Biology subjects

Whishaw, I.

Publications and source records attributed to Whishaw, I..

6 recordsLinked to original sources

bioRxiv2026

Parkinson Disease vs Aging Features Impairments in Formation and Release of a Power Grip in Real and Pantomimed String-Pulling

Parkinson disease (PD) impairs skilled reaching tasks but less is known about its effects on rhythmic bimanual actions. We used a bimanual hand-over-hand string-pulling task that requires repeated reach, grasp, pull, push and release movements. We predicted that participants with PD would show impairment in making the rotary skilled hand movement of retrieving the string, analogous to impairments observed in single handed target reaching. Nine participants with PD (mean UPDRS-III: 24.6), 16 older adults, and 10 young adults successfully performed a real string-pulling task and then pantomimed the action. Video analyses combined optical-flow estimation of whole-body movement speed, markerless 2D pose estimation of upper-limb kinematics, and expert frame-by-frame scoring of hand and finger shaping. Machine-learning classification then identified the discriminative information carried by these multilevel movement components. Participants with PD showed lower movement speed, a smaller hand workspace, and reduced hand and finger shaping, with older adults showing intermediate values. All participants grasped the real string with a power grip, but participants with PD showed reduced rotary movements of the arm and the wrists and absent of arpeggio-like sequential finger movement during grasp and release. During pantomime, participants with PD moved faster and made larger hand movements, while grasp-related hand opening and finger sequencing was reduced or absent. The findings suggest that PD is expressed across this multicomponent movement manifold, and that the movement organization changes with task demands: real string pulling requires formation and release of a power grip, whereas pantomime does not place demands on grasping ability.

neuroscience↗

bioRxiv2025

Vision and touch used for catching small balls with a power grip and large balls with a precision grip supports dual visuomotor channel theory

The dual visuomotor channel theory of grasping posits that distinct neural pathways mediate hand shaping in response to a targets extrinsic (e.g., location) and intrinsic (e.g., size and shape) properties. To evaluate this theory, we examined grasp behavior in human participants as they caught balls of four diameters (2.5-9 cm) thrown toward them. Hand shaping during catching was compared with that observed during the pickup of stationary balls and the interception of rolling balls. Kinematic measures included digit opposition distance (thumb pad to index finger pad) and prehension span (digit pad to palm distance), obtained using electromagnetic sensors, 3D video capture, and frame-by-frame video analysis. Participants displayed significantly greater hand opening when catching thrown balls than when interacting with static or rolling balls. Nonetheless, the maximum pregrasp aperture (MPA), contact grasp aperture (CGA), and terminal grasp aperture (TGA) scaled proportionally with ball size across all conditions. Ball size further influenced grasp type: small thrown balls were caught with power grips, while larger balls were caught with precision grips. In contrast, precision grips were used consistently when picking up stationary balls or grasping intercepting rolling ones. In the catching condition, grasp type and the trajectory of digit closure were also affected by the location of ball to hand contact. These findings support the dual visuomotor channel theory by demonstrating that anticipatory hand opening reflects target location, whereas grip selection reflects target size. Moreover, the modulation of grasp type and digit closure by tactile contact suggests that somatosensory input may operate within a dual-channel framework analogous to that of vision.

neuroscience↗

bioRxiv2023

Information-theory analysis of mouse string-pulling agrees with Fitts's Law: Increasing task difficulty engages multiple sensorimotor modalities in a dual oscillator behavior

Mouse string pulling, in which a mouse reels in a string with hand-over-hand movements, can provide insights into skilled motor behavior, neurological status, and cognitive function. The task involves two oscillatory movements connected by the string. The snout tracks the pendulum movement of the string produced by hand-over-hand pulls and so guides the hands to grasp the string. The present study examines the allocation of time required to pull strings of varying diameter. Movement is also described with end-point measures, string-pulling topography with 2D markerless pose estimates based on transfer learning with deep neural networks, and Mat-lab image-segmentation and heuristic algorithms for object tracking. With reduced string diameter, mice took longer to pull 60cm long strings. They also made more pulling cycles, misses, and mouth engagements, and displayed changes in the amplitude and frequency of pull cycles. The time measures agree with Fittss law in showing that increased task difficulty slows behavior and engages multiple compensatory sensorimotor modalities. The analysis reveals that time is a valuable resource in skilled motor behavior and information-theory can serve as a measure of its effective use.

animal behavior and cognition↗

bioRxiv2022

A cortical circuit for orchestrating oromanual food manipulation

The seamless coordination of hands and mouth--whether in humans eating corn on the cob or mice extracting sunflower seeds--represents one of evolutions most sophisticated motor achievements. Whereas spinal and brainstem circuits implement basic forelimb and orofacial actions, whether there is a specialized cortical circuit that assembles these actions to enable skilled oromanual manipulation remains unclear. Here, we discover a cortical area and its cell-type-specific circuitry that govern oromanual food manipulation in mice. An optogenetic screen of cortical areas and projection neuron types identified a rostral forelimb-orofacial area (RFO), wherein activation of pyramidal tract (PTFezf2) and intratelencephalic (ITPlxnD1) neurons induced concerted posture, forelimb and orofacial movements resembling eating. In a freely moving pasta-eating behavior, pharmacological RFO inactivation impaired the sitting posture, hand recruitment, and oromanual coordination in pasta eating. RFO PTFezf2 and ITPlxnD1 activity was closely correlated with oromanual pasta manipulation and hand-assisted biting. Optogenetic inhibition revealed that PTsFezf2 regulate dexterous hand and mouth movements while ITsPlxnD1 play a more prominent role in oromanual coordination. RFO forms the hub of an extensive network, with reciprocal connections to cortical forelimb and orofacial sensorimotor areas, as well as insular and visceral areas. Within this cortical network, RFO PTsFezf2 project unilaterally to multiple subcortical, brainstem and spinal areas associated with forelimb and orofacial control, while ITsPlxnD1 project bilaterally to the entire network and the ventrolateral striatum, and can mediate concurrent forelimb and mouth movement in part through their striatal projection. Together, these findings uncover the cell-type-specific implementation of a cortical circuit that orchestrates oromanual manipulation, essential for skilled feeding.

neuroscience↗

bioRxiv2022

Memory for a day: Olfactory place episodic-like memory for dung droppings by the domestic horse (Equus ferus caballus)

The domestic horse (Equus ferus caballus) makes dung deposits to form "stud-piles" and investigates dung droppings more generally, suggesting that dung contains species-relevant communicative information. This natural behavior provides a behavior with which to examine a species-typical form of memory used by horses in relation to their social behavior. Horses were video recorded in indoor and outdoor riding arenas as they were lightly taken on a lead line to experimenter-determined objects or dung-piles. Frame-by-frame video analysis was used to measure sniffing duration and spatial memory of dung dropping visitations. Horses readily approached and sniffed dung for longer durations than they sniffed other objects. They always approached dung at new locations, made head movements across the extent of dung-piles as they sniffed, showed no preference in the nostril directed to the target, and might blink during sniffing and always blinked when disengaging from sniffing. Horses did remember dung visited withing a day by reducing visits and sniff duration but displayed little retention between days. The results are discussed in relation to the idea that this form of episodic-like memory is time limited because it competes with safety-related behavior related to horse movement within foraging areas.

animal behavior and cognition↗

bioRxiv2020

Cholinergic upregulation by optogenetic stimulation of nucleus basalis after photothrombotic stroke in forelimb somatosensory cortex improves endpoint and motor but not sensory control of skilled reaching in mice

A network of cholinergic neurons in the basal forebrain innerve the forebrain and are proposed to contribute to a variety of functions including attention, and cortical plasticity. This study examined the contribution of the nucleus basalis cholinergic projection to the sensorimotor cortex on recovery on a skilled reach-to-eat task following photothrombotic stroke in the forelimb region of the somatosensory cortex. Mice were trained to perform a single-pellet skilled reaching task and their pre and poststroke performance, from Day 4 to Day 28 poststroke, was assessed frame-by-frame by video analysis with end point, movement and sensorimotor integration measures. Somatosensory forelimb lesions produced impairments in endpoint and movement component measures of reaching and increased the incidence of fictive eating, a sensory impairment in mistaking a missed reach for a successful reach. Upregulated acetylcholine (ACh) release, as measured by local field potential recording, elicited via optogenetic stimulation of the nucleus basalis improved recovery of reaching and improved movement scores but did not affect a sensorimotor integration impairment poststroke. The results show that the mouse cortical forelimb somatosensory region contributes to forelimb motor behavior and suggest that ACh upregulation could serve as an adjunct to behavioral therapy for the acute treatment of stroke.

neuroscience↗