Social Neuroscience

Goals

• Explore the anatomy and functions of the cingulate cortex.
• Examine the neural basis of empathy.
• Discuss oxytocin as a neuropeptide associated with affiliative behaviors.
• Analyze Theory of Mind (ToM) and its neural underpinnings.
• Introduce alternative formulations of ToM, including set-shifting and self-projection.

The Cingulate Cortex

• Anatomy and Layers:
  • Transitional paleocortex with 3-5 layers (in some areas), compared to the 6-layered neocortex.
  • Divided into anterior (ACC), mid (MCC), and posterior regions, with distinct cytoarchitectonics and connectivity.
  • Strong connectivity to the anterior insula, particularly in ACC and MCC, highlights its role in emotional and social processing.
• Functions:
  • Motor: Projections to corticospinal tracts and brainstem motor nuclei.
    • Lesions can cause akinetic mutism (lack of voluntary speech or movement) and release reflexive grasping or “alien hand syndrome.”
  • Pain and Emotion:
    • Modulates both physical and emotional pain.
    • Emotional modulation is evident in anterior regions, often targeted by cingulotomy for chronic, emotionally-augmented pain.
  • Social Behaviors: Plays a central role in empathy and related behaviors, with strong overlap in areas responding to pain and social rejection.
• Cingulotomy:
  • Introduced as a more targeted alternative to prefrontal lobotomy.
  • Effective for chronic pain, OCD, anxiety, and depression.
  • Patients report reduced distress about pain despite its persistence, suggesting a dissociation between physical pain and its emotional components.

Empathy

• Definitions and Types:
  • Cognitive Empathy: Understanding others’ internal states.
  • Emotional Empathy: Sharing others’ emotions through emotional contagion.
  • Aesthetic Empathy: Intuiting or projecting oneself into another’s situation.
• Pain and Social Pain:
  • Social and physical pain share neural substrates, activating the ACC and insula.
  • Social rejection studies (e.g., Cyberball) demonstrated reduced brain activation in these areas when participants were given acetaminophen.
  • However, acetaminophen also reduces empathy for others, showing its dual impact on social and emotional processing.
• Empathy and Fairness (Singer, 2006):
  • Trust Game experiments revealed participants’ neural and emotional responses to fair versus unfair players.
  • Males showed reduced empathy and increased nucleus accumbens activation (suggesting reward) when watching unfair players receive punishment.

Oxytocin

• Role and Production:
  • Produced in the hypothalamus (paraventricular and supraoptic nuclei).
  • Acts on targets including the nucleus accumbens and amygdala to facilitate trust, bonding, and affiliative behaviors.
• Prairie vs. Montane Voles (Young and Insel):
  • Prairie voles (monogamous) have dense oxytocin receptor binding, particularly in the nucleus accumbens.
  • Montane voles (non-monogamous) exhibit less oxytocin receptor activity, correlating with reduced affiliative behaviors.
• Human Studies:
  • Intranasal oxytocin enhances social task performance (e.g., face recognition) but requires an intact amygdala for effectiveness.
  • Promotes “in-group love” without increasing “out-group hate” under neutral conditions but can drive defensive aggression under perceived out-group threat.
• Oxytocin and Autism:
  • Oxytocin has shown promise in improving social cognition in individuals with autism spectrum disorder (ASD).
  • Cyberball Experiment: ASD participants typically fail to discriminate between “good” and “bad” players in social interactions. After intranasal oxytocin, participants learned to avoid “bad” players, aligning their behavior with typically developing controls.
  • Oxytocin increases emotional empathy (experiencing others’ emotions) but has limited impact on cognitive empathy (recognizing others’ emotions).

Theory of Mind (ToM)

• Definition:
  • The ability to attribute mental states (e.g., beliefs, intents) to oneself and others.
• Key Studies:
  • Chimpanzee ToM (Premack, 1978): Chimps demonstrated goal understanding but did not conclusively show mental-state reasoning.
  • Human ToM (Saxe and Kanwisher): Stories requiring mental-state inference activated the temporoparietal junction (TPJ), ventromedial PFC, and medial frontal cortex.
• Neuroimaging Meta-analysis:
  • Identified consistent activation of the TPJ, vmPFC, and PCC across 181 ToM studies.
  • Highlighted overlapping networks for ToM, memory, and future event simulation.
• Alternative Perspectives:
  • Overlap in brain areas for ToM, self-projection, and empathy suggests a broader cognitive framework linking social and emotional reasoning.

Applications and Implications

• Empathy research has practical applications for treating mental health conditions and fostering prosocial behaviors.
• Oxytocin studies suggest therapeutic pathways for improving social interactions in autism and related disorders.
• Theory of Mind research sheds light on cognitive impairments in conditions like autism and schizophrenia.

Conclusion

This lecture synthesized key aspects of social neuroscience, exploring the complex interplay of empathy, oxytocin, and Theory of Mind in understanding human cognition, behavior, and social relationships.