temporal lobe function + dysfunctions

the temporal lobe is inferior to the ____ and anterior to the ____

1. Sylvian fissure

2. occipital cortex

functions of the temporal include: (3)

1. auditory + visual perception

2. object recognition

3. long-term memory (medial temporal)

lateral surface of the temporal cortex is divided into: (3)

• superior temporal gyrus

• middle temporal gyrus

• inferior temporal gyrus

visual areas → _____ stream in the ___ part of the temporal cortex

1. ventral

2. inferior part

auditory areas of the lateral surface of the temporal lobe (3)

1. 1º auditory cortex (tonographically organized) → (A1)

2. 2º auditory cortex

3. Wernicke’s area (posterior superior)

Wernicke’s Area responsible for ____

speech comprehension

anterior A1 is for ___ hz and posterior A1 is for ___

1. higher

2. lower

superior temporal sulcus (STS) (3)

• polymodal region

• takes inputs from multiple sensory regions + polymodal regions

  • visual, auditory, somatosensory

temporo-parietal junction (TPJ) responsible for 2:

• attention

• social processing

medial and subcortical areas of the temporal cortex (5)

1. amygdala

2. hippocampus

3. fusiform gyrus

4. insula

5. areas below hippocampus (3)

areas that lie below//wrap around hippocampus (3)

1. parahippocampal cortex

2. entorhinal cortex

3. perirhinal cortex

afferent projections into the temporal come from:

• sensory systems

  • auditory, visual, somatic regions

efferent projections (sends info to) (3):

• frontal + parietal association regions

• limbic system

• basal ganglia

hierarchical sensory pathway (A) (2)

• ends up in temporal pole → most anterior part of temporal

• function: stimulus recognition

dorsal auditory pathway (E) (4)

• ends up in posterior parietal cortex

  • v. similar to dorsal visual pathway

• function: detection of spatial location → movement of sound

  • where in space sound is coming from

polymodal pathway (A) (3)

• function: stimulus categorization

  • visual + auditory input

• ends up in the superior temporal sulcus (STS)

medial temporal projection (A)

• also ends up in medial temporal lobe

• function: learning + LT memory

frontal lobe projection (E)

• ends up in frontal lobe

• function: movement control, working memory, affect

you lose your phone and a friend calls to help find it → what pathway is involved?

dorsal auditory pathway (E)

you are trying to keep up w the lecturer + write notes (remember what they are saying while you write) → what pathway is involved

frontal lobe projection (E)

overview of functions of the lateral regions of the temporal lobe (4)

1. process speech (L hemisphere), music (R) + other auditory stimuli

   1. 1º+2º auditory cortex

2. visual object recognition

   1. 2º visual areas → ventral pathway

3. identification + categorization of stimuli

   1. inferior temporal cortex

4. cross-model matching

   1. STS

overview of medial + subcortical regions functions of the temporal lobe

1. affective response (esp. fear)

   1. amygdala (emotions in general)

2. encoding info. into long-term memory

   1. hippocampus, perirhinal cortex

3. spatial navigation

   1. hippocampus

STS and biological motions

• movement relevant to species

• important for social cognition

in monkeys, ____ cells respond to eye gaze, ______, facial expression

1. STS

2. mouth movement

theory of mind

• attributing intentions/beliefs/desires to ourselves + others

• ie. I won’t talk about a certain thing excessively if I know the person I am talking to doesn’t like that thing

which direction of walking stimulates the STS the most?

• towards you bc more threatening

why are dots used to represent biological motion?

• motion element singled out vs other visual input stimulating other areas

visual precessing areas

• fusiform face area (FFA) → faces

• parahippocampal place area (PPA) → scenes/places

temporal regions for visual processing activate to ____ versus _____ → highlighting ______

1. faces

2. scenes

3. double dissociation

face processing (4)

• selective activation of FFA

  • especially right hemisphere

  • shown in lesion + non-lesion individuals

• distributed network that processes different aspects of face

how does speech differ from other sounds? (4)

• Wernicke’s area → speech comprehension area in left temporal lobe

• restricted range of frequencies tuned to perceive speech frequencies

• same perception despite differing contexts → the ‘T’ in travel, Toronto, tea sound different but are all the letter ‘T’

• speech sounds processed v. rapidly (30 vs 5 segments/s)

four characteristics of music perception

1. loudness

2. timbre

3. pitch

4. rhythm

loudness

magnitude of sensation judged by an individual

timbre

distinctive characteristic of sound

pitch

position of sound in musical scale (prosody/tone in speech)

rhythm

sound duration grouping and temporal regularity (beat)

temporal lobe lesion symptoms (3)

1. attention selection disturbances

2. language comprehension problems

3. disorders of memory

auditory disturbances (3)

1. cortical deafness

2. problems in discriminating speech sounds

   1. Wernicke’s area

3. auditory hallucination → common symptom of schizophrenia

   1. A1, Broca’s area, speech zones in left temporal cortex, hippocampus, amygdala

music perception disorders (3)

1. pitch discrimination → right posterior STG

2. meter discrimination → right/left anterior STG

3. amusia: tone deafness → inability to produce/comprehend musical sounds

   1. music as pots and pans

imparements in visual perception (3)

• impaired:

  • object + complex pattern recognition

  • biological motion recognition → STS

• abnormal face perception → right temporal lobe (FFA)

  • prosopagnosia

altered personality + affect (6)

• disrupted fear response → amygdala lesion

• temporal lobe “personality”

  • egocentricity

  • perseveration

  • paranoia

  • proneness to aggression

evidence from lesion + stimulation studies

association btw sensory input + emotion

Klüver Bucy Syndrome

• damage to bilateral amygdala + inferior temporal lobe

  • hyperphagia: strong sensation of hunger/desire to eat

  • hypersexuality: abnormal preoccupation w sexual fantasy

  • hyperorality: excessive oral activities

  • visual agnosia

  • loss of normal fear/anger responses

  • memory loss

Temporal lobe epilepsy

• epileptic source is the temporal lobe

• treatment: medication → or surgery

what does surgical removal of selective regions in temporal lobe say about temporal lobe function? (3)

1. left temporal lobectomy led to greater loss in verbal memory

2. nonverbal memory loss is comparable btw left/right temporal lobectomies

3. medial temporal lobe lesion led to impaired precision in spatial navigation towards targets in a virtual navigation task