Yusuf Daniju - Academia.edu (original) (raw)

Papers by Yusuf Daniju

Research paper thumbnail of Daily and intermittent smoking are associated with low prefrontal volume and low concentrations of prefrontal glutamate, creatine, myo‐inositol, and N ‐acetylaspartate

Addiction Biology, 2020

Cigarette smoking is still the largest contributor to disease and death worldwide. Successful ces... more Cigarette smoking is still the largest contributor to disease and death worldwide. Successful cessation is hindered by decreases in prefrontal glutamate concentrations and gray matter volume due to daily smoking. Because non-daily, intermittent smoking also contributes greatly to disease and death, understanding whether infrequent tobacco use is associated with reductions in prefrontal glutamate concentrations and gray matter volume may aid public health. Eighty-five young participants (41 non-smokers, 24 intermittent smokers, 20 daily smokers, mean age ~23 years old), underwent 1 H-magnetic resonance spectroscopy of the medial prefrontal cortex, as well as structural MRI to determine whole-brain gray matter volume. Compared to non-smokers, both daily and intermittent smokers exhibited lower concentrations of glutamate, creatine, N-acetylaspartate and myo-inositol in the medial prefrontal cortex, and lower gray matter volume in the right inferior frontal gyrus; these measures of prefrontal metabolites and structure did not differ between daily and intermittent smokers. Finally, medial prefrontal metabolite concentrations and right inferior frontal gray matter volume were positively correlated, but these relationships were not influenced by smoking status. This study provides the first evidence that both daily and intermittent smoking are associated with low concentrations of glutamate, creatine, N-acetylaspartate and myo-inositol, and low gray matter volume in the prefrontal cortex. Future tobacco cessation efforts should not ignore potential deleterious effects of intermittent smoking by considering only daily smokers. Finally, because low glutamate concentrations hinder cessation, treatments that can normalize tonic levels of prefrontal glutamate, such as N-acetylcysteine, may help intermittent and daily smokers to quit.

Research paper thumbnail of Relationship between depression, prefrontal creatine and grey matter volume

Journal of Psychopharmacology, 2021

Background: Depression and low mood are leading contributors to disability worldwide. Research in... more Background: Depression and low mood are leading contributors to disability worldwide. Research indicates that clinical depression may be associated with low creatine concentrations in the brain and low prefrontal grey matter volume. Because subclinical depression also contributes to difficulties in day-to-day life, understanding the neural mechanisms of depressive symptoms in all individuals, even at a subclinical level, may aid public health. Methods: Eighty-four young adult participants completed the Depression, Anxiety and Stress Scale (DASS) to quantify severity of depression, anxiety and stress, and underwent 1H-Magnetic Resonance Spectroscopy of the medial prefrontal cortex and structural magnetic resonance imaging (MRI) to determine whole-brain grey matter volume. Results/outcomes: DASS depression scores were negatively associated (a) with concentrations of creatine (but not other metabolites) in the prefrontal cortex and (b) with grey matter volume in the right superior medi...

Research paper thumbnail of Daily and Intermittent Smoking Decrease Gray Matter Volume and Concentrations of Glutamate, Creatine, Myo-Inositol and N-acetylaspartate in the Prefrontal Cortex

Cigarette smoking is still the largest contributor to disease and death worldwide. Successful ces... more Cigarette smoking is still the largest contributor to disease and death worldwide. Successful cessation is hindered by decreases in prefrontal glutamate concentrations and gray matter volume due to daily smoking. Because non-daily, intermittent smoking also contributes greatly to disease and death, understanding whether infrequent tobacco use is associated with reductions in prefrontal glutamate concentrations and gray matter volume may aid public health. Eighty-five young participants (41 non-smokers, 24 intermittent smokers, 20 daily smokers, mean age ~23 years old), underwent 1H-magnetic resonance spectroscopy of the medial prefrontal cortex, as well as structural MRI to determine whole-brain gray matter volume. Compared to non-smokers, both daily and intermittent smokers exhibited lower concentrations of glutamate, creatine, N-acetylaspartate and myo-inositol in the medial prefrontal cortex, and lower gray matter volume in the right inferior frontal gyrus; these measures of pref...

Research paper thumbnail of Stimulating cognition in schizophrenia: A controlled pilot study of the effects of prefrontal transcranial direct current stimulation upon memory and learning

Brain stimulation, Jan 28, 2016

Schizophrenia is characterized by prominent cognitive deficits, impacting on memory and learning;... more Schizophrenia is characterized by prominent cognitive deficits, impacting on memory and learning; these are strongly associated with the prefrontal cortex. To combine two interventions, transcranial direct current stimulation (tDCS) over the prefrontal cortex and cognitive training, to examine change in cognitive performance in patients with schizophrenia. A double blind, sham-controlled pilot study of 49 patients with schizophrenia, randomized into real or sham tDCS stimulation groups. Subjects participated in 4 days of cognitive training (days 1, 2, 14, 56) with tDCS applied at day-1 and day-14. The primary outcome measure was change in accuracy on working memory and implicit learning tasks from baseline. The secondary outcome measure was the generalization of learning to non-trained task, indexed by the CogState neuropsychological battery. Data analysis was conducted using multilevel modelling and multiple regressions. 24 participants were randomized to real tDCS and 25 to sham. ...

Research paper thumbnail of The effects of benzofury (5-APB) on the dopamine transporter and 5-HT2-dependent vasoconstriction in the rat

Progress in Neuro-Psychopharmacology and Biological Psychiatry, 2014

5-APB, commonly marketed as 'benzofury' is a new psychoactive substance and erstwhile 'legal high... more 5-APB, commonly marketed as 'benzofury' is a new psychoactive substance and erstwhile 'legal high' which has been implicated in 10 recent drug-related deaths in the UK. This drug was available on the internet and in 'head shops' and was one of the most commonly sold legal highs up until its recent UK temporary ban (UK Home Office). Despite its prominence, very little is known about its pharmacology. This study was undertaken to examine the pharmacology of 5-APB in vitro. We hypothesized that 5-APB would activate the dopamine and 5-HT systems which may underlie its putative stimulant and hallucinogenic effects. Autoradiographic studies showed that 5-APB displaced both [ 125 I]RTI-121 and [ 3 H]ketanserin from rat brain tissue suggesting affinity at the dopamine transporter and 5-HT 2 receptor sites respectively. Voltammetric studies in rat accumbens brain slices revealed that 5-APB slowed dopamine reuptake, and at high concentrations caused reverse transport of dopamine. 5-APB also caused vasoconstriction of rat aorta, an effect antagonized by the 5-HT 2A receptor antagonist ketanserin, and caused contraction of rat stomach fundus, which was reversed by the 5-HT 2B receptor antagonist RS-127445. These data show that 5-APB interacts with the dopamine transporter and is an agonist at the 5-HT 2A and 5-HT 2B receptors in the rat. Thus 5-APB's pharmacology is consistent with it having both stimulant and hallucinogenic properties. In addition, 5-APB's activity at the 5-HT 2B receptor may cause cardiotoxicity.

Research paper thumbnail of Do the effects of cannabis on the hippocampus and striatum increase risk for psychosis?

Neuroscience & Biobehavioral Reviews, 2020

Cannabis use is associated with increased risk of psychotic symptoms and in a small number of cas... more Cannabis use is associated with increased risk of psychotic symptoms and in a small number of cases it can lead to psychoses. This review examines the neurobiological mechanisms that mediate the link between cannabis use and psychosis risk. We use an established preclinical model of psychosis, the methylazoxymethanol acetate (MAM) rodent model, as a framework to examine if psychosis risk in some cannabis users is mediated by the effects of cannabis on the hippocampus, and this region's role in the regulation of mesolimbic dopamine. We also examine how cannabis affects excitatory neurotransmission known to regulate hippocampal neural activity and output. Whilst there is clear evidence that cannabis/cannabinoids can affect hippocampal and medial temporal lobe function and structure, the evidence that cannabis/cannabinoids increase striatal dopamine function is less robust. There is limited evidence that cannabis use affects cortical and striatal glutamate levels, but there are currently too few studies to draw firm conclusions. Future work is needed to test the MAM model in relation to cannabis using multimodal neuroimaging approaches.

Research paper thumbnail of Prefrontal cortex and putamen grey matter alterations in cannabis and tobacco users

Journal of Psychopharmacology

Background: Previous magnetic resonance imaging studies in regular cannabis users report altered ... more Background: Previous magnetic resonance imaging studies in regular cannabis users report altered grey matter volume (GMV) in brain regions, including the prefrontal cortex (PFC), putamen and hippocampus. However, most studies have tended to recruit recreational users with high levels of cannabis use, and have not controlled for the possible confounding effects of tobacco use. We attempt to address these limitations in the present study. Methods: We acquired volumetric images in sex, age and IQ-matched groups of (1) regular Cannabis users who also smoke Tobacco cigarettes (‘CT’; n = 33), (2) non-cannabis-using Tobacco cigarette smokers (‘T’; n = 19) and (3) non-cannabis/tobacco-using Controls (‘C’; n = 35). GMV in bilateral PFC, putamen and hippocampal regions was compared across groups. We also examined the associations between GMV differences and levels of cannabis and tobacco use, measures of intellectual function, and of depression, anxiety and stress. Results: Relative to contro...

Research paper thumbnail of Daily and intermittent smoking are associated with low prefrontal volume and low concentrations of prefrontal glutamate, creatine, myo‐inositol, and N ‐acetylaspartate

Addiction Biology, 2020

Cigarette smoking is still the largest contributor to disease and death worldwide. Successful ces... more Cigarette smoking is still the largest contributor to disease and death worldwide. Successful cessation is hindered by decreases in prefrontal glutamate concentrations and gray matter volume due to daily smoking. Because non-daily, intermittent smoking also contributes greatly to disease and death, understanding whether infrequent tobacco use is associated with reductions in prefrontal glutamate concentrations and gray matter volume may aid public health. Eighty-five young participants (41 non-smokers, 24 intermittent smokers, 20 daily smokers, mean age ~23 years old), underwent 1 H-magnetic resonance spectroscopy of the medial prefrontal cortex, as well as structural MRI to determine whole-brain gray matter volume. Compared to non-smokers, both daily and intermittent smokers exhibited lower concentrations of glutamate, creatine, N-acetylaspartate and myo-inositol in the medial prefrontal cortex, and lower gray matter volume in the right inferior frontal gyrus; these measures of prefrontal metabolites and structure did not differ between daily and intermittent smokers. Finally, medial prefrontal metabolite concentrations and right inferior frontal gray matter volume were positively correlated, but these relationships were not influenced by smoking status. This study provides the first evidence that both daily and intermittent smoking are associated with low concentrations of glutamate, creatine, N-acetylaspartate and myo-inositol, and low gray matter volume in the prefrontal cortex. Future tobacco cessation efforts should not ignore potential deleterious effects of intermittent smoking by considering only daily smokers. Finally, because low glutamate concentrations hinder cessation, treatments that can normalize tonic levels of prefrontal glutamate, such as N-acetylcysteine, may help intermittent and daily smokers to quit.

Research paper thumbnail of Relationship between depression, prefrontal creatine and grey matter volume

Journal of Psychopharmacology, 2021

Background: Depression and low mood are leading contributors to disability worldwide. Research in... more Background: Depression and low mood are leading contributors to disability worldwide. Research indicates that clinical depression may be associated with low creatine concentrations in the brain and low prefrontal grey matter volume. Because subclinical depression also contributes to difficulties in day-to-day life, understanding the neural mechanisms of depressive symptoms in all individuals, even at a subclinical level, may aid public health. Methods: Eighty-four young adult participants completed the Depression, Anxiety and Stress Scale (DASS) to quantify severity of depression, anxiety and stress, and underwent 1H-Magnetic Resonance Spectroscopy of the medial prefrontal cortex and structural magnetic resonance imaging (MRI) to determine whole-brain grey matter volume. Results/outcomes: DASS depression scores were negatively associated (a) with concentrations of creatine (but not other metabolites) in the prefrontal cortex and (b) with grey matter volume in the right superior medi...

Research paper thumbnail of Daily and Intermittent Smoking Decrease Gray Matter Volume and Concentrations of Glutamate, Creatine, Myo-Inositol and N-acetylaspartate in the Prefrontal Cortex

Cigarette smoking is still the largest contributor to disease and death worldwide. Successful ces... more Cigarette smoking is still the largest contributor to disease and death worldwide. Successful cessation is hindered by decreases in prefrontal glutamate concentrations and gray matter volume due to daily smoking. Because non-daily, intermittent smoking also contributes greatly to disease and death, understanding whether infrequent tobacco use is associated with reductions in prefrontal glutamate concentrations and gray matter volume may aid public health. Eighty-five young participants (41 non-smokers, 24 intermittent smokers, 20 daily smokers, mean age ~23 years old), underwent 1H-magnetic resonance spectroscopy of the medial prefrontal cortex, as well as structural MRI to determine whole-brain gray matter volume. Compared to non-smokers, both daily and intermittent smokers exhibited lower concentrations of glutamate, creatine, N-acetylaspartate and myo-inositol in the medial prefrontal cortex, and lower gray matter volume in the right inferior frontal gyrus; these measures of pref...

Research paper thumbnail of Stimulating cognition in schizophrenia: A controlled pilot study of the effects of prefrontal transcranial direct current stimulation upon memory and learning

Brain stimulation, Jan 28, 2016

Schizophrenia is characterized by prominent cognitive deficits, impacting on memory and learning;... more Schizophrenia is characterized by prominent cognitive deficits, impacting on memory and learning; these are strongly associated with the prefrontal cortex. To combine two interventions, transcranial direct current stimulation (tDCS) over the prefrontal cortex and cognitive training, to examine change in cognitive performance in patients with schizophrenia. A double blind, sham-controlled pilot study of 49 patients with schizophrenia, randomized into real or sham tDCS stimulation groups. Subjects participated in 4 days of cognitive training (days 1, 2, 14, 56) with tDCS applied at day-1 and day-14. The primary outcome measure was change in accuracy on working memory and implicit learning tasks from baseline. The secondary outcome measure was the generalization of learning to non-trained task, indexed by the CogState neuropsychological battery. Data analysis was conducted using multilevel modelling and multiple regressions. 24 participants were randomized to real tDCS and 25 to sham. ...

Research paper thumbnail of The effects of benzofury (5-APB) on the dopamine transporter and 5-HT2-dependent vasoconstriction in the rat

Progress in Neuro-Psychopharmacology and Biological Psychiatry, 2014

5-APB, commonly marketed as 'benzofury' is a new psychoactive substance and erstwhile 'legal high... more 5-APB, commonly marketed as 'benzofury' is a new psychoactive substance and erstwhile 'legal high' which has been implicated in 10 recent drug-related deaths in the UK. This drug was available on the internet and in 'head shops' and was one of the most commonly sold legal highs up until its recent UK temporary ban (UK Home Office). Despite its prominence, very little is known about its pharmacology. This study was undertaken to examine the pharmacology of 5-APB in vitro. We hypothesized that 5-APB would activate the dopamine and 5-HT systems which may underlie its putative stimulant and hallucinogenic effects. Autoradiographic studies showed that 5-APB displaced both [ 125 I]RTI-121 and [ 3 H]ketanserin from rat brain tissue suggesting affinity at the dopamine transporter and 5-HT 2 receptor sites respectively. Voltammetric studies in rat accumbens brain slices revealed that 5-APB slowed dopamine reuptake, and at high concentrations caused reverse transport of dopamine. 5-APB also caused vasoconstriction of rat aorta, an effect antagonized by the 5-HT 2A receptor antagonist ketanserin, and caused contraction of rat stomach fundus, which was reversed by the 5-HT 2B receptor antagonist RS-127445. These data show that 5-APB interacts with the dopamine transporter and is an agonist at the 5-HT 2A and 5-HT 2B receptors in the rat. Thus 5-APB's pharmacology is consistent with it having both stimulant and hallucinogenic properties. In addition, 5-APB's activity at the 5-HT 2B receptor may cause cardiotoxicity.

Research paper thumbnail of Do the effects of cannabis on the hippocampus and striatum increase risk for psychosis?

Neuroscience & Biobehavioral Reviews, 2020

Cannabis use is associated with increased risk of psychotic symptoms and in a small number of cas... more Cannabis use is associated with increased risk of psychotic symptoms and in a small number of cases it can lead to psychoses. This review examines the neurobiological mechanisms that mediate the link between cannabis use and psychosis risk. We use an established preclinical model of psychosis, the methylazoxymethanol acetate (MAM) rodent model, as a framework to examine if psychosis risk in some cannabis users is mediated by the effects of cannabis on the hippocampus, and this region's role in the regulation of mesolimbic dopamine. We also examine how cannabis affects excitatory neurotransmission known to regulate hippocampal neural activity and output. Whilst there is clear evidence that cannabis/cannabinoids can affect hippocampal and medial temporal lobe function and structure, the evidence that cannabis/cannabinoids increase striatal dopamine function is less robust. There is limited evidence that cannabis use affects cortical and striatal glutamate levels, but there are currently too few studies to draw firm conclusions. Future work is needed to test the MAM model in relation to cannabis using multimodal neuroimaging approaches.

Research paper thumbnail of Prefrontal cortex and putamen grey matter alterations in cannabis and tobacco users

Journal of Psychopharmacology

Background: Previous magnetic resonance imaging studies in regular cannabis users report altered ... more Background: Previous magnetic resonance imaging studies in regular cannabis users report altered grey matter volume (GMV) in brain regions, including the prefrontal cortex (PFC), putamen and hippocampus. However, most studies have tended to recruit recreational users with high levels of cannabis use, and have not controlled for the possible confounding effects of tobacco use. We attempt to address these limitations in the present study. Methods: We acquired volumetric images in sex, age and IQ-matched groups of (1) regular Cannabis users who also smoke Tobacco cigarettes (‘CT’; n = 33), (2) non-cannabis-using Tobacco cigarette smokers (‘T’; n = 19) and (3) non-cannabis/tobacco-using Controls (‘C’; n = 35). GMV in bilateral PFC, putamen and hippocampal regions was compared across groups. We also examined the associations between GMV differences and levels of cannabis and tobacco use, measures of intellectual function, and of depression, anxiety and stress. Results: Relative to contro...