The Neural Underpinnings of Waiting
Qiang Zheng, Yujing Liu, Yue Huang, Jiaming Cao, Xuanning Wang, and Jianing Yu
(see article e1820242025)
Waiting is important for action control during motor tasks. Zheng and colleagues explored rat brain regions involved in waiting during a reactive lever release task in this issue. They discovered that neurons in the motor cortex and dorsolateral striatum exhibited similar firing patterns during waiting and responding in the task. However, by using targeted lesions of the motor cortex and dorsolateral striatum to determine how rats behaved in the absence of these brain regions, the researchers found dissociable roles for each brain region. Bilateral lesions of motor cortex prolonged reaction times, while bilateral lesions of dorsolateral striatum increased premature responses and diminished wait time. In another task where rats were trained to hold the lever for a fixed time interval and then release it for a reward, lesions of dorsolateral striatum led to more premature responses, though the movements were made with less vigor. According to the authors, this study provides new insight into the dissociable roles of the motor cortex and dorsolateral striatum in action timing that may be informative for researchers studying motor responses.
Shown is the lesion site in the dorsolateral striatum of a rat. Cyan represents FoxP1 immunofluorescent staining, which labels the striatal projection neurons. See Zheng et al. for more information.
Behavioral Outcomes from Neurofibromin Deficiency
Genesis Omana Suarez, Divya S. Kumar, Hannah Brunner, Anneke Knauss, Jenifer Barrios et al.
(see article e1531242025)
Neurofibromatosis type 1 increases vulnerability to cognitive and behavioral conditions. It is caused by genetic mutations that reduce neurofibromin protein (Nf1) levels, but how Nf1 deficiency affects brain circuits to increase cognitive and behavioral comorbidities is not well understood. Suarez et al. explored this using a Drosophila model of neurofibromatosis type 1. They discovered that loss of Nf1 from sensory neurons or grooming command neurons increased spontaneous grooming of the abdomen, head, and wings. This grooming was state dependent, whereby hungry, foraging flies groomed less than flies that were not hungry. Grooming patterns triggered by a stimulus were also affected, though the frequency of grooming was unchanged. These findings suggest that loss of Nf1 may distinctly influence higher level circuits. Walking was also affected by loss of Nf1. Although flies without Nf1 walked with the same leg kinematics, they moved at a faster velocity. According to the authors, these findings ultimately suggest that Nf1 may not influence low-level motor functions, like coordination, but may regulate patterning and prioritization of behavior by impacting higher level motor circuits.
Footnotes
This Week in The Journal was written by Paige McKeon
