Burgdorf Jeffrey S, Moskal Joseph R
Falk Center for Molecular Therapeutics, Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL, 60201, USA.
Gate Neurosciences Inc., Carmel, IN, 46032, USA.
Discov Ment Health. 2023 Oct 10;3(1):19. doi: 10.1007/s44192-023-00044-3.
Positive and negative emotional states in rats can be studied by investigating ultrasonic vocalizations (USVs). Positive affect in rats is indexed by 50 kHz hedonic USVs, and negative affect is indexed by 22 kHz aversive calls. We examined the relationship of emotional states in rats using medial prefrontal cortex (MPFC) quantitative electroencephalograms (qEEG) and found that hedonic USVs were associated with active wake qEEG (high alpha/low delta power), and aversive USVs occurred with groggy wake qEEG (low alpha/high delta). Further, alpha frequency electrical stimulation of the MPFC induces hedonic calls and reward-seeking behavior, whereas delta frequency stimulation produces aversive calls and avoidance behavior. The brain region responsible for generating motor output for USVs, the periaqueductal gray (PAG), shows a motor-evoked potential that is temporally locked to the alpha (hedonic) and delta (aversive) motor-evoked potential. Closed-loop alpha frequency electrical stimulation could prevent delta qEEG and aversive USVs. At the neuronal circuit level, the alpha rhythm was associated with synaptic long-term potentiation (LTP) in the cortex, whereas the delta rhythm was associated with synaptic depotentiation (LTD) in the cortex. At the pharmacological level, NMDAR and growth factor modulation regulated these forms of neuroplasticity. At the single neuron level, excitatory neurons show increased activity in response to alpha frequencies and decreased activity during delta frequencies. In humans, the feeling of joy increased alpha and decreased delta power in frontal scalp qEEG, and the opposite response was seen for sadness. Thus, the synchronization of alpha/delta oscillations through the neuronal circuit responsible for emotional expression coordinates emotional behavior, and the switch between active wake/positive affect and groggy wake/negative affect is under the control of an LTP- LTD synaptic plasticity mechanism.
通过研究超声波发声（USV）可以探究大鼠的积极和消极情绪状态。大鼠的积极情绪以50kHz享乐性USV为指标，消极情绪以22kHz厌恶性叫声为指标。我们使用内侧前额叶皮质（MPFC）定量脑电图（qEEG）研究了大鼠情绪状态之间的关系，发现享乐性USV与活跃觉醒qEEG（高α/低δ功率）相关，而厌恶性USV与昏沉觉醒qEEG（低α/高δ）相关。此外，对MPFC进行α频率电刺激会诱发享乐性叫声和奖赏寻求行为，而δ频率刺激则会产生厌恶性叫声和回避行为。负责为USV产生运动输出的脑区，即导水管周围灰质（PAG），显示出一种运动诱发电位，其在时间上与α（享乐性）和δ（厌恶性）运动诱发电位同步。闭环α频率电刺激可以预防δ qEEG和厌恶性USV。在神经元回路水平，α节律与皮质中的突触长期增强（LTP）相关，而δ节律与皮质中的突触去增强（LTD）相关。在药理学水平，NMDAR和生长因子调节这些神经可塑性形式。在单个神经元水平，兴奋性神经元对α频率的反应表现为活动增加，而在δ频率期间活动减少。在人类中，喜悦感会使额部头皮qEEG中的α增加而δ功率降低，悲伤时则出现相反的反应。因此，通过负责情绪表达的神经元回路实现的α/δ振荡同步协调了情绪行为，并且活跃觉醒/积极情绪与昏沉觉醒/消极情绪之间的转换受LTP-LTD突触可塑性机制的控制。
