Repeated mild closed head injury impairs short-term visuospatial memory and complex learning.

Area of Science:

• Neuroscience
• Traumatic Brain Injury Research
• Animal Modeling

Background:

• Concussions can lead to persistent neurocognitive and neurobehavioral issues, particularly with repeated injuries.
• Current understanding of repeated concussion pathophysiology and effective treatments remains limited.
• Developing reliable animal models is crucial for advancing drug discovery for post-concussive symptoms (PCSs).

Purpose of the Study:

• To evaluate if repeated mild closed head injury (mCHI) in mice can replicate the neurocognitive and histopathological outcomes observed in humans after repeated concussions.
• To establish a suitable animal model for preclinical drug discovery and translational research into PCSs.

Main Methods:

• Mice were subjected to daily controlled cortical impact (CCI) for 4 days to induce mCHI.
• Neurological and neurocognitive functions were assessed using tests like beam balance, foot-fault, Morris water maze, context discrimination, and active place avoidance.
• Histopathological analyses included assessment of cerebral perfusion, inflammatory response, and hippocampal neuronal loss.

Main Results:

• Repeated mCHI significantly worsened vestibulomotor, motor, short-term memory, and conflict learning impairments compared to single mCHI.
• Learning and memory deficits persisted for at least 3 months post-injury in mice with repeated mCHI.
• Repeated mCHI led to reduced cerebral perfusion, prolonged inflammation, and, in some cases, hippocampal neuronal loss.

Conclusions:

• Repeated mCHI in mice effectively reproduces key neurocognitive and histopathological deficits associated with repeated concussions in humans.
• This mCHI model serves as a valuable tool for studying the consequences of repetitive head trauma and for facilitating drug discovery for PCSs.