Further studies are certainly needed, but we suggest that the lower homeostatic sleep drive of older flies causes their decreased arousal threshold. < /p > < /div > < div class="section" > < a name="d7e157" > < !-- named anchor -- > < /a > < h3 class="section-title" > Citation: < /h3 > < p id="d7e160" > Vienne J, Spann R, Guo F, Rosbash M. Age-related reducti..."> Further studies are certainly needed, but we suggest that the lower homeostatic sleep drive of older flies causes their decreased arousal threshold. < /p > < /div > < div class="section" > < a name="d7e157" > < !-- named anchor -- > < /a > < h3 class="section-title" > Citation: < /h3 > < p id="d7e160" > Vienne J, Spann R, Guo F, Rosbash M. Age-related reducti..." /> Further studies are certainly needed, but we suggest that the lower homeostatic sleep drive of older flies causes their decreased arousal threshold. < /p > < /div > < div class="section" > < a name="d7e157" > < !-- named anchor -- > < /a > < h3 class="section-title" > Citation: < /h3 > < p id="d7e160" > Vienne J, Spann R, Guo F, Rosbash M. Age-related reducti..." />