Brain cooling marginally increases acute upper thermal tolerance in Atlantic cod

Physiological mechanisms determining thermal limits in fishes are debated but remain elusive. It has been hypothesised that motor function loss, observed as loss of equilibrium during acute warming, is due to direct thermal effects on brain neuronal function. To test this, we mounted cooling plates...

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Bibliographic Details
Main Authors: F Jutfelt, DG Roche, Timothy Clark, T Norin, SA Binning, B Speers-Roesch, M Amcoff, R Morgan, AH Andreassen, J Sundin
Format: Article in Journal/Newspaper
Language:unknown
Published: 2019
Subjects:
LOE
Online Access:http://hdl.handle.net/10536/DRO/DU:30130494
https://figshare.com/articles/journal_contribution/Brain_cooling_marginally_increases_acute_upper_thermal_tolerance_in_Atlantic_cod/20739280
Description
Summary:Physiological mechanisms determining thermal limits in fishes are debated but remain elusive. It has been hypothesised that motor function loss, observed as loss of equilibrium during acute warming, is due to direct thermal effects on brain neuronal function. To test this, we mounted cooling plates on the heads of Atlantic cod (Gadus morhua) and quantified whether local brain cooling increased whole-organism acute upper thermal tolerance. Brain cooling reduced brain temperature by 2-6°C below ambient water and increased thermal tolerance by 0.5 and 0.6°C on average relative to instrumented and uninstrumented controls, respectively, suggesting that direct thermal effects on brain neurons may contribute to setting upper thermal limits in fish. However, the improvement in thermal tolerance with brain cooling was small relative to the difference in brain temperature, demonstrating that other mechanisms (e.g., failure of spinal and peripheral neurons, or muscle) may also contribute to controlling acute thermal tolerance.