This review discusses pharmacological and electrophysiological approaches to research on hemispheric asymmetry. Much of this work has been done on birds, particularly the domestic chick. The discussion is prefaced by descriptions of behavior in the chick and the underlying neural mechanisms of filial imprinting, passive avoidance learning, predispositions, sensory processing, feeding, aggression, copulation, and attention. Quantitation and specificity of drug administration, receptor ligand binding, plasticity, hemispheric inactivation, neurotransmission in commissural neurons, and optogenetic techniques are discussed as relevant. The application of these techniques is then considered, with emphasis on imprinting, predispositions, and passive avoidance learning. Unilateral intracerebral injection of cycloheximide and glutamate shows laterality of several behaviors, with control commonly ascribed to the left hemisphere; such influence can, however, be modified by visual experience late in incubation. The intermediate medial mesopallium (IMM) has been identified as a memory region for imprinting within the chick forebrain. Lesion studies and injection of L-glutamate into this region provide evidence that the left and right IMM have different roles in the acquisition and retention phases of imprinting and in subsequently establishing memory outside the IMM. A range of morphological and biochemical changes associated with synaptic function, which are specifically related to memory formation after imprinting, occur predominantly or entirely in the left IMM. Electrophysiological analysis with microelectrodes in freely moving chicks shows differences between the left and right IMM after imprinting, including in recognition of familiar individuals. Passive avoidance learning in the chick is also impaired by surgical and pharmacological intervention in the IMM, where lateralized effects have also been described. Interference with nitric oxide metabolism and glutamate receptor activity was found to be particularly effective when applied to the left hemisphere, but the right hemisphere is vulnerable to these manipulations at particular times after passive avoidance training. Electrophysiological recording in songbirds has revealed hemispheric asymmetry in response to song reception in Field L, a forebrain auditory projection area, and in the nidopallium caudale pars medialis, a candidate region for memory of learned song. Electrical stimulationElectrical stimulation and recording in the higher vocal center (HVC), a forebrain song control area to which Field L projects, have revealed laterality and an association between laterality and socialization.

Pharmacological Agents and Electrophysiological Techniques

实验方案
发表日期：

2025年

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Brian McCabe

摘要

This review discusses pharmacological and electrophysiological approaches to research on hemispheric asymmetry. Much of this work has been done on birds, particularly the domestic chick. The discussion is prefaced by descriptions of behavior in the chick and the underlying neural mechanisms of filial imprinting, passive avoidance learning, predispositions, sensory processing, feeding, aggression, copulation, and attention. Quantitation and specificity of drug administration, receptor ligand binding, plasticity, hemispheric inactivation, neurotransmission in commissural neurons, and optogenetic techniques are discussed as relevant. The application of these techniques is then considered, with emphasis on imprinting, predispositions, and passive avoidance learning. Unilateral intracerebral injection of cycloheximide and glutamate shows laterality of several behaviors, with control commonly ascribed to the left hemisphere; such influence can, however, be modified by visual experience late in incubation. The intermediate medial mesopallium (IMM) has been identified as a memory region for imprinting within the chick forebrain. Lesion studies and injection of L-glutamate into this region provide evidence that the left and right IMM have different roles in the acquisition and retention phases of imprinting and in subsequently establishing memory outside the IMM. A range of morphological and biochemical changes associated with synaptic function, which are specifically related to memory formation after imprinting, occur predominantly or entirely in the left IMM. Electrophysiological analysis with microelectrodes in freely moving chicks shows differences between the left and right IMM after imprinting, including in recognition of familiar individuals. Passive avoidance learning in the chick is also impaired by surgical and pharmacological intervention in the IMM, where lateralized effects have also been described. Interference with nitric oxide metabolism and glutamate receptor activity was found to be particularly effective when applied to the left hemisphere, but the right hemisphere is vulnerable to these manipulations at particular times after passive avoidance training. Electrophysiological recording in songbirds has revealed hemispheric asymmetry in response to song reception in Field L, a forebrain auditory projection area, and in the nidopallium caudale pars medialis, a candidate region for memory of learned song. Electrical stimulationElectrical stimulation and recording in the higher vocal center (HVC), a forebrain song control area to which Field L projects, have revealed laterality and an association between laterality and socialization.