What's the role of the basolateral amygdala?

MS marshmallow5 at yahoo.com
Fri Dec 22 09:24:59 EST 2000


I've seen research on both reinforcing/appetitive roles of the basolateral
amygdala, as well as aversive/fear conditioning. My best guess is that it's
involved in the emotional significance of sensory stimuli, either whether
positive or negative in valence. Concordantly, it's probably involved in
conditioning of those same emotional situations.

here's another reference:

Neural systems for behavioral activation and reward.
Kalivas PW, Nakamura M
Department of Physiology and Neuroscience, Medical University of South
Carolina, 167 Ashley Avenue - Suite 607, 250677, Charleston, South Carolina
29425, USA. kalivasp at musc.edu

The circuitry mediating the integration of reward perception and adaptive
behavioral responses has been further refined. Recent developments indicate
that the nucleus accumbens has a primary role in motivational circuitry,
whereas afferents to the nucleus accumbens, in part, subserve distinct
functions. Dopaminergic afferents serve to signal changes in rewarding
stimuli, whereas glutamatergic input from the amygdala serves to cue
behavior to conditioned reward, and afferents from the prefrontal cortex
integrate information from short-term memory into behavioral responses.


--
Marcello
optimism32 at hotmailNOSPAM.com

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Shamim Khaliq <shamim at khaliq.intensive.co.uk> wrote in message
news:3a3798ed_2 at news.intensive.net...
> What's the role of the basolateral amygdala? I thought it was important in
> classical conditioning of fear responses, i.e. associating a neutral
> stimulus with an internal aversive affective state generated by an
> unconditioned aversive stimulus. But I'm reading Depue's paper where he
says
> it's important in stimulus-reinforcement conditioning, with lesions
> impairing association of stimuli with reinforcement (appetitive stimuli).
Is
> the basolateral amygdala then also important in associating a neutral
> stimulus with an internal appetitive affective state?
>
> And then why have I heard about conditioned fear responses and not
> conditioned pleasure responses?
>
> I include two contradictory quotes about the role of the basal amygdala
> below.
>
> "In both monkey and human, the basolateral amygdala plays a critical role
in
> classical stimulus-reinforcement conditioning (Aggleton 1992; Bechara,
> Tranel, Damascio, Adolphs, Rockland & Damascio 1995; Cahill & McGaugh
1990;
> Everitt & Robbins 1992; Gaffan 1992; LeDoux 1996; LeDoux, Cicchetti,
> Xagoraris & Romanski 1990; Selden, Everitt, Jarrad & Robbins 1991).
> Bilateral basolateral amygdala lesions specifically impair the association
> of discrete stimuli with reinforcement, whereas the motivational efficacy
of
> food rewards or of DA injections in the NAS (nucleus accumbens) remains
> intact (Aggleton 1992; Everitt & Robbins 1992; Gaffan 1992). This
indicates
> that the basolateral amygdala performs stimulus-reinforcement associative
> functions, whereas DA release in the NAS modulates an incentive
motivational
> influence. Nevertheless, lesions of either the basolateral amygdala or NAS
> impair responding for reward, suggesting that these two structures are
> serially connected (Everitt & Robbins 1992; Mogenson et al. 1993)."
> http://www.cogsci.soton.ac.uk/bbs/Archive/bbs.depue.html
>
> "The CTA (conditioned taste aversion) can be differentiated from the CCP
> (conditioned place preference) in two ways. First, in contrast to the CCP,
> CTAs are not readily elicited by conditioned external cues (Garcia &
> Koelling, 1966; Reicher & Holman, 1977; Shennan et al., 1980b; Stefurak,
> Martin & van der Kooy, 1990). Neutral or even rewarding taste cues are
most
> easily conditioned in the CTA paradigm, suggesting that these conditioned
> incentive cues elicit aversive internal states. Secondly, CTAs are blocked
> by lesions of the basolateral nucleus of the amygdala (Nachman & Ashe,
1974;
> Elkins, 1980; Dunn & Everitt, 1988; Yamamoto & Fujimoto, 1991), while the
> CCP is eliminated by lesions of the lateral nucleus of the amygdala
> (McDonald & White, 1993). This difference suggests that positive and
> negative incentive learning are mediated by different neural substrates."
> http://niagara.rivier.edu/students/jlalmond/yes
>
>
>







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