Dopamine and the Origins of Human Intelligence

Previc, Fred H.

doi:10.1006/brcg.1999.1129

Cited by 173 publications

(114 citation statements)

References 244 publications

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“…Indeed, high MI might also predict a later mood disorder (Chapman et al, 1994) and is a common feature not only of the schizophrenia spectrum disorders but also a symptom of some personality disorders (eg Lyons et al, 1995;Kwapil et al, 1997). Thus, positive schizotypy may be accompanied by a relative hyperdopaminergia, but yet reflects just one of the many DA-mediated variations of the human mind and personality (Horrobin, 1998;Previc, 1999) accompanied by distinct cognitive capacities (Gianotti et al, 2001;Weinstein and Graves, 2002) and, ultimately, an unusual way of perceiving the world (Wolfradt et al, 1999;Sto + ckenius and Brugger, 2000;McCreery and Claridge, 2002;Van de Ven and Merckelbach, 2003).…”

Section: Discussionmentioning

confidence: 99%

Nonstereotyped Responding in Positive Schizotypy after a Single Dose of Levodopa

Möhr

Landis

Sándor

et al. 2004

Neuropsychopharmacol

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Stereotyped behavior and left-sided orientation biases, associated with the dopamine (DA) system, were observed in populations of the schizophrenia spectrum disorders. We investigated whether heightened DA concentrations influence both side biases and stereotyped responding in a visuo-motor computer task, in which 90, 180, and 2701 rotated objects had to be brought into a target position. To account for the role of the schizophrenia spectrum, task performance was also analyzed as a function of healthy participants' high or low magical ideation (MI), a positive schizotypal feature. The first 36 participants (20 women) remained substance free. In a second sample, 20 men received levodopa and 20 men a placebo in a double-blind procedure. Results showed that high MI scorers responded more stereotyped than low MI scorers, without being specifically biased towards the left side. Rotation preferences toward one or the other side made high MI scorers less flexible for objects efficiently to be rotated into the opposite direction. This inflexibility may reflect impaired left hemisphere functioning. Unexpectedly, in the levodopa group, high MI scorers performed superior to low MI scorers. Since DA actions appear to follow an inverted U-shape function, the 'low' performing high MI scorers profited from the enhanced DA availability. Our observation in the levodopa group points to a dissociation between schizotypy and schizophrenia: while cognitive improvement in schizophrenia can occur after treatment with atypical neuroleptic agents, in our positive schizotypal participants a DA agonist resulted in improved task performance. This dissociation may point to protective neurochemical mechanisms preventing healthy schizotypes from developing full-blown psychotic symptoms.

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Section: Discussionmentioning

confidence: 99%

Nonstereotyped Responding in Positive Schizotypy after a Single Dose of Levodopa

Möhr

Landis

Sándor

et al. 2004

Neuropsychopharmacol

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“…Furthermore, certain specific receptors (D2) that bind dopamine are low in number when there is a decline in abstraction and cognitive flexibility, highlighting the role of dopamine in tasks requiring a high degree of neural plasticity (Volkow et al, 1998). Previc (1999) asserts that there are four lines of evidence supporting the role of dopamine in cognitive flexibility or "cognitive shifting." The first is that dopaminergic mechanisms in the prefrontal cortex exert the inhibitory action on subcortical centers required for the cessation of current behavior.…”

Section: Cognitive Distortionsmentioning

confidence: 99%

“…Third, dopaminergic levels in clinical and aging populations are highly correlated with cognitive-shifting ability, and the administration of dopaminergic agonists results in improved cognitive flexibility; removal of them or administration of dopaminergic antagonists reduces cognitive shifting ability. The final line of evidence consists of disturbances in cognitive shifting as being one of the principal intellectual deficits in dopaminergic disorders, such as Parkonsonism (Previc, 1999). Dopamine is involved in other cognitive processes that seem related to cognitive flexibility including working memory, abstract representation, temporal analysis/sequencing, and generativity (Previc, 1999).…”

Section: Cognitive Distortionsmentioning

confidence: 99%

“…The final line of evidence consists of disturbances in cognitive shifting as being one of the principal intellectual deficits in dopaminergic disorders, such as Parkonsonism (Previc, 1999). Dopamine is involved in other cognitive processes that seem related to cognitive flexibility including working memory, abstract representation, temporal analysis/sequencing, and generativity (Previc, 1999). Dopamine levels appear to influence the extent of cognitive distortion; higher dopamine levels promote more extensive cognitive distortions.…”

Section: Cognitive Distortionsmentioning

confidence: 99%

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Psychological Defense Mechanisms: A New Perspective

Bowins¹

2004

Am J Psychoanal

112

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Approaching psychological defense mechanisms from the perspective of an evolved strategy, it is proposed that there are two basic templates-dissociation and cognitive distortions. Frequently conceived of as pathological, these psychological phenomena actually constitute overlapping spectrums with milder manifestations being common and highly functional, and more severe variants less common and typically dysfunctional. Dissociation provides the capacity to adaptively detach from disturbing emotional states, and cognitive distortions place a positive ego-enhancing spin on experience. Most of the classical defense mechanisms described in the psychoanalytic literature represent a form of cognitive distortion with some containing strong elements of dissociation.

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“…There is also considerable evidence indicating that DA plays a significant role in a number of neuropsychiatric disorders presenting with cognitive deficits that appear to be exclusive to humans, including Alzheimer's disease, Parkinson's disease, and schizophrenia (Akil et al, 1999;Ciliax et al, 1999;Venator et al, 1999;Sutoo et al, 2001;Winterer and Weinberger, 2004). For these reasons, it has been proposed that the human neocortex might have an expanded and denser cortical DA innervation compared with other species (Previc, 1999), making it a candidate neural substrate for modification by natural selection in the evolution of human cognitive specializations.…”

Section: Introductionmentioning

confidence: 99%

Cortical dopaminergic innervation among humans, chimpanzees, and macaque monkeys: A comparative study

et al. 2008

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In this study, we assessed the possibility that humans differ from other primate species in the supply of dopamine to the frontal cortex. To this end, quantitative comparative analyses were performed among humans, chimpanzees, and macaques using immunohistochemical methods to visualize tyrosine hydroxylase-immunoreactive axons within the cerebral cortex. Axon densities and neuron densities were quantified using computer-assisted stereology. Areas 9 and 32 were chosen for evaluation due to their roles in higher-order executive functions and theory of mind, respectively. Primary motor cortex (area 4) was also evaluated because it is not directly associated with cognition. We did not find an overt quantitative increase in cortical dopaminergic innervation in humans relative to the other primates examined. However, several differences in cortical dopaminergic innervation were observed among species which may have functional implications. Specifically, humans exhibited a sublaminar pattern of innervation in layer I of areas 9 and 32 that differed from that of macaques and chimpanzees. Analysis of axon length density to neuron density among species revealed that humans and chimpanzees together deviated from macaques in having increased dopaminergic afferents in layers III and V/VI of areas 9 and 32, but there were no phylogenetic differences in area 4. Finally, morphological specializations of axon coils that may be indicative of cortical plasticity events were observed in humans and chimpanzees, but not macaques. Our findings suggest significant modifications of dopamine's role in cortical organization occurred in the evolution of the apes, with further changes in the descent of humans.

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Dopamine and the Origins of Human Intelligence

Cited by 173 publications

References 244 publications

Nonstereotyped Responding in Positive Schizotypy after a Single Dose of Levodopa

Nonstereotyped Responding in Positive Schizotypy after a Single Dose of Levodopa

Psychological Defense Mechanisms: A New Perspective

Cortical dopaminergic innervation among humans, chimpanzees, and macaque monkeys: A comparative study

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