Biomedical subjects

James K Rilling

Publications and source records attributed to James K Rilling.

11 recordsLinked to original sources

PubMed2006

Neural correlates of social cooperation and non-cooperation as a function of psychopathy.

BACKGROUND: Psychopathy is a disorder involving a failure to experience many emotions that are necessary for appropriate social behavior. In this study, we probed the behavioral, emotional, and neural correlates of psychopathic traits within the context of a dyadic social interaction. METHODS: Thirty subjects were imaged with functional magnetic resonance imaging while playing an iterated Prisoner's Dilemma game with human confederates who were outside the scanner. Subjects also completed two self-report psychopathy questionnaires. RESULTS: Subjects scoring higher on psychopathy, particularly males, defected more often and were less likely to continue cooperating after establishing mutual cooperation with a partner. Further, they experienced more outcomes in which their cooperation was not reciprocated (cooperate-defect outcome). After such outcomes, subjects scoring high in psychopathy showed less amygdala activation, suggesting weaker aversive conditioning to those outcomes. Compared with low-psychopathy subjects, subjects higher in psychopathy also showed weaker activation within orbitofrontal cortex when choosing to cooperate and showed weaker activation within dorsolateral prefrontal and rostral anterior cingulate cortex when choosing to defect. CONCLUSIONS: These findings suggest that whereas subjects scoring low on psychopathy have emotional biases toward cooperation that can only be overcome with effortful cognitive control, subjects scoring high on psychopathy have an opposing bias toward defection that likewise can only be overcome with cognitive effort.

Adult↗

PubMed2006

A Bayesian approach to determining connectivity of the human brain.

Recent work regarding the analysis of brain imaging data has focused on examining functional and effective connectivity of the brain. We develop a novel descriptive and inferential method to analyze the connectivity of the human brain using functional MRI (fMRI). We assess the relationship between pairs of distinct brain regions by comparing expected joint and marginal probabilities of elevated activity of voxel pairs through a Bayesian paradigm, which allows for the incorporation of previously known anatomical and functional information. We define the relationship between two distinct brain regions by measures of functional connectivity and ascendancy. After assessing the relationship between all pairs of brain voxels, we are able to construct hierarchical functional networks from any given brain region and assess significant functional connectivity and ascendancy in these networks. We illustrate the use of our connectivity analysis using data from an fMRI study of social cooperation among women who played an iterated "Prisoner's Dilemma" game. Our analysis reveals a functional network that includes the amygdala, anterior insula cortex, and anterior cingulate cortex, and another network that includes the ventral striatum, orbitofrontal cortex, and anterior insula. Our method can be used to develop causal brain networks for use with structural equation modeling and dynamic causal models.

Adult↗

PubMed2006

Determining hierarchical functional networks from auditory stimuli fMRI.

We determined connectivity of the human brain using functional magnetic resonance imaging (fMRI) while subjects experienced auditory stimuli in a 2-by-2 factorial design. The two factors in this study were "speaker" (same or different speaker) and "sentence" (same or different sentences). Connectivity studies allow us to ask how spatially remote brain regions are neurophysiologically related given these stimuli. In the context of this study, we examined how the "speaker" effect and "sentence" effect influenced these relationships. We applied a Bayesian connectivity method that determines hierarchical functional networks of functionally connected brain regions. Hierarchy in these functional networks is determined by conditional probabilities of elevated activity. For example, a brain region that becomes active a superset of the time of another region is considered ascendant to that brain region in the hierarchical network. For each factor level, we found a baseline functional network connecting the primary auditory cortex (Brodmann's Area [BA] 41) with the BA 42 and BA 22 of the superior temporal gyrus (STG). We also found a baseline functional network that includes Wernicke's Area (BA 22 posterior), STG, and BA 44 for each factor level. However, we additionally observed a strong ascendant connection from BA 41 to the posterior cingulate (BA 30) and Broca's Area and a stronger connection from Wernicke's Area to STG and the posterior cingulate while passively listening to different sentences rather than the same sentence repeatedly. Finally, our results revealed no significant "speaker" effect or interaction between "speaker" and "sentence."

Acoustic Stimulation↗

PubMed2006

Effects of tryptophan depletion on the performance of an iterated Prisoner's Dilemma game in healthy adults.

Adaptive social behavior often necessitates choosing to cooperate with others for long-term gains at the expense of noncooperative behaviors giving larger immediate gains. Although little is know about the neural substrates that support cooperative over noncooperative behaviors, recent research has shown that mutually cooperative behavior in the context of a mixed-motive game, the Prisoner's Dilemma (PD), is associated with increased neural activity within reinforcement circuitry. Other research attests to a role for serotonin in the modulation of social behavior and in reward processing. In this study, we used a within-subject, crossover, double-blind design to investigate performance of an iterated, sequential PD game for monetary reward by healthy human adult participants following ingestion of an amino-acid drink that either did (T+) or did not (T-) contain l-tryptophan. Tryptophan depletion produced significant reductions in the level of cooperation shown by participants when playing the game on the first, but not the second, study days. This effect was accompanied by a significantly diminished probability of cooperative responding given previous mutually cooperative behavior. These data suggest that serotonin plays a significant role in the acquisition of socially cooperative behavior in human adult participants, and suggest novel hypotheses concerning the serotonergic modulation of reward information in socially cooperative behavior in both health and psychiatric illness.

Brain↗

PubMed2004

Opposing BOLD responses to reciprocated and unreciprocated altruism in putative reward pathways.

Mesencephalic dopamine neurons are believed to facilitate reward-dependent learning by computing errors in reward predictions. We used fMRI to test whether this system was activated as expected in response to errors in predictions about whether a social partner would reciprocate an act of altruism. Nineteen subjects received fMRI scans as they played a series of single-shot Prisoner's Dilemma games with partners who were outside the scanner. In both ventromedial prefrontal cortex and ventral striatum, reciprocated and unreciprocated cooperation were associated with positive and negative BOLD responses, respectively. Our results are consistent with the hypothesis that mesencephalic dopamine projection sites carry information about errors in reward prediction that allow us to learn who can and cannot be trusted to reciprocate favors.

Adolescent↗

PubMed2004

The neural correlates of mate competition in dominant male rhesus macaques.

BACKGROUND: Male sexual jealousy provoked by threatened exclusive access to a female mate is a frequently reported motive in cases involving spousal abuse. Dominant male rhesus macaques also respond aggressively to threats to mating exclusivity. METHODS: Nine dominant male monkeys were injected with [(18)F]-fluorodeoxyglucose ([(18)F]-FDG) and then exposed to one of two conditions: a "challenge" condition in which they witnessed a potential sexual interaction between their female consort and a rival male, and a control condition in which the consort was present without the rival male. After the brain uptake period for [(18)F]-FDG, dominant males were sedated, blood samples were drawn, and regional cerebral glucose metabolism was measured with positron emission tomographic imaging. RESULTS: Males that showed larger increases in plasma testosterone in the challenge condition showed more aggression and greater activation in the central gray matter of the midbrain, a brain area rich in androgen receptors. The challenge condition was associated with activation in both right superior temporal sulcus and right amygdala, which might relate to increased social vigilance and anxiety, respectively. CONCLUSIONS: Sexual jealousy in male humans is also often accompanied by vigilance behavior and anxiety and might recruit a similar neural network to that described here.

Analysis of Variance↗

PubMed2004

Placebo-induced changes in FMRI in the anticipation and experience of pain.

The experience of pain arises from both physiological and psychological factors, including one's beliefs and expectations. Thus, placebo treatments that have no intrinsic pharmacological effects may produce analgesia by altering expectations. However, controversy exists regarding whether placebos alter sensory pain transmission, pain affect, or simply produce compliance with the suggestions of investigators. In two functional magnetic resonance imaging (fMRI) experiments, we found that placebo analgesia was related to decreased brain activity in pain-sensitive brain regions, including the thalamus, insula, and anterior cingulate cortex, and was associated with increased activity during anticipation of pain in the prefrontal cortex, providing evidence that placebos alter the experience of pain.

Analgesia↗

PubMed2004

The neural correlates of theory of mind within interpersonal interactions.

Tasks that engage a theory of mind seem to activate a consistent set of brain areas. In this study, we sought to determine whether two different interactive tasks, both of which involve receiving consequential feedback from social partners that can be used to infer intent, similarly engaged the putative theory of mind neural network. Participants were scanned using fMRI as they played the Ultimatum Game (UG) and the Prisoner's Dilemma Game (PDG) with both alleged human and computer partners who were outside the scanner. We observed a remarkable degree of overlap in brain areas that activated to partner decisions in the two games, including commonly observed theory of mind areas, as well as several brain areas that have not been reported previously and may relate to immersion of participants in real social interactions that have personally meaningful consequences. Although computer partners elicited activation in some of the same areas activated by human partners, most of these activations were stronger for human partners.

Adult↗

PubMed2003

The neural basis of economic decision-making in the Ultimatum Game.

The nascent field of neuroeconomics seeks to ground economic decision making in the biological substrate of the brain. We used functional magnetic resonance imaging of Ultimatum Game players to investigate neural substrates of cognitive and emotional processes involved in economic decision-making. In this game, two players split a sum of money;one player proposes a division and the other can accept or reject this. We scanned players as they responded to fair and unfair proposals. Unfair offers elicited activity in brain areas related to both emotion (anterior insula) and cognition (dorsolateral prefrontal cortex). Further, significantly heightened activity in anterior insula for rejected unfair offers suggests an important role for emotions in decision-making.

Adult↗

PubMed2003

Expansion of the neocerebellum in Hominoidea.

Technological and conceptual breakthroughs have led to more serious consideration of the cerebellum as an essential element in cognition. Recent studies show the lateral cerebellum, seat of the neocerebellum, to be most active in cognitive tasks. An examination of the relative volumes of the cerebellar hemispheres in anthropoids would reveal whether some groups show greater neocerebellar development through hemispheric expansion beyond expected allometry, implying a greater contribution of the lateral hemispheres to cognition. This study expands the existing data on primate brain and brain part volumes by incorporating data from both magnetic resonance scans and histological sections for a total sample size of 97 specimens, including 42 apes, 14 humans and 41 monkeys. The resulting volumes of whole brain, cerebellum, vermis, and hemisphere enable a reliable linear regression contrast between hominoids and monkeys, and demonstrate a striking increase in the lateral cerebellum in hominoids. The uniformity of the grade shift suggests that this increase took place in the common ancestor to the hominoids. The importance of the neocerebellum in visual-spatial skills, planning of complex movements, procedural learning, attention switching, and sensory discrimination in manipulation would facilitate the adaptation of these early hominoids to frugivory and suspensory feeding.

Anatomy, Comparative↗

PubMed2002

A quantitative morphometric comparative analysis of the primate temporal lobe.

Given their importance in language comprehension, the human temporal lobes and/or some of their component structures might be expected to be larger than allometric predictions for a nonhuman anthropoid brain of human size. Whole brain, T1-weighted MRI scans were collected from 44 living anthropoid primates spanning 11 species. Easyvision software (Philips Medical Systems, The Netherlands) was used to measure the volume of the entire brain, the temporal lobes, the superior temporal gyri, and the temporal lobe white matter. The surface areas of both the entire temporal lobe and the superior temporal gyrus were also measured, as was temporal cortical gyrification. Allometric regressions of temporal lobe structures on brain volume consistently showed apes and monkeys to scale along different trajectories, with the monkeys typically lying at a higher elevation than the apes. Within the temporal lobe, overall volume, surface area, and white matter volume were significantly larger in humans than predicted by the ape regression lines. The largest departure from allometry in humans was for the temporal lobe white matter volume which, in addition to being significantly larger than predicted for brain size, was also significantly larger than predicted for temporal lobe volume. Among the nonhuman primate sample, Cebus have small temporal lobes for their brain size, and Macaca and Papio have large superior temporal gyri for their brain size. The observed departures from allometry might reflect neurobiological adaptations supporting species-specific communication in both humans and old world monkeys.

Anatomy, Comparative↗