House of Mind

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

  • 15th October
    2012
  • 15

Motherhood Exerts a Protective Effect Against Drug Abuse

Are you a mother? If so, research presented at SfN suggests that you are less likely to develop a drug addiction problem. Behavioral research from the Becker lab at U Michigan-Ann Arbor has shown that motherhood alters a female rat’s response to cocaine in a way that attenuates (i.e. dampens) her drug abuse liability. For example, the group found that virgin rats will not only press a lever more readily to self-administer cocaine via brain infusion, but they will also escalate (or increase their drug take) during the first week of cocaine use. In contrast, rat mothers having the maternal experience of rearing at least one litter maintain a steady level of self-administration. Moreover, virgin rats are willing to expend more energy and press the lever over 70 times to receive a single cocaine infusion, suggesting that they are willing to work harder to receive the drug even when it is challenging to obtain. 

So why do these virgin rats go crazy for cocaine? In order to answer this question, the group used microdialysis, a procedure in which a probe can be inserted into a specific brain area in order to collect extracellular fluid including neurotransmitters and metabolites, to examine cocaine-induced dopamine release in the nucleus accumbens after an injection of cocaine in virgin rats and mother rats having NO prior experience with cocaine.Using this technique, they were able to show that virgin rats release significantly more dopamine in response to cocaine than females that have had a least a litter, suggesting that the same dose of cocaine has less of an effect (i.e., is less reinforcing) female rats that have been mothers before. Thus, these data indicate that mothers are less susceptible to the effects of cocaine than virgins. 


This research was presented on October 15, 2012 by J.A. Cummings as a short talk titled: Maternal experience protects female rats against drug abuse liability. 


  • 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


  • 31st January
    2011
  • 31