This paper introduces an investigation on the thermal effects of dielectrophoresis on cerebrospinal fluid (CSF). It highlights the temperature propagation in CSF according to applied voltage and generated electrical field in a limited area of the brain. Through the described study, the temperature increase is considerable in the close surrounding area of electrodes where applied voltage goes up to 20 V(rms) in order to generate dielectrophoretic forces for CSF sampling. Matlab simulations detailed in this work are based on the assumption that the propagation of temperature in CSF is linear. The objective of this research is to study the thermal side effects of direct measurements and manipulations of neurotransmitters in the brain versus in-channel measurement of neurotransmitter concentration. Indeed, according to simulation results, if the temperature in the top of electrodes is 46.85 °C then it will decrease only to 45.35 °C at 1 mm away from electrode surface.