Temporal Lobe questions
I. Visual Processing & Face Recognition
1. In which half of the visual field do humans have a perceptual bias for face processing?
• Answer: Humans have a perceptual bias for the left visual field (which is processed by the Right Hemisphere).
• Scientific Explanation: While both hemispheres can process faces, the Right Hemisphere contains more specialized "hardware" (like the Fusiform Face Area) for holistic, invariant face recognition. Because the visual system is cross-wired, the left half of what you see goes to the right brain. This is why we often focus more on the right side of a person's face (from our perspective, their right) to determine identity and emotion.
2. Correct or incorrect: Damage to the left temporal lobe causes bilateral visual processing deficits when two stimuli are presented in both visual fields simultaneously?
• Answer: Incorrect.
regarding visual processing RH lesions produce bilateral
deficit, LH lesions contralateral deficit in dichotic listening
• Scientific Explanation: Damage to the Right Temporal Lobe is much more likely to cause a deficit known as Extinction or Contralateral Neglect. In this case, if two stimuli are shown at once, the patient will ignore the one in the left visual field. Left temporal damage generally affects language-related visual tasks (like reading words) rather than basic bilateral visual awareness.
II. Auditory Processing: Music & Pitch
3. Which are the three variables in which music can differ?
• Answer: Loudness, Timbre, and Pitch.
• Scientific Explanation: * Loudness: Related to the amplitude of the sound wave.
• Timbre: The "texture" of a sound (e.g., the difference between a piano and a flute playing the same note), determined by the spectral profile.
• Pitch: The psychological perception of a frequency's "height" on a musical scale.Pitch is the quality of sound that allows us to play musical melodies. Pitch is related (but not equal to) frequency, it refers to the position of sound in a musical scale
4. What is a missing fundamental stimulus, and how do people differ in their perception of tones?
• Answer: A missing fundamental is a complex tone where the lowest frequency (the root note or f_0) is removed, leaving only the overtones (harmonics).
• Scientific Explanation: The brain usually "fills in" the missing base note. However, the Schneider study showed that Fundamental Listeners (mostly non-musicians) hear the perceived pitch go down by focusing on the missing root, while Spectral Listeners (mostly musicians) hear the pitch go up because they are more sensitive to the higher-frequency harmonics.
5. Describe the location and function of Heschl’s gyri, as well the effect of lateralization of gray matter volume on auditory perception (Schneider study).
• Answer: Located in the Primary Auditory Cortex (A1) within the Lateral Fissure.
• Scientific Explanation: Heschl’s gyri are the first cortical stop for auditory input. The Schneider study found that musicians have significantly larger gray matter volume here. Left-side volume relates to Temporal (timing/speech) processing, while Right-side volume relates to Spectral (pitch/music) processing.
III. Language & Hemispheric Specialization
6. Where is the mechanism for speech perception thought to be localized?
• Answer: Primarily in the Anterior Left Superior Temporal Sulcus (STS) and Wernicke’s Area.
• Scientific Explanation: Research (like the Scott et al. study) shows that while both ears hear noise, only the left STS "lights up" when the sound contains intelligible speech. The Left Hemisphere is specialized for the rapid temporal changes required to decode phonemes and syntax.
7. Patients with damage to which hemisphere have the worst performance on a dichotic listening task, and why?
• Answer: Left Hemisphere.
• Scientific Explanation: In a dichotic listening task, different words are played into each ear at once. Since the Left Temporal Lobe is the "Language Specialist," damage there makes it impossible for the brain to resolve the competition between the two verbal signals, leading to massive drops in word recall.
8. What kind of damage causes cortical deafness?
• Answer: Bilateral damage to the Wernicke’s aphasia (disturbed word recognition, word deafness)
• Scientific Explanation: If both sides of the auditory cortex are destroyed, the person is functionally deaf even if their ears and auditory nerves are perfectly healthy. The "signal" reaches the brain, but there is no "processor" to let the person consciously hear it.
IV. Localized Lesions & Deficits
9. Damage to which specific areas results in these deficits?
• Deficits in auditory sensation/perception: Heschl’s Gyrus (A1).
• Wernicke’s aphasia: Left Posterior Superior Temporal Gyrus.
• Difficulty with musical rhythm and meter: Right Temporal Lobe (specifically for meter/melody).pitch discrimination impairment after RH lesion in AC - anterior RH STG lesions meter discrimination impairment - posterior RH STG lesions rhythm discrimination impairment - Congenital amusia (tone deaf or beat deaf)
• Problems interpreting cartoons or social signals: Superior Temporal Sulcus (STS) (the "Social Brain" hub).
impaired interpretation despite correct
description of cartoon drawings (RH) - impaired detection of object in complex figures - impaired processing, recognition and recall of faces (RH) - impairment in perceiving subtle social signals
• Deficits in selective attention (Auditory): Superior Temporal Gyrus.
impaired recognition of words in dichotic listening task
(LH) - regarding visual processing RH lesions produce bilateral
deficit, LH lesions contralateral deficit in dichotic listening
• Impaired categorization: Inferior Temporal Cortex (loss of the "mental filing system").
• Deficits in conscious recall of information: Medial Temporal Lobe (Hippocampus/Amygdala).
V. Biological Basis of Music
10. List three lines of evidence supporting a biological basis of music perception in the brain.
1. Specialized Neural Hardware: The Right Temporal Lobe is uniquely tuned for spectral processing (harmonics), separate from speech hardware.
2. Clinical Dissociation: Patients can have Amusia (can't hear music) but still speak perfectly, proving the brain treats music as a distinct biological category.
3. Neuroplasticity: The physical expansion of Heschl’s Gyrus in musicians proves the brain has an innate "music center" that grows with use.
11. Describe deficits that occur mainly in unilateral left vs. right temporal damage.
• Left Damage: Results in Verbal deficits (impaired speech comprehension, loss of verbal memory, difficulty with rapid sounds).
• Right Damage: Results in Non-Verbal deficits (difficulty recognizing faces, loss of music appreciation, inability to read social body language or "biological motion").