Physiological activity of inhibition
Whenever there is a new and strange stimulus acting at the same time as the stimulus causing the conditioned response, that conditioned response does not appear.
The cerebral cortex consists of two processes, excitatory and inhibitory. The effect of excitement is to develop conditioned reflexes. The effect of inhibition is to reduce the intensity or eliminate the conditioned reflex.
Based on the conditions for the establishment of the inhibitory process, people divide the inhibitory processes in the cerebral cortex into two types:
Unconditioned or extrinsic (congenital) inhibition.
External inhibition (unconditioned inhibition)
There are two types of unconditioned inhibition:
Inhibition above limit
Whenever there is a new and strange stimulus, acting at the same time as the stimulus causing the conditioned reflex, that conditioned reflex does not appear, does not take place.
For example, we construct a conditioned reflex to salivate to light on a dog. Turn on the light on the salivating dog. But as soon as I turned on the light, I clipped the dog's tail. Tail clamping is a novel, sudden stimulus that interferes with the salivary reflex, the dog will not salivate.
Thus, the tail clamp in this experiment was an extrinsic inhibitory stimulus.
The mechanism of extrinsic inhibition is as follows: the new and strange stimulus, which comes on suddenly, causes a reflex that Pavlov calls the "directive reflex" or "reflex what?" get the dog to focus his attention on the new stimulus, turn his head toward the new stimulus, and prepare to deal with it. The directional reflex had a blocking effect i.e. an inhibitory effect on salivation.
Inhibition above limit
If the conditioned stimulus exceeds a certain intensity, the conditioned response does not appear.
For example, causing salivation by ringing bells.
If the bell rings suddenly too loudly, it will lose the salivary reflex. Ringing bells for too long also causes loss of salivary reflexes. Ringing too strong or too long has exceeded the tolerance of cortical cells, so it does not cause excitement but inhibits. That is the upper limit inhibition.
Internal inhibition must be through a process of training, there are many types of internal inhibition.
That is, the conditioned reflex is not reinforced, the link is temporarily lost.
When two nearly identical stimuli act but only one is reinforced, only the reinforced stimulus will trigger a response. As for the other stimulus, because it is almost the same as the previous stimulus, although it causes a reflex at first, but continues to not reinforce it, the reflex gradually decreases and then does not appear. This is due to the formation of discriminant inhibition.
Pavlov, for example, induces the conditioned reflex to salivate with light.
Red signal (flesh salivating).
Green signal (no meat, no saliva).
Through the process of strengthening the dog will distinguish which signals are meat and which are not. Thanks to the training process, the dog can distinguish between the (+) signal and the (-) signal.
Inhibition slows down reflexes
When the conditioned and unconditioned stimulus are separated by a certain time, the conditioned response also slows down at the same time.
For example, Pavlov did an experiment to turn on the light, then give him food 3 minutes later, and then after turning on the light for 3 minutes, the dog would salivate. It is slow inhibition of reflexes.
The effect of inhibition
Inhibition is an active cortical activity rather than a loss or inactivity of the cortex. During life, the cerebral cortex receives a lot of stimulation, thanks to its inhibitory activity, it eliminates unnecessary or harmful stimuli for life, thereby reducing unnecessary activities of the cortex.
Inhibition contributes to changing the body's response to suit the ever-changing conditions of the environment.
The process of excitement increases the catabolic activity that consumes energy, the process of inhibition ensures the body increase the level of material assimilation, and restore strength.
In general, inhibitory processes have a protective cortical effect.
In life, thanks to inhibitory activity, people become mature, consider before each stimulus, select before responding, thereby avoiding mistakes, sometimes serious consequences that may occur. .