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Biomedical subjects

Marcello Spinella

Publications and source records attributed to Marcello Spinella.

28 records · Page 2Linked to original sources

Evolutionary mismatch, neural reward circuits, and pathological gambling.

Evolutionary mismatch theory has been applied to disorders of self-regulation such as maladaptive eating patterns and drug abuse. Modern gambling represents a refinement of the elements of risk and chance, which draw upon the faculties of judgment and novelty-seeking. A set of neuroanatomical structures, including prefrontal-subcortical systems and associated limbic structures, have been implicated in the processing of reward and punishment, including gambling-related situations. Neurobiological systems guiding choice and behavior have evolved to maximize chances for survival under hunter-gatherer conditions, and modern gambling represents an abrupt departure from these circumstances, sometimes resulting in pathological gambling.

Biological Evolution↗

Relationship between drug use and prefrontal-associated traits.

The prefrontal cortex plays an important role in the strategic and emotional regulation of behavior. Both cognitive and neuroimaging studies have implicated prefrontal cortex in processes of reward and addiction. Prefrontal-associated neurobehavioral traits may be measured psychometrically with the Frontal Systems Behavior Scale (FrSBe), so it was hypothesized that self-ratings on this instrument would correlate with parameters of psychoactive drug use in a community sample. Modest but significant correlations were found for various parameters of tobacco use, even after controlling for demographic variables. Significant differences were noted in the mean scores when non-users were compared with users of cannabis, major stimulants (e.g. cocaine, amphetamine), and dissociative hallucinogens (e.g. phencyclidine, ketamine) and polysubstance use, particularly with the Disinhibition subscale. Smokers rated greater dysfunction than non-smokers on all three subscales, with ex-smokers showing intermediate ratings between the two. Polysubstance users showed greater dysfunction on the Disinhibition subscale compared to non-polysubstance users. In summary, this study further supports a relationship between prefrontal dysfunction and drug use in normal individuals, convergently with other methodologies for studying addiction.

Adolescent↗

A relationship between smell identification and empathy.

Olfaction is a sense that has close relationships with the limbic system and emotion. Empathy is a vicarious feeling of others' emotional states. The two functions are known to be subserved by common neuroanatomical structures, including orbitofrontal cortex, mediodorsal thalamus, and the amygdala. This study demonstrates a correlation between smell identification and empathy, using the Mehrabian and Epstein Empathy Questionnaire and Alberta Smell Test. Right nostril smell identification correlated with empathy, whereas the left nostril did not. Given the predominantly ipsilateral representation in the olfactory system, this is in accordance with right hemisphere dominance for emotional functions and empathy. Further, the emotional component of empathy (feeling another's emotions) correlated with smell, whereas a cognitive component (comprehending another's emotions) did not. This study is the first to demonstrate a relationship between empathy and smell in normal subjects, suggesting common neural substrates.

Adult↗

Correlations among behavioral measures of orbitofrontal function.

Orbitofrontal cortex plays an important role in guiding behavior based on emotional input and rewards. It receives multimodal higher order sensory information and mediates reinforcement for primary as well as secondary or conditioned forms of reinforcement (e.g., monetary rewards). Several behavioral measures have demonstrated putative sensitivity to orbitofrontal function: smell identification, delayed alternation, and response inhibition (go/no-go and antisaccades). A correlational study of performances on these tasks by healthy controls demonstrated some interrelationships: go/no-go correlated with antisaccades, left nostril smell correlated with go/no-go, and right nostril smell correlated with delayed alternation. Further analysis showed that certain smells correlated with tasks more strongly than others. Given the diversity of these tasks, it is suggested that these intercorrelations results from at least the partial overlap of the neural substrates for olfactory identification and tasks requiring response modification based on reinforcement contingencies.

Adult↗

Hypomania induced by herbal and pharmaceutical psychotropic medicines following mild traumatic brain injury.

The use of herbal medicines has become a very common practice. While many are safe enough to be available over-the-counter, they may pose risks due to interactions with pharmaceutical medications and effects in specific clinical populations. The case of a female patient with a history of mild traumatic brain injury and resulting depression is presented. She experienced hypomania after adding St John's wort and Ginkgo biloba to her regimen of fluoxetine and buspirone, which remitted after discontinuation of the herbal medicines. Implications for interactions between various psychopharmacologic agents, including herbal medicines and selective serotonin reuptake inhibitors (SSRIs), as well as the need for appropriate patient and health care provider education are discussed.

Adult↗

Correlations between orbitofrontal dysfunction and tobacco smoking.

Orbitofrontal cortex is involved in various reward and reinforcement processes in the human brain. There is both anatomical and functional evidence for a dysfunction of orbitofrontal cortex in substance abusers, and nicotine has been shown to activate reward-related structures in the brain similarly to other abused drugs. This study shows positive correlations between smoking parameters (smoking status and packs smoked per day) and impairment on putative measures of orbitofrontal dysfunction (go/no-go, antisaccades, delayed alternation and impulsivity ratings). While causality could not be determined, other research suggests that an orbitofrontal dysfunction predisposes one toward tobacco abuse.

Adult↗

The importance of pharmacological synergy in psychoactive herbal medicines.

The therapeutic effects of many herbal medicines have been well established; however, definitive mechanisms of action remain to be elucidated for many psychoactive herbal medications. Although several mechanisms have been identified, they are often insufficient to account for the observed effects of the plant or its extracts. This review emphasizes that, in addition to searching for more potent mechanisms, one must consider the additive and supra-additive effects of a plant's multiple constituents. Synergy may occur through pharmacokinetic and/or pharmacodynamic interactions. Examples are given that illustrate synergistic actions in St. John's wort (Hypericum perforatum), kava kava (Piper methysticum), and valerian (Valeriana officinalis).

Drug Synergism↗

Herbal Medicines and Epilepsy: The Potential for Benefit and Adverse Effects.

The widespread availability and use of herbal medicines raise the potential for adverse effects in the epilepsy population. Herbal sedatives (kava, valerian, chamomile, passionflower) may potentiate the effects of antiepileptic medications, increasing their sedative and cognitive effects. Despite some antiseizure effects in animal models, they should not be used in place of standard seizure medications because efficacy has not been established. Anecdotal, uncontrolled observations suggest that herbal stimulants containing ephedrine (ephedra or ma huang) and caffeine (cocoa, coffee, tea, maté, guarana, cola or kola) can exacerbate seizures in people with epilepsy, especially when taken in combination. Ginkgo and ginseng may also exacerbate seizures although the evidence for this is similarly anecdotal and uncertain. St. John's wort has the potential to alter medication pharmacokinetics and the seizure threshold. The essential oils of many plants contain epileptogenic compounds. There is mixed evidence for evening primrose and borage lowering the seizure threshold. Education of both health care providers and patients is the best way to avoid unintentional and unnecessary adverse reactions to herbal medicines.

Journal Article↗

Excitatory amino acid antagonists in the rostral ventromedial medulla inhibit mesencephalic morphine analgesia in rats.

Supraspinal opioid analgesia is mediated in part by connections between the periaqueductal gray (PAG) and rostral ventromedial medulla (RVM). Morphine analgesia elicited from the PAG is respectively decreased by selective serotonergic and opioid receptor antagonists administered into the RVM, and increased by RVM neurotensin antagonists. Since glutamate and excitatory amino acid (EAA) receptors are also active in the RVM, the present study evaluated whether either competitive (AP7) or non-competitive (MK-801) N-methyl-D-aspartate (NMDA) antagonists or a kainate/AMPA (CNQX) antagonist microinjected into the RVM altered morphine (2.5 micrograms) analgesia elicited from the PAG as measured by the tail-flick and jump tests. Mesencephalic morphine analgesia was markedly reduced on both tests after RVM pretreatment with either AP7 (0.01-1 microgram, 0.08-7.8 nmol) or MK-801 (0.03-3 micrograms, 0.04-4.4 nmol). In contrast, small but significant reductions in mesencephalic morphine analgesia occurred on the jump test following CNQX (0.5 microgram, 2.2 nmol) in the RVM. NMDA antagonists did not markedly alter either basal nociceptive thresholds following RVM administration, or mesencephalic morphine analgesia following administration into medullary placements lateral or dorsal to the RVM. These data implicate EAA and particularly NMDA receptors in the RVM in modulating the transmission of opioid pain-inhibitory signals from the PAG.

2-Amino-5-phosphonovalerate↗