Unconscious learning during surgery with propofol anaesthesia † †This article is accompanied by Editorial II

Abstract

Learning during anaesthesia seems more likely to occur during rather than before surgical stimulation at comparable anaesthetic depth. We hypothesize that surgical stimulation facilitates learning during anaesthesia, independently of its effects on anaesthetic depth.

The roles of cannabinoid and dopamine receptor systems in neural emotional learning circuits: implications for schizophrenia and addiction

“…Interestingly, this neuronal associative encoding takes place while animals are conditioned under chloral hydrate anesthesia, demonstrating that neuronal associative learning can occur in a non-conscious state. Such non-conscious learning has also been demonstrated in memory-encoding studies with human subjects [22,23]. Similarly, we have recently shown that a subpopulation of neurons in the mPFC that receive an orthodromic input from the BLA actively encode and express emotional associative learning in the same Pavlovian paradigm, demonstrating that neuronal subpopulations within both the mPFC and amygdala are capable of actively encoding and expressing emotional associative learning.…”

Is priming during anesthesia unconscious?

“…Also note that stimuli in this study were presented before surgery, whereas typical studies present them during surgery. We have hypothesized that the surgical stress response facilitates implicit priming during anesthesia (Deeprose et al, 2004;Stapleton & Andrade, 2000). If we are correct, then this study is not a strong test of the hypothesis that priming can occur when surgical patients are unconscious.…”

“…Studies by Mü nte and colleagues suggest continued auditory processing during deep anesthesia, shown by the presence of mismatch negativity in the EEG response to ÔoddballÕ auditory stimuli Quandt et al, 2004). If at least a small amount of auditory processing persists when people are anesthetized, then memory formation for this information may be facilitated by the high levels of catecholamines released in response to surgery and known to act via the amygdala to facilitate memory formation for emotional stimuli (Deeprose, Andrade, Varma, & Edwards, 2004;Stapleton & Andrade, 2000).…”

Human mediotemporal EEG characteristics during propofol anesthesia

“…Fell (email: juergen.fell@ukb.uni-bonn.de, Tel. : +49-228-2879347, Fax: +49-228-2876294) ing deep sedation found evidence for nondeclarative (implicit), but no evidence for declarative (explicit) memory, i.e., for subsequent conscious recollection of events and facts (e.g., Bethune et al 1992;Cork et al 1996;Deeprose et al 2004;Munte 1999). However, in studies implementing the so-called process dissociation procedure (Jacoby 1991), evidence for some kind of declarative memory formation during deep anesthesia was reported (Kerssens et al 2002;Stapleton et al 2000).…”