FIG. 9A, both type I and type II mice exhibit reduced weight gain in contrast to their wild-type counterparts, with type I displaying the slowest growth rates (P<0.05).”

1. Three-Chamber Social Test

The foundation of the three-chamber social test lies in the innate sociability of normal mice. When faced with conspecifics, they exhibit a preference for social interaction over isolation. Furthermore, when faced with unfamiliar conspecifics, normal mice have the ability to distinguish them from familiar companions and tend to engage in more interactions with the stranger ones, demonstrating a social novelty response.

As shown in FIG. 10A, the three-chamber test involves dividing three chambers using transparent partitions. A Csf1r^P853T/+ mouse is placed in the central chamber and allowed to acclimate to the environment for 5 minutes.

First Phase: The partition is removed, and a cage containing an unfamiliar C57/BL6 mouse (stranger1) is placed in the left chamber, while an empty cage is placed in the right chamber. A 10-minute timer is started, and the time Csf1r^P853T/+ mouse spends in each chamber (with all four limbs inside as the criteria) is recorded.

Second Phase: The empty cage in the right chamber is replaced with another unfamiliar C57/BL6 mouse (stranger2), and once again, the time and frequency of entry by the Csf1r^P853T/+ mouse into the right chamber are recorded. After testing one mouse, the apparatus is cleaned with 10% alcohol.

The test is repeated three times, and the same test setup is also prepared for C57/BL6 mice as a control.

2. Maze Test

As illustrated in FIG. 11A, a Y-maze is consisted of three arms: the novel arm, the start arm, and the other arm. Novel Arm: The novel arm is blocked off by partitions in the first phase of the test, and is opened in the second phase (i.e., the testing period). Start Arm: The start arm is the arm where the mouse is placed at the beginning of the maze test. Throughout the entire test, both the start arm and the other arm remain open.

First Phase: This is the training period. The novel arm is blocked off with partitions, and the Csf1r^P853T/+ mouse is introduced into the maze from the start arm. The mouse is allowed to freely explore both the start arm and the other arm for 10 minutes. The next phase begins 1 hour later.

Second Phase: This is the testing period. The partition blocking the novel arm is removed, and the Csf1r^P853T/+ mouse is placed in the maze from the start arm. The mouse is given 5 minutes to freely explore all three arms. The time spent in each arm and the number of shuttle movements within the 5-minute period are recorded. Each consecutive entry into all three arms of the Y-maze is counted as one shuttle.

The test is repeated three times, and the same test setup is also prepared for C57/BL6 mice as a control.

3. Nest-Building Test

On the testing day in the evening, clean cotton of the same mass is provided to the Csf1r^P853T/+ mice using sterile forceps. After 24 hours, photographs are taken to record the condition of nest-building, and a scoring system for the nest-building is employed for evaluation, as follows:

- 5 points: Over 90% of the cotton pieces are torn into shreds, forming a complete nest with edges higher than half the height of a curled-up mouse;
- 4 points: Over 90% of the cotton pieces are torn, creating a flat nest with edges not exceeding half the height of a curled-up mouse;
- 3 points: 50%-90% of the cotton pieces are torn, but no nest is formed; cotton pieces are scattered throughout the cage;
- 2 points: 50%-90% of the cotton pieces remain untorn and intact;
- 1 point: Over 90% of the cotton pieces remain untouched and undamaged.

The test is repeated three times, and the same test setup is also prepared for C57/BL6 mice as a control.

4. Prepulse Inhibition Test

As illustrated in FIG. 16A, Csf1r^P853T/+ mice are acclimated for 5 minutes in a testing chamber with a background noise level of 62 dB to reduce interference from background noise. Subsequently, the following prepulse stimuli are administered:

Block 1: Ten shock stimuli at 120 dB.

Block 2 includes the following six modes:

- (1) Background noise at 62 dB only.
- (2) Shock stimulus at 120 dB only.
- (3) Prepulse stimuli at 74 dB, 78 dB, or 86 dB only.
- (4)-(6) Prepulse stimuli at 74 dB, 78 dB, and 86 dB, followed by a 100 ms interval and a 120 dB shock stimulus. A total of 40 shock stimuli are presented to assess the mouse's PPI strength. These six modes are presented in a pseudo-randomized order, ensuring that the prepulse-only mode (Mode (3)) occurs once every 6 trials with intervals of 10-20 seconds between adjacent modes.

Block 3 is similar to Block 1 and serves as an adaptive contrast to analyze whether the mice exhibit adaptation during the test. After collecting the startle response amplitude data, Shanghai Xinruan VisuStartle Startle Reflex Test Software is employed for data processing and analysis. Prepulse Inhibition Efficiency (PPI %) is used to represent the strength of PPI, calculated as follows: PPI %=(startle response amplitude to shock stimulus−startle response amplitude to prepulse combined with shock stimulus)÷startle response amplitude to shock stimulus×100%. The startle response amplitude to shock stimulus is the mean response amplitude induced under shock stimulus conditions in Block 1, while the startle response amplitude to prepulse combined with shock stimulus is the mean response amplitude induced under certain prepulse intensity combined with shock stimulus conditions in Block 2.

The test is repeated three times, and the same test setup is also prepared for C57/BL6 mice as a control.

As shown in FIG. 10B, results from the Three-Chamber Social Test indicate that Csf1r^P853T/+ type I mice spent more time exploring stranger1, but significantly less time exploring stranger2, with the time spent exploring stranger2 being significantly lower than that spent exploring stranger1. Csf1r^P853T/+ type II mice spent significantly less time exploring stranger1 than stranger2. In FIG. 11B, results from the Y-Maze Test demonstrate that both Csf1r^P853T/+ type I and type II mice had significantly reduced instances of correct exploration compared to wild-type C57/BL6 mice. As shown in FIGS. 13A and 13B, results from the Nest-Building Test reveal that Csf1r^P853T/+ type I mice exhibited a significantly reduced nest-building score, while Csf1r^P853T/+ type II mice did not show a significant reduction. In