Newsgroup: it.scienza.biologia
Titolo: è impossibile comprendere la capacità percettive degli animali?

mi pare che sia quanto riportato qui sotto che l'esperimento fatto su animali 
allevati in ambiente monocromatico (di cui avevo postato il link recentemente) 
dimostrino che i mezzi per capire quali suoni/colori siano in grado di 
discriminare gli animali ci sono (al contrario di quanto si ostina ad 
affermare fuzzy con la sua logica sempre più fuzzy)
Response Properties of the Auditory Telencephalon in Songbirds Change with 
Recent Experience and Season. PLoS One, 3(8): e2854 DOI: 
10.1371/journal.pone.0002854
<
http://www.sciencedaily.com
­/releases/2008/08/080805214404.htm>
Research conducted at Rutgers University has shown that exposure to a changed 
acoustic and social environment can rewire the way the brain processes sounds. 
Beginning in the cochlea of the inner ear, nerve cells of the auditory system 
parse incoming sounds into their different components.
Study of the responses of individual brain cells has shown that they respond 
best to a particular frequency (pitch) of sound, less well to nearby 
frequencies, and poorly to distant sound frequencies. The range of effective 
frequencies can be measured as the "tuning width." Cells with similar tuning 
are found together, producing an orderly map of all the possible frequencies 
spread out across the auditory part of the brain.
These tuning properties were used to study the way experience can change the 
brain in two species of songbirds. Songbirds provide the best-developed animal 
system for studying vocal learning because juvenile birds learn to sing by 
hearing and imitating adults, much as human infants do. The songbird brain 
contains an area similar to the mammalian auditory cortex (the NCM) that is 
specialized to discriminate and remember the songs of other birds of the same 
species.
In this study, adult zebra finches (which normally live in a single-species 
colony) were moved to a canary colony, and adult canaries were moved to a 
zebra finch colony. These birds experienced a novel environment because 
canaries and zebra finches produce learned species-typical vocalizations that 
differ in their acoustic components. Other birds of each species remained in 
their home colony and still others were placed in individual isolation.
After nine days of altered experience, the tuning width was assessed in the 
brains of these animals and was found to be significantly different from birds 
that remained at home. In birds of both species that experienced life in a 
foreign colony, the tuning became narrower (i.e. more selective). In canaries, 
which can learn new song elements in adulthood, these effects were also 
influenced by season, and may reflect the role of vocal imitation in the 
seasonal breeding behavior of this species. Isolation had the opposite effect: 
the tuning became wider (i.e. less selective).
In other words, when a bird is exposed to a new acoustic and social 
environment, basic auditory properties in its brain change to become more 
finely tuned. In human terms, a possible analogy for this experiment is when a 
person travels to a foreign country where an unfamiliar language is spoken. 
The individual has to pay close attention and gradually begins to make out the 
words in the speech stream (and perhaps to recognize a few from the phrase 
book). This process of "tuning in" to the new sound and social environment may 
involve increased sensitivity to fine acoustic details and may produce 
measurable tuning changes such as those observed at the neural level in these 
songbirds.
In contrast, the songbirds' tuning coarsened in the impoverished, monotonous 
environment provided by being housed in isolation.
The researchers suggest that these songbird results provide a useful 
experimental model of sensory plasticity accessibility, which is worthy of 
further study. Consistent with observations in other sensory systems, the 
tuning map in the brain is not rigid, but adjusts dynamically to current 
experience.
-- 
bye
main(){printf("%u\n",!(!1|1));}

 
era necessario aprire un altro thread per lusingare quel mentecatto?
Fuzzy viene qui per spiegarci, bonta' sua, che la filosofia e' il modo
per capire l'universo, ed e' famigerato per non leggere neanche i link
che posta lui stesso, figurati quelli degli altri.
Noi che riduciamo il mondo a quattro formulette e un po di numeri
abbiamo la presunzione di voler capire come stanno le cose
sperimentalmente. Per fortuna che ci sono i wannabe filosofi che ci
spiegano come va il mondo, va, se non saremmo fregati.
-- 
allo spegnersi delle lucciole
oscurita'
nella gabbietta
http://www.lorologiaiomiope.com

 era necessario aprire un altro thread per lusingare quel mentecatto?
Vedo che non sono l'unico a usare il termine "mentecatto"
nell'accezione di "strenuamente attaccato a un'idea fissa".
Sul tema del thread, pare che un Cambridge Colour Test adattato
confermi le predizioni basate sull'ERG (elettroretinografia):
 
http://www.ncbi.nlm.nih.gov/pubmed/16962014
 Vis Neurosci. 2006 May-Aug;23(3-4):695-701.
 An adaptation of the Cambridge Colour Test for use with animals.
 Mancuso K, Neitz M, Neitz J.
 Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
 Recently, molecular biological techniques have presented new opportunities
 for addressing questions concerning the neural mechanisms involved in color
 coding, thereby rousing renewed interest in animal color vision testing.
 We have modified a computer-based assessment tool, the Cambridge
 Colour Test, to make it suitable for use with animals. Here, the validity
 and reliability of the testing method were evaluated using squirrel 
monkeys.
 Because the chromatic stimuli and the achromatic backgrounds of the test
 consist of dots that vary in lightness, the stimulus parameters can be
 adjusted so that animals are not able to use luminance differences to make
 correct discriminations. Thus, in contrast to methods used previously,
 this test does not require that time be spent equating the luminance of 
each
 chromatic stimulus examined. Furthermore, the computer video-display based
 design of the testing apparatus can be easily replicated and adapted for 
use
 with many species in a variety of settings. In the present experiments,
 the squirrel monkeys' behavioral results agreed with the predictions
 for their color vision based on genetic analysis and electroretinography
 (ERG) spectral sensitivity data. Repeated measurements were highly
 consistent. Thus, an adaptation of the Cambridge Colour Test provides
 a valid and reliable method for testing color vision in animals.
Bye,
  *GB* 

 affermare fuzzy con la sua logica sempre più fuzzy)
Scusa, dove avrei affermato che non ci sono i mezzi per fare questo?
Gli studi che ho citato io sono proprio esperimenti di questo tipo.
Non sarà forse che ti sfugge il problema che sto ponendo, forse anche
perche non e' semplice da esporre?
fuzzy