House of Mind

"Biology gives you a brain. Life turns it into a mind" - Jeffrey Eugenides

  • 12th October
    2012
  • 12
Effects of Early Life Stress and Infant Experiences on Neurobehavioral Development M. Rincón Cortés and R.M. Sullivan In altricial species, infant attachment to the caregiver serves to maintain the infant’s proximity to the caregiver as well as programming the infant’s brain development for later life emotional and cognitive outcomes. The infant’s unique neural circuitry for attachment learning ensures the formation of attachment regardless of the quality of care received, including learning attachment to an abusive caregiver. Unfortunately, while the short-term effects of abusive attachment appear beneficial, the long-term effects of abusive care compromise cognitive/emotional development, including a susceptibility to psychopathologies such as depression. However, the underlying mechanisms by which early life abuse initiates the pathway to pathology are poorly understood. For this reason, we use a rodent model of infant perturbation and focus on the infant’s immediate neurobehavioral response to abuse and its relationship to future neurobiological consequences. Methods: Our lab has been modeling abusive attachment in infant rats using two paradigms that support attachment from postnatal (PN) days 8-12: odor-shock conditioning and a more naturalistic paradigm consisting of a mother rat maltreating her pups due to having insufficient shavings for nest building. Following infant manipulations, animals were tested for social behavior, depressive-like behavior and sucrose intake throughout early development. Results: Using this approach we have found that following infant abuse neurobehavioral deficits emerge prior to weaning age (~PN23) with the disruption of rat social behavior, as indexed by a reduction in sociability. A reduction in sucrose consumption was identified around postweaning age (PN24-27 while other depressive-like behaviors such as increased immobility in the Forced Swim Test (FST) and abnormal amygdala function emerged in adolescence (PN45). Discussion: These results suggest that infant experience with an abusive caregiver results in a depressive-like behavioral phenotype during later life, as manifested by decreased sociability and sucrose consumption and increased immobility in the FST. Morever, these results suggest that disruptions in social behavior may serve as a predictive marker for the emergence of depressive-like behaviors in adolescent and adult rats experiencing abusive attachment during infancy. Importantly, our lab has found that early life stress plays a significant role in the development and expression of these neurobehavioral deficits and is currently assessing the role of the infant’s neurobehavioral response to abuse and its potential contribution to aberrant neurobehavioral development. References: Raineki C., Moriceau, S., and Sullivan R.M. Biol Psychitary 67 (12): 1137-45 (2010); Raineki C., Rincón Cortés M., Belnoue, L., and Sullivan, R.M. J Neurosci 32 (22): 7758-65 (2012). Funding was provided by NIH grants MH091451 and DC009910 to RMS and NSF GRF DGE-1137475 to MRC.  This is the poster that I gave at the 2012 NIDA Mini Convention Early Career Investigator Poster session :)

Effects of Early Life Stress and Infant Experiences on Neurobehavioral Development

M. Rincón Cortés and R.M. Sullivan

In altricial species, infant attachment to the caregiver serves to maintain the infant’s proximity to the caregiver as well as programming the infant’s brain development for later life emotional and cognitive outcomes. The infant’s unique neural circuitry for attachment learning ensures the formation of attachment regardless of the quality of care received, including learning attachment to an abusive caregiver. Unfortunately, while the short-term effects of abusive attachment appear beneficial, the long-term effects of abusive care compromise cognitive/emotional development, including a susceptibility to psychopathologies such as depression. However, the underlying mechanisms by which early life abuse initiates the pathway to pathology are poorly understood. For this reason, we use a rodent model of infant perturbation and focus on the infant’s immediate neurobehavioral response to abuse and its relationship to future neurobiological consequences.

Methods: Our lab has been modeling abusive attachment in infant rats using two paradigms that support attachment from postnatal (PN) days 8-12: odor-shock conditioning and a more naturalistic paradigm consisting of a mother rat maltreating her pups due to having insufficient shavings for nest building. Following infant manipulations, animals were tested for social behavior, depressive-like behavior and sucrose intake throughout early development.

Results: Using this approach we have found that following infant abuse neurobehavioral deficits emerge prior to weaning age (~PN23) with the disruption of rat social behavior, as indexed by a reduction in sociability. A reduction in sucrose consumption was identified around postweaning age (PN24-27 while other depressive-like behaviors such as increased immobility in the Forced Swim Test (FST) and abnormal amygdala function emerged in adolescence (PN45).

Discussion: These results suggest that infant experience with an abusive caregiver results in a depressive-like behavioral phenotype during later life, as manifested by decreased sociability and sucrose consumption and increased immobility in the FST. Morever, these results suggest that disruptions in social behavior may serve as a predictive marker for the emergence of depressive-like behaviors in adolescent and adult rats experiencing abusive attachment during infancy. Importantly, our lab has found that early life stress plays a significant role in the development and expression of these neurobehavioral deficits and is currently assessing the role of the infant’s neurobehavioral response to abuse and its potential contribution to aberrant neurobehavioral development.

References: Raineki C., Moriceau, S., and Sullivan R.M. Biol Psychitary 67 (12): 1137-45 (2010); Raineki C., Rincón Cortés M., Belnoue, L., and Sullivan, R.M. J Neurosci 32 (22): 7758-65 (2012).

Funding was provided by NIH grants MH091451 and DC009910 to RMS and NSF GRF DGE-1137475 to MRC. 

This is the poster that I gave at the 2012 NIDA Mini Convention Early Career Investigator Poster session :)

  • 3rd May
    2011
  • 03
Anatomically Distinct Dopamine Release During Anticipation and Experience of Peak Emotion to Music Music has long been recognized as both an abstract and rewarding stimulus that produces feelings of euphoria and pleasure in many listeners.  Music may also elicit emotional responses from listeners and alter affective states. While music has been present across multiple cultures and societies throughout time, the experience of pleasure while listening to music is highly specific, personal and subjective. In a study featured in Nature Neuroscience last February, Salimpoor and others set out to study what goes on in the brain of individuals while they listened to enjoyable/pleasurable music.  For the study, subjects were asked to bring their own pleasurable music, and the other subjects’ music was used as neutral music for comparison. Dopamine release while listening to music was estimated indirectly by using ligand-based positron emission tomography (PET) scan in which 11C raclopride, a radioactively labeled ligand, competes with endogenous dopamine for D2 receptor binding. The assumption is that if brain areas are experiencing surges of dopamine release, they binding capacity of 11C raclopride will decrease in these areas. The experience of feeling chills, a marker of peak emotional responses to music, was self-reported by the subjects. In addition, psychophysiological measurements (i.e. respiration rate, heart rate, skin conductance, temperature) were also conducted while the subjects listened to music while undergoing PET scanning.  PET scanning revealed changes in 11C raclopride binding in the striatum, specifically in the right caudate and the right nucleus accumbens. There was also a significant positive correlation between reports of chills and feelings of overall pleasure, perhaps indicating that chills may serve as an objective measure of pleasure while listening to music. The experience of overall greater pleasure while music listening was also correlated with greater autonomic nervous system arousal, as indexed by changes in psychophysiological measurements.  To assess the temporal dynamics in dopamine release, the group employed functional magnetic resonance imaging (fMRI) while subjects listened to neutral or pleasurable music. Subjects were asked to press a button whenever they felt chills (typically during pleasurable moments), and the 15s prior to the pressing of the button, which indicated chills + pleasure, were denoted as the anticipation window. Thus, dopamine release was studied in two different time periods: anticipation period (15s before reported pleasure and chills), and peak response (chills/pleasure). When the fMRI scans were conjoined with the PET masks, the group was able to identify a temporally mediated BOLD response in the right side of dorsal (caudate) and ventral (nucleus accumbens) striatum that corresponded with anticipation epochs and peak experience, respectively. Moreover, as demonstrated above, behavioral measures like the number of reported chills were more correlated with 11C raclopride binding changes in the right caudate while intensity of chills and overall degree of reported pleasure were more significantly correlated with changes in 11C raclopride binding potential in the right nucleus accumbens.  In summary, the experience of pleasure while listening to music acts on the brain similarly to other rewards like food, sex and drugs. Listening to pleasurable music targets striatal areas associated with mesolimbic reward circuitry and dopaminergic neurotransmission.  Source: Salimpoor, et al. 2011. Anatomically Distinct Dopamine Release During Anticipation and Experience of Peak Emotion to Music. Nature Neuroscience. doi:10.1038/nn.2726

Anatomically Distinct Dopamine Release During Anticipation and Experience of Peak Emotion to Music

Music has long been recognized as both an abstract and rewarding stimulus that produces feelings of euphoria and pleasure in many listeners.  Music may also elicit emotional responses from listeners and alter affective states. While music has been present across multiple cultures and societies throughout time, the experience of pleasure while listening to music is highly specific, personal and subjective. In a study featured in Nature Neuroscience last February, Salimpoor and others set out to study what goes on in the brain of individuals while they listened to enjoyable/pleasurable music. 

For the study, subjects were asked to bring their own pleasurable music, and the other subjects’ music was used as neutral music for comparison. Dopamine release while listening to music was estimated indirectly by using ligand-based positron emission tomography (PET) scan in which 11C raclopride, a radioactively labeled ligand, competes with endogenous dopamine for D2 receptor binding. The assumption is that if brain areas are experiencing surges of dopamine release, they binding capacity of 11C raclopride will decrease in these areas. The experience of feeling chills, a marker of peak emotional responses to music, was self-reported by the subjects. In addition, psychophysiological measurements (i.e. respiration rate, heart rate, skin conductance, temperature) were also conducted while the subjects listened to music while undergoing PET scanning. 

PET scanning revealed changes in 11C raclopride binding in the striatum, specifically in the right caudate and the right nucleus accumbens. There was also a significant positive correlation between reports of chills and feelings of overall pleasure, perhaps indicating that chills may serve as an objective measure of pleasure while listening to music. The experience of overall greater pleasure while music listening was also correlated with greater autonomic nervous system arousal, as indexed by changes in psychophysiological measurements. 

To assess the temporal dynamics in dopamine release, the group employed functional magnetic resonance imaging (fMRI) while subjects listened to neutral or pleasurable music. Subjects were asked to press a button whenever they felt chills (typically during pleasurable moments), and the 15s prior to the pressing of the button, which indicated chills + pleasure, were denoted as the anticipation window. Thus, dopamine release was studied in two different time periods: anticipation period (15s before reported pleasure and chills), and peak response (chills/pleasure).

When the fMRI scans were conjoined with the PET masks, the group was able to identify a temporally mediated BOLD response in the right side of dorsal (caudate) and ventral (nucleus accumbens) striatum that corresponded with anticipation epochs and peak experience, respectively. Moreover, as demonstrated above, behavioral measures like the number of reported chills were more correlated with 11C raclopride binding changes in the right caudate while intensity of chills and overall degree of reported pleasure were more significantly correlated with changes in 11C raclopride binding potential in the right nucleus accumbens. 

In summary, the experience of pleasure while listening to music acts on the brain similarly to other rewards like food, sex and drugs. Listening to pleasurable music targets striatal areas associated with mesolimbic reward circuitry and dopaminergic neurotransmission. 

Source:

Salimpoor, et al. 2011. Anatomically Distinct Dopamine Release During Anticipation and Experience of Peak Emotion to Music. Nature Neuroscience. doi:10.1038/nn.2726


  • 27th March
    2010
  • 27
Stanley Milgram's Behavioral Study of Obedience

Where does one draw the line between obedience and conformity?

Stanley Milgram, a psychology professor at Yale University, conducted a series of social psychology experiments to find out.

The series of experiments were titled “The Milgram experiments on obedience to authority figures.” The study was designed to measure the willingness of experimental subjects to follow orders from a higher authority, regardless of the negative impact these may have on another individual. These experiments were contemporary with the trials of Nazi war criminals who claimed that they were following orders from superiors, which sparked major interest in the study. The study aimed at gaining some understanding of how ordinary human beings can carry out cruel and horrific orders that involve causing pain and suffering to another being.

In short, volunteers were told that they had to deliver electric shocks as part of a learning experiment. The individuals administering the shocks were assigned as “teachers” and the individuals receiving the shocks were termed “learners”. Each time the learner made a mistake, the teacher was instructed by a higher authority figure (in a white lab coat) to deliver increasing electrical shocks. The intensity of the shocks was indicated by screaming, yelling, and other marks of pain and distress from the learners, which were kept out of sight so that the teachers would form their own assumptions about the pain that they were inflicting. When the teachers were hesitant or reluctant to keep administering the shocks, the superiors kept instructing them to continue. Sounds cruel and unethical, I know. The trick? The so-called learners, were in fact, actors following a rehearsed script. 

As for the results, Milgram discovered that people are more obedient than what they think they are. Over 60% of the participants continued administering the shocks until the very end (which was marked by an XXX in the shocking device). This means that they followed orders despite believing that their actions were causing harm to someone else. Can you believe that? The teachers kept shocking despite painful yells, agonizing screams, pleads begging for them to stop, and eventually silence.

Some have argued that one of the study’s flaws was the usage of actors because some of the participants may have thought about the possibility of the learners being actors. However, they still did what they believed to be expected of them. Thus, Stanley Milgram’s study on obedience could be more properly named a study on the power of conformity. 

Where would have you drawn the line, if at all?

Source: Milgram, S. (1963). Behavioral study of obedience. Journal of Abnormal and Social Psychology, 67(4), 371-378.