title: Encoding and retrieval of artificial visuoauditory memory traces in the auditory cortex requires the entorhinal cortex.
abstract: Damage to the medial temporal lobe impairs the encoding of new memories and the retrieval of memories acquired immediately before the damage in human. In this study, we demonstrated that artificial visuoauditory memory traces can be established in the rat auditory cortex and that their encoding and retrieval depend on the entorhinal cortex of the medial temporal lobe in the rat. We trained rats to associate a visual stimulus with electrical stimulation of the auditory cortex using a classical conditioning protocol. After conditioning, we examined the associative memory traces electrophysiologically (i.e., visual stimulus-evoked responses of auditory cortical neurons) and behaviorally (i.e., visual stimulus-induced freezing and visual stimulus-guided reward retrieval). The establishment of a visuoauditory memory trace in the auditory cortex, which was detectable by electrophysiological recordings, was achieved over 20-30 conditioning trials and was blocked by unilateral, temporary inactivation of the entorhinal cortex. Retrieval of a previously established visuoauditory memory was also affected by unilateral entorhinal cortex inactivation. These findings suggest that the entorhinal cortex is necessary for the encoding and involved in the retrieval of artificial visuoauditory memory in the auditory cortex, at least during the early stages of memory consolidation.
authors.affiliation: Laboratory of Applied Neuroscience, Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.forename: Yiping
authors.initials: Y
authors.lastname: Guo
authors.forename: Jingyu
authors.initials: J
authors.lastname: Feng
authors.forename: Zhengli
authors.initials: Z
authors.lastname: Liao
authors.forename: Xinjian
authors.initials: X
authors.lastname: Li
authors.forename: Haitao
authors.initials: H
authors.lastname: Wang
authors.forename: Xiao
authors.initials: X
authors.lastname: Li
authors.forename: Jufang
authors.initials: J
authors.lastname: He
mesh_terms: D000161:Acoustic Stimulation; D000200:Action Potentials / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D001303:Auditory Cortex / Q000166:cytology / Q000293:injuries / Q000502:physiology*; D001931:Brain Mapping; D003214:Conditioning, Classical / Q000502:physiology; D004558:Electric Stimulation; D018728:Entorhinal Cortex / Q000502:physiology*; D018691:Excitatory Amino Acid Antagonists / Q000009:adverse effects; D005108:Extinction, Psychological; D005260:Female; D007839:Functional Laterality; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D009434:Neural Pathways / Q000502:physiology; D009474:Neurons / Q000502:physiology; D010775:Photic Stimulation; D011810:Quinoxalines / Q000009:adverse effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D012201:Reward; D013997:Time Factors; D014796:Visual Perception / Q000502:physiology*
chemical_list: D018691:Excitatory Amino Acid Antagonists; D011810:Quinoxalines; C056723:FG 9041