Lateral visual field stimulation reveals extrastriate cortical activation in the contralateral hemisphere: an fMRI study

The challenge of remote treatment in neuropsychological intervention for reading and spelling in dyslexia: A prospective observational cohort study

Telemedicine approaches have proved to be valuable solutions for the delivery of treatment for many health-related issues, and crucial during the pandemics. Nonetheless, the efficacy of such Web-based practices in developmental dyslexia needs to be thoroughly evaluated. To this aim, the effects of a multi-componential program for neuropsychological intervention in dyslexia delivered as an outpatient program were compared with those obtained with a remotely delivered, Web-based treatment, based on the same methodological principles and delivered with the same duration and intensity. The treatment-related changes obtained with a combination of visual hemisphere-specific stimulation and training of visual-spatial attention through action video games, were compared to those obtained through remote treatment via the Tachidino Web-based platform. Both treatments had a duration of 4 weeks. The same battery of reading and phonemic awareness tests was delivered in presence, before and after treatment, as well as at 6-months follow-up. User satisfaction was assessed through parents and user questionnaires. Both treatments were significantly and similarly effective in improving reading speed, reading accuracy, and writing accuracy. No reduction in the effects was observed after treatment discontinuation. The Web-based treatment may thus offer a valid alternative to in-person intervention, optimizing the flexibility, capillary diffusion and cost-effectiveness of intervention.

Simulating Local Biases in Visual Attention in Neurocognitive Performance

Typical visual perception includes an attention bias toward right hemisphere mediated global, holistic cortical processing. An atypically local, detail-oriented focus of attention is characteristic of left hemisphere processing and is often observed in patients whose field of attention is restricted by certain types of neurocognitive impairment. We designed the present pair of studies to induce a local attentional focus to observe its consequences on neurocognitive measures of visuospatial processing. In Experiment I, participants wore glasses mimicking simultanagnosia, a disorder of visual attention, to induce a narrowed, atypical attentional style while they completed visual neuropsychological tasks. This simulation impaired participants' capacities to visually synthesize and efficiently reproduce Complex Figure stimuli as measured with the Boston Qualitative Scoring System (BQSS), and it induced an atypical attentional style on Rorschach Performance Assessment System (R-PAS) responses. In Experiment II, participants wore glasses designed to provoke differential hemispheric activation, also hypothesized to influence style of visual attention; but this manipulation did not influence neurocognitive task performance. We discuss implications for the interpretation of BQSS and R-PAS scores and offer directions for future research.

Dual-Brain Psychology: A novel theory and treatment based on cerebral laterality and psychopathology

Dual-Brain Psychology is a theory and its clinical applications that come out of the author's clinical observations and from the Split-brain Studies. The theory posits, based on decades of rigorous, peer-reviewed experiments and clinical reports, that, in most patients, one brain's cerebral hemisphere (either left or right) when stimulated by simple lateral visual field stimulation, or unilateral transcranial photobiomodulation, reveals a dramatic change in personality such that stimulating one hemisphere evokes, as a trait, a personality that is more childlike and more presently affected by childhood maltreatments that are usually not presently appreciated but are the proximal cause of the patient's symptoms. The personality associated with the other hemisphere is much more mature, less affected by the traumas, and less symptomatic. The theory can be applied to in-depth psychotherapy in which the focus is on helping the troubled side to bear and process the traumas with the help of the therapist and the healthier personality. A person's symptoms can be evoked to aid the psychotherapy with hemispheric stimulation and the relationship between the dual personalities can be transformed from conflicted and sabotaging to cooperating toward overall health. Stimulating the positive hemisphere in most therapy patients rapidly relieves symptoms such as anxiety, depression, or substance cravings. Two randomized controlled trials used unilateral transcranial photobiomodulation to the positive hemisphere as a stand-alone treatment for opioid cravings and both revealed high effect sizes. The theory is supported by brain imaging and rTMS studies. It is the first psychological theory and application that comes out of and is supported by rigorous peer-reviewed experimentation.

Individual Differences in Hemispheric Emotional Valence by Computerized Test Correlate with Lateralized Differences in Nucleus Accumbens, Hippocampal and Amygdala Volumes

Purpose

Conventional theories of hemispheric emotional valence (HEV) postulate fixed hemispheric differences in emotional processing. Schiffer’s dual brain psychology proposes that there are prominent individual differences with a substantial subset showing a reversed laterality pattern. He further proposed that hemispheric differences were more akin to differences in personality than in emotional processing. This theory is supported by findings that unilateral treatments, such as transcranial magnetic stimulation, are effective if they accurately target individual differences in laterality. The aim of this paper was to assess if a computer test of hemispheric emotional valence (CTHEV) could effectively identify individual differences in HEV and to ascertain if these individual differences were associated with underlying differences in brain structure and connectivity.

Patients and Methods

The CTHEV was administered to 50 (18 male/32 female) right-handed participants, aged 18–19 years, enrolled in a study assessing the neurobiological effects of childhood maltreatment. Based on a literature review, we determined whether CTHEV correlated with lateralized volumes of the nucleus accumbens, amygdala, hippocampus, and subgenual anterior cingulate as well as volume of the corpus callosum.

Results

CTHEV scores correlated with laterality indices of the nucleus accumbens (p = 0.00016), amygdala (p = 0.0138) and hippocampus (p = 0.031). A positive left hemispheric valence was associated with a larger left-sided nucleus accumbens and hippocampus and a smaller left amygdala. We identified four eigenvector network centrality DTI measures that predict CTHEV, most notably the left amygdala, and found that CTHEV results correlated with total and segment-specific corpus callosal volumes.

Conclusion

Individual differences in HEV can be readily assessed by computer test and correlate with differences in brain structure and connectivity that could provide a mechanistic understanding. These findings provide further support for a revised understanding of HEV and provide a tool that could be used to guide lateralized brain treatments.

An Effective and Safe Novel Treatment of Opioid Use Disorder: Unilateral Transcranial Photobiomodulation

Background: The opioid epidemic is a global tragedy even with current treatments, and a novel, safe, and effective treatment would be welcomed. We report here our findings from our second randomized controlled trial to evaluate unilateral transcranial photobiomodulation as a treatment for opioid use disorder. Methods: We enrolled 39 participants with active opioid cravings at 2 sites, 19 received the active treatment which consisted of a 4-min twice weekly (every 3 or 4 days) application of a light-emitting diode at 810 nm with an irradiance of 250 mW/cm2 and a fluence of 60 J/cm2 to the forehead over either the left or right dorsolateral prefrontal cortex with a fluence to the brain of 2.1 J/cm2. Twenty participants received a sham treatment with the same device with foil over the bulb. The side of the treatment was based on Dual-Brain Psychology, which posits that one hemisphere is more affected by past maltreatments and is more prone to anxiety and drug cravings that the other hemisphere. We treated the hemisphere with the more positive hemispheric emotional valence (HEV) by 2 tests for HEV. Results: Our primary outcome was changes in pre-treatment opioid craving scale (OCS) minus baseline, and we found using a mixed model that the active group had a highly significant treatment * time benefit over the sham group, p < 0.0001, effect size at the last follow-up of 1.5. The active treatment benefited those not on buprenorphine as well as those not on it. The TimeLine Follow Back measure of opioid use was significantly better in the actively treated group, p = 0.0001, with an effect size of 0.45. We observed no adverse effects. Conclusion: Active unilateral transcranial photobiomodulation to the brain hemisphere with the better HEV was better than sham in the reduction of opioid cravings and opioid use to a very significant degree in a RCT of 39 participants at 2 independent sites. In the active group those on buprenorphine and those not on it both had improvements in cravings over the study. No adverse responses were reported in either group. ClinicalTrials.gov Identifier: NCT04340622.

A Dual Mind Approach to Understanding the Conscious Self and Its Treatment

In this paper I will address questions about will, agency, choice, consciousness, relevant brain regions, impacts of disorders, and their therapeutics, and I will do this by referring to my theory, Dual-brain Psychology, which posits that within most of us there exist two mental agencies with different experiences, wills, choices, and behaviors. Each of these agencies is associated as a trait with one brain hemisphere (either left or right) and its composite regions. One of these agencies is more adversely affected by past traumas, and is more immature and more symptomatic, while the other is more mature and healthier. The theory has extensive experimental support through 17 peer-reviewed publications with clinical and non-clinical research. I will discuss how this theory relates to the questions about the nature of agency and I will also discuss my published theory on the physical nature of subjective experience and its relation to the brain, and how that theory interacts with Dual-Brain Psychology, leading to further insights into our human nature and its betterment.

Unilateral transcranial photobiomodulation for opioid addiction in a clinical practice: A clinical overview and case series

INTRODUCTION

Opioid Use Disorders (OUD) cause great disfunction and pain to individuals, families, and societies. There are few good treatments. This paper presents a novel, easily applied, painless, therapy that can be applied as an adjunct to psychotherapies and medications.

METHODS

The author presents a retrospective overview and 4 brief case reports. Two are typical of very positively responsive patients, one is of a positively but not remarkably responsive patient, and one of a non-responsive patient. The author used unilateral transcranial photobiomodulation (UtPBM), near infrared mode, applied to the hemisphere with the more positive hemispheric emotional valence (HEV) as a treatment to augment the patients' usual treatment.

RESULTS

The case reports are from 42 consecutive patients in his practice with OUD where he has given 382 treatments over 18 months, as needed. The author's subjective clinical observations were that of the 42 patients, 26 (62%) consistently had responses to the UtPBM (as described in the case reports) that were easily observable to the patient and the author as strikingly beneficial, 8 (19%) had helpful, but not remarkable responses, and 8 (19%) had no noticeable response. These 3 characterizations will be illustrated with clinical examples. There were no side-effects reported or observed aside from 2 women who experienced anxiety which resolved with psychotherapy.

CONCLUSIONS

Using UtPBM as an adjunctive treatment to the author's usual in-depth psychotherapy and medication management, he found subjectively that for the majority of his patients, this treatment was a valuable, safe benefit to their treatment for OUD.

A Novel Treatment of Opioid Cravings With an Effect Size of .73 for Unilateral Transcranial Photobiomodulation Over Sham

BACKGROUND

Opioid use disorders (OUDs) are an epidemic causing catastrophic consequences to individuals, families, and society despite treatments including psychotherapy, substitution therapy or receptor blockers, and psychoeducation. We have developed a novel treatment that combines unilateral transcranial photobiomodulation (t-PBM) to the hemisphere with a more positive valence by Dual Brain Psychology (DBP).

METHODS

We used a randomized, double blind, placebo-controlled protocol in which 22 patients with significant opioid cravings and a history of recent or current OUD attended three 1-h weekly sessions. After baseline measures of opioid craving and other psychometrics, subjects received two unilateral t-PBM applications (810 nm CW LED, 250 mW/cm², 60 J/cm², 4 min) or a sham (foil-covered LED) at F3 or F4. Prior to any treatment we used two tests to determine which hemisphere was more associated with a negative outlook and cravings and treated that side before the more positive hemisphere. Primary outcome measure was an opioid craving scale (OCS). Secondary outcomes were weekly Hamilton Depression (HDRS) and Anxiety (HARS) Rating Scales prior to treatments and at follow-up.

RESULTS

Immediately after treatment the OCS improved significantly for both the sham and active treatments, but one week later the active treatment showed a 51.0% (SD 33.7) decrease in OCS while a week after the sham treatments there was a decrease of only 15.8% (SD 35.0) (by Wilcoxon Sign Rank Test, p = 0.004) and by a mixed model it was p = 0.0071. The effect size for the differences between active and sham was 0.73. For the active treatment from before and after treatment the effect size was 1.51 and for the sham, 0.45. The HDRS improved from a baseline of 15.1 to 8.8 (SD 10.3) a week after the active treatment and to 13.3 (SD 12.9) after the sham (p = 0.0071). HARS improved from 14.7 to 8.0 (SD 13.2) after the active treatments and to 14.3 (SD 16.0) after the sham, p = 0.08. Active treatment of the positive hemisphere after the negative hemisphere significantly improved the OCS, but there was no significant difference after the sham treatment. One patient complained of 2 h of abdominal bloating and dropped out; no other adverse effects were observed.

DISCUSSION

Unilateral t-PBM to the hemisphere with a more positive hemispheric emotional valence was an effective and safe treatment for opioid cravings as well as for depression and anxiety. Our results also lend support to the underlying premises of DBP.

Plasticity of the Right-Lateralized Cognitive Reserve Network in Ageing

Cognitive reserve (CR) is the phenomenon where older adults with more cognitively stimulating environments show less age-related cognitive decline. The right-lateralized fronto-parietal network has been proposed to significantly contribute to CR and visual attention in ageing. In this study we tested whether plasticity of this network may be harnessed in ageing.We assessed CR and parameters of visual attention capacity in older adults. Transcranial direct current stimulation (tDCS) was employed to increase right fronto-parietal activity during a lateralized whole-report task. At baseline, older adults with greater CR showed a stronger hemifield asymmetry in processing speed towards the left visual-field, indicative of stronger involvement of the right hemisphere in these individuals. Correspondingly, processing speed improved during right prefrontal tDCS. Older adults with lower levels of CR showed tDCS-related improvements in processing speed in the left but not right hemifield: thus tDCS temporarily altered their processing speed asymmetry to resemble that of their high reserve peers.The finding that stronger right hemisphere involvement is related to CR supports Robertson's theory. Furthermore, preserved plasticity within the right prefrontal cortex in older adults suggests this is a viable target area to improve visual processing speed, a hallmark of age-related decline.

The effects of changes in object location on object identity detection: A simultaneous EEG-fMRI study

Object identity and location are bound together to form a unique integration that is maintained and processed in visual working memory (VWM). Changes in task-irrelevant object location have been shown to impair the retrieval of memorial representations and the detection of object identity changes. However, the neural correlates of this cognitive process remain largely unknown. In the present study, we aim to investigate the underlying brain activation during object color change detection and the modulatory effects of changes in object location and VWM load. To this end we used simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) recordings, which can reveal the neural activity with both high temporal and high spatial resolution. Subjects responded faster and with greater accuracy in the repeated compared to the changed object location condition, when a higher VWM load was utilized. These results support the spatial congruency advantage theory and suggest that it is more pronounced with higher VWM load. Furthermore, the spatial congruency effect was associated with larger posterior N1 activity, greater activation of the right inferior frontal gyrus (IFG) and less suppression of the right supramarginal gyrus (SMG), when object location was repeated compared to when it was changed. The ERP-fMRI integrative analysis demonstrated that the object location discrimination-related N1 component is generated in the right SMG.

Gaze direction affects visuo-spatial short-term memory

Hemispheric asymmetries were investigated by changing the horizontal position of stimuli that had to be remembered in a visuo-spatial short-term memory task. Observers looked at matrices containing a variable number of filled squares on the left or right side of the screen center. At stimulus offset, participants reproduced the positions of the filled squares in an empty response matrix. Stimulus and response matrices were presented in the same quadrant. We observed that memory performance was better when the matrices were shown on the left side of the screen. We distinguished between recall strategies that relied on visual or non-visual (verbal) cues and found that the effect of gaze position occurred more reliably in participants using visual recall strategies. Overall, the results show that there is a solid enhancement of visuo-spatial short-term memory when observers look to the left. In contrast, vertical position had no influence on performance. We suggest that unilateral gaze to the left activates centers in the right hemisphere contributing to visuo-spatial memory.

Increased anger is associated with increased hemispheric asymmetry: support for anger-tympanic membrane relationships

We recently reported that increased anger/hostility is associated with an increased imbalance of hemispheric activity, regardless of which particular hemisphere is more active (as indicated by increased absolute difference in temperature between the right and left tympanic membrane (ar-lTMT; Propper et al., J Nerv Ment Dis 198:691-694, 2010). In that study, we examined baseline levels of emotion and ar-lTMT; in this study, we used sustained unilateral gaze to manipulate hemispheric activity to further investigate the nature of the relationship between anger, ar-lTMT, and hemispheric imbalance. Both rightward (significantly) and leftward (modestly) sustained unilateral gaze increased anger, providing further evidence that anger is associated with the asymmetry of hemispheric activation. We also support our previous work demonstrating a relationship between increased anger and increased ar-lTMT. This is the second study supporting the use of ar-lTMT as a simple and convenient measure of hemispheric activation and as an objective correlate of anger.

Psychological benefits 2 and 4 weeks after a single treatment with near infrared light to the forehead: a pilot study of 10 patients with major depression and anxiety

Background

Many studies have reported beneficial effects from the application of near-infrared (NIR) light photobiomodulation (PBM) to the body, and one group has reported beneficial effects applying it to the brain in stroke patients. We have reported that the measurement of a patient's left and right hemispheric emotional valence (HEV) may clarify data and guide lateralized treatments. We sought to test whether a NIR treatment could 1. improve the psychological status of patients, 2. show a relationship between immediate psychological improvements when HEV was taken into account, and 3. show an increase in frontal pole regional cerebral blood flow (rCBF), and 4. be applied without side effects.

Methods

We gave 10 patients, (5 M/5 F) with major depression, including 9 with anxiety, 7 with a past history of substance abuse (6 with an opiate abuse and 1 with an alcohol abuse history), and 3 with post traumatic stress disorder, a baseline standard diagnostic interview, a Hamilton Depression Rating Scale (HAM-D), a Hamilton Anxiety Rating Scale (HAM-A), and a Positive and Negative Affect Scale (PANAS). We then gave four 4-minute treatments in a random order: NIR to left forehead at F3, to right forehead at F4, and placebo treatments (light off) at the same sites. Immediately following each treatment we repeated the PANAS, and at 2-weeks and at 4-weeks post treatment we repeated all 3 rating scales. During all treatments we recorded total hemoglobin (cHb), as a measure of rCBF with a commercial NIR spectroscopy device over the left and the right frontal poles of the brain.

Results

At 2-weeks post treatment 6 of 10 patients had a remission (a score ≤ 10) on the HAM-D and 7 of 10 achieved this on the HAM-A. Patients experienced highly significant reductions in both HAM-D and HAM-A scores following treatment, with the greatest reductions occurring at 2 weeks. Mean rCBF across hemispheres increased from 0.011 units in the off condition to 0.043 units in the on condition, for a difference of 0.032 (95% CI: -0.016, 0.080) units, though this result did not reach statistical significance. Immediately after treatment the PANAS improved to a significantly greater extent with NIR "on" relative to NIR "off" when a hemisphere with more positive HEV was treated than when one with more negative HEV was treated. We observed no side effects.

Conclusion

This small feasibility study suggests that NIR-PBM may have utility for the treatment of depression and other psychiatric disorders and that double blind randomized placebo-controlled trials are indicated.

Trial registration

ClinicalTrials.gov Identifier: NCT00961454

A tale of two recognition systems: implications of the fusiform face area and the visual word form area for lateralized object recognition models

Two areas of current intense interest in the neuroimaging literature are that of the visual word form area (VWFA) and of the fusiform face area (FFA) and their roles in word and face perception, respectively. These two areas are of particular relevance to laterality research because visual word identification and face identification have long been shown to be especially lateralized to the left hemisphere and the right hemisphere, respectively. This review therefore seeks to evaluate their significance for the broader understanding of lateralization of object recognition. A multi-level model of lateralized object recognition is proposed based on a combination of behavioral and neuroimaging findings. Rather than seek to characterize hemispheric asymmetries according to a single principle (e.g., serial-parallel), it is suggested that current observations can be understood in terms of three asymmetric levels of processing, using the framework of the Janus model of hemispheric function. It is suggested that the left hemisphere represents features using an abstract-category code whereas the RH utilizes a specific-exemplar code. The relationships between these features are also coded asymmetrically, with the LH relying on associative co-occurrence values and the RH relying on spatial metrics. Finally, the LH controlled selection system focuses on isolating features and the RH focuses on conjoining features. It is suggested that each hemisphere utilizes efficient (apparently parallel) processing when stimuli are congruent with its preferred processing style and inefficient (apparently serial) processing when they are not, resulting in the typical left-lateralization for orthographic analysis and right-lateralization for face analysis.

Handedness differences in body image distortion and eating disorder symptomatology

OBJECTIVE

Previous research has shown decreased access in strong right-handers to processes lateralized to the right cerebral hemisphere. The current studies tested the hypothesis that decreased access to right hemisphere processes, as indexed by increasing strength of right-hand preference, is associated with deficits in body image representation.

METHOD

Experiment 1 measured individual's perceived versus actual BMI values. Experiment 2 involved the administration of the Eating Disorders Inventory-2 (EDI-2).

RESULTS

Experiment 1 revealed that strong right-handedness was associated with a larger discrepancy between actual and perceived BMI, relative to mixed-handedness. In Experiment 2, strong-handers scored higher on the EDI-2 than did mixed-handers.

CONCLUSION

The results indicate that strong degrees of handedness are associated with deficits in accurate representation of body image and with increased eating disorder symptomatology in a nonclinical sample. Implications for research into the neural bases of eating disorders are discussed.

Determination of hemispheric emotional valence in individual subjects: a new approach with research and therapeutic implications

BACKGROUND

Much has been theorized about the emotional properties of the hemispheres. Our review of the dominant hypotheses put forth by Schore, Joseph, Davidson, and Harmon-Jones on hemispheric emotional valences (HEV) shows that none are supported by robust data. Instead, we propose that individual's hemispheres are organized to have differing HEVs that can be lateralized in either direction.

METHODS

Probe auditory evoked potentials (AEP) recorded during a neutral and an upsetting memory were used to assess HEV in 28 (20 F) right-handed subjects who were either victims of childhood maltreatment (N = 12) or healthy controls. In a sub-population, we determined HEV by emotional response to lateral visual field stimulation (LVFS), in which vision is limited to one, then the other hemifield. We compare a number of morphometric and functional brain measures between individuals who have right-negative versus left-negative HEV.

RESULTS

Using AEPs to determine HEV, we found 62% of controls and 67% of maltreated subjects had right negative HEV. There was a strong interaction between HEV-laterality and gender, which together accounted for 60% of individual variability in total grey matter volume (GMV). HEV-laterality was associated with differences in hippocampal volume, amygdala/hippocampal ratios, and measures of verbal, visual and global memory. HEV-laterality was associated also with different constellations of symptoms comparing maltreated subjects to controls. Emotional response to LVFS provided a convenient and complementary measure of HEV-laterality that correlated significantly with the HEVs determined by AEPs.

CONCLUSION

Our findings suggest that HEV-laterality, like handedness or gender, is an important individual difference with significant implications for brain and behavioral research, and for guiding lateralized treatments such as rTMS.