Artificial intelligence is attracting billions of dollars in investment globally, but genuine ASX AI shares remain surprisingly difficult to find. That scarcity could create opportunities for investors willing to look beyond the obvious names. A handful of smaller ASX AI companies offer exposure to the long-term AI theme, with potential catalysts that could drive significant growth if execution improves. Two names attracting increasing attention are Appen Ltd (ASX: APX) and Macquarie Technology Group Ltd (ASX: MAQ). Image source: Getty Images Appen: A risky AI turnaround play Appen sits directly inside the AI ecosystem. The company provides training data used by many artificial intelligence models, helping businesses build and improve machine learning systems. However, the journey has been far from smooth. The ASX AI share surged 71% to an annual high of $1.90 in January after a strong quarterly update boosted investor confidence. That optimism faded quickly after the company's next update in April. While revenue increased 9% to $54.8 million, investors were disappointed by the company's weak profitability. Appen Global's performance was a particular concern, with revenue falling 37% to $19.9 million. The result triggered a sharp sell-off, sending shares down around 30%. Since then, the recovery has failed to materialise, with Appen shares trading near $0.86 and down around 30% over the past year. Management has since reaffirmed FY26 revenue guidance of between $270 million and $300 million, ahead of FY25 revenue of $231 million. The key question now is whether demand for AI training data can translate into stronger earnings. If Appen can prove its turnaround is working, secure new partnerships, and return to sustainable growth, the market could quickly reassess the company's value. The next major test arrives with its first-half FY26 results in late August. Macquarie Technology: The infrastructure behind AI While many investors focus on AI software companies, Macquarie Technology is targeting the infrastructure powering the revolution. The company operates data centres, cloud services, cybersecurity solutions, and sovereign hosting platforms — all areas expected to benefit from rising AI adoption. In March, Macquarie Technology secured a $200 million hybrid investment from the government-backed National Reconstruction Fund Corporation. The funding will support the expansion of sovereign cloud, cybersecurity, and AI infrastructure for government agencies, defence organisations, and critical industries. Unlike many speculative AI plays, Macquarie Technology already has a profitable business. The ASX AI share has delivered 20 consecutive half-years of operating income growth, demonstrating consistent execution. As demand for data centre capacity continues rising, additional infrastructure coming online could provide a significant earnings boost. If investors begin valuing Macquarie Technology closer to established data centre operators such as NextDC Ltd (ASX: NXT), the shares could have further upside. Foolish takeaway AI investing is still dominated by global giants, but opportunities exist across the ASX. Appen offers a higher-risk turnaround opportunity tied directly to AI model development, while Macquarie Technology provides exposure to the essential infrastructure supporting the AI boom. Neither ASX AI share is guaranteed to succeed, but both show why investors shouldn't overlook the smaller companies helping build the next generation of artificial intelligence.