1,336 research outputs found
Operant Discriminative Learning and Evidence of Subtelencephalic Plastic Changes After Long-Term Detelencephalation in Pigeons
We analyzed operant discrimination in
detelencephalated pigeons and neuroanatomical
substrates after long-term detelencephalation.
In Experiment I, experimental pigeons with
massive telencephalic ablation and control
pigeons were conditioned to key peck for food.
Successive discrimination was made under
alternating red (variable-ratio reinforcement)
and yellow (extinction) lights in one key of the
chamber. These relations were interchanged
during reversal discrimination. The sessions
were run until steady-state rates were achieved.
Experiment II analyzed the morphology of the
nucleus rotundus and optic tectum in long-term
detelencephalated and control birds, using a
KlĂĽver-Barrera staining and image analyzer
system. Detelencephalated birds had more
training sessions for response shaping and
steady-state behavior (p<0.001), higher red key
peck rates during discrimination (p<0.01), and reversal discrimination indexes around 0.50.
Morphometric analysis revealed a decreased
number of neurons and increased vascularity,
associated with increases in the perimeter
(p<0.001)
in the nucleus rotundus. In the optic
tectum, increases in the perimeter (p<0.05)
associated with disorganization in the layers
arrangement were seen. The data indicate that
telencephalic systems might have an essential
function in reversal operant discrimination
learning. The structural characteristics of subtelencephalic
systems after long-term detelencephalation
evidence plastic changes that
might be related to functional mechanisms of
learning and neural plasticity in pigeons
- …