This article reviews three experiments on event-related potentials (ERPs) testing the hypothesis that primary visual consciousness (stimulus self-report) is related to enhanced cortical neural synchronization as a function of stimulus features. ERP peak latency and sources were compared between "seen" trials and "not seen" trials, respectively related and unrelated to the primary visual...
Opioids are traditionally associated with pain, analgesia and drug abuse. It is now clear, however, that the opioids are central players in mood. The implications for mood disorders, particularly clinical depression, suggest a paradigm shift from the monoamine neurotransmitters to the opioids either alone or in interaction with monoamine neurons. We have a special interest in dynorphin, the...
S. divinorum is a psychoactive plant that has been consumed as a recreational drug of abuse in the last years. Salvinorin A is its main constituent, and is responsible for the observed psychoactive effects. Both S. divinorum and salvinorin A have become controlled drugs in several countries, but they are not listed in the Schedules of the United Nations Drug Conventions. Regarding the effects...
Do fish consciously feel pain? Addressing this question, Key (2016) asks whether the neural mechanisms underlying conscious pain reports in humans can be identified in fish. This strategy fails in three ways. First, non-mammalian consciousness — if it exists — may depend on different mechanisms. Second, accumulating neurophysiological and behavioural evidence, evolutionary considerations, and...
A main goal of the neuroscience of consciousness is: find the neural correlate to conscious experiences (NCC). When have we achieved this goal? The answer depends on our operationalization of "NCC." Chalmers (2000) shaped the widely accepted operationalization according to which an NCC is a neural system with a state which is minimally sufficient (but not necessary) for an experience. A deeper...
Causal interactions within complex systems such as the brain can be analyzed at multiple spatiotemporal levels. It is widely assumed that the micro level is causally complete, thus excluding causation at the macro level. However, by measuring effective information—how much a system’s mechanisms constrain its past and future states—we recently showed that causal power can be stronger at macro...
This PhD work consists of an in vitro and in vivo part. In the in vivo part, we investigated the role of dopamine in the acute clinical effects of 3,4-methylenedioxymethamphetamine (MDMA, “ecstasy”) in healthy human subjects. The role of dopamine in the addictive effects of drug of abuse is well established, but whether it contributes to the acute psychotropic effects of MDMA is unclear. \nIn...
Mescaline,β-3,4,5-trimethoxy phenethylamin, is a psycho-active hallucinogen alkalloid extracted from cactus of peyote that resemble natural neurotransmitters epinephrine and dopamine. Peyote is a long-time expanding herb in the desert sand area along Texas and Mexico region and continues to be used hundreds of years by Residents of Mexico and South-western America for rituals. Following the...
ALTERED PERCEPTIONS: HOW VARIOUS SUBSTANCES INFLUENCE OUR PERCEPTION OF TIME BY AAYA ABDELSHAFY D o you ever feel as though you are stuck in time, or as if there are just never enough hours in a day? Our sense of time is unlike any other sense we experi- ence. It is physically intangible and yet is sustained throughout our lives from the moment we are born, unless a brain disor- der presents...
The iboga alkaloids are a class of naturally occurring and synthetic compounds, some of which modify drug self-administration and withdrawal in humans and preclinical models. Ibogaine, the prototypic iboga alkaloid that is utilized clinically to treat addictions, has been associated with QT prolongation, torsades de pointes and fatalities. hERG blockade as IKr was measured using the whole-cell...