Publications by authors named "F Gonzalez-Lima"

172 Publications

Photobiomodulation for the aging brain.

Ageing Res Rev 2021 09 26;70:101415. Epub 2021 Jul 26.

Núcleo de Pesquisas Tecnológicas, Universidade de Mogi das Cruzes, Mogi das Cruzes, SP, Brazil; Centro Universitário UNIFAMINAS (UNIFAMINAS), Muriaé, MG, Brazil; Hospital do Câncer de Muriaé, Fundação Cristiano Varella (FCV), Muriaé, MG, Brazil. Electronic address:

Longevity is one of the great triumphs of humanity. Worldwide, the elderly is the fastest growing segment of the population. As a consequence, the number of cases of age-related cognitive decline and neurological diseases associated with aging, such as Alzheimer's and Parkinson's, has been increasing. Among the non-pharmacological interventions studied for the treatment or prevention of age-related neurocognitive impairment, photobiomodulation (PBM) has gained prominence for its beneficial effects on brain functions relevant to aging brains. In animal models, the neuroprotective and neuromodulatory capacity of PBM has been observed. Studies using both animals and humans have shown promising metabolic and hemodynamic effects of PBM on the brain, such as improved mitochondrial and vascular functions. Studies in humans have shown that PBM can improve electrophysiological activity and cognitive functions such as attention, learning, memory and mood in older people. In this paper we will review the main brain effects of PBM during aging, discuss its mechanisms of action relevant to the aging brain, and call for more controlled studies in older populations.
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http://dx.doi.org/10.1016/j.arr.2021.101415DOI Listing
September 2021

Singular and combined effects of transcranial infrared laser stimulation and exposure therapy on pathological fear: a randomized clinical trial.

Psychol Med 2021 Jul 21:1-10. Epub 2021 Jul 21.

Department of Psychology, The University of Texas at Austin, Austin, TX, USA.

Background: Preclinical findings suggest that transcranial infrared laser stimulation (TILS) improves fear extinction learning and cognitive function by enhancing prefrontal cortex (PFC) oxygen metabolism. These findings prompted our investigation of treating pathological fear using this non-invasive stimulation approach either alone to the dorsolateral PFC (dlPFC), or to the ventromedial PFC (vmPFC) in combination with exposure therapy.

Methods: Volunteers with pathological fear of either enclosed spaces, contamination, public speaking, or anxiety-related bodily sensations were recruited for this randomized, single-blind, sham-controlled trial with four arms: (a) Exposure + TILS_vmPFC (n = 29), (b) Exposure + sham TILS_vmPFC (n = 29), (c) TILS_dlPFC alone (n = 26), or (d) Sham TILS _dlPFC alone (n = 28). Post-treatment assessments occurred immediately following treatment. Follow-up assessments occurred 2 weeks after treatment.

Results: A total of 112 participants were randomized [age range: 18-63 years; 96 females (85.71%)]. Significant interactions of Group × Time and Group × Context indicated differential treatment effects on retention (i.e. between time-points, averaged across contexts) and on generalization (i.e. between contexts, averaged across time-points), respectively. Among the monotherapies, TILS_dlPFC outperformed SHAM_dlPFC in the initial context, b = -13.44, 95% CI (-25.73 to -1.15), p = 0.03. Among the combined treatments, differences between EX + TILS_vmPFC and EX + SHAM_vmPFC were non-significant across all contrasts.

Conclusions: TILS to the dlPFC, one of the PFC regions implicated in emotion regulation, resulted in a context-specific benefit as a monotherapy for reducing fear. Contrary to prediction, TILS to the vmPFC, a region implicated in fear extinction memory consolidation, did not enhance exposure therapy outcome.
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http://dx.doi.org/10.1017/S0033291721002270DOI Listing
July 2021

The FDA Approves Aducanumab for Alzheimer's Disease, Raising Important Scientific Questions1.

J Alzheimers Dis 2021 ;82(3):881-882

George I. Sanchez Centennial Professor, Department of Psychology, Institute for Neuroscience, Director, Texas Consortium in Behavioral Neuroscience, University of Texas at Austin, Austin, TX, USA.

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http://dx.doi.org/10.3233/JAD-210736DOI Listing
September 2021

Transcranial laser stimulation: Mitochondrial and cerebrovascular effects in younger and older healthy adults.

Brain Stimul 2021 Mar-Apr;14(2):440-449. Epub 2021 Feb 23.

Department of Psychology and Institute for Neuroscience, University of Texas at Austin, Austin, TX, USA. Electronic address:

Background: Transcranial laser stimulation is a novel method of noninvasive brain stimulation found safe and effective for improving prefrontal cortex neurocognitive functions in healthy young adults. This method is different from electric and magnetic stimulation because it causes the photonic oxidation of cytochrome-c-oxidase, the rate-limiting enzyme for oxygen consumption and the major intracellular acceptor of photons from near-infrared light. This photobiomodulation effect promotes mitochondrial respiration, cerebrovascular oxygenation and neurocognitive function. Pilot studies suggest that transcranial photobiomodulation may also induce beneficial effects in aging individuals.

Objectives: Randomized, sham-controlled study to test photobiomodulation effects caused by laser stimulation on cytochrome-c-oxidase oxidation and hemoglobin oxygenation in the prefrontal cortex of 68 healthy younger and older adults, ages 18-85.

Methods: Broadband near-infrared spectroscopy was used for the noninvasive quantification of bilateral cortical changes in oxidized cytochrome-c-oxidase and hemoglobin oxygenation before, during and after 1064-nm wavelength laser (IR-A laser, area: 13.6 cm, power density: 250 mW/cm) or sham stimulation of the right anterior prefrontal cortex (Brodmann Area 10).

Results: As compared to sham control, there was a significant laser-induced increase in oxidized cytochrome-c-oxidase during laser stimulation, followed by a significant post-stimulation increase in oxygenated hemoglobin and a decrease in deoxygenated hemoglobin. Furthermore, there was a greater laser-induced effect on cytochrome-c-oxidase with increasing age, while laser-induced effects on cerebral hemodynamics decreased with increasing age. No adverse laser effects were found.

Conclusion: The findings support the use of transcranial photobiomodulation for cerebral oxygenation and alleviation of age-related decline in mitochondrial respiration. They justify further research on its therapeutic potential in neurologic and psychiatric diseases.
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http://dx.doi.org/10.1016/j.brs.2021.02.011DOI Listing
February 2021

Transcranial Infrared Laser Stimulation Improves Cognition in Older Bipolar Patients: Proof of Concept Study.

J Geriatr Psychiatry Neurol 2021 Feb 2:891988720988906. Epub 2021 Feb 2.

Department of Psychology and Institute for Neuroscience, 7067University of Texas at Austin, TX, USA.

This is the first study to examine if transcranial infrared laser stimulation (TILS) improves cognition in older euthymic bipolar patients, who exhibit greater cognitive decline than is expected for age-matched controls. TILS is a non-invasive novel form of photobiomodulation that augments prefrontal oxygenation and improves cognition in young adults by upregulating the mitochondrial respiratory enzyme cytochrome-c-oxidase. We used a crossover sham-controlled design to examine if TILS to bilateral prefrontal cortex produces beneficial effects on cognition in 5 euthymic bipolar patients (ages 60-85). We measured cognitive flexibility, verbal fluency, working memory, sustained attention and impulsivity with tasks that have been shown to differentiate between healthy older adults and older bipolar adults. We found TILS-induced improvements in cognitive performance on the tasks that measure cognitive flexibility and impulsivity, after 5 weekly sessions of TILS. We concluded that TILS appeared both safe and effective in helping alleviate the accelerated cognitive decline present in older bipolar patients.
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http://dx.doi.org/10.1177/0891988720988906DOI Listing
February 2021
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