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Noback M, Bhakta SG, Talledo JA, Kotz JE, Benster L, Roberts BZ, Nungaray JA, Light GA, Swerdlow NR, Brigman JL, Cavanagh JF, Young JW. Amphetamine increases motivation of humans and mice as measured by breakpoint, but does not affect an Electroencephalographic biomarker. Cogn Affect Behav Neurosci 2024; 24:269-278. [PMID: 38168850 PMCID: PMC11060428 DOI: 10.3758/s13415-023-01150-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/15/2023] [Indexed: 01/05/2024]
Abstract
Translation of drug targets from preclinical studies to clinical trials has been aided by cross-species behavioral tasks, but evidence for brain-based engagement during task performance is still required. Cross-species progressive ratio breakpoint tasks (PRBTs) measure motivation-related behavior and are pharmacologically and clinically sensitive. We recently advanced elevated parietal alpha power as a cross-species electroencephalographic (EEG) biomarker of PRBT engagement. Given that amphetamine increases breakpoint in mice, we tested its effects on breakpoint and parietal alpha power in both humans and mice. Twenty-three healthy participants performed the PRBT with EEG after amphetamine or placebo in a double-blind design. C57BL/6J mice were trained on PRBT with EEG (n = 24) and were treated with amphetamine or vehicle. A second cohort of mice was trained on PRBT without EEG (n = 40) and was treated with amphetamine or vehicle. In humans, amphetamine increased breakpoint. In mice, during concomitant EEG, 1 mg/kg of amphetamine significantly decreased breakpoint. In cohort 2, however, 0.3 mg/kg of amphetamine increased breakpoint consistent with human findings. Increased alpha power was observed in both species as they reached breakpoint, replicating previous findings. Amphetamine did not affect alpha power in either species. Amphetamine increased effort in humans and mice. Consistent with previous reports, elevated parietal alpha power was observed in humans and mice as they performed the PRBT. Amphetamine did not affect this EEG biomarker of effort. Hence, these findings support the pharmacological predictive validity of the PRBT to measure effort in humans and mice and suggest that this EEG biomarker is not directly reflective of amphetamine-induced changes in effort.
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Affiliation(s)
- Michael Noback
- Department of Psychiatry, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA, 92093-0804, USA
| | - Savita G Bhakta
- Department of Psychiatry, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA, 92093-0804, USA
| | - Jo A Talledo
- Department of Psychiatry, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA, 92093-0804, USA
| | - Juliana E Kotz
- Department of Psychiatry, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA, 92093-0804, USA
| | - Lindsay Benster
- Department of Psychiatry, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA, 92093-0804, USA
| | - Benjamin Z Roberts
- Department of Psychiatry, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA, 92093-0804, USA
| | - John A Nungaray
- Department of Psychiatry, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA, 92093-0804, USA
| | - Gregory A Light
- Department of Psychiatry, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA, 92093-0804, USA
- Research Service MIRECC, VISN 22, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA
| | - Neal R Swerdlow
- Department of Psychiatry, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA, 92093-0804, USA
| | - Jonathan L Brigman
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM, USA
| | - James F Cavanagh
- Psychology Department, University of New Mexico, Albuquerque, NM, USA
| | - Jared W Young
- Department of Psychiatry, University of California, San Diego School of Medicine, 9500 Gilman Drive, La Jolla, CA, 92093-0804, USA.
- Research Service MIRECC, VISN 22, Veterans Affairs San Diego Healthcare System, San Diego, CA, USA.
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Swerdlow NR, Bhakta SG, Talledo J, Benster L, Kotz J, Vinogradov S, Molina JL, Light GA. Auditory discrimination and frequency modulation learning in schizophrenia patients: amphetamine within-subject dose response and time course. Psychol Med 2023; 53:140-148. [PMID: 33849683 PMCID: PMC8514598 DOI: 10.1017/s0033291721001239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 03/11/2021] [Accepted: 03/17/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND Auditory frequency modulation learning ('auditory learning') is a key component of targeted cognitive training (TCT) for schizophrenia. TCT can be effective in enhancing neurocognition and function in schizophrenia, but such gains require significant time and effort and elude many patients. METHODS As a strategy to increase and/or accelerate TCT-induced clinical gains, we tested the dose- and time-course effects of the pro-attentional drug, amphetamine (AMPH; placebo, 2.5, 5 or 10 mg po; within-subject double-blind, order balanced) on auditory learning in schizophrenia patients [n = 32; M:F = 19:13; age 42.0 years (24-55)]. To understand predictors and/or mechanisms of AMPH-enhanced TCT, we also measured auditory fidelity (words-in-noise (WIN), quick speech-in-noise (QuickSIN)) and neurocognition (MATRICS comprehensive cognitive battery (MCCB)). Some measures were also acquired from age-matched healthy subjects (drug free; n = 10; M:F = 5:5). RESULTS Patients exhibited expected deficits in neurocognition. WIN and QuickSIN performance at low signal intensities was impaired in patients with low v. high MCCB attention/vigilance (A/V) scores; these deficits were corrected by AMPH, maximally at 2.5-5 mg (d's = 0.79-1.29). AMPH also enhanced auditory learning, with maximal effects at 5 mg (d = 0.93), and comparable effects 60 and 210 min post pill. 'Pro-learning' effects of AMPH and AMPH-induced gains in auditory fidelity were most evident in patients with low MCCB A/V scores. CONCLUSIONS These findings advance our understanding of the impact of pro-attentional interventions on auditory information processing and suggest dose- and time-course parameters for studies that assess the ability of AMPH to enhance the clinical benefits of TCT in schizophrenia patients.
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Affiliation(s)
- Neal R. Swerdlow
- Department of Psychiatry, School of Medicine, University of California, San Diego, USA
| | - Savita G. Bhakta
- Department of Psychiatry, School of Medicine, University of California, San Diego, USA
| | - Jo Talledo
- Department of Psychiatry, School of Medicine, University of California, San Diego, USA
| | - Lindsay Benster
- Department of Psychiatry, School of Medicine, University of California, San Diego, USA
| | - Juliana Kotz
- Department of Psychiatry, School of Medicine, University of California, San Diego, USA
| | - Sophia Vinogradov
- Department of Psychiatry, School of Medicine, University of Minnesota, USA
| | - Juan L. Molina
- Department of Psychiatry, School of Medicine, University of California, San Diego, USA
| | - Gregory A. Light
- Department of Psychiatry, School of Medicine, University of California, San Diego, USA
- VISN-22 Mental Illness Research Education and Clinical Center, VA San Diego Healthcare System, San Diego, CA, USA
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Bhakta SG, Cavanagh JF, Talledo JA, Kotz JE, Benster L, Roberts BZ, Nungaray JA, Brigman JL, Light GA, Swerdlow NR, Young JW. EEG reveals that dextroamphetamine improves cognitive control through multiple processes in healthy participants. Neuropsychopharmacology 2022; 47:1029-1036. [PMID: 35042948 PMCID: PMC8938448 DOI: 10.1038/s41386-021-01257-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/28/2021] [Accepted: 12/09/2021] [Indexed: 12/29/2022]
Abstract
The poor translatability between preclinical and clinical drug trials has limited pro-cognitive therapeutic development. Future pro-cognitive drug trials should use translatable cross-species cognitive tasks with biomarkers (1) relevant to specific cognitive constructs, and (2) sensitive to drug treatment. Here, we used a difficulty-modulated variant of a cross-species cognitive control task with simultaneous electroencephalography (EEG) to identify neurophysiological biomarkers sensitive to the pro-cognitive effects of dextroamphetamine (d-amp) (10 or 20 mg) in healthy adults (n = 23), in a randomized, placebo-controlled, counterbalanced, double blind, within-subject study, conducted across three test days each separated by one week. D-amp boosted d-prime, sped reaction time, and increased frontal P3a amplitude to non-target correct rejections independent of task difficulty. Task difficulty did however, moderate d-amp effects on EEG during target performance. D-amp suppressed frontal theta power during easy target responses which negatively correlated with drug-induced improvement in hit rate while d-amp-induced changes in P3b amplitude during hard target trials strongly correlated with drug-induced improvement in hit rate. In summary, d-amp affected both behavioral and neurophysiological measures of cognitive control elements. Under low-demand, d-amp diminished cognitive control by suppressing theta, yet under high-demand it boosted control in concert with higher P3b amplitudes. These findings thus appear to reflect a gain-sharpening effect of d-amp: during high-demand processes were boosted while during low-demand processes were neglected. Future studies will use these neurophysiological measures of cognitive control as biomarkers to predict d-amp sensitivity in people with cognitive control deficits, including schizophrenia.
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Affiliation(s)
- Savita G Bhakta
- Department of Psychiatry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA, 92093, USA
| | - James F Cavanagh
- Psychology Department, University of New Mexico, Albuquerque, NM, USA
| | - Jo A Talledo
- Department of Psychiatry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA, 92093, USA
| | - Juliana E Kotz
- Department of Psychiatry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA, 92093, USA
| | - Lindsay Benster
- Department of Psychiatry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA, 92093, USA
| | - Benjamin Z Roberts
- Department of Psychiatry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA, 92093, USA
| | - John A Nungaray
- Department of Psychiatry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA, 92093, USA
| | - Jonathan L Brigman
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM, 87131, USA
| | - Gregory A Light
- Department of Psychiatry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA, 92093, USA
- Desert Pacific Mental Illness Research, Education, and Clinical Center (MIRECC), VA San Diego Healthcare System, San Diego, CA, USA
| | - Neal R Swerdlow
- Department of Psychiatry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA, 92093, USA
| | - Jared W Young
- Department of Psychiatry, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA, 92093, USA.
- Desert Pacific Mental Illness Research, Education, and Clinical Center (MIRECC), VA San Diego Healthcare System, San Diego, CA, USA.
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Swerdlow NR, Bhakta SG, Talledo J, Benster L, Kotz J, Lavadia M, Light GA. Lessons learned by giving amphetamine to antipsychotic-medicated schizophrenia patients. Neuropsychopharmacology 2019; 44:2277-2284. [PMID: 31445502 PMCID: PMC6897898 DOI: 10.1038/s41386-019-0495-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 07/29/2019] [Accepted: 08/13/2019] [Indexed: 11/09/2022]
Abstract
Experimental Medicine studies in psychiatric populations test specific, mechanistic hypotheses related to the biology of mental illness, by combining well-characterized neurobiological probes and laboratory-based measures of behavioral performance and neurobiology. However, scientific inquiry through the acute administration of psychoactive drugs to patients with serious mental illness raises important ethical issues. These issues arise in studies in which the psychostimulant, amphetamine, is used as an Experimental Medicine probe in patients with schizophrenia. In this study, we summarize relevant aspects of our experience with acute, laboratory-based challenges of amphetamine in schizophrenia patients. Schizophrenia patients participated in one or more Experimental Medicine studies involving limited doses of amphetamine with clinical monitoring, over a 4-year period. Acute (within hours of ingestion; collective n = 53), subacute (three active doses over 4 weeks; n = 28), and long-term (mean = 17 months after ingestion; n = 19) effects of amphetamine ingestion were assessed. In antipsychotic (AP)-medicated schizophrenia patients, amphetamine was associated with no detrimental subjective, autonomic, or functional changes. Symptoms assessed acutely, subacutely, or long term were either unchanged or diminished. No adverse acute, subacute, or long-term consequences from the Experimental Medicine use of amphetamine in antipsychotic-medicated schizophrenia patients were detected. These findings do not address the safety or effectiveness of the use of amphetamine in unmedicated patients, or as an adjunctive treatment for schizophrenia. Indeed, it is important to distinguish evidence-based risks of symptom exacerbation in an Experimental Medicine setting vs. risks associated with long-term, daily clinical use or even misuse of amphetamine.
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Affiliation(s)
- Neal R. Swerdlow
- Department of Psychiatry, 0804, University of California, San Diego, La Jolla, CA 92093 USA
| | - Savita G. Bhakta
- Department of Psychiatry, 0804, University of California, San Diego, La Jolla, CA 92093 USA
| | - Jo Talledo
- Department of Psychiatry, 0804, University of California, San Diego, La Jolla, CA 92093 USA
| | - Lindsay Benster
- Department of Psychiatry, 0804, University of California, San Diego, La Jolla, CA 92093 USA
| | - Juliana Kotz
- Department of Psychiatry, 0804, University of California, San Diego, La Jolla, CA 92093 USA
| | - Maria Lavadia
- Department of Psychiatry, 0804, University of California, San Diego, La Jolla, CA 92093 USA
| | - Gregory A. Light
- Department of Psychiatry, 0804, University of California, San Diego, La Jolla, CA 92093 USA ,0000 0004 0419 2708grid.410371.0VA Desert Pacific Mental Illness Research, Education and Clinical Center (MIRECC), VA San Diego Healthcare System, San Diego, CA USA
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