Neuroanatomy Functional circuits in the brain

Contralateral – opposite side Ipsilateral – same side Two Hemispheres Contralateral – opposite side Ipsilateral – same side

Contralateral connections with the visual cortex Ipsilateral connections to the olfactory bulbs Optic Chiasm Contralateral connections with the visual cortex

Diencephalon Thalamus

Thalamus The gateway of all senses (except smell)

GATE Thalamus Lateral Geniculate Nucleus – LGN - Visual Medial Geniculate Nucleus – MGN - Auditory Ventral Geniculate Nucleus – Somatosensory GATE Selective attention Sleep

03-18 Primary secondary W. W. Norton

Primary visual cortex Primary auditory cortex Primary somatosensory cortex Primary motor cortex

05-07 Primary Visual Cortex Calcarine sulcus Retinotopic W. W. Norton

Primary Auditory Cortex Heschl's gyrus (transverse temporal gyrus) Tonotopic

Somatosensory cortex (pre and post central gyrus)

p.65

Homunculus Homunculus

Premotor Cortex (“secondary” motor cortex) Lateral Planning/Intention to move to external cue. Cells fire before movement starts Medial Intention to move based on Internal cues

03-18 Association Areas W. W. Norton

Two Hemispheres Contralateral – opposite side Ipsilateral – same side Left Hemisphere – Input from the right side Right Hemisphere – Input from the left side Contralateral – opposite side Ipsilateral – same side

Two Hemispheres symmetric? Small anatomical asymmetries

Functional Asymmetries Handedness (motor)

Hemispheric Asymmetries Handedness (motor) Language

09-24b Language Inferior prefrontal cortex W. W. Norton

Broca’s Area

Language areas In the left hemisphere 09-25 Language areas In the left hemisphere W. W. Norton

But prosody (happy vs sad voice) In the right hemisphere 10-20 Dichotic Listening Task But prosody (happy vs sad voice) In the right hemisphere

10-21

Hemispheric Asymmetries Handedness (motor) Language Visual-spatial

Global vs local Visual Perception 10-19 Global vs local Visual Perception

Global vs local Visual Perception 10-19 Global vs local Visual Perception

Corpus Callosum connects the two hemispheres

Split Brain Syndrome Visual system Contralateral Roger Sperry Nobel 1981

Split Brain Syndrome Roger Sperry Nobel 1981 Left hemisphere – is the talking hemisphere

Superior parietal cortex Allocation of visual attention Unilateral parietal damage Neglect

Unilateral parietal damage Neglect W. W. Norton

Standard assessment of unilateral neglect 1. Line cancellation task 2. Line bisection task 3. Object drawings

Limbic System Limbic Cortex Hippocampus Amygdala Mammillary Bodies Fornix

Limbic System

Amygdala Fear Conditioning Light + Shock Light only Damage to the amygdala – no fear conditioning

Fear Conditioning in humans + shock Amygdala Important for emotional learning Not emotional response per se Is it only for fear?

Patients with Amygdala damage Impaired perception of fear

also if subliminal Strong Amygdala activation to fearful faces fMRI – amygdala activation

Limbic System

Hippocampus Memory

Patient H.M Hippocampus Surgically removed Anterograde Amnesia (some retrograde too) episodic memories

08-40 W. W. Norton

Hippocampus Memory Episodic memory Consolidation Association

Amygdala damage – no fear conditioning but intact episodic memory 13-13 Dissociation between Amygdala and hippocampus Amygdala damage – no fear conditioning but intact episodic memory Hippocampus damage – normal fear conditioning but no episodic memory of the event W. W. Norton

Hippocampus Volume Alzheimer’s disease

Hippocampus of London taxi drivers Posterior hippocampus – important for navigation