Brain regions/functions (cerebral cortex)

the outer layer of the brain containing right and left hemispheres

cerebral cortex

four lobes of cerebral cortex

frontal, temporal, parietal, occipital

the frontal lobe contains… (3)

broca’s area

prefrontal cortex (PFC)

primary motor cortex

broca’s area

major language area in the dominant (usually left) frontal lobe

damage to broca’s area causes what?

broca’s aphasia - aka expressive aphasia and nonfluent aphasia

characterized by:

• slow, labored speech that is mostly nouns and verbs

• impaired repetition

• anomia (inability to recall names of familiar object)

comprehension of written/spoken language is still intact

anomia

inability to recall names of familiar objects (often associated with broca’s aphasia)

prefrontal cortex (PFC)

plays an essential role in executive functions (aka higher-order cognitive processes) including planning, decision-making, working memory, prospective memory, social judgment, and self-monitoring

also involved in emotions, motivation, and personality

4 major regions of the PFC

1. dorsolateral prefrontal cortex (DLPFC)

2. ventrolateral prefrontal cortex (VLPFC)

3. ventromedial prefrontal cortex (VMPFC)

4. orbitofrontal cortex (OFC)

dorsolateral prefrontal cortex (DLPFC) (role, damage, disorders)

role: executive functions

damage: impairment in goal-directed behavior, concrete thinking, judgement and insight, working memory, perseverative responses, and disinterest and apathy

disorders: MDD, GAD, OCD, schizophrenia

ventrolateral prefrontal cortex (VLPFC) (role, damage, disorders)

role: goal-directed behavior, decision-making, memory, motor inhibition, emotion regulation

damage: impaired decision-making, behavioral and emotional self-control

disorders: social anxiety disorder, GAD

ventromedial prefrontal cortex (VMPFC) (role, damage, disorders)

role: decision-making, social cognition, memory, emotion regulation

damage: impaired decision-making and moral judgment, lack of insight, confabulation, deficits in social cognition (impaired facial emotion recognition, reduced empathy), and blunted emotional responses

disorders: MDD, OCD, GAD, PTSD, schizophrenia

orbitofrontal cortex (OFC) (role, damage, disorders)

role: emotion regulation, response inhibition, social behaviors
damage: impulsivity, social inappropriateness, lack of empathy, aggressive or abusive behavior, emotion dysregulation

disorders: MDD, bipolar, OCD, PTSD, schizophrenia, SUD

primary motor cortex

• responsible for initiation of purposeful movement and is active not only when people perform movements but also when they imagine performing them or when they watch someone else perform them

• damage: ranges from weakness to paralysis in muscles on the opposite (contralateral) side of the body

temporal lobe contains (2)

auditory cortex and Wernicke’s area

auditory cortex

part of temporal lobe, involved in processing sound

damage to this area can produce auditory agnosia, auditory hallucinations, or cortical deafness

Wernicke’s area

part of temporal lobe

major language area located in the dominant (usually left) hemisphere

damage produces Wernicke’s aphasia (aka receptive aphasia or fluent aphasia)

Wernicke’s aphasia

AKA receptive aphasia and fluent aphasia

impacted comprehension of written and spoken language, impaired repetition, anomia

speech is fluent but contains many word substitutions and other errors and is devoid of meaning

parietal lobe (role)

contains the somatosensory cortex which processes sensory information related to touch, pressure, temperature, pain, and body position.

damage to parietal lobe

somatosensory agnosias:

• tactile agnosia - inability to recognize objects by tough

• asomatognosia - lack of interest in or recognition of part(s) of body

• anosognosia - denial of one’s illness

apraxias (inability to perform purposeful, skilled movements that is not due to motor, sensory, or language impairment):

• limb-kinetic apraxia - inability to make precise, coordinated movements using a finger, hand, arm, or leg

• ideomotor apraxia - inability to imitate a motor activity or perform a motor activity in response to a verbal request (e.g., “pretend to comb your hair”)

• ideational apraxia - inability to plan and execute a task that requires a sequence of actions (e.g., make a sandwhich)

contralateral neglect (AKA unilateral neglect or hemispatial neglect) - usually caused by damage to right (nondominant) parietal lobe and involves neglect of the left side of the body and stimuli on the left side of the body

Gerstmann’s syndrome - caused by damage to the left (dominant) parietal lobe and involves:

• right-left disorientation

• finger agnosia - inability to identify one’s on fingers

• agraphia - loss of writing skills

• acalculia - loss of arithmetic skills

occipital lobe (damage)

• visual agnosia

• visual hallucinations

• achromatopsia - loss of color vision

• cortical blindness - primary visual cortex damaged but eyes and optic nerves are intact

  • can cause blindsight (can’t consciously see but have the appropriate behavioral or physiological response)

• prosopagnosia - inability to recognize faces of familiar people and sometimes one’s own face or faces of pets and other familiar animals

what each side of the brain does (for most people)

for 95% of right-handed people and 50-70% of left-handed people:

• RIGHT - holistic thinking, intuition, spacial relationships, creativity, negative emotions, emotional prosody (expression of emotion through variation in intonation, tone, stress, loudness, rate, and rhythm), and emotional pragmatics (use and understanding of language in different situational and social contexts such as humor and sarcasm), basic sounds of language (babies and ESL learning phonemes)

• LEFT - written and spoken language, logic, analytical thinking, positive emotions

dominant vs nondominant sides of brain

dominant = left for most people

nondominant = right for most people

Generally, the right hemisphere controls the left side of the body and vice versa, with the exception of _____

smell - odors that enter the left nostril are transmitted to the left hemisphere and vice versa

Sperry’s split-brain research

epilsepy treated by severing corpus callosum. then, photo of spoon is shown to:

• right visual field → left (dominant) hemisphere → say they see a spoon and can pick it out (by only touch) with right but not left hand

  • Say only

• left visual field → right (nondominant) hemisphere → can’t say they see it but can pick it out by touch with left but not right hand

  • touch only

assumes the left hemisphere is dominant for language (since this is true for most patients)

dichotic listening task

used to study speech lateralization

present two different words simultaneously, one to right ear and one to left ear. right-handed people will repeat the word presented to their right ear (because that sends the signal to their left auditory cortex)

confirmed language = left hemisphere for most right-handed people

locaion of broca’s area and wernickes area

left frontal lobe

left temporal lobe

(because language is usually in the left hemipshere)

specifically: left inferior frontal gyrus; left superior temporal gyrus