Behavioral responses learned

Iversen (1991) stresses the need for some in vivo testing for neurotoxicity and emphasizes the value of sensitive behavioral tests. Behavioral tests are described for mice and rats, which provide measures of mood, posture, CNS excitation, motor coordination, sedation, exploration, responsiveness, learning, and memory function. Such assays can function as primary screens for neurotoxicity before adopting a stepwise scheme of in vitro tests to discover more about the initial site of action of neurotoxic compounds. It is argued that the requirement for animal testing can be drastically reduced by adopting structured in vitro protocols such as these. 

Taken together, this body of work demonstrates that adult behavioral responses to social odors are shaped by early olfactory experience. Indeed, heterospecific or artificial odor cues associated with the rearing environment acquire attractive properties that can last into adulthood in many rodent species. Furthermore, early experience with opposite-sex odors appears to be critical for the normal development of appropriate behavioral responses to sexual odors in mice and hamsters. Importantly, the behavioral plasticity observed using these different experimental approaches may all be mediated by a classical conditioning model of olfactory learning. The experience-dependent development of odor preference in rodents therefore provides a powerful model for understanding how the olfactory system recognizes and learns the salience of social odors, a function that is critical for the appropriate expression of reproductive behavior. 

During the expression of fear-related behaviors, the LA engages the central nucleus of the amygdala (CEA), which, as the principal output nucleus, projects to areas of the hypothalamus and brain stem that mediate the autonomic, endocrine, and behavioral responses associated with fear and anxiety (Schafe et al. 2001). The molecular and cellular mechanisms that underlie synaptic plasticity in amygdala-dependent learned fear is an area of very active investigation (Shumyatsky et al. 2002). Long-term potentiation (LTP) in the LA appears to be a critical mechanism for storing memories of the CS-US associa-... 

Newborn humans have few olfactory preferences most of the wiring has to be put in place during the early years of development, though we continue to learn and acquire odor preferences throughout our lives. The cultural implications of this and its relation to perfumery are of course immense, since each of us is able to learn and respond to an enormous range of odorous materials rather than only to those dictated by a genetically predetermined system of behavioral responses. 

Wood and Coleman (1995) assessed the behavioral response to formaldehyde exposure in male Swiss mice. Eight mice were trained to terminate exposure to noxious gases, using 1,000 ppm ammonia. All animals learned to terminate 100% of the ammonia exposures. After mice consistently terminated... 

Behavioral Responses Innate and Modified by Olfactory Learning.283... 

The presence of different receptor neuron types forms the basis for detection of and discrimination among odorants in the environment. In addition, important processing of the information takes place in the brain, resulting in the behavioral responses. The three olfactory areas of the insect brain are the antennal lobe, the mushroom bodies (important in learning and memory), and the lateral... 

BEHAVIORAL RESPONSES INNATE AND MODIFIED BY OLFACTORY LEARNING... 

Carson, T. L., van Gelder, G. A., Karas, G. C. and Buck, W. B. (1974). Slowed learning in lambs prenatally exposed to lead. Arch, Env, Health, 29, 154 Caruso, V., Zenick, H. and Michaelson, I. A. (1981). Attenuated behavioral response to D-amphetamine in male and female lead-exposed rats. Fed, Proc., 40, 700... 

Acute pain is an adaptive physiological response that follows traumatic injuries and surgery. It has two primary components. (1) The sensory discriminative component describes the location and quality of the stimulus. It is characterized by rapid response, short latency to peak response, and short duration of action. Noxious information is conveyed by rapidly conducting A-delta fibers, and monosynaptic transmission to the sensory cortex [10,12]. This component rapidly identifies the site of injury or potential injury, and initiates reflexive/cognitive withdrawal responses. (2) The affective-motivational component underlies suffering and the emotional components of pain and is responsible for learned avoidance and other adaptative and non-adaptative behavioral responses. 

Classical conditioning is the acquisition of a behavioral response to a new stimulus by association with a previous stimulus. Contextual fear conditioning is a form of classical conditioning used to evaluate the learned response to an environment where the animal previously experienced an aversive stimulus. For example, rats freeze when placed in a chamber where they have previously been subjected to an electric shock. This freezing response is either absent or reduced in... 

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