<p>Communication departments at research centers and universities play a key role in transferring research results and scientific advances to society. This responsibility is inherent to publicly funded research and benefits both: researchers, by increasing visibility and opportunities for further funding, and citizens, who are better informed to make decisions. To fulfil this role, communication specialists use a range of strategies, such as issuing press releases (PRs) and posting on social media. However, despite the widespread use of these tools, evidence-based protocols to optimize promotion are still lacking. In this context, alternative metrics (altmetrics) are particularly useful, as they allow the effects of communication campaigns to be measured and the impact of specific actions to be assessed. In this research, conducted by the communication department of a neuroscience research center, we use simple altmetrics (mainly news mentions and posts on <i>X</i>) and a composite metric (the <i>Altmetric Attention Score</i>, AAS) to evaluate the reach and effectiveness of issuing a PR and posting on <i>X</i> about a scientific article. A retrospective analysis revealed that articles supported by active communication efforts achieved stronger altmetrics. This pattern was further supported by a prospective experiment with 25 publications, where the issuance of a PR was followed by a clear rise in online attention. Overall, the study points to the importance of communication activities in shaping the online visibility of scientific outputs, highlighting the value of PRs, while indicating that the <i>Altmetric</i> platform, which aggregates altmetrics and provides the AAS, although useful, may underestimate the social impact of a publication by not capturing all mentions.</p>