Shifting to unrelated field after postdoc? Neurobiology to linguistics I am a 4th-year postdoc in molecular neurobiology, but I would like to shift to linguistics-related fields, particularly cognitive linguistics.
Long story short: I realized that I've been mixing up my interest and my true passion, neurobiology and linguistics. While both fields aim to understand the human mind (at different levels), I just find linguistics more fascinating and more rewarding to study. I am ready to commit myself to linguistics research.
I have thought about several options:

Look for a postdoc position directly in a lab which does cognitive linguistics. However, PIs usually hire postdocs in the same field, or at least possess some particular skills they need. I've met people who did a PhD in engineering but doing a postdoc in cognitive linguistics. However, given my background, how possible is this option? Do you know anyone who has similarly unrelated background but successfully switched their fields?
Do a postdoc in a lab which does interdisciplinary research, such as neurolinguistics (related to neurobiology, but more closely related to psycholinguistics). However, I think this option may not be much easier than option 1... Besides, it doesn't guarantee that I can eventually work in my favourite field, or it may take several postdoc positions to get there. This means I may need to go through more years of instability as a postdoc...
Do a second PhD. I am willing to do a second PhD, but the thing is, I am not sure if most PIs would recruit a PhD holder who was once committed to another field, not to mention that some universities may have special regulations on second PhD (e.g. funding).

Which options would you think is the best? What are the things I should also consider but I have missed? Do you have any experience that you would like to share?
Any advice would be appreciated greatly!
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Edit:
From the comments I've got so far, option 3 doesn't sound like a good idea... I will focus on the other two options now.
From what I've learnt from other similar posts, most people switch between related fields, or at least there are overlaps between their current and target fields. I've also noticed that many successful field changes are from quantitative science to a field which requires quantitative skills (e.g. from computer science to synthetic biology). Unfortunately, none of the above cases applies to me, except that my current field and some sub-fields in my target field could be remotely related.
While I can still find links between these fields, my real challenge is:
What can I do to demonstrate to potential PIs that I will do well in a new field without relevant experience? (I don't have publications in my target field or related field.)
Disclaimer: I know nothing about research in neuroscience or linguistics, so my answer is about a general person who finished a PhD in topic X and wants to switch to topic Y.
I would go for options 1 or 2. Option 3 is generally not a great idea. A PhD means spending several years on starvation wages, and a good chunk of that would be spent rehashing things you already know, like research methodology, how to explore data and so on. A postdoc allows you to explore whether your true passion really is linguistics. Treat the postdoc as you would a PhD - you have two years to write a thesis (well, not really write a thesis, but get enough results to fill one). Postdocs are often given much more freedom to explore their interests so you could build your knowledge on the topic while not having to do like a decade of PhD studies.
I would suggest a fourth option: would you be able to get a faculty position in neuroscience and then start exploring your dream at your own pace? Faculty members are masters of their own fate (to an extent, certainly more than PhD and postdocs). You can decide that you want to change your focus, and as a faculty member you may actually find it much easier to do so.