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== '''[[Food reward]]''' ==
== '''[[Emergence (biology)]]''' ==
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Food intake involves both 'homeostatic feeding' (energy demands) and ‘non-homeostatic feeding’; the latter is associated with  '''food reward''', which involves both 'liking’ (pleasure/palatability) and ‘wanting’ (incentive motivation) according to the ''salience theory''. Experiments in mice suggest that ‘liking’ involves the release of mu-[[opioid peptide]]s in brain, while ‘wanting’ involves the neurotransmitter [[dopamine]] <ref>Berridge KC (2007) The debate over dopamine’s role in reward: the case for incentive salience. ''Psychopharmacology'' 191:391–431</ref>.
The term '''emergence''' refers to the exhibition of novel collective phenomena in some large systems stemming from a complex organization of their many constituent parts.<ref name=Feltz>  


==='''Motivated behaviour and food as a reinforcer'''===
{{cite book |title=Self-organization and Emergence in Life Sciences |chapter=Introduction |author=Bernard Feltz, Marc Crommelinck, Philippe Goujon |editor=Bernard Feltz, Marc Crommelinck, Philippe Goujon, eds |url=http://books.google.com/books?id=V_fen8hnnFsC&pg=PA1&lpg=PA1 |isbn=1402039166 |year=2006 |publisher=Springer}}
The brain’s reward systems react to stimuli such as sight, smell and taste, and other cues that predict food. However, hunger cannot result in unconditioned goal-directed behaviour; <ref>Changizi MA ''et al.'' (2002) Evidence that appetitive responses for dehydration and food-deprivation are learned ''Physiol Behav'' 75:295–304</ref> chance encounters with palatable foods are required before goal-directed behaviour can occur, which link the internal needs with the salience of environmental stimuli <ref>Wise RA (2006) Role of brain dopamine in food reward and reinforcement ''Phil Trans R Soc Lond B Biol Sci'' 361:1149–58</ref>For exa mple, an infant recognises and learns to seek out sweet tastes, but the desire for any particular food is controlled by the interaction of peptide levels (related to hunger) with neural circuits in the brain which store the animal’s past experience of that particular food. <ref>Steiner JE ''et al.''(2001) Comparative expression of hedonic impact: affective reactions to taste by human infants and other primates ''Neurosci Biobehav Rev'' 25:53–74</ref> Subsequently, the infant will taste both food and non-food objects indiscriminately until it has received reinforcing feedback from enough stimuli. A monkey’s appetite for yellow bananas requires that the monkey learns to relate the sight of the yellow skin of a banana with the sweet taste of the banana, plus the consequences of eating it. Preference for a particular food results only when the post-ingestional consequences of that food ’reinforce’ the tendency to eat that food. For these reasons, food is considered to be a strong reinforcer. When the response of a behaviour stimulated by a reinforcer increases the frequency of that  behaviour; that is ''positive reinforcement'' or ''reward learning'', and the positive events are called ''rewards'' <ref>Epstein LH ''et al.''(2007) Food reinforcement and eating: a multilevel analysis ''Psychol Bull'' 133:884–906</ref>. The reinforcing efficacy of food reward is the ability of the reward to maintain rather than to establish behaviour; consequently the stimulus learning contributes to the response learning.


''[[Food reward|.... (read more)]]''
</ref> In [[systems biology]] and [[theoretical biology]], one topic is ''emergence'' in living systems. Often-used examples are termite and bees' nests, made by the cooperative action of multitudes of individuals.
 
In biology emergent behavior includes such things as locomotion, sexual display, flocking, and conscious experiencing.  Emergence is found even in biological ''subsystems'', such as mitochondria and other organelles of living cells.
 
Emergent properties are viewed by some as novel properties, functions and behaviors, ones not observed in the system's subsystems and their components, and neither explicable nor predictable from even a complete understanding of the components' properties/functions/behaviors considered in isolation. Others take the view that these novel properties are the outcome of interactions between the constituents understandable from microscopic behavior, but more readily envisioned by introduction of novel organizational concepts.
 
''[[Emergence (biology)|.... (read more)]]''


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Revision as of 00:47, 31 August 2012

Emergence (biology)

The term emergence refers to the exhibition of novel collective phenomena in some large systems stemming from a complex organization of their many constituent parts.[1] In systems biology and theoretical biology, one topic is emergence in living systems. Often-used examples are termite and bees' nests, made by the cooperative action of multitudes of individuals.

In biology emergent behavior includes such things as locomotion, sexual display, flocking, and conscious experiencing. Emergence is found even in biological subsystems, such as mitochondria and other organelles of living cells.

Emergent properties are viewed by some as novel properties, functions and behaviors, ones not observed in the system's subsystems and their components, and neither explicable nor predictable from even a complete understanding of the components' properties/functions/behaviors considered in isolation. Others take the view that these novel properties are the outcome of interactions between the constituents understandable from microscopic behavior, but more readily envisioned by introduction of novel organizational concepts.

.... (read more)

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