Research Article Corresponding Author: Anil Pawar, Assistant Professor, Department of Zoology, D.A.V. College for Girls, Yamunanagar (Haryana); Mobile:919467604205; Email: sumanil27@yahoo.co.in Received: 16.6.2014 Revised: 11.7.2014 Accepted: 29.7.2014 Int J Cur Res Rev | Vol 6 • Issue 17 • August 2014 41 STUDY OF VISUAL ONLINE REACTION TIME IN DIFFERENT PHASES OF MENSTRUAL CYCLE IN HEALTHY FEMALES Rinku Garg, Varun Malhotra, Usha Dhar, Yogesh Tripathi Department of Physiology, Santosh Medical College, Ghaziabad. ABSTRACT Aims and objectives: The present study was designed to study the influence of various phases of menstrual cycle on visual online reaction time. Material and Methods: Fifty females in the age group of 18-25 years were recruited for the study. Visual reaction time test was taken online. Statistical Analysis: Results were analysed by ANOVA with SPSS version 17.0 using paired ‘t’ test. Results: showed that there was significant prolongation of reaction time (p<0.05) in luteal phase as compared to follicular and menstrual phase. Conclusions: Variation in visual reaction time could be due to the fluctuating levels the female sex hormones across the men- strual cycle. Key Words: Follicular phase, Luteal phase, Online reaction time Corresponding Author: Rinku Garg, Varun Malhotra, Usha Dhar, Yogesh Tripathi, Department of Physiology, Santosh Medical College, Ghaziabad, E-mail: rgrinkigarg6@gmail.com Received: 20.06.2014 Revised: 19.07.2014 Accepted: 15.08.2014 INTRODUCTION The biological activity of the menstrual cycle is created by the coordination among hypothalamic, hypophyseal and ovarian hormones. [1] . The established hypothalamic, hypophyseal and ovarian axis and its cyclical hormonal changes during the three phases of normal menstrual cycle are as follows. [2] . Follicular phase: is mainly a phase of oestrogen, influ- enced by follicular stimulating hormone. Luteal phase: primarily a phase of progesterone influ- enced both by follicular stimulating hormone and lutein- izing hormone. Menstrual cycle: the cervical bleeding phase, due to the withdrawal of hormonal effect on endometrium. The fluctuations in hormonal levels affect not only the fe- male reproductive tract but also many other tissues of the body. Various studies have shown that female sex hormones modulate auditory, visual and taste threshold, latency and amplitude. [3] Behavioural and neurological symptoms like decreased concentration, nervous, irritability, emotional instability, poor judgement, tension and depression are seen in women during premenstrual phase. [4] This may be due to due to effect of gonadal hormones on neural func- tions. [5] Reaction time is the measure of how fast a person re- sponds to a particular type of stimuli. It can be defined as the time interval between the application of a stimulus and an appropriate voluntary response from the subject. It measures the ability to process information and judges the ability to concentrate and coordinate. [6] Flow of information in an organism can be depicted in this way: [7,8,9] Stimulus Receptors Integrators Effectors Response Stimulus Sensory neuron Spinal cord or Brain Motor neuron Response Various studies have shown that ovarian steroids influ- ence dopamine release in the nigrostriatal pathway. [10,11] Estradiol has widespread effects throughout the brain re- gions involved in affective state as well as cognition. [12,13] IJCRR