• Part 1 The Big Picture

• Part 2 Know the Tracts

• Part 3 Understand the Terminology

The Big Picture

Neuroscience is unique in that it incorporates an understanding of science on multiple levels, from a molecular understanding of events such as with receptors, at the synaptic level, to a global understanding of the sensory/motor tracts and their spatial interactions. It is by understanding all these concepts that a student can better grasp the clinical presentations of neurological disorders and the theory behind treatment options. The student should thus approach each neuroscience topic from both aspects if applicable. For example, when studying multiple sclerosis (MS), the student should understand that on the molecular level this disease involves destruction of oligodendrocytes, which are responsible for creating and maintaining myelin sheaths around axons of the central nervous system. The student should then review the nodes of Ranvier and concepts pertaining to saltatory conduction. Next, the student should take a step back and look at the condition from a neuroanatomic perspective. For example, if the patient with MS presents with left impaired adduction on right gaze, but has normal convergence, and normal left abduction on left gaze, not only should the student be able to diagnose the patient with a left intranuclear ophthalmoplegia (INO), but should also understand that the lesion is in the left medial longitudinal fasciculus (MLF) and then proceed to review the anatomy of the MLF tract (ie, that the left MLF yokes the left cranial nucleus VI to the right cranial nucleus III). The student should strive for an understanding such that symptoms should make sense rather than rely on blind memorization!

Know the Tracts

There is no way to avoid it; the student has to memorize the various neural tracts (ie, spinothalamic tract, corticospinal tract, etc.) forward and backward. It is easier to first take each tract separately and memorize the exact pathway the neurons in that tract travel throughout the body, noting any decussations or synapses so that the student can determine whether lesions would have ipsilateral (same side as the lesion) or contralateral (opposite side of the lesion) symptoms, or which nuclei are involved. The second step would be to synthesize this information by taking various cross-sections of the nervous system (from the spinal cord to the brain) and being able to identify where each tract is, reviewing at the same time where that tract is coming from upstream and going to downstream. It is important to note that the terms upstream and downstream may be different spatially, depending on the tract referred to. For example, upstream means a cross-section above the one being studied when referring to the corticospinal tract since the tract travels caudally. However, upstream means a cross-section below the one being studied when referring to the spinothalamic tract since this tract travels cranially (from the peripheral inputs to the cortex). The third step involves knowing the cross-sections so thoroughly that the student can draw any cross-section, incorporating all the tracts and nuclei involved in that cross-section. Throughout the studying process, the students should be asking themselves, if there is a lesion in this structure or at this level, what symptoms will be manifested?

Understand the Terminology

Although it takes less effort to memorize medical terminology without understanding the origin of the term, it is much more effective in the long term to understand the reason behind the name of a structure or pathological condition. Going back to our example of MS, the scleroses refers to the plaques or lesions in the white matter, while the term multiple refers to variety in location and time. In other words, in order to diagnose MS, a patient must have at least two anatomically separate lesions occurring at two distinct time periods. Similarly, the student should not just simply memorize structures like the previously mentioned spinothalamic tract and corticospinal tracts. Rather, the student should understand that the spinothalamic tract receives input at the spinal cord level that travels to and synapses in thalamic nuclei. Likewise, the corticospinal tract sends information originating from cells in motor cortex to the spinal cord, which eventually coordinates muscular movement via the lower motor neurons.