Neural consequences of imprinting in birds

242 p r o j e c t i o n was respectively). The

same

centralis

always

much

fraction

in the

of

stronger

the

than

labelled

ipsilateral

as w e l l

the

cells

ipsilateral lies

as in the

near

(i0

the

: ]

area

contralateral

retina. We

identified

few s p a r c e l y large

cell

branches cell

the

branching

bodies,

were

distinction

by

in a d d i t i o n site

different more

to t h e

central

no b e t a

gamma-

sure

cell

body

of

of the

receive

the N O T

we

and

projections

A few

alpha

cell

bodies

could

of

conclude

is a l -

project

to

By c o m p a r i n g

labelled that

cells

rostral

in

and

from more

and more

from peripheral

site

be r e c o n s t r u c t e d

projections

superficial

for

morphological

gamma-cells

the n u m b e r

receive

gamma

injection

size measurements.

with

retina

the

pattern

their

reaching

complete

beta-

by

a

of the

labelled.

through

only

tree

were

axons

and

that

and

far r e a c h i n g

their

Although

bodies

cells

and

cells

cells

because

cell

and a l p h a

3-5 m a i n

and p a s s i n g

are

small

labelled

excentricities

parts

parts

of the N O T

were

injection

retinal

deeper

all

the d e n d r i t i c

of the

and

injection.

we

their

dendrites

axons

of H R P m a r k e d

because

by

labelled

the

impossible,

the N O T

the

there

colliculus

injured

most

thin

Neaily

probably

superior

were

cells

thick

dendrites.

population,

cells

gamma

caudal

parts

of

parts

the

retina.

NEURAL

CONSEQUENCES

BATESON,

Sub-Department

of

filial

cally

of A n i m a l

Cambridge

the

biologists

measures

last

CB3

IN B I R D S

imprinting as a m e a n s

I have

designed

in d o m e s t i c of

of the

localising

study

University

of C a m b r i d g e ,

8AA, (England)

in i m p r i n t i n g ,

as in any

consequences

Behaviour,

ten y e a r s

on a p r o j e c t

involved

However,

IMPRINTING

P.

Mading~ey,

Over

OF

the

of t h i s

training

collaborated

to a n a l y s e chicks. the

Using

areas

forebrain kind,

procedure

the

of

with

simple

basis biochemical

the b r a i n

"roof"

was

the m e a s u r e d might

neuro-

neural

have

specifi-

implicated.

neural

been

associated,

243 not with

learning

of memory,

which must

accompany

experiment

excludes

years, which

however, excludes

altered

the all

we have

storage

a series

in the

optimistic

events

are both n e c e s s e s a r y

which

that

areas

medial

part of the h y p e r s t r i a t u m

before

imprinting

microscopic

study had

are only

found

is towards

on the

looking

organization

shown

at the

approach

has given much

provides

us with

PERCEPTUAL

BERARDI,

N.

Instituto

The

AND

of complex

gratings

sinusoidal

gratings,

up new on the

synapses these

While

increase changes

my own bias

of the b e h a v i o u r a l

to these

the

analytical

issues-

and also

surprises.

DISCRIMINATION

TASK

IS S P E C I F I C

A.

del

of judgement

The

after

FREQUENCY

tasks was m e a s u r e d

procedure.

the

the

an e l e c t r o n

unquestionable

focus

IN A G R A T I N G SPATIAL

di N e u r o f i s i o l o g i a

improvement

in terms

stimuli

Pisa, (Italy)

practice

in 9 subjects

in a number with

to be d i s c r i m i n a t e d

of d i f f e r e n t differing

C.N.R.,

with

had

the area

attack

Interestingly,

of r e w a r d i n g

AND F I O R E N T I N I ,

discrimination choice

sharper

a number

LEARNING

FOR O R I E N T A T I O N

issues

information

opened

Already

that the d e n d r i t i c

animal,

neural

precisely

have

left side of the brain.

of the w h o l e

of

and l e s i o n i n g

storage.

of imprinting.

resulted

Lesioning

results

of

becoming

implicated

and anatomical

of i n f o r m a t i o n

as a result

ventrale.

These

each

to it. We have

to localise and have

the

time

may r e p r e s e n t

related

acquisition,

recall.

roof

for the storage

roof

for p h y s i o l o g i c a l

problem

in size

prevents

prevents

possibilities general

forebrain

Over

Each

therefore,

changes

technique

active

imprinting,

of the

such

and e x c l u s i v e l y

used an a u t o r a d i o g r a p h i c

No single

of p r o c e d u r e s

forebrain

We are,

increasingly

events

explanations.

set of p o s s i b i l i t i e s .

procedure.

from the e n v i r o n m e n t ,

other

of information.

devised

activity

imprinting

numerous

the a l t e r n a t i v e

a different

biochemical

from the

but with

waveforms,

in spatial

were

and a pair

frequency.

of

a forced pairs of