Infrared sensing in vampire bats

[1] Trigeminal nerve fibers that innervate these IR-sensitive receptors may be involved in detection of infrared thermal radiation emitted by their prey.

[1][2] In addition, neuroanatomical and molecular research has suggested possible similarities of IR-sensing mechanisms between vampire bats and IR-sensitive snakes.

During predation, bats first spend a few minutes in the air circling the target prey, eventually landing on the back or neck crest of the animal, and sometimes the ground.

[9] Kürten and Schmidt (1982) were the first to suggest that infrared perception in vampire bats is possibly used in detecting regions of maximal blood flow on targeted prey.

[10] In 1982, Kürten and Schmidt performed behavioral studies to examine the ability of vampire bats to detect infrared radiation.

Their study showed that when given a choice between a warm and cold object, vampire bats can be trained to choose the infrared emitting signal unit (SU).

[1] Kürten and Schmidt (1982)[1] first suggested that the location and orientation of each pit structure provided directional information in infrared radiation detection.

Later in 1984, Kürten and collaborators made electrophysiological recordings from nerve fibers of temperature-sensitive infrared thermoreceptors located on the central nose-leaf and upper lip, but did not find such receptors in the nasal pits (see Physiology).

[10] Klüver-Barrera and Nissl staining of vampire bat brain sections uncovered a unique nucleus located lateral to the descending trigeminal tract (dv).

[5] Although the morphological organization of neurons suggests convergent evolution with IR-sensing snakes lineages, it remains unclear what the exact neural pathway is for infrared sensing in vampire bats.

After stimulation of these receptors, there is a transient increase in impulse activity which quickly decays due to adaptation and thus strengthens temporal acuity.

[4] TRPV1 channels are activated by capsaicin (a chemical which can be extracted from chili peppers), noxious temperature ranges (>43 °C), membrane-derived lipids, low pH, and voltage changes.

[4] TRPV1-S isoform results from alternative splicing during post-transcriptional regulation, a variation of the TRPV1 C-terminus due to insertion of 23-base-pair sequence, exon14a, that contains a stop codon.

[1] Activation of TRPV1-S channels in the TG may then suggest a similar mechanism (as seen in IR-sensing snakes) for how infrared sensing may work in vampire bats.

Trigeminal nerves which innervate specialized temperature sensitive receptors on the nose-leaf may in turn activate TRPV1-S channels in the TG in response to infrared thermal radiation.