Postural Influence in Cortical Integration

The influence of the postural substrate in cortically integrated behavior is very marked. In sensory fusion the act of attending to various parts of the external milieu is clearly postural. It involves a general increase in tonicity in the total postural substrate. The amplitude of the knee-jerk elicited by a tendon blow of constant intensity and uniform rate is increased about ten times over the passive state when the subject is attending to mathematical symbols. There may also be an augmentation in the tension of muscles which serve to place the appropriate end-organ in an effective position relative to the sought-after stimulus. The occurrence of these reactions is generally recognized by the fixed gaze of the look-out at sea, the inclined ear and cocked head of the eavesdropper, and the concentrated expression of the tea-taster. These postural responses contribute to efficient sense impression; furthermore, the shunting of proprioceptive excitation into the cortical channels concerned in the transmission and elaboration of the peripheral disturbance renders these channels (by summation) dominant in intercerebral fields.

The foregoing argument may be carried over, pari-passu, to the redintegrational sequences. One may take a set to recall the historical events connected with visually presented symbols, or he may associate these same symbols with different blocks in his street of residence. Word series will arouse different responses, depending upon whether the subject is set to give subordinates, opposites, or synonyms. The "control" in these controlled association tests seems to be essentially a matter of canalizing proprioceptive excitation in even more particular and limited cerebral fields. A general postural increment can be shown to accompany all redintegrational acts. Since there is little evidence of specific muscular foci, we must conclude that the selectional aspect is almost entirely central.

Our account of the postural substrate would be incomplete without some mention of its role in the highly elaborate processes of cerebral incitation. First recognized in connection with experiments on thought and volition through their accompanying "conscious attitudes," the relational postures have come to play an important part in all functional treatments of psychology. For example, speaks of them as "sudden flashes of something which seem to mean 'now I have it,''this is working out well,''how shall I proceed?''this is difficult' . . . indicatory transfers, so to say, which represent the position of the organism from moment to moment upon matters of issue." While it is a long step from this description to physiological principles, we can probably regard the general thought problem, carried by a particular pattern of dynamic stresses and perpetuated by proprioceptive excitation, as undergoing various shifts and changes as transitory (phasic) solutions appear, are accepted, or are rejected. That these shifts are reflected in tissues under the dominance of the tonic reaction system. She correlated galvanometric records from the skin with reports on the course of thinking and found that marked galvanic deflections occurred in the case of a sudden checking of this process. We are still far from understanding the complex incitor activities which appear to us as thought; hence it is difficult to conceive how their determinants operate.