There's more than one way to scan a cat: imaging cat auditory cortex with high-field fMRI using continuous or sparse...

Area of Science:

• Neuroscience
• Auditory Neuroscience
• Neuroimaging

Background:

• Functional magnetic resonance imaging (fMRI) auditory investigations face confounds from scanner noise.
• Continuous fMRI acquisition produces high sound levels (>90 dB), potentially masking auditory stimuli and evoked neural activity.
• Sparse scanning offers a brief quiet period for stimulus presentation, minimizing scanner noise interference.

Purpose of the Study:

• To compare sparse and continuous fMRI scanning methods.
• To determine the optimal fMRI approach for investigating acoustically evoked activity in the cat's auditory cortex, thalamus, and midbrain.

Main Methods:

• Utilized a 7 Tesla magnet for fMRI acquisition in cats.
• Presented broadband noise, 10 kHz tones, and 0.5 kHz tones using a block design.
• Compared activation patterns between continuous and sparse scanning sequences.

Main Results:

• Continuous scanning yielded larger activation clusters and more peak voxels in the auditory cortex.
• No significant thalamic activation was detected with either method.
• Both continuous and sparse scanning showed no significant difference in midbrain structure activation.
• Auditory cortex activations were consistently higher in magnitude than midbrain activations.

Conclusions:

• Continuous scanning is the preferred fMRI method for studying auditory cortex activity in cats.
• The choice of fMRI scanning method for midbrain investigations should consider other factors like stimulus intensity and task performance.