically assessed the efficacy of aerobic training on cognitive and brain outcomes in this group at risk for functional decline.

AIM

To examine the effect of moderate-intensity aerobic training on executive functions and functional neural activity among older adults with mild subcortical ischaemic VCI (SIVCI).

METHODS

Older adults with mild SIVCI were randomly assigned to: (1) 6-month, 3×/week aerobic training (n=10) or (2) usual care (control; n=11). Participants completed functional MRI (fMRI) at baseline and trial completion. During the fMRI sessions, behavioural performance on the Eriksen flanker task and task-evoked neural activity were assessed.

RESULTS

At trial completion, after adjusting for baseline general cognition, total white matter lesion volume and flanker performance, compared with the control group, the aerobic training group significantly improved flanker task reaction time. Moreover, compared with the controls, the aerobic training group demonstrated reduced activation in the left lateral occipital cortex and right superior temporal gyrus. Reduced activity in these brain regions was significantly associated with improved (ie, faster) flanker task performance at trial completion.

SUMMARY

Aerobic training among older adults with mild SIVCI can improve executive functions and neural efficiency of associated brain areas. Future studies with greater sample size should be completed to replicate and extend these findings.