Dec 13, 2024
New Insights into Brain Mechanisms Underlying Empathy
Posted by Shubham Ghosh Roy in categories: genetics, neuroscience
A specific brain mechanism modulates how animals respond empathetically to others’ emotions. This is the latest finding from the research unit Genetics of Cognition, led by Francesco Papaleo, Principal Investigator at the Istituto Italiano di Tecnologia (IIT – Italian Institute of Technology) and affiliated with IRCCS Ospedale Policlinico San Martino in Genova. The study, recently published in Nature Neuroscience, provides new insights into psychiatric conditions where this socio-cognitive skill is impaired, such as post-traumatic stress disorder (PTSD), autism, and schizophrenia.
Psychological studies have shown that the way humans respond to others’ emotions is strongly influenced by their own past emotional experiences. When a similar emotional situation—such as a past stressful event—is observed in another person, we can react in two different ways. On one hand, it may generate empathy, enhancing the ability to understand others’ problems and increasing sensitivity to others altered emotions. On the other hand, it may induce self-distress resulting into an avoidance towards others.
The research group at IIT has demonstrated that a similar phenomenon also occurs in animals: recalling a negative experience strongly influences how an individual responds to another who is experiencing that same altered emotional state. More specifically, animals exhibit different reactions only if the negative event they experienced in the past is identical to the one they observe in others. This indicates that even animals can specifically recognize an emotional state and react accordingly even without directly seeing the triggering stimuli.
The Call is still open on senescence in brain aging and Alzheimers disease!
Cognitive models of reading assume that speech production occurs after visual and phonological processing of written words. This traditional view is at odds with more recent magnetoencephalography studies showing that the left posterior inferior frontal cortex (pIFC) classically associated with spoken production responds to print at 100–150 ms after word-onset, almost simultaneously with posterior brain regions for visual and phonological processing. Yet the theoretical significance of this fast neural response remains open to date. We used transcranial magnetic stimulation (TMS) to investigate how the left pIFC contributes to the early stage of reading. In Experiment 1, 23 adult participants (14 females) performed three different tasks about written words (oral reading, semantic judgment and perceptual judgment) while single-pulse TMS was delivered to the left pIFC, fusiform gyrus or supramarginal gyrus at different time points (50 to 200 ms after word-onset). A robust double dissociation was found between tasks and stimulation sites — oral reading, but not other control tasks, was disrupted only when TMS was delivered to pIFC at 100 ms. This task-specific impact of pIFC stimulation was further corroborated in Experiment 2, which revealed another double dissociation between oral reading and picture naming. These results demonstrate that the left pIFC specifically and causally mediates rapid computation of speech motor codes at the earliest stage of reading and suggest that this fast sublexical neural pathway for pronunciation, although seemingly dormant, is fully functioning in literate adults. Our results further suggest that these left-hemisphere systems for reading overall act faster than known previously.
