Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
28 Cards in this Set
- Front
- Back
Temporal Lobe |
– Auditory, speech processing |
|
• White matter: |
Long-range mostly myelinated axons – |
|
• Grey matter: |
Local networks of cell bodies and dendrites |
|
Herscl's Gyrus** |
Individual temporal lobes, with primary auditory cortex shaded. |
|
Phrenology: |
a 19thC pursuit of assigning specific personality traits and functions to specific brain “organs”. |
|
Brain lesions can occur from: |
• Trauma (accidents, etc.) |
|
A “gold standard” for cognitive neuropsychology. |
• Double dissociations help to make a case for specificity |
|
• Broca’s and Wernicke’s areas |
Speech production and perception, respectively. Both in left hemisphere.
*deficits in musical tests after removal of right temporal lobe. |
|
Left-right distinction no longer so clear |
• Music processing not confined to right hemisphere, even for individuals without musical training. |
|
• Patient IR, studied by Peretz and colleagues (Montreal), showed severe music impairments following damage to both temporal lobes and right frontal lobe. |
Results: No effect on verbal abilities, and was still able to distinguish emotional content of music. |
|
• Damage to temporal lobes can affect pitch-contour and/or pitch-interval perception and tune agnosia (inability to name previously familiar tunes). |
• Conversely, left hemisphere damage can affect speech while leaving music unimpaired |
|
Limitations of Lesion-based studies |
By definition, these brains are not normal. Effects of plasticity may have altered the normal place-function relations. |
|
PET – Positron Emission Tomography |
• Measures cerebral blood flow using a (weak) radioactive tracer that is injected into the blood stream. |
|
(+) PET |
• Good spatial resolution |
|
(-) PET |
• Poor temporal resolution • Limit to number of repetitions a subject can do (because of radioactive tracer). |
|
fMRI – Functional Magnetic Resonance |
• Measures blood oxygenation level differences |
|
Pros of fMRI: |
• Less invasive than PET – no radioactive (or other) injection needed. |
|
Cons of fMRI: |
• Very noisy – levels during each scan can exceed 100 dB SPL.
*fMRI can only ever measure differences |
|
Addressing challenges to using fMRI for auditory experiments
Clustered image acquisition: |
A method for removing the impact of scanner acoustic noise on auditory fMRI activation |
|
• Voxel-based Morphometry: |
Assesses anatomical (structural) aspects, using slight differences in magnetic properties of white and grey matter in the brain. |
|
Diffusion Tensor Imaging (DTI): |
Used to identify tracts and connectivity within cortex. Measures direction of water diffusion, taking advantage of the fact that axon bundles, and their myelin sheaths facilitate the diffusion |
|
Resting state fMRI |
Correlations in spontaneous fluctuations suggest functional connectivity. |
|
EEG and MEG |
• Measures of electrical or magnetic fields |
|
Pros of EEG and MEG |
• Excellent temporal resolution (milliseconds). |
|
Cons of EEG and MEG: |
• Poorer spatial resolution. |
|
Recent Trend in Brain Imaging |
Combining spatial resolution of (f)MRI with |
|
EEG |
• Measures summed activity of at least 1,000,000 neurons under each cm2 of scalp. |
|
Auditory evoked potentials (AEPs) |
• “Automatic” responses found in Auditory brainstem response and early-latency |