August 14, 2011

From Cognition to Behavior: The Intermediate Zone




How are our cognitive processes integrated together to produce a seemingly flawless behavior/motor output? 


In short, the ‘Perception-Action Cycle,’ proposed by Joaquin M. Fuster (Fuster, 1990), who I had the distinct pleasure of conversing with at SfN, tries to link the two distinct neural processes into a coherent sum via what he terms a ‘cognit’ (resembles a cell assembly but is distinctly dedicated to cortical linking).


This perception-action cycle focuses on just the question posed here.  





Continue reading for more detailed analysis and pictures.





Before I go further, let me explain the picture above and the image to my left.  Both images came from Fuster's book (Fuster, 2005) – probably the greatest book ever, FYI.  Highly recommend!






In these two figures (fig. 1 and 2), the blue areas represent perceptual/memory cortical regions that are then cycled to the red (frontal) regions for executive planning and/or modification of current ongoing motor programs. Where these programs are modified is in the prefrontal (before prefrontal, the septo- and intermediate hippocampus, too? see below for details), which sends this 'plan' to the premotor for analysis, then the supplementary motor area to set into action, and finally the motor cortex which sends out the executive order to the skeletal muscles on how to proceed with future behavioral action, again which are fed back to the perceptual (blue areas) and the cycle to the red areas continues to modify/adjust motor output and also perception and cognitive processing (bottom-up and top-down processing occurs).


Now, on to the rodent (and human?) and how it (may) transforms its cognition into behavioral output from subcortical areas.  Many of their (rodents’) behaviors can be readily explained via an approach/avoidance stance (along with some human behaviors) in order to keep safe, a mechanism/urge built in through millennia of evolutionary processes.  This is not to say that cognition does not play a role.  On the contrary -- cognitive processes play a significant role, especially with humans.  They may have this “instinctive” urge(s) to do a simple activity but cognition can override this urge (or can it? the case of 'free will' comes to mind!). Many of the simpler phenomena in rats, however, can be explained by behavioral approaches: either "information-seeking behavior," “take a risk to get the food,” "freeze to keep safe," or "get the hell out of here". But, what are the anatomical locations for such a transformation?
description at end of article

Recently, research in conjunction from Bast and Morris's labs reported that the intermediate hippocampus (as opposed to the dorsal or ventral for spatial and emotional processing, respectively, for simplicity's sake; fig. 3, right) is uniquely situated and responsible for transforming cognitive and emotional processes in to behavioral outputs.  This research tends to focus on one main region, but the authors do recognize the highly interconnectivity of this region with cortical and subcortical areas, such as the prefrontal cortex (hence, above when I mentioned this interconnectivity between PFC and hippocampus), accumbens, hypothalamus, amygdala, and several other areas (Bast, 2007; Rugg, Bast, Wilson, Witter, & Morris, 2009).  This intermediate region within the hippocampus may interact with these motor areas to adjust/modify behavioral output depending on information that is gathered by the hippocampus, via the entorhinal cortex and the septum, gated by aminergic inputs, and these two streams of incoming information are compared in area CA1 -- the‘real word model’ with ‘expected model’.  (Duncan, Ketz, Inati, & Davachi, 2011; McNaughton & Wickens, 2003; Vinogradova, 2001).







 This is obviously a simplified and incomplete explanation but represents a good start for others just interested in the process... 




Fig. 3: [(adapted from Rugg, et al., 2009)]. Dorsal, intermediate, and ventral hippocampal connectivity in conjunction with visual and spatial precision.  (left) Inverted triangle represents that degree of visuo-spatial information that is received by the hippocampal regions, where magenta means high precision and blue represents low precision.  The entorhinal cortex is segregated in such a way that different areas here send out different amounts of precision of visual and spatial information. (middle) Segregation of the dorsal (magenta), ventral (blue), and intermediate (light magenta) that receive these entorhinal and septal connections.  (right) The corresponding colors serve as location cortical and subcortical connectivity with the hippocampus, which contribute to their motivation, sensori-motor, emotion, and executive functioning, which all are attributes that feed in to cognition and, hence, behavioral output.


References




Barkus, C., McHugh, S. B., Sprengel, R., Seeburg, P. H., Rawlins, J. N., & Bannerman, D. M. (2010). Hippocampal NMDA receptors and anxiety: at the interface between cognition and emotion. [Review]. Eur J Pharmacol, 626(1), 49-56. doi: 10.1016/j.ejphar.2009.10.014


Bast, T. (2007). Toward an integrative perspective on hippocampal function: from the rapid encoding of experience to adaptive behavior. Reviews in Neuroscience, 18, 253-281.


Duncan, K., Ketz, N., Inati, S. J., & Davachi, L. (2011). Evidence for area CA1 as a match/mismatch detector: A high-resolution fMRI study of the human hippocampus. [Journal Article]. Hippocampus. doi: 10.1002/hipo.20933


Fuster, J. M. (1990). Prefrontal cortex and the bridging of temporal gaps in the perception-action cycle. [Review]. Ann N Y Acad Sci, 608, 318-329; discussion 330-316.


Fuster, J. M. (2005). Cortex and Mind: Unifying Cognition. USA: Oxford University Press.


McNaughton, N. (1997). Cognitive dysfunction resulting from hippocampal hyperactivity--a possible cause of anxiety disorder? Pharmacol Biochem Behav, 56(4), 603-611.


McNaughton, N., & Wickens, J. (2003). Hebb, pandemonium and catastrophic hypermnesia: the hippocampus as a suppressor of inappropriate associations. Cortex, 39(4-5), 1139-1163. 

2 comments :

  1. nice, i like your banner and the aesthetic in general, it is very friendly to read... is your banner from real data? I think that your posts may not be suitable for a general audience; to me they seem appropriate to neuroscientists and people with a keen interest in neuroscience... i prefer the 'introduce with the big picture and then zoom into the details' approach rather than some general posts and some specific posts... hope this helps, and good luck with your blog!

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  2. So what is the role of the hippocampus in the perception-(reason)-action cycle? To modulate the connections between perception (sensory cortext and perceptual memory) and action (motor cortext and executive memory) or just to temporarily enhance memories in both areas?

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