How a parent responds to an infant's cry may be a major indicator of the quality of parenting behavior (i.e. neglect). Some data suggest that mothers who maltreat their children may have different psychophysiological responses to infant cries. Crying is the most conspicuous of the early attachment behaviors. Crying normally arouses a parent's alarm and elicits caretaking activity to stop the crying. While the functional neuroanatomy of human infant crying and parental response is largely unknown, studies of non-human mammals suggest that the brain's thalamocingulate circuit (a region including the cingulate and anterior part of the thalamus) may play a large role. First, the thalamocingulate circuit (TC circuit) is present in mammals but not in reptiles, who unlike mammals, are generally not parental, do not hear well, and do not cry as infants. Second, there is evidence suggesting that experimentally-induced cingulate damage in non-human mammals impairs infant crying on separation and causes mothers to neglect their young. A well-developed functional imaging 'assay' of the brain's response to cries would be an enormously useful tool for the research of neglectful mothers, and could be used to measure different interventions (psychosocial or pharmacological). Recent pilot work by the PI using functional MRI suggests that the TC circuit displays increased activity when healthy mothers hear recorded tapes of crying babies as compared with matched control noises. This three year RO1 study proposes to further develop this functional MRI technique in order to eventually be able to test whether TC circuit activity differs in neglectful mothers. We propose to study the regional brain activity in 46 physically and psychiatrically healthy mothers while they listen to their own infant cry, a standardized infant cry, and control sounds matched for intensity, frequency, and temporal pattern with each of these cries. There will also be an attentional control task. The immediate goals of this project are to (1) replicate the finding of increased TC circuit activity with the cries, using better matched control noises and a control for attention, (2) determine whether TC circuit activity is higher with a mother's own infant cry than with a standard infant cry, and (3) determine whether measures of social bonding or the quality of mother-infant interaction correlates with the level of TC circuit activity during the cries. This developmental work would provide the groundwork to use this paradigm to test whether neglectful mothers have less TC circuit activity with cries than do non-neglectful parents, which would be consistent with the nonhuman mammal cingulate damage literature.
| Lorberbaum, Jeffrey P; Newman, John D; Horwitz, Amy R et al. (2002) A potential role for thalamocingulate circuitry in human maternal behavior. Biol Psychiatry 51:431-45 |
