functional neuroanatomy bradd@nmr.mgh.harvard.edu attention language knowledge imagery memory...

Functional neuroanatomy

bradd@nmr.mgh.harvard.edu

• Attention• Language• Knowledge• Imagery• Memory

– States ‘of mind’ (and body)– Adaptation/plasticity– Language; visual processing; mental imagery

• How our brains integrate types of information to develop concepts; how previous experience affects processing of new information

What are we doing with our brains at this moment?

(The student’s brain)

• Feeling your chair

• Squirming (moving)

• Watching

• Listening

• Remembering

• Paying attention

• Sleeping

• Feeling anxious

• Feeling hungry

• What happens when you ask a question?

• Learning

5 types of cortical tissue

Localization of function in the nervous system: Functional networks

5 major brain systems subserving

cognition and behaviorLeft perisylvian language networkParieto-frontal network for spatial attentionOccipitotemporal network for object/face recognitionMedial temporal/limbic network for learning & memoryPrefrontal network for attention & comportment

Knowledge: The convergence of language, perception, and memory

Language & naming

Visual systems & category-specific processing

Imagery/sensory memory

Knowledge: The convergence of language, perception, and memory

Language & naming

Visual systems & category-specific processing

Imagery/sensory memory

Lesion studies of the language network:The major nodes

Broca’s (production) Wernicke’s (comprehension)

Lesion studies of the language network:Disconnection syndromes

Alexia without agraphia

Geschwind N & Kaplan E, Neurology, 1962

Functional neuroimaging of the language network

One to many, many to oneCJ Price, J Anat 2002

Language function: Using neuroimaging to test hypotheses

CJ Price, J Anat 2002

What’s in a name?A means to access specific types of

knowledge

What’s in a name?A means to access specific types of

knowledge

Elephant

Linguistic access to specific types of knowledge

Damasio H, Nature 1996

Knowledge: The convergence of language, perception, and memory

Language & naming

Visual systems & category-specific processing

Imagery/sensory memory

Visual processing: Two pathwaysDorsal (Occipito-parietal): Object & object feature recognition

Disorders:

visual object agnosia

prosopagnosia

achromatopsia

Ventral (Occipito-temporal): Visual recognition of spatial location

Disorders: optic ataxia, ocular apraxia, simultanagnosia (Balint’s); constructional apraxia, akinotopsia

Visual processing streams: Confirmation of hypotheses using neuroimaging

Ungerleider LG, PNAS 1998

Visual processing: Attention influences which stream is used

Ungerleider LG, PNAS 1998

Visual object recognition: Lesion studies

Agnosias may be specific to certain categories of information

Visual object recognition: Distinct but overlapping functional areas

Haxby JV, Science 2001

Visual object recognition: Faces & places

Kanwisher N, Science, 2006

Visual object recognition: Faces

Tsao

Knowledge: The convergence of language, perception, and memory

Language & naming

Visual systems & category-specific processing

Imagery/sensory memory

Visual perception & imagery

Ganis G, Cog Brain Res 2004

Auditory imagery

Kosslyn SM, Nat Rev Nsci 2001

Motor imagery

Kosslyn SM, Nat Rev Nsci 2001

Naming vs. recognition: Networks for conceptual knowledge

Name this animal and tell me what you know about it

Naming vs. recognition: Networks for conceptual knowledge

Name this person and tell me what you know about him

Naming vs. recognition: Networks for conceptual knowledge

Damasio H, Cognition 2004

Object-specific naming deficits Object-specific recognition deficits

Encoding & recall of category-specific information

Encoding of category-specific information activates relevant areas of cortex

Polyn SM et al., Science, 2005

Faces: Fusiform gyrus Places: Parahippocampal gyrus

Encoding & recall of category-specific information

Reactivation of category-specific areas occurs prior to verbal recall Polyn SM et al., Science, 2005

Plasticity in heteromodal cortical regions: The basis for learning

Recovery of language function after stroke: Mapping plasticity in the human brain

Fernandez B, Stroke 2004

1 year after stroke

1 month after stroke

Plasticity: Many levels of scale in both time & space

Attention, arousal, awareness

•Focused attention & visuospatial attention

•Arousal

•Coma

•Persistent vegetative state

•Sleep

•Conscious awareness

Attention

Attention: Trinodal cortical network

Mesulam MM, Phil Trans R Soc London, 1999

Hypothesized from patients & animals with lesions

Attention: Trinodal cortical network

Gitelman DR et al., Ann Neurol 1996;39:174-9Gitelman DR et al., Brain 1999;122:1093-1106

Confirmed with functional neuroimaging (fMRI & PET)

Attention

Mesulam MM, Phil Trans R Soc London, 1999

State vs channel functions

StatesSleep/arousalNeeds (e.g., hunger)Mood

Channels

The limbic system directs heteromodal cortex toward relevant information

LaBar KS, Behavioral Neuroscience 2001

Neurotransmitter systems

Neurotransmitter systems

Genetic variations in neurotransmitter substrates

Enzymes, receptors, etc (e.g., Weinberger DR)

Pharmacologic fMRI

e.g., dopaminergic modulation of attention

PET imaging of receptors & enzymes

Sleep/Anatomy

ARAS & thalamus

Sleep/EEG

Sleep/EEG

Conscious awareness:Default mode

Raichle M, et al.,

Conscious awareness:Persistent vegetative state

Owen A, et al., Science, 2006

What are we doing with our brains at this moment?

(The student’s brain)

• Feeling your chair

• Squirming (moving)

• Watching

• Listening

• Remembering

• Paying attention

• Sleeping

• Feeling anxious

• Feeling hungry

• What happens when you ask a question?

• Learning