Biomedical subjects

Pierre Bourgouin

Publications and source records attributed to Pierre Bourgouin.

9 recordsLinked to original sources

PubMed2005

Brain activity during emotionally negative pictures in schizophrenia with and without flat affect: an fMRI study.

The aim of this functional magnetic resonance imaging (fMRI) study was to compare regional brain activity in schizophrenia subjects with (FA+) and without (FA-) flat affect during the viewing of emotionally negative pictures. Thirteen FA+ subjects and 11 FA- subjects were scanned while being presented with a series of emotionally negative and neutral pictures. Experientially, the viewing of the negative pictures induced a negative emotional state whose intensity was significantly greater in the FA- group than in the FA+ group. Neurally, the Negative minus Neutral contrast revealed, in the FA- group, significant loci of activation in the midbrain, pons, anterior cingulate cortex, insula, ventrolateral orbitofrontal cortex, anterior temporal pole, amygdala, medial prefrontal cortex, and extrastriate visual cortex. In the FA+ group, this contrast produced significant loci of activation in the midbrain, pons, anterior temporal pole, and extrastriate visual cortex. When the brain activity measured in the FA+ group was subtracted from that measured in the FA- group, only the lingual gyrus was significantly activated. Perhaps in FA+ subjects an amygdaloid malfunction rendered the amygdala unable to correctly evaluate the emotional meaning of the pictures presented, thus preventing effective connectivity linking the amygdala to the brain regions implicated in the physiological and experiential dimensions of emotion. Alternatively, a disturbance of effective connectivity in the neural networks linking the midbrain and the medial prefrontal system may have been responsible for the quasi absence of emotional reaction in FA+ subjects, and the abnormal functioning of the medial prefrontal cortex and anterior cingulate cortex in the FA+ group.

Adult↗

PubMed2004

Neural correlates of lexical and sublexical processes in reading.

The purpose of the present study was to compare the brain regions and systems that subserve lexical and sublexical processes in reading. In order to do so, three types of tasks were used: (i). silent reading of very high frequency regular words (lexical task); (ii). silent reading of nonwords (sublexical task); and, (iii). silent reading of very low frequency regular words (sublexical task). All three conditions were contrasted with a visual/phonological baseline condition. The lexical condition engaged primarily an area at the border of the left angular and supramarginal gyri. Activation found in this region suggests that this area may be involved in mapping orthographic-to-phonological whole word representations. Both sublexical conditions elicited significantly greater activation in the left inferior prefrontal gyrus. This region is thought to be associated with sublexical processes in reading such as grapheme-to-phoneme conversion, phoneme assembly and underlying verbal working memory processes. Activation in the left IFG was also associated with left superior and middle temporal activation. These areas are thought to be functionally correlated with the left IFG and to contribute to a phonologically based form of reading. The results as a whole demonstrate that lexical and sublexical processes in reading activate different regions within a complex network of brain structures.

Adult↗

PubMed2003

Prefrontal cortex contribution to associative recognition memory in humans: an event-related functional magnetic resonance imaging study.

The present event-related fMRI study examined in ten healthy participants neural correlates of recognition memory for intact, rearranged, and new pairs of visual stimuli. The correct categorization of both intact and rearranged pairs relative to pairs of new, never presented before stimuli relies on the retrieval of associative information whereas the discrimination of rearranged pairs from intact pairs additionally involves a recall-to-reject process by which subjects retrieve additional information to reach a recognition decision. Relative to new pairs, both intact and rearranged pairs yielded activation in inferior prefrontal cortex bilaterally and left dorsolateral prefrontal cortex. Relative to intact pairs, rearranged pairs were associated with increased activity in left dorsolateral prefrontal cortex. The latter could reflect the neural correlates of a recall-to-reject process, a pivotal process of associative recognition memory.

Adult↗

PubMed2003

Separate neural circuits for primary emotions? Brain activity during self-induced sadness and happiness in professional actors.

The question of whether distinct or similar neural substrates underlie primary emotions has not been resolved yet. To address this issue, we used fMRI to scan professional actors during self-induced states of sadness and happiness. Results demonstrated that, relative to an emotionally Neutral state, both the Sad and the Happy states were associated with significant loci of activation, bilaterally, in the orbitofrontal cortex, and in the left medial prefrontal cortex, left ventrolateral prefrontal cortex, left anterior temporal pole, and right pons. These loci of activation were localized distinctly within these regions, that is, in different sub-regions. These results suggest that sadness and happiness may be associated with similar brain regions but distinct sub-regions and neural circuits.

Adult↗

PubMed2003

Neural circuitry underlying voluntary suppression of sadness.

BACKGROUND: The ability to voluntarily self-regulate negative emotion is essential to a healthy psyche. Indeed, a chronic incapacity to suppress negative emotion might be a key factor in the genesis of depression and anxiety. Regarding the neural underpinnings of emotional self-regulation, a recent functional neuroimaging study carried out by our group has revealed that the dorsolateral prefrontal cortex (DLPFC) and anterior cingulate cortex are involved in voluntary suppression of sexual arousal. As few things are known, still, with respect to the neural substrate underlying volitional self-regulation of basic emotions, here we used functional magnetic resonance imaging to identify the neural circuitry associated with the voluntary suppression of sadness. METHODS: Twenty healthy female subjects were scanned during a Sad condition and a Suppression condition. In the Sad condition, subjects were instructed to react normally to sad film excerpts whereas, in the Suppression condition, they were asked to voluntarily suppress any emotional reaction in response to comparable stimuli. RESULTS: Transient sadness was associated with significant loci of activation in the anterior temporal pole and the midbrain, bilaterally, as well as in the left amygdala, left insula, and right ventrolateral prefrontal cortex (VLPFC) (Brodmann area [BA] 47). Correlational analyses carried out between self-report ratings of sadness and regional blood oxygen level dependent (BOLD) signal changes revealed the existence of positive correlations in the right VLPFC (BA 47), bilaterally, as well as in the left insula and the affective division of the left anterior cingulate gyrus (BA 24/32). In the Suppression condition, significant loci of activation were noted in the right DLPFC (BA 9) and the right orbitofrontal cortex (OFC) (BA 11), and positive correlations were found between the self-report ratings of sadness and BOLD signal changes in the right OFC (BA 11) and right DLPFC (BA 9). CONCLUSIONS: These results confirm the key role played by the DLPFC in emotional self-regulation. They also indicate that the right DLPFC and right OFC are components of a neural circuit implicated in voluntary suppression of sadness.

Adult↗

PubMed2003

Neural correlates of dual task interference in rapid visual streams: an fMRI study.

In rapid streams of visual stimuli, identification of a first target interferes with identification of a second target presented within the next half second (the attentional blink or AB). It has been suggested that rapid perceptual decisions under masking interference involve interactions between frontal and posterior cortex. We investigated the neural correlates of the AB using functional magnetic resonance imaging (fMRI). Twelve subjects viewed rapid streams of black letters in which were embedded two white target letters (T1 and T2) separated by either 300 or 700 ms. As expected, fewer correct T2 identifications were observed in the short-delay condition. Corresponding fMRI statistical images showed increased activation in inferotemporal and posterior parietal cortex, but also in lateral frontal cortex and cerebellum in the short-delay condition suggesting that these brain regions are associated with perceptual decisions under masking interference.

Adult↗

PubMed2003

"Change the mind and you change the brain": effects of cognitive-behavioral therapy on the neural correlates of spider phobia.

Questions pertaining to the neurobiological effects of psychotherapy are now considered among the most topical in psychiatry. With respect to this issue, positron emission tomography (PET) findings indicate that cognitive and behavioral modifications, occurring in a psychotherapeutic context, can lead to regional brain metabolic changes in patients with major depression or obsessive-compulsive disorder. The goal of the present functional magnetic resonance imaging (fMRI) study, which constitutes the first neuroimaging investigation of the effects of cognitive-behavioral therapy (CBT) using an emotional activation paradigm, was to probe the effects of CBT on the neural correlates of spider phobia. In order to do so, fMRI was used in subjects suffering from spider phobia (n = 12) to measure, before and after effective CBT, regional brain activity during the viewing of film excerpts depicting spiders. Normal control subjects were also scanned (once) while they were exposed to the same film excerpts. Results showed that, in phobic subjects before CBT, the transient state of fear triggered, during the viewing of the phobogenic stimuli, was correlated with significant activation of the right dorsolateral prefrontal cortex (Brodmann area-BA 10), the parahippocampal gyrus, and the visual associative cortical areas, bilaterally. For normal control subjects (n = 13), only the left middle occipital gyrus and the right inferior temporal gyrus were significantly activated. In phobic subjects before CBT, the activation of the dorsolateral prefrontal cortex (BA 10) may reflect the use of metacognitive strategies aimed at self-regulating the fear triggered by the spider film excerpts, whereas the parahippocampal activation might be related to an automatic reactivation of the contextual fear memory that led to the development of avoidance behavior and the maintenance of spider phobia. After successful completion of CBT, no significant activation was found in the dorsolateral prefrontal cortex (BA 10) or the parahippocampal gyrus. These findings suggest that a psychotherapeutic approach, such as CBT, has the potential to modify the dysfunctional neural circuitry associated with anxiety disorders. They further indicate that the changes made at the mind level, within a psychotherapeutic context, are able to functionally "rewire" the brain.

Adaptation, Psychological↗

PubMed2003

The impact of individual differences on the neural circuitry underlying sadness.

Several functional neuroimaging studies have been carried out in healthy subjects to investigate the neural correlates of sadness. Importantly, there is little consistency among the results of these studies. Hypothesizing that individual differences may account for the discrepancies among these investigations, we conducted two functional magnetic resonance imaging (fMRI) studies to identify the neural circuitry underlying this basic emotion. In these two methodologically identical studies, two different groups (n = 10 for each study) of healthy female subjects were scanned while they were experiencing a transient state of sadness induced by viewing sad film excerpts. In the first of these studies, sadness was correlated with significant loci of activation in the anterior temporal pole and insula (P < 0.05, corrected). In the second study, however, sadness was correlated with significant activation in the orbitofrontal and medial prefrontal cortices (P < 0.05, corrected). In addition, individual statistical parametric maps revealed a marked degree of interindividual variability in both Study 1 and Study 2. These results strongly support the view that individual differences may be responsible for the inconsistencies found in the literature regarding the neural substrates of sadness and of other basic emotions. These findings also suggest that individual data should be reported in addition to group data, because they provide useful information about the variability present in the subjects investigated and, thus, about the typicality and generalizability of the results.

Adult↗

PubMed2002

Areas of brain activation in males and females during viewing of erotic film excerpts.

Various lines of evidence indicate that men generally experience greater sexual arousal (SA) to erotic stimuli than women. Yet, little is known regarding the neurobiological processes underlying such a gender difference. To investigate this issue, functional magnetic resonance imaging was used to compare the neural correlates of SA in 20 male and 20 female subjects. Brain activity was measured while male and female subjects were viewing erotic film excerpts. Results showed that the level of perceived SA was significantly higher in male than in female subjects. When compared to viewing emotionally neutral film excerpts, viewing erotic film excerpts was associated, for both genders, with bilateral blood oxygen level dependent (BOLD) signal increases in the anterior cingulate, medial prefrontal, orbitofrontal, insular, and occipitotemporal cortices, as well as in the amygdala and the ventral striatum. Only for the group of male subjects was there evidence of a significant activation of the thalamus and hypothalamus, a sexually dimorphic area of the brain known to play a pivotal role in physiological arousal and sexual behavior. When directly compared between genders, hypothalamic activation was found to be significantly greater in male subjects. Furthermore, for male subjects only, the magnitude of hypothalamic activation was positively correlated with reported levels of SA. These findings reveal the existence of similarities and dissimilarities in the way the brain of both genders responds to erotic stimuli. They further suggest that the greater SA generally experienced by men, when viewing erotica, may be related to the functional gender difference found here with respect to the hypothalamus.

Adult↗