Cerebral Cortex 3

Visual-spatial Analysis Regions of cerebrum –Parietal association cortex Junction of P,T, and O lobes Most important –Parietal association cortex Nondominant (R) > Dominant (L)

Parietal Association cortex Analyzing location and movement of visual objects in space

Hemineglect Syndrome Damage to R parietal or frontal cortex –Fig 19.8 (p. 841) Neglect –Worse with acute injury –Recovery can take weeks to months –Some patients will have permanent deficit

Types of Hemineglect Sensory neglect (visual, tactile, auditory) Motor-intentional neglect Combination of sensory and motor neglect Conceptual neglect

Sensory Neglect Ignore visual, auditory or tactile stimuli from contralateral side Tactile > Visual > Auditory Double simultaneous stimulation –Look for extinction –Bilateral –Proximal vs. distal Allesthesia – sensation on R reported as on L

Motor-intentional neglect Decreased spontaneous movement or akinesia Ipsilateral gaze preference toward lesion Motor impersistence, especially of contralateral limbs Allokinesia – moves normal limb when told to move involved limb

Combined Sensory-Motor Neglect Line bisection – to R Cancellation tasks – ignore left side Drawing

Conceptual neglect Anosognosia – lack of awareness of hemineglect –Also seen in: Wernicke’s aphasia Frontal lobe dysfunction Anosodiaphoria –Aware of disability, but no emotional concern or distress Hemiasomatognosia –Deny L body is part of them

Other possible effects of non- dominant side lesions Difficulty in tasks requiring visual/spatial analysis or constructional abilities Can have relatively severe personality and emotional changes

Frontal Cortex Damage can result in an inability to function in the real world Overall functions 1.Restraint – inhibition of inappropriate responses 2.Initiative – motivation to pursue positive activities 3.Order – sequencing tasks

Specific Functions Working Memory Learning New Materials Shifting Cognitive Set Selective Attention Integrate Information from Limbic and heteromodal Association areas in decision making

Prefrontal Cortex AKA Frontal Association area Location: rostral to motor planning areas Connections –Sensory Association Areas –Limbic areas

Prefrontal Cortex Functions –Self-awareness –Motivation –Goal oriented behavior Deciding on a goal Planning how to accomplish goal Executing the plan Monitoring the execution of the plan –Abstract thought –Problem Solving

Injury to Prefrontal Cortex Apathy Loss of goal-directed behaviors –Choosing goals –Planning –Executing plans –Monitoring execution –Behavior may be misinterpreted as uncooperative or unmotivated

Injury to Prefrontal Cortex Difficulties with divergent thinking –Thinking of possibilities rather than choosing the correct answer out of several possibilities Generating word lists –Can do well on standardized tests –Tend to function poorly in daily life

Other effects of frontal lobe lesions Incontinence – more medial frontal regions Inability to suprress inappropriate responses –Go-no-go test Attention impairments

Problems with abstract reasoning –Proverbs –Similarities –Can assess as normal or concrete