Electrical lesion of bilateral ventrolateral orbital cortex impairs fear- and space-related learning and affects subsequent choice behavior

ABSTRACT

Objectives

Although many studies have indicated that orbitofrontal cortex plays an important role in the learning and retrieval of memory and subsequent decision-making, the role of ventrolateral orbital cortex (VLO) still remains unclear, especially related to fear and space.

Methods

Four separate cohorts of rats were used in this study. After sham surgery and electrical lesion of bilateral VLO, four cohorts received active avoidance test, passive avoidance test, Morris water maze and T maze separately.

Results

Firstly, data shown that electrolytic lesions of bilateral VLO of Sprague–Dawley rats shortened the latency of rats to escape to darkroom in passive avoidance test. Besides, the damage of VLO also resulted in decrease of the number of active avoidance of rats from the third day during 5 consecutive days’ training in active avoidance test. What’s more, the impairment of VLO significantly shortened the exploring time in the target quadrant of rats in Morris water maze. Furthermore, VLO-lesions group shown lower correct alternation percentage than sham group in T maze.

Conclusions

These results indicated that not only in the learning and retrieval of fear-related memory, VLO also plays an important role in the learning and retrieval of spatial-related memory guided by visual cues.

KEYWORDS:

• Ventrolateral orbital cortex
• avoidance learning
• spatial memory
• decision making

Disclosure statement

No potential conflict of interest was reported by the author(s).

Ethics approval

This study was approved by the Animal Protection Committee of Xi’an Jiaotong University.

Consent to participate

Not applicable.

Consent for publication

Not applicable.

Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Author contributions

CZ and DYh conceived and designed the experiments. CZ, LP, LG, LF, LSf and WYm performed the experiments. CZ, DLs and YL analyzed the data. CZ wrote the manuscript.

Abbreviations

AAT active avoidance test

CS conditioned stimulus

i.p. intraperitoneally

MWM Morris water maze

OFC orbitofrontal cortex

PAT passive avoidance test

US unconditioned stimulus

VLO ventrolateral orbital cortex

Additional information

Funding

This research was supported by the National Natural Science Foundation of China [NSFC No. 81771435 to Yong-hui Dang]; the Opening Foundation of NHC Key Laboratory of Drug Addiction Medicine [No. 2020DAMOP-0011 to Yong-hui Dang] and the Opening Foundation of Shanghai Key Lab of Forensic Medicine, Key Lab of Forensic Science, Ministry of Justice [No. KF202105 to Yong-hui Dang].