'I'm not gonna do this again', we often say when faced with negative feedback, adverse effects, or disappointing outcomes. Thus, we attempt to learn from such negative experiences. This principle is also a cornerstone of our education system: failing an exam ought to encourage students to do better next time.
How does the brain achieve this type of learning? Positive and negative reinforcement appear as two sides of the same coin in parts of the brain's valuation system. Notably, some neurons that release the neuromodulator 'dopamine' represent outcomes better vs. worse than expected with increase or decrease of their activity, respectively. At the same time, ample accumulating evidence suggests that other parts of the brain handle 'negative' and 'positive' fundamentally differently.
Negative experiences, when encountered, often have an arousing effect: they do not leave us indifferent or heedless. Beyond this general arousal, specific parts of the neocortex are activated that allow us to pay attention to relevant features, and eventually, draw consequences and learn – a concept sometimes called 'attention for learning'. When focusing on the negative side of things, we may coin this 'attention for aversive learning'.
A team of neuroscientists at the HUN-REN Institute of Experimental Medicine Budapest, Hungary, led by Principal Investigator Balazs Hangya MD PhD, asked which brain regions and neuron types might be responsible for 'attention for aversive learning'. In a new study published today in Nature Communications, the team reports that long-range projecting inhibitory neurons that express the calcium-binding protein parvalbumin (PV) known for their capabilities of very fast activity, located in a deep brain nucleus called 'the horizontal limb of the diagonal band of Broca' or HDB play a key role in this process.
