Epilepsy May Disrupt Brain Temperature Regulation, Linking Hypothalamus Changes to Seizure Activity

Author: The Conversation

New findings indicate the brain's temperature control system can be altered by epilepsy. In mice, the hippocampus showed higher temperatures days after an brain injury, prior to the first seizures, and this heat persisted after epilepsy was established. In the same study, the hypothalamus showed cellular and inflammatory changes, and human brain scans revealed corresponding hypothalamic differences in people with epilepsy. The authors discuss how fever and heat exposure can influence seizures, and how temperature changes could reflect broader brain network alterations. They also identify hormonal and inflammatory changes and point to potential pharmacological leads for future research. These results raise questions about heat tolerance in people with epilepsy amid climate change.

Overview of the study context

The brain maintains its own thermostat, with the hypothalamus coordinating temperature responses. Fever can trigger seizures in some epilepsy cases, and in rare syndromes overheating can provoke seizures. Building on earlier animal work suggesting epilepsy disrupts daily temperature rhythms, researchers conducted a cross-national study (Italy, Ireland, the UK, Netherlands) to determine how early these changes begin and what brain regions are involved, and whether similar patterns appear in people with epilepsy.

Key findings from the mouse model

In mice subjected to an initial brain injury used to induce epilepsy, the hippocampus showed an elevated temperature three days after the injury, before the first seizures. This higher temperature persisted once epilepsy was established. The timing argues against the change being solely a consequence of seizures, since it occurred before seizures began. Temperature also rose around individual seizures, with the rise often starting before the seizure itself, suggesting a link between temperature and seizure dynamics that is not simply heat from convulsions.

Changes in temperature control centers

When examining the hypothalamus in epileptic mice, researchers found fewer nerve cells in two temperature-regulating regions, a reduction of about one-fifth compared with non-epileptic controls. Inflammation, altered activity in surviving cells, and reduced volume in portions of the hypothalamus were also observed. Parallel analyses of brain scans from hundreds of people with epilepsy showed corresponding reductions in similar hypothalamic regions, particularly in those with visible brain damage or other changes. While these human data cannot prove that the same cellular processes occur, the convergence between mice and humans strengthens the case for a connection between epilepsy and altered temperature regulation.

Hormonal and inflammatory signals

In mice, researchers observed changes in thyroid hormones, suggesting disruption somewhere along the brain–thyroid axis rather than pinpointing a single brain region. The findings point to a broader network disruption that could affect temperature regulation and neural signaling in epilepsy following injury or other brain changes.

What the findings mean for hotter weather and climate change

The study did not test epilepsy patients under extreme heat, so it cannot claim that heat increases seizure risk for all individuals with epilepsy. However, a 2024 London study in drug-resistant epilepsy patients during heatwaves found more abnormal brain activity and more seizures during heat periods. These observations offer a potential mechanistic explanation: if temperature-control networks are altered in some forms of epilepsy, heat could further disrupt these networks and raise seizure susceptibility. The authors emphasize that more work is needed to establish causality and to explore whether temperature-targeted interventions could help certain patients.

Therapeutic leads and future directions

By analyzing gene expression in affected brain regions, the team identified inflammation and tissue-repair pathways as potential targets. They used computational approaches to screen existing medicines that might modulate these processes, but stress that these are leads requiring experimental testing. The broader implication is that temperature regulation may be an underappreciated aspect of epilepsy that warrants further study, particularly as climate change increases the prevalence of extreme temperatures and heat exposure.

Conclusion

The study proposes that post-injury epilepsy can alter brain temperature regulation networks, potentially affecting how people with epilepsy respond to heat. While the work stops short of proving a causal role for temperature in driving seizures, it lays groundwork for future research into temperature control, hormonal signaling, and anti-inflammatory strategies as part of a broader effort to understand and treat epilepsy in a warming world.