Sixth sense: Does it really make 'sense'?
“My sixth sense told me this”
“My sixth sense told me this”, is a phrase that we hear commonly; very often in hindsight, after an event has occurred. Sometimes it is also spoken in the form of a premonition. People often claim that they could sense an impending catastrophe or just some simple event in advance. Is it really a case of para-psychology with some (if any) physiological basis to it, or is it just boastfulness on the part of the claimant?
There is a variety of general sensations (such as, touch, pain, etc), and there are 5 special senses – vision, hearing, taste, smell, and equilibrium.
However, the most ‘special’ is the so-called sixth sense. It works in an abstract fashion. The logic behind it is never understood. A person claiming to have a sixth sense would often claim after an occurrence to have seen it coming beforehand. However, there are people who really possess some kind of extra ‘power’ to guess some future events correctly. I believe there may be some physiological basis to this power of sixth sense.
Our five senses are never fully active, at their maximum strength, at any given point of time. Vision and hearing are the most evolved senses in humans; or, having the dedicated cortices to analyze and interpret them, they are the most used special senses.
All the special senses are apparently disconnected from one another; their perceptions or representations being located in different cortices. However, one sense can evoke the memory of another sense.
At any given point of time, only one special sense is put to use with maximal stimulus value. The synaptic connections are designed such that the principle of convergence is applicable and a sharp focus may be maintained. Also, it may be noted that some people have extra strength in a particular sense, others may be stronger in another sense. A case in point is the visually challenged individuals. In such people, it is often said that their other sensations are stronger than normal. One set of impulses (via visual pathway) not reaching the cortex may be leading to a sharp focus and greater development of the lobes other than the occipital lobe.
Another example, not of special senses, is phantom pain sensation. Even after amputation of a limb, the person may complain of pain in that lost limb. The representation of the lost limb is intact, at least for some period. However, with training, the cortical plasticity may be induced whereby, the representation of the lost limb may be encroached upon by the neighboring neurons; eventually that limb may not find a representation in the cortex and the phantom pain may stop.
The point is, the cortical plasticity occurs with training; our cortex is a dynamically evolving structure.
Can the sixth sense be developed or nurtured?
This question may sound little bizarre. It is generally believed that the sixth sense is a very special extra-corporal sense that is either there or not there (“all-or-nothing”). How can it be developed then if it is non-existant in a person.
In my opinion, the sixth sense is an ability to foresee or predict certain contextualized events, based on the past memories of all the five (or at least vision and hearing) senses, with inputs from neocortex and other regions of brain. The past events get stored in our memories; some of them remain as long-term memories in our hippocampus and neocortex/prefrontal cortex. These parts of our brain do have synaptic inputs from all other major areas and also the temporal (auditory) and occipital (visual) cortices. Most of the events, as they occur and are stored in the memory, remain unanalyzed. Those events just remain as facts from the past. However, every time an important event occurs, if conscious efforts are made to analyze it (with - when/where/why/what/how), such analysis may establish the synaptic connections that will store the analytical memory of the events. With specific inputs from posterior parietal cortex, visual & auditory cortices, archicortex & Papez circuit, such synaptic connections may enhance the judgmental prowess of a person. The efforts should also be made to bring any one special sense into sharp focus while an important event is occurring. It may later get converted into hippocampal storage in the form of specific synaptic connection.
After all, cortex is a dynamically evolving structure. With some training, the cortex may evolve (the “cortical plasticity” may be induced) to possess a better sense of judgment about persons and events; even the sixth sense may develop that can predict the occurrences. Any takers for the idea?
-Dr. Vivek Nalgirkar