Claire-Dominique Walker

Claire-Dominique Walker
 

Bureau: 
E-2133, Pavillon Perry

6875 Boulevard Lasalle
Montréal, QC
H4H 1R3


(514) 761-6131 x4934

Fax: 
(514) 762-3034

Champs de recherche: 
Neurosciences fondamentales / Recherche animale

Thème de recherche: 
Stress, désordres de l'humeur et de l'impulsivité


PhD
Professeur
Département de psychiatrie et département d'anatomie de biologie cellulaire, Université McGill
Directrice des technologies - Centre de recherche de l'hôpital Douglas



Stress postnatal, régulation maternelle et développement neuroendocrinien


Optimal early development in most species is critically dependent upon a stable relationship between the mother and her infant. The research focus of our laboratory concentrates on the reciprocal nature of this dyad, with respect to the regulation of stress responsiveness in both mother and offspring and the long term neurophysiological and behavioral consequences of early environmental stressors in the offspring. Non-genomic maternal influences on the infant are primarily routed through changes in nutrition and maternal care in the early postnatal period. It is now well recognized in rodents and to a certain extent in humans that variations in maternal care for instance, are associated with molecular changes in the central nervous system leading to modifications in stress responsiveness and coping mechanisms in the long-term. Dietary influences are critical not only to regulate infant growth, but also to modulate the response of the neuroendocrine system to stress and possibly to influence some aspects of brain development. In particular, we examine the consequences of early exposure to high fat diet on the development of reward pathways and preference towards specific food intake in the offspring and investigate the role of metabolic hormones such as leptin, ghrelin and insulin in mediating these effects. Dietary fat intake is also important in providing precursor molecules that have important neurotransmitter functions such as endocannabinoids, which are lipid-derived retrograde transmitters and actively participate in regulation of stress responses in the adult. We are actively seeking to define their role in the establishment of vulnerability to stress during the developmental period.
While maternal regulatory influences are critical for the development of the stress axis (HPA axis) and behavioral regulation in the offspring, there is also evidence to support the reverse regulatory influence in which maternal state is profoundly affected by stimulation from the young. Indeed, earlier studies have shown that infant temperament might influence mothering style and that sensory stimuli provided by the infant are able to modify physiological and behavioral responses in the mother. During the period of lactation, mothers exhibit lower neuroendocrine and behavioral responses to several types of stressors except possibly those representing a threat to the infant. This ability to “filter” relevant from irrelevant stimuli while caring for their young might be viewed as adaptive for the mother-infant dyad and emphasizes the importance of the concept of stimulus salience in regulating neuroendocrine and behavioral responses in the mother. Such a concept might apply to post-partum mothers as well since they exhibit a certain degree of stress hyporesponsiveness, in particular breast-feeding mothers. Studies directed towards understanding the mechanisms by which infants can regulate their mothers’ stress responses are currently underway in the laboratory as we are seeking to identify neuronal structures that are part of a “salience filter network” in the maternal brain. These studies should help us identify whether the inability to adequately “filter” stressful stimuli could at least in part be associated with the development of postpartum depression and whether breastfeeding in high risk populations could be seen as a protective factor against exaggerated responses to challenges in both mother and offspring.


Wood C, Walker CD 2015 Fetal and Neonatal HPA Axis. Comprehensive Physiology, (in press)

Walker C-D, Woodside B. 2015 “Mothering influences on offspring stress response mechanisms”. In: INF Masterclass in Neuroendocrinology Series: “Neuroendocrinology of Stress”. ed J A Russell & M J Shipston: Wiley-Blackwell. Chap 13, p279

Naef L, Gjerde E, Long H, Richard D, Walker CD 2014 Neonatal onset of leptin signaling in dopamine neurons of the ventral tegmental area in the rat. J Neuroendocrinol. 2014 Dec;26(12):835-43

Campbell-Yeo M, Johnston C, Benoit B, Latimer M, Vincer M, Walker CD, Streiner D, Inglis D, Caddell K. 2013 Trial of repeated analgesia with Kangaroo Mother Care (TRAKC Trial). BMC Pediatr. 2013 Nov 9;13:182

Naef L, Gratton A, Walker CD.2013 Exposure to high fat during early development impairs adaptations in dopamine and neuroendocrine responses to repeated stress.Stress. 2013 Sep;16(5):540-8. doi: 10.3109/10253890.2013.805321.

Buwembo A, Long H, Walker CD 2013 Participation of endocannabinoids in rapid suppression of stress responses by glucocorticoids in neonates.Neuroscience. 2013 Sep 26;249:154-61.

Naef L, Moquin L, Gratton A, Walker CD 2013 Blunted anticipatory dopamine responses to food in animals exposed to high-fat during early development. Int J Obes (Lond). 2013 Jun;37(6):885-8.

Walker C-D. 2010 Maternal touch and feed as critical regulators of behavioural and stress responses in the offspring. Dev Psychobiol. Nov;52(7):638-50.2010 Sep 22.

DeMedeiros C, Fleming AS, Johnston CC, Walker C-D. 2009 Artificial rearing of rat pups reveals the beneficial effects of mother care on neonatal inflammation and adult sensitivity to pain. Pediatric Res. 66(3):272-7

Léonhardt MM, Matthews SG, Meaney MJ, Walker C-D 2007 Psychological stress as a model of early maternal adversity: diurnal modulation of corticosterone responses and changes in maternal behaviour. Horm Behav. 2007 Jan;51(1):77-88


Dr Claire-Dominique Walker a obtenu son PhD de l'Université de Genève en Suisse suite à des travaux effectués au Salk Institute de San Diego et a l'Université de Genève. Elle a poursuivi sa formation postdoctorale a l'Université de Californie a San Francisco avant de se joindre au corps professoral de L'Université McGill dans les départements de psychiatrie ainsi que d'anatomie et biologie cellulaire. Ses activités de recherche s'effectuent à l'interieur du centre de recherche de l'Institut en santé mentale Douglas. Sa recherche vise à comprendre les conséquences à long terme du stress et des changements environnementaux ayant lieu au cours du développement néonatal et qui peuvent augmenter la vulnérabilite de l'organisme à diverses pathologies comme les maladies mentales ou métaboliques. Les études en cours présentement cherchent à elucider les changements induits par la diète maternelle, le stress et les endocannabinoides sur les voies neuronales responsables des réponses au stress et des réponses de récompense (à la prise alimentaire par exemple). Afin de pouvoir étudier plus à fond certaines des conséquences de la douleur subie par les nouveaux-nés prematurés aux soins intensifs, Dr Walker a developpé un modele animal de douleur repetée au cours de la periode néonatale. Ce modèle permet de mieux comprendre comment la douleur subie dans une periode de vulnérabilite du cerveau, peut affecter les réponses au stress et la morphologie de certaines régions du cerveau plus tard dans la vie.


1994-1997: NSERC Women’s Faculty Award
1994-1995: FRSQ Chercheur Boursier Junior I (Fondation des maladies mentales)
1997-1999: NSERC Women’s Faculty Award
1997-2000: FRSQ Chercheur Boursier Junior II
2000-2004: FRSQ Chercheur Boursier Senior
2002: CCNP Young Investigator Award


Membres courants:
Angela Guadagno, MSc student
Emily Opala, MSc student
Hong Long, Research assistant
Silvanna Verlezza, research assistant

Membres ayant quitte le laboratoire (5 dernieres annees):
PDFs:
Xiu Jing Cao (PhD, University of Science and Technology of China)
Katharina Hillerer (PhD, University of Regensburg, Germany)
Ryan McLaughlin (PhD, UBC, Canada)
PhD:
Lindsay Naef, PhD
Francis Bambico, PhD
MSc:
Cynthia de Medeiros, MSc
Alice Buwembo, MSc
Eva Gjerde, MSc
MinGi Cho, MSc


Publications récentes

Publications récentes

McGill Logo

CIUSSS ouest montreal logo

 



  • Douglas Hospital
  • Dobell Pavillion
  • Brain imaging centre