Is there a "foreplay" equivalent, priming activity for thinking or conversation? I've noticed the following phenomenon and am trying to find out if it is indeed true and if there is a scientific term for it:

When I think about ideas, I notice that I can rarely jump straight into "heavy" stuff, like thinking about a cognitive neuroscience article I read. Instead, doing another activity that "primes" my brain first tends to make me more conductive to heavy thinking. This can be watching a talk on TED.com or reading some lighter article.  

In conversation, I find that it's fairly hard to have a "heart to heart" talk with a person right off the bat, but a casual conversation can evolve in that direction.

When thinking about the phenomenon, the following supporting evidence comes to mind:

I've read that in some asian cultures, it is traditional to start a business deal with small talk, or over a friendly dinner. The motivation for this tradition was weird to me, until I thought about it light of the phenomenon described above.

Most of my successful job interviews started with small talk, unrelated to skills or position at hand. 

When thinking about other human "priming" behaviors, the one I can think of most clearly is  foreplay before sexual encounters, which serves the following role


  Foreplay is important from at least two considerations, one of which
  is purely physiological.[6] On the other hand, foreplay implies a
  certain level of confidence and trust between the partners and creates
  intimacy. Psychologically, foreplay lowers inhibitions and increases
  emotional intimacy between partners. Physically, it stimulates the
  process that produces sexual arousal.


I'm interested if there is indeed some "priming" activity that can put the human brain in a state of mind, where thinking or conversation is easier?  If so, what is the term for such activity? Has any neurotransmitter been implicated in the phenomenon described above?
Yes, there is such an activity and it is called priming.  It is the same technique that involves mental, sexual foreplay. There has been a fair bit of research about the psychological effects of priming. I have limited the discussion, purely to priming, but there are many other interesting, associations with priming that could be discussed within another post.

I find the following points provide a good summary of the various modes of priming.


  Priming is providing a stimulus that influences their near-term future
  thoughts and actions, even though they may not seem to be connected.
  Conceptual priming occurs where related ideas are used to prime the
  response, for example 'hat' may prime for 'head'.
  Semantic priming
  occurs where the meaning created influences later thoughts. Semantic
  and conceptual priming are very similar and the terms may be used
  interchangeably.
  Non-associative semantic priming refers to related
  concepts but where one is less likely to trigger thoughts of the
  other, for example 'Sun' and 'Venus'.
  Perceptual priming, is based
  on the form of the stimulus, for example where a part-picture is
  completed based on a picture seen earlier.
  Associative priming
  happens when a linked idea is primed, for example when 'bread' primes
  the thought of 'butter'. This particularly applies to 'free
  association' word pairs.
  Masked priming occurs where a word or image
  is presented for a very short time but is not consciously recognized.
  Repetitive priming occurs where the repetition of something leads to
  it influencing later thoughts.
  Reverse priming occurs where people
  realize they are being primed and, feeling they have been biased,
  over-respond in their choices which are now biased in the reverse
  direction


Meyer and Schvanveldt (1971), Neely (1977), Bargh and Pietromonaco (1982), Marcel, (1983), Draine and Greenwald (1998), Sherman and Kim (2002)

On the down side:
I have been unable to find studies investigating the neurotransmitters involved in priming (at this stage). One thought occurred to me from when I studied Neuroscience (many years ago). That arousal (as in attention) is required to LTP cells. Although, this specific example may not apply to priming, it is a parallel between the effects of psychological priming and physiological priming. I am sure there are better articles, I, currently, have limited access to journals. 

Learning-facilitated long-term depression and long-term potentiation at mossy fiber-CA3 synapses requires activation of β-adrenergic receptors.
Hagena H, Manahan-Vaughan D.
Source
Medical Faculty,
 Department of Neurophysiology,
Ruhr University
Bochum Bochum, Germany.