THE EFFECTS OF MOTOR PROCESS ON REACTION TIME - Essay Example

Consequently, it has been postulated that the principal anatomic structures affected by these disorders, namely, the cerebellum and basal ganglia are important in the effective running of the timing apparatus for these functions. The involvement of the cerebellum and the basal ganglia in the motor and perceptual timing has been documented by imaging of brain while performing various timing tasks, such as, repetitive and tapping maneuvers. This involves other parameters such as duration discrimination, velocity discrimination, rhythm discrimination, temporal discrimination, and time production and reproduction.

Voluntary movements are prepared before they are executed. If there is an instruction stimulus, before the go cue, there would be a delay. With this concept, the reaction time can be defined as the latent period or time interval from the go cue to time of onset of movement. Reactions times are shorter when the delays are longer, suggesting there is some time-consuming preparatory process that is given a head start by this delay. Delay-period activity is typically tuned for the instruction and is therefore predictive of reaction time, and it is suspected that delay period activity is the substrate of motor preparation occurring at that time.

A neural activity, if at all it is designed to generate movement must rise above a threshold to trigger the motor activity (Akkal, D., Escola, L., Bioulac, B., Burbaud, P., 2004). If there is an instructed delay, that could allow activity to attain threshold leading to reduction in the subsequent reaction time. If the motor system takes some time to rise to threshold, as is expected, higher firing rates would lead to shorter reaction times. Alternatively, the produced movement is a function of the state of preparatory activity after the trigger.

For each probable movement, it is necessary that there would be a firing rate in the subspace that is optimal, optimal in the sense that it would be appropriate and sufficient to generate a sufficiently accurate movement. The time given for motor preparation thus therefore essentially is optimization that brings firing rates from their initial state to the appropriate subspace. This allows for a wait time for execution of the movement, and this wait time may lead to subtle drifts in the activity, but as long as firing rates remain within the optimal subspace, the motor preparation would remain complete.

It can be predicted consequently that the delay period firing occupy a smallish subspace that is different and unique for each instructed movement.The reaction time is the time between the onset of a stimulus and the motor response to it. As a result, there would be a perceptual latency that is denoted by the time from stimulus onset to time of stimulus detection as well as in the motor time, which is the time it takes to perform the motor task. The motor process can vary from one to another individual depending on type, intensity, and the background of the stimulus.

Subjective variations in motor process have been observed between individuals based on subject age, sex, educational levels, socioeconomic status, affective state, and attentional and arousal states (Doherty, J.R., Rao, A.,