Neuroanatomy and Functions of the Temporal and Parietal Lobes

Superior temporal gyrus (STG)

Processes auditory information.

Middle & inferior temporal gyri

Associated with visual object recognition.

Superior temporal sulcus (STS)

Polymodal area; integrates multiple sensory modalities.

Lateral fissure (Sylvian)

Separates the temporal lobe from the frontal and parietal lobes.

Auditory object specification pathway

Primary/secondary auditory regions → lateral temporal cortex → temporal pole.

Visual object specification pathway

Primary/secondary visual regions → inferior temporal gyrus → temporal pole.

Dorsal auditory pathway function

Sound localization; spatial awareness; coordinates movement relative to sound.

Polymodal area location

Superior temporal sulcus (STS).

Perforant pathway function

Memory formation, recognition.

Temporal cortex connection with frontal lobes

Posterior temporal → dorsolateral prefrontal cortex; Anterior temporal → orbitofrontal cortex.

Theory of object perception

Processes object perception, biological motion, face recognition; involves grouping elements, matching with stored 3D structures, and assigns meaning.

Evidence against progressive focus

Object recognition can occur without the occipital cortex, supporting parallel processing instead of strict progressive focus.

Sparse coding

Few neurons respond to specific stimuli (e.g., 'grandmother cells').

Population coding

Many neurons together encode an object.

Evidence for object-specific cells

Specific neurons respond to complex stimuli.

Problems with object-specific neurons

Fragility if neurons die, limited ability to recognize novel or altered objects.

View-dependent shape perception

Some perspectives may be harder to identify.

View-invariant shape perception

You group elements to identify the object regardless of perspective.

Agnosia

Failure to know, recognize.

Apperceptive agnosia

No recognition of objects; damage in occipital.

Associative agnosia

Can perceive objects but can't identify them; damage in temporal lobe.

Biological motion perception

Perception of motion from biological entities.

Region involved in biological motion perception

Superior temporal sulcus (STS).

Role of biological motion perception

Basis for social perception and cognition; recognizes subtle social signals.

Fusiform face area (FFA)

Facial recognition.

Superior temporal sulcus (STS)

Processes facial expressions, gaze direction.

Striate cortex (V1)

Initial processing of visual input, including faces.

Prosopagnosia

Inability to recognize faces.

Congenital prosopagnosia

Present from birth.

Acquired prosopagnosia

Due to brain damage.

Conductive hearing disorders

Blockages/damage to the outer, eardrums, ear bones in middle ear.

Sensorineural hearing disorders

Dysfunction of inner ear (cochlea), auditory nerve or higher auditory processing centers.

Tubes in ears

Drain fluid from middle ear, preventing infections, improving hearing.

Causes of sensorineural hearing disorders

Exposure to loud music, scarlet fever, physical trauma, strokes affecting 8th cranial nerve.

Cochlear implants

Bypass the damaged part of the ear, stimulating the auditory nerve (8th cranial nerve).

Requirement for cochlear implant

The auditory nerve (8th cranial nerve) must be intact to transmit electrical signals to the brain.

Result of bilateral lesions of the primary auditory cortex

Doesn't lead to cortical deafness.

Auditory hallucinations

False perceptions of sounds, hear whole sentences.

Disorder with auditory hallucinations

Common in schizophrenia.

Cause of auditory hallucinations

Increased activity in the auditory cortex interacts with language areas in temporal lobe and limbic area.

Difference in emotional valence of auditory hallucinations

Those who have schizophrenia experience different emotional valence compared to those who don't.

Two kinds of auditory processing

Rapidly presented stimuli and complex patterns of stimuli.

Characteristics of speech

3 restricted ranges of frequencies and context-dependent sounds.

Achievement of auditory system categorizing sounds

Allows perception of same sound regardless of changes in context.

Symptoms of left auditory cortex damage

Discriminating sounds, complain people are talking too fast, trouble judging temporal sequence of sounds.

Symptoms of right auditory cortex damage

Difficulty understanding emotional tone of speech.

Main characteristics of music perceived

Musical sounds: loudness, pitch, timbre; Timing in music: Rhythm- L, Meter- R; Melody.

Impaired music perception

Left Hemisphere concerned with speed and grouping (rhythm), Right Hemisphere frequency differences (pitch discrimination).

Amusia

Pitch discrimination impairment.

Temporal lobe damage effect

Impaired selection in auditory perception.

Dichotic listening task

A task where normally more words from the right ear are recalled due to left temporal lobe dominance.

MPAT test

McGill Picture Anomalies Test used to assess right temporal lobe damage.

Contextual information

Helps in interpreting ambiguous situations; for example, recognizing a familiar face in context.

Temporal lobe damage and context

People may struggle to interpret or remember things without contextual cues.

Medial temporal lobe damage effect

Impairment in long-term memory.

Left temporal lobe function

More involved in language and temporal sequence processing.

Right temporal lobe function

Involved in emotional interpretation and pitch discrimination.

Temporal lobe epilepsy personality changes

Changes such as aggressiveness, self-focus, and paranoia, referred to as 'temporal lobe personality.'

Interoception

Perception of internal body states (e.g., hunger, pain, or internal organ function).

Exteroception

Perception of external stimuli from the environment (e.g., touch, temperature).

Somatosensation submodalities

Nociception (pain and temperature), Hapsis (fine touch and pressure), Proprioception (limb position and movement), Balance (body orientation and equilibrium).

Nociceptors

Receptors for pain and temperature.

Hapsis receptors

Fine touch and pressure receptors.

Proprioceptive receptors

Muscle spindles (detect muscle stretch), Golgi tendon organs (detect tension in tendons), Joint receptors (detect movement and position of joints).

Spinothalamic tract submodalities

Carries pain and temperature.

Spinothalamic tract pathway

Runs from the spinal cord to the thalamus, crosses (decussates) at the level of entry into the spinal cord, terminates in the ventral posterior inferior (VPI) nucleus of the thalamus.

Dorsal column medial lemniscal pathway submodalities

Carries touch and proprioception.

Dorsal column medial lemniscal pathway pathway

Runs through the spinal cord to the medulla, crosses (decussates) in the medulla, terminates in the ventral posterior nucleus (VPN) of the thalamus.

Vestibular system subparts

Otolith organs (saccule and utricle) respond to head tilt and linear acceleration; Semicircular canals respond to rotational head movements.

Semicircular canals

Structures filled with a jellylike substance that help detect rotational movements.

Vestibulocochlear nerve (CN VIII)

Cranial nerve that deals with information from the vestibular system.

Purposes of vestibular information

Maintaining balance and posture, coordinating eye movements with head movements, and providing spatial orientation.

Proprioception and Hapsis

Information that goes to the ventral posterior nucleus (VPN) of the thalamus.

Vestibular Information

Relayed to the ventral posterior inferior (VPI) nucleus of the thalamus.

Somatosensory Mapping

The organization of sensory input on the somatosensory cortex, where different body parts correspond to specific cortical areas.

Homunculus Representation

Distorted representation on the somatosensory cortex with larger cortical representation for body parts requiring finer sensory discrimination.

Multiple representations of the body

Different parts of the somatosensory cortex represent overlapping but distinct maps of the body based on specific sensory modalities.

Anterior Parietal Area

Includes the postcentral gyrus (Brodmann 1, 2, 3) and parietal operculum (Brodmann 43), processing sensory information.

Superior Parietal Lobule

Brodmann areas 5 & 7, providing sensory feedback to guide limb movement.

Inferior Parietal Lobe

Includes supramarginal gyrus (Brodmann 40) and angular gyrus (Brodmann 39), integrating sensory inputs for spatial tasks.

Intraparietal Sulcus

Divides superior and inferior parietal lobes, coordinating sensory information for actions like grasping objects.

Precentral Gyrus

Located in the frontal lobe; controls voluntary movement.

Postcentral Gyrus

In the parietal lobe (Brodmann 1, 2, 3), processes sensory input from the body.

Supramarginal gyrus

Involved in spatial awareness and language processing.

Angular gyrus

Associated with mathematical ability, language, and spatial cognition.

Superior Posterior Parietal Lobe

Guides movements by integrating sensory information about limb position and motion.

Inferior Posterior Parietal Lobe

Supports spatially guided actions, combining sensory data from various modalities.

Intermodal integration

Combines sensory data from vision, touch, hearing, and other modalities.

Route-based navigation

Uses sequences of actions or landmarks for navigation.

Map-based navigation

Uses a mental representation of the environment for flexible movement.

Parahippocampal place area (PPA)

Processes landmarks in the environment.

Retrosplenial cortex (RSC)

Connects landmarks with broader spatial orientation.

Medial temporal lobe (MTL)

Develops map-like representations of environments.

Intermodal integration

Combines vision, touch, and hearing for spatial understanding.

Spatially guided actions

Helps with tool use and navigation by processing spatial relationships.

Spatial reasoning

Involves understanding numbers on a number line.

Attentional processes

Four types include alertness and arousal, vigilance & sustained attention, selective attention, and attentional control.

Alertness and arousal

Involves the ascending reticular activating system.

Vigilance & sustained attention

Involves the basal forebrain and right hemisphere.

Selective attention

Involves the superior colliculus for automatic orienting and the parietal lobe.