Cognitive Neuroscience Exam 2 Review: Movement Disorders, Spatial Attention, and Frontal Lobe Functions

Comprehensive vocabulary flashcards covering Exam 2 lecture topics in cognitive neuroscience: movement disorders, apraxia, motor control loops, visual-spatial attention networks, Bálint's syndrome, neglect syndrome, and frontal lobe executive function.

Ideomotor Apraxia

A motor disorder characterized by difficulty selecting, sequencing, and spatially orienting movements, typically observed on the non-paralyzed, non-dominant side of hemiplegic patients with left hemisphere lesions.

Gradient of Impairment in Apraxia

The clinical progression of apraxic difficulty, which is most severe for pantomime ("Show me how…"), moderate for imitation ("Watch how I…"), and least impaired for direct object use ("Here is a…, show me how…").

Transitive vs. Intransitive Movements

Two diagnostic movement categories used to clinically assess apraxia: transitive movements do not require an imaginary prop (e.g., waving, saluting), whereas intransitive movements require pantomiming tool manipulation with an imaginary prop (e.g., unlocking a door with a key, blowing out a match).

Liepmann and Maas (1907) Disconnection Theory

The proposal that skilled motor engrams are dominantly stored in the left hemisphere, causing lesions of the corpus callosum to isolate the right hemisphere motor cortex and result in apraxia of the left hand.

Geschwind's Language Mechanism Hypothesis (1962)

The hypothesis attributing apraxia to a disconnection between Wernicke's language area in the left hemisphere and right hemisphere motor cortex via damage to the anterior four-fifths of the corpus callosum; later contested by evidence that apraxic patients also fail imitation tasks.

Heilman et al. (1982) Parietal Engram Hypothesis

The finding that a left-handed patient with premotor/motor injury suffered left hemiplegia and apraxia despite intact language, demonstrating that apraxia stems from disruption of motor engrams stored in the parietal lobe of the motor-dominant hemisphere.

Chao and Martin (2000)

A neuroimaging investigation showing preferential activation spikes in the supramarginal gyrus (SMG) and angular gyrus (AG) when subjects view tools compared to animals or faces, confirming the parietal localization of motor engrams.

Stages of Skill Acquisition

The three-stage model of motor learning: the Cognitive phase (closed-loop, strategy formulation, verbalized components), the Associative phase (closed-loop, component assembly, critical feedback), and the Autonomous phase (open-loop, automatization, simulated internal feedback).

Closed-Loop vs. Open-Loop Motor Control

Closed-loop control is slow, attentional, and dependent on ongoing sensory feedback to correct errors, whereas open-loop control is fast, automatic, and executes pre-programmed actions relying on internal simulated predictions.

Motor Engrams vs. Motor Programs

Motor engrams are early, conscious movement templates supported by the parietal cortex, whereas motor programs are late, complex, automatic action sequences executed without conscious feedback by the basal ganglia.

Contention Scheduling System

An automatic, horizontal selection network that coordinates competition among routine motor schemas triggered directly by perceptual cues without requiring executive intervention.

Supervisory Attentional System (SAS)

A vertical, top-down cognitive control mechanism linked to the frontal lobes that modulates contention scheduling when routine actions fail or when tasks demand planning, novelty handling, or response inhibition.

Neostriatum

A primary component of the basal ganglia motor circuit composed of the caudate nucleus and putamen; it serves as the neural substrate for contention scheduling and motor program execution.

Huntington's Disease (HD)

An inherited autosomal dominant neurodegenerative disease characterized by $80\text{--}90\%$ neuronal loss in the neostriatum, choreiform movements, progressive dementia, and an inability to acquire or automate new motor programs.

Pursuit Tracking Task (Huntington's Disease)

A visual-motor learning test in which healthy controls, amnesic patients, and Alzheimer's patients steadily improve time on target across blocks, while patients with Huntington's disease fail to show learning or motor program automation.

Parkinson's Disease (PD)

A movement disorder caused by the loss of dopaminergic neurons in the substantia nigra, resulting in basal ganglia circuit dysregulation and the clinical motor triad of resting tremors, rigidity, and bradykinesia.

Kinesia Paradoxica

The clinical phenomenon in Parkinson's disease where unmedicated patients experiencing severe immobility or freezing can suddenly execute fluid, complex movements in response to urgent or novel stimuli, bypassing damaged basal ganglia circuits.

Double Dissociation of Movement Disorders

The neurological dissociation where cortical (parietal) lesions produce apraxia by disrupting early motor engrams while leaving motor programs intact, whereas subcortical (basal ganglia) lesions produce Parkinson's or Huntington's disease by disrupting late motor programs while leaving motor engrams intact.

Early vs. Late Selection Models of Attention

Early selection models propose that sensory stimuli are selectively filtered before reaching semantic evaluation, whereas late selection models posit that all inputs are analyzed for semantic meaning prior to selection for awareness.

Pop-Out Search vs. Conjunction Search

Pop-out visual search is a parallel, pre-attentive process where target detection time is independent of set size, whereas conjunction search is a serial process requiring attention to bind multiple visual features, causing reaction time to increase with set size.

Re-entrant Feedback

The neural signaling process wherein the parietal cortex integrates spatial coordinates with ventral sensory representations (such as color, motion, and shape) to bind discrete visual features at a specific attended location.

Ventral vs. Dorsal Visual Streams

The ventral stream ("What" pathway) projects to the inferior temporal cortex for object recognition and fine feature processing, while the dorsal stream ("Where/How" pathway) projects to the parietal cortex for spatial processing and guiding motor action.

Mishkin et al. (1983) Lesion Study

A landmark non-human primate study establishing a double dissociation: ventral stream lesions cause deficits in object discrimination but spare landmark discrimination, whereas dorsal stream lesions cause deficits in landmark discrimination but spare object discrimination.

Bálint's Syndrome

A severe neuro-ophthalmological disorder caused by bilateral posterior parietal damage (often secondary to posterior cerebral artery watershed strokes), characterized by the diagnostic triad of simultanagnosia, optic ataxia, and ocular apraxia.

Simultanagnosia

A visual-spatial attention impairment defined by the inability to perceive more than one object or visual element at a time; shifting focus to a new stimulus extinguishes awareness of the previous one.

Optic Ataxia

A visuo-motor disorder resulting from damage to the dorsal visual stream, causing directional and orientation errors when reaching or grasping for visual objects despite intact visual recognition and motor strength.

Ocular Apraxia

An impairment in voluntary eye movement control characterized by chaotic, non-selective saccades and "sticky fixation," which prevents patients from intentionally disengaging their gaze from a fixated object.

Patient DF vs. Patient RV Double Dissociation

The clinical dissociation demonstrating that Patient DF (ventral visual form agnosia) showed preserved visuomotor grasp calibration despite impaired manual width estimation, while Patient RV (dorsal optic ataxia) showed preserved manual estimation despite impaired grasp calibration.

Illusory Conjunctions (Patient RM)

The perceptual phenomenon observed in Patient RM following bilateral parieto-occipital damage, where the absence of spatial attention causes separate visual features (e.g., color and letter shape) to bind incorrectly into illusory objects.

Hemispatial Neglect

A neuropsychological syndrome caused by unilateral parietal damage (predominantly in the right hemisphere) characterized by the failure to orient toward, explore, or report stimuli presented in the contralateral hemispace.

Extinction to Simultaneous Stimuli

A sensory manifestation of neglect in which a patient reliably detects a solitary stimulus presented to the contralesional visual field, but fails to perceive it when identical stimuli are presented concurrently to both hemifields.

Burning House Experiment (Marshall & Halligan, 1988)

A classic experiment showing that a left neglect patient perceived two houses as identical despite flames billowing on the left of one house, yet selected the non-burning house $81\%$ of the time ($17/21$ trials), evidencing preserved implicit processing without conscious awareness.

Posner Cueing Task Disengagement Deficit

The attentional deficit in neglect patients marked by disproportionately prolonged reaction times on invalid trials in the contralesional hemispace, caused by an inability to disengage attentional focus from the intact ipsilesional hemispace.

Dorsal vs. Ventral Attention Networks (Corbetta & Shulman)

The dual-network model of attention where the bilateral Dorsal Attention Network (DAN) controls voluntary goal-directed orienting, while the right-dominant Ventral Attention Network (VAN) mediates stimulus-driven reorienting and disengagement, corresponding anatomically to the primary lesion locus of neglect.

Representational Neglect (Piazza del Duomo)

The finding by Bisiach and Luzzatti in which Milanese left neglect patients describing the Piazza del Duomo omitted landmarks on their left side from both vantage points, proving that neglect distorts internalized mental representations independent of direct perception.

Mental Number Line Bisection Bias (Zorzi et al.)

A study demonstrating that left neglect patients bisecting numerical intervals (e.g., 1 to 5) systematically misjudge the midpoint toward higher numerical values (e.g., answering 4), indicating a representational distortion of the pseudo-spatial mental number line.

Temporal Neglect (Saj et al.)

The experimental finding showing that patients with left hemispatial neglect fail to accurately recall items associated with the past, systematically neglecting the "left side" of the mental timeline and misattributing events to the future.

Ferrier's Frontal Lobe Inhibition Theory

The 19th-century doctrine established from cortical electrical stimulation studies arguing that because the frontal lobes failed to produce overt movements upon excitation, their primary evolutionary role was behavioral inhibition supporting higher volitional faculties.

Behavioral Rigidity vs. Distractibility

The two primary markers of Supervisory Attentional System (SAS) dysfunction: behavioral rigidity results from unrestrained perseveration of dominant schemas (stuck-in-set), while distractibility results from inappropriate trigger capture by environmental stimuli.

Wisconsin Card Sorting Test (WCST)

A standard clinical assessment of executive function requiring participants to discover sorting rules (color, number, or shape); patients with dorsolateral frontal damage exhibit stuck-in-set perseverative errors when rules change due to defective supervisory regulation.

Utilization Behavior

An executive impairment stemming from frontal lesions where patients automatically use nearby objects (e.g., grasping a pitcher, pouring water, and drinking) in their typical manner despite instructions to refrain, driven entirely by environmental affordances.

Tower of London vs. WAIS Blocks Double Dissociation (Shallice, 1982)

The double dissociation showing that frontal lesion patients perform significantly worse than posterior patients on the Tower of London (planning task), whereas posterior lesion patients perform significantly worse than frontal patients on WAIS Block Design (visuospatial task).

Cognitive Estimation Deficit (Shallice & Evans, 1978)

A clinical impairment where patients with frontal lobe lesions produce bizarre, extreme estimations for open-ended questions without immediate factual answers (e.g., estimating spine length or item pricing) due to an inability to generate problem-solving strategies or monitor plausibility.

Frontal P300 Novelty Attenuation

An ERP finding in which healthy individuals display a maximal frontal $P3$ potential in response to novel auditory stimuli, whereas patients with prefrontal damage show an attenuated response and fail to orient to or recognize novelty.