Which layer of the brain membranes is described as the center layer?

The center layer of the brain membranes is known as the arachnoid. It is one of the three layers of membranes, collectively called the meninges, that cover and protect the brain and spinal cord. The arachnoid is situated between the outermost layer, which is the dura mater, and the innermost layer, known as the pia mater. The arachnoid serves as a crucial layer as it contains the subarachnoid space filled with cerebrospinal fluid (CSF), which acts as a cushion for the brain, providing a protective barrier against injury and helping to maintain intracranial pressure.

In contrast, the dura mater is the tough, outermost membrane, providing a durable protective layer, while the pia mater is the delicate innermost layer that closely adheres to the surface of the brain and spinal cord. The cerebellum, mentioned as a choice, is not a layer of membrane but rather a part of the brain responsible for coordination and balance.