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Biomedical subjects

Turhan Canli

Publications and source records attributed to Turhan Canli.

10 recordsLinked to original sources
PubMed2005

Effect of estrogen-serotonin interactions on mood and cognition.

Both the neurotransmitter serotonin and the ovarian steroid estrogen have been implicated in the modulation of mood and cognition. Although significant functional interactions between estrogen and serotonin are acknowledged, the nature of their relationship has not been fully elucidated. Research using ovariectomized animals has identified estrogen-induced changes in serotonin transmission, binding, and metabolism in brain regions implicated in the regulation of affect and cognition. Studies in humans, particularly of menopausal women undergoing estrogen treatment, have provided some support for these findings and identified instances in which change in mood or cognition is accompanied by alterations in serotonin function and hormonal status. However, it is apparent that further research is required to understand the neural processes involved in the interplay between estrogen and serotonin. By reviewing animal and human data regarding estrogen and serotonin's effects on mood and cognition, the authors aim to better define their relationship and highlight areas for further research.

Affect↗
PubMed2004

Brain activation to emotional words in depressed vs healthy subjects.

Depression involves either enhanced processing of negative stimuli or diminished processing of positive stimuli. We used functional magnetic resonance imaging to assess brain activation in depressed vs healthy participants. Fifteen participants diagnosed with major depressive disorder and 15 controls were scanned during a lexical decision task involving neutral, happy, sad, and threat-related words. For happy words, depressed subjects exhibited less activation than did controls to happy words in fronto-temporal and limbic regions. For sad words, depressed subjects showed more activation than did controls in the inferior parietal lobule and less activation in the superior temporal gyrus and cerebellum, suggesting a complex activation pattern that varies for neural sub-circuits that may be associated with different cognitive or behavioral processes.

Adult↗
PubMed2004

Individual differences in emotion processing.

Recent functional brain imaging studies of the neurobiology of emotion have investigated how individual differences among subjects modulate neural responses during emotion processing. Differences in personality, dispositional affect, biological sex, and genotype can all substantially modulate the neural bases of emotion processing in prefrontal, limbic, and other brain regions, across a variety of domains including emotional reactions, emotional memory, and emotion perception. Analysis of individual differences provides a new window into the neurobiology of emotion processing that complements traditional approaches.

Brain↗
PubMed2004

A double dissociation between mood states and personality traits in the anterior cingulate.

Neuroticism and extraversion are personality traits associated with negative and positive mood states, respectively, confounding trait and state factors that may affect brain responses to emotional stimuli. The authors dissociated these factors using fMRI and the emotional Stroop attention task: Anterior cingulate (AC) response to positive stimuli varied as a function of personality trait, but not mood state, whereas AC response to negative stimuli varied as a function of mood state, but not personality trait. Negative mood, but not personality trait, also increased the functional connectivity between AC and other regions. Variance in AC activation can thus be ascribed to an intersubject variable (extraversion) when responding to positive stimuli and an intrasubject variable (mood) when responding to negative stimuli. The former may explain stable differences between extraverts and introverts. The latter may provide an adaptive mechanism to expand an individual's dynamic range in response to potentially dangerous or threatening stimuli.

Adolescent↗
PubMed2004

Amygdala responses to emotionally valenced stimuli in older and younger adults.

As they age, adults experience less negative emotion, come to pay less attention to negative than to positive emotional stimuli, and become less likely to remember negative than positive emotional materials. This profile of findings suggests that, with age, the amygdala may show decreased reactivity to negative information while maintaining or increasing its reactivity to positive information. We used event-related functional magnetic resonance imaging to assess whether amygdala activation in response to positive and negative emotional pictures changes with age. Both older and younger adults showed greater activation in the amygdala for emotional than for neutral pictures; however, for older adults, seeing positive pictures led to greater amygdala activation than seeing negative pictures, whereas this was not the case for younger adults.

Adolescent↗
PubMed2004

Functional brain mapping of extraversion and neuroticism: learning from individual differences in emotion processing.

This review outlines how functional brain imaging, using an individual-differences approach in the processing of emotional stimuli, has begun to reveal the neural basis of extraversion (E) and neuroticism (N), two traits that are linked to both emotion and health. Studies using functional magnetic resonance imaging have shown that individual differences in participants' E and N scores are correlated with individual differences in brain activation in specific brain regions that are engaged during cognitive-affective tasks. Imaging studies using genotyped participants have begun to address the molecular mechanisms that may underlie these individual differences. The multidisciplinary integration of brain imaging and molecular genetic methods offers an exciting and novel approach for investigators who seek to uncover the biological mechanisms by which personality and health are interrelated.

Amygdala↗
PubMed2002

Sex differences in the neural basis of emotional memories.

Psychological studies have found better memory in women than men for emotional events, but the neural basis for this difference is unknown. We used event-related functional MRI to assess whether sex differences in memory for emotional stimuli is associated with activation of different neural systems in men and women. Brain activation in 12 men and 12 women was recorded while they rated their experience of emotional arousal in response to neutral and emotionally negative pictures. In a recognition memory test 3 weeks after scanning, highly emotional pictures were remembered best, and remembered better by women than by men. Men and women activated different neural circuits to encode stimuli effectively into memory even when the analysis was restricted to pictures rated equally arousing by both groups. Men activated significantly more structures than women in a network that included the right amygdala, whereas women activated significantly fewer structures in a network that included the left amygdala. Women had significantly more brain regions where activation correlated with both ongoing evaluation of emotional experience and with subsequent memory for the most emotionally arousing pictures. Greater overlap in brain regions sensitive to current emotion and contributing to subsequent memory may be a neural mechanism for emotions to enhance memory more powerfully in women than in men.

Behavior↗
PubMed2002

Neuroimaging of emotion and personality: scientific evidence and ethical considerations.

Affective neuroscience has seen an explosion of research efforts using modern neuroimaging approaches to uncover the neural basis of emotion and personality. The first section of this paper reviews studies from the domains of affective and forensic neuroimaging. These studies illustrate some of the topics likely to be the subject of future ethical debates. The second section relates limitations of the neuroimaging approach to ethical considerations in predicting future psychopathology on the basis of brain state analysis.

Brain↗